Document 3eOgo3qoMv0byKxOOkoODwVY3

FILE NAME: Texaco (TEX) DATE: 1937 July DOC#: TEX007 DOCUMENT DESCRIPTION: Industry Report - Dust Producing Operations in the Production of Petroleum Products ST PRO DU CIN G -O KRAtW N S IN THE PRODUCTION OF PETROLEUM. PRODUCT^ AND .ASSOCIATED ACTMTIES: M EDICO-SAFETY SURVEY BY Re/ .5. Benib,lt.A.,E.V1enteri*rtrrKSrccib* . STMO**0on.COMMHT t'NiJLi; rORCWORO BY. Wtllari J. Dtnni, U..D< CCNUUL MCOKM. MCC70* :STAH04M0*COUFANTJN.jlr STANDARD OIL COM PANYN.' J.) 30 ROCKEFELLER PLAZAN E W YORK.N.Y. JU L f- 1 9 3 . 7 1PLAIN TIFF EXHIBIT^ | . > M T fT M MUITMIIATtc lUMCATO M klMU I . WIMVT WWTUM K I M M M l6,0000001 , aoi42cr 176 JAM 014668 FOREWORD Beoaust It i> the doty of industry to proteot It employ* 1 and because n oonprchenalve urvey of the hazard* Isold eat to oc cupational dust probleas had yet been Bade, It wa* felt that her* was an opportunity to render a eeriroe to the petroleua Industry and Its enployees by asking suoh a surrey. Zt is hoped that the lnforaatioa presented In this bulletin will assist In finding proper answers to sene of the any questions which hare recently arisen eoneernlsg the health hazards of wsployw *s whose work isroVr* exposure to dusts of Tarlous origin. in attespt has been Bade to consolidate opinions fro the aost experienced students of cceupatienal-dust probloas to show the relatlro hazards of-dusts and the duration of exposure which nay prore hamful to the worker* . JUrtheraoro, a .study of the preraleaee of dost particles oc curring in various operations in the.petroleua industry has been aade and included in this reportj also a description of the pro ' tsetiT* derless and equlpaent provided for the protection of the workmen. - This report should err# as a guide to operating executives and safety engineers in handling personnel end in providing adequate protection in duety ooeupetions* Zt should also resolve assy of . the fears end questions of industrial workers in these occupations. The study ooaflms an opinion that dusty oocupationa, thor oughly understood and Intelligently handled should result in no serious disability* Hillard J. Deans. M.D. General Medical Director Standard Oil Company (X. J. ) 18-0000002 001421 177 JAM 014669 MEDICO - SAFETY MEMORANDUM D U S T PRODUCING OPERATIONS IN T HE PRODUCTION OF PETROLEUM PRODUCTS * A N D ASSOCIATED ACTIVITIES CONTENTS ^ PACE ZBIBODOCXIOB P A R T I-D U ST A S A HEALTH HAZARD i - war is zee vasz frosizh so jmposzahzi..... ........ ....... ZZ - WHAZ IS MEAHZ BT "DDSZ*?....... ............... ...... ....... . ZZZ - WHAT ARE ZES mSIOLOOICAL EFFECTS PBCEOCED BT Zhe Inhalation of Out................................ ........... S U l < u U in S n m L .... ..................... .......... First Rational Sllloosls Cacferenoe.......................... . Silicatosis................... .............. ........... Asbsstosis..... .............. 17 - WHAT IS THE HAXMBM PDKISSABLE DOST C0NCEHZRAZXQH7 Formula For Dstsndnlng Maximum Permlasibls Concentration 2 2 3 4 . 4 8 7 af.SiliM la Tho Air B r e a t h e d . . . . . . . . . . 7, 8 Safi Dust Concentrations, Inprlnger Samples...7.................... .9 T - HOW HAT ZES COKCEBTRATICH ABD CHARACTER OF XHDUSTHIAL POSTS BE DEZSSMIHEDt..... ................... ..... .......... . 9 Zhe Dapinger Apparatus........... ....... ............ ........ 10,11 Zhe Zslss IcdMier.'............. ...... .......... ........... 11 Tbs Sausoh 4 Lcrab DustCounter...........................1....... 11 PART n -D U S T PRODUCING OPERATIONS STUD IED ' WHAT ARE ZEE FRQCZFAXt DOST PR0DUCZSO OFERAXTOBST Z - SASP-BIASZZ1B...... ..... .............. ....................... 13-15 JZ - H U ERIBS OPERATIOHS....... ....... ........ ............... ...... 15-27 .X . Flltsr.Ciar or Fullera Earth What is FUtsir Clay or Fullsrs Earth!........................ Hew Is TUtar-Clay Mined aad Treperedl....................... Htm is FUtar Clay U s e d ! . . . ........ "Burning" Clay........................................ Charging Filters.......................................... Dmping Filter*.......... . Compositi of Filter House Air Borne Dust!.................. Control Of Filter Clay Dust.....................,........'.... 15.15 18.17 17.18 18.19 19.20 20,21 21 22 H - Contact Clay _ Main Constituents of Contact Claya........................... 22,23 What la "filtro!" and Bow Is It Produoedt.................... 23,24 What is the Chemical Compositi of Filtrili....... 24,28 How.is Cmtaot Clay Used!..................---.............. 28,26 18-0000003 001 422 178 JAM 014670 -2- PAGB C - Doe * Black or Charred Bene ------------- _ . How is Bene Black U s e d . . . . . 2 S ttt - issu u n g c PSRATIOUSt ' e X - What Physiological Reactions are Provoked .by Insulating Materials?............ .............. . . 27. B - What Are The Principal Insulating Operations and fc Bow Much Dust Is Produced During Suoh Operations!..... . 27 Insulating 12* Steaa Lines................................ 27,28 Insulating a 750-Pound Cracking Coll Accumulator.......... 2B Insulating Treating Plant Acid Suction Une............... 28 . Insulating Cracking Cell Hot-Oil Lines*................... 2B Disnautliug or Reaerring Old Insulation.................... 28,29 Crushing Sorap Asbestos....................... 29 ' Crushing Old Cork Insulation............ . 29 17 - sccriro Or-PATICHS . ^ What Is Cunits and Bow Is It Applladt................. . Removal of Gunite Lingiss.......... ........... . 29,30 90 T WnDIBS A3P CUTTISG P5RATI0USt A - Welding Operations 1. Electric Are Welding..................v.................. * 30 ' What re Coated Eloetrodest........ 30,31 What do These Eleotrodes Contain and What . Products Result PTon Their Uset...... ................ 31,32 What is The Amount and What Are the . - s Characteristics of Ptases or Dust Produced i ' By The Various Eleotrie Arc Welding Operatlane....... 32-35 What Pfcysiologioal Effect* cm Welders Is Produced by The Use of Coated Hleotrodea............. 35-37 2. Oxy-Aeetylene Welding.................................... Poses or Dust Produoed by Csy-Aoetylene Welding........ 37 .. 37 B -- Burning or Cutting Operations . ' 1. With Oay-Acetylene....... ................... 37,38 Pumas or Oust produoed by Oxy-Aoetylone Burning.......... 38 2. With natural Cas......................................... 38 C - Health Batards Produoed by Welding and Cutting Operations.... 38 vi - 0RI3PIW0 opsamoBS ' What is The Composition of Grinding Wheels).. . . . . . . 3 9 / Is Abrasive Dust Huufult....... ......................... 3?,10 1 - What are the Were Frequently Used TTVS3. 9 Grinders. . the Quantity and Charaoter of the Dust they Produces....... 40 10-0000004 001423.. 179 JAM 014671 -3- PACE X - TAS1TM FLOOR TOO. CRIBDERS.................. Dust Produoed by Tandea floor Criadera.... B - `lASpEIi BESCH GRIUDERS..... .............. Dust Producid by Tandea Beaoh Criadera..... Cbaraeterlstie* of Duet Produeed by Taadea Seash Criadera............. . , c - SIMOLE FLOCR ICOL CRIUPERS,............... Dust Produoed by Single Floor Criadera..... Charaeterlsties of Dust Produoed......... 40.41 41.42 41 41 42 45 43 43 D - URX7ERSAL GRISDSaS....... ..... ..... .................... Dust Produoed 3y Ualrersal Grladers.................... . Charaeterslties of Dust Produoed.................... . 44.45 44 45 Z SURFACE CRXKDERS.................................... . Dust Produoed by Surface Grladers.......... .......... . F - LASDIS TOCt CRISPERS......... ............... ........... Dust Produoed by Loadla Tool Criadera....................... s . r u o s i m o l m a ................ *............... Dust Produoed by Teakeo Drill Criador........... . 45 45 45.4 45 4 4 H . AUTOMATIC CIRCULAR SAM SHA3FEHI3G HACHTUE.................. 4 Dust Produoed by Tefcee Drill Criador......r........i....... . 48 Z - AUTOMATIC BATO SAW GEODES........ .................. . Dust Produoed by lutosata Bend Sur Criador............... 48,47 47 G - AUTOMATIC BAH) SAH U P CRISPER. 47 Dust Produoed by Lap Orlador.. 47 Z - PUX2HG USOZ BLADE GRISUES...., 47 Dust Produoed by Biado Criador 47 L - IIBDEHHAH CUTTER CHIUDER......, 47 Dust Produoed by Cutter Criada 47 M - GASO SAH BUDE CRISPER................................... 47 Dust Produoed by Gaag Sa Blade Grlader..................... 47 S - EDGER SAH CHIUDER.... ......................... .......... 47 *' Dust Produeed by Edger Sur Criador.......................... . 47 0 - CIRCULAR SUB CUT-OFF SAU CHIUDER....................... . Duet Produoed by Cut-Oft Sarr Orlador........................ 47.48 48 ? . "HOC XSXFE? CHIUDER..... ........ . 48 Duet Produoed by "Bog Xnlfe" Criador, 48 Q - CUTTER CRISPER......................... 18-0000005 ~ 48 Duet Prodused by Cutter Orlador........... . ......... 48 2 - Hhat Preoautloas SRould Be Adopted For Safeguarding 00.1424 Xhoee Ubo Use Grindlag HheelsT........... ............ . 48 130 JAM 014672 PAGE Control of Oust frost Grinding Wheels........... . 48 TU HA3PLXPS POWDERED OR F0LVERI2SD MATERIALS t A - UMBt* il) .Hydrated Liao.............. ........... 2) Lump Quiok Lint...............,........ .......... .... Kbit Physiological Effect is Prodiused by Lia# Dust...... 49,50 60,81 . 51 B . METALLIC 2ZBC DOST Typical Screen Analysis.......... ........................ / - Bust Produoed........... .......... ................... :..... si What Physiological Effect Is Prodttoed byZiso Oust........... 51 C - ASBESTOS "ILOAT" Oust Produced,...... ................ Physiological Effeot of Asbestos I'artiolea.......... 81,52 52 1 0 - GROCSD IUCAt Oust Produced.*................... ................ 52 .Physiologic! Effeot of tfioa Oust. ...................... . 52 2 - SULPHUR* (1) Sulphur Plour........ ......... ....... 52 (2) Crude Sulphur......... .............................. 52,55 Ihyslologleal Effeot of Sulphur... ................ 55 ? - UZSASSS* - Oust Produoed................................................ Hoeeaaary Precautionary Measures When Handling Litharge.......................................... . S3 53,S4 0 - SODA ASH* ' Oust P r o d u o e d . . . 84,85. H - TALC or SeAPSTOHE"* . Oust P r o d u o e d . . . 65 Physlologloal Effeot* Produoed by Talo Oust.................. 85 Z - GRAPHITE* . Oust Produoed...........................................C.... 55,58 J . SLATE PLOURt ' Dust Produced................................................ 56 " Effeot of Slate Plour on the laaigs........................... 57 X - GRIBDXHG UERRIS ROOT ' Oust Produoed................................................ ST To What Extent is Oerris'ToxioT............*................. 67 L - GRIBDXHG PXBETBRW P10UERS , ' Oust ftroduoed................... .................I............ 57,58 t 99 001425 181 JAM 014673 PAGE 72X1 - CLEANING TUBES AND DRUMS I . CRACKING COIL SOAKING DRUMS* Duct Produeed............ . 22 - CRACK INC COIL TUBES Dart Produced............ III WATER READERS ASP BOILER TUBES Dust Produoed..................... ......... . Coapoiitlpn of Dust froa Front Water Wall Reader. 58,59 9 89 80 IE FOOtgar OPSRATIQHS A - POURINC MOLTEN KEIAL INTO SAND MOULDS, B "SHAKING OUT" CASTINGS............. . U m CLEANINO CASTINGS Preliminary Cleaning.............. T u a b l a s t * . ............. Sly Tusbllng Mill....... Tumbling Barrels........ ....... . Air*Blastla g.. Sough Snagging Wheels.............. Fine Snagging and Polishing Wheels, Cone Grinding Wheels............... Average Dustiness of Cleaning Roan Air, D - CORE MAKS..;..................... . E - SEPARATION OP BRASS FOUHDKT SKMONCS, 80,81 J61 61 1.62 62 ' 62 . 62.63 3 . 63.64 64 . 4 64.65 65 X - MASONS OPERATIONS I XI - . . . TEARING OUT"STH i FIRE BOXES;.................... .... ....... CHIPPING OR CUTTING CONCRETE...................... .......... CHIPPING MORTAR PROM BETWEEN BRICK........................... CRUSHING FIRS BRICK.......... * ............................. SHAPING FIRS BRICK OR EMEHT WHEEL............................ DISMANTLING MASQNS7....... .................................. 65 . 35 > 65,66 66 66 66 XX WOODWORKING OPERATIONS A - BOI SHOOK MANUFACTURE (a) B e e a w l n ^ . 67 (h) Blpeawlng............................ . . r * . 67 io) Cut of S a w i n g . . . 67 d) Planing.....................*........................... 67,68 Dustiness of Shook-Faotory Air.............................. 68 B - BELT SANDERS; SAND DISCS AND SPINDLES OR CtUNDERSe (a) Belt Sanders............................................ 88 Cb) Sand Discs or Wheels.................................... 66,69 (o) Sand Spindles or Cylinders............................... 69,70 C - MAKING WOODEN CRATES (a) Band Sates..................... 18-0000007 ..... 70 (h) Railroad Sam.......................*........... ...... 70 00142<J 182 JAM 014674 PACE xri - RCCK EXCAYATIOHt A - DR1LLIWO............................................. 70 B - B U S 7 2 B . ............ 71 C - HCCCCS........... 71 D - BEST CCTTRCL MEASURESt ~ (e) Wot Drilling and Wetting Dora Rook Walls and . . * Muok Piles..................................... 71 (b) General Ventilation.................................. 71 (o) Dost Eschenst Roods on Drills end Other Kuoking Operations and Local Sources of Dust................ 71,72 b (d) Personal Protection bp Heans of Respirators and Positive - Pressure Bosks...... ...... 72 PART in - M EASURES FOR REDUCTION'OF THE D UST H AZARD HOT CAR ITS DPS? HAZARD gE REDUCEDt A . DESZSI PLATS PQR DUST CCOS3GU...................... 74 B - PROVIDE BCTLDZUB YZSTXLATI03........................ 74 C - STORE DDSTT MATERIALS ZB DCSS-TZGHT B O B ............. 74 . D - ENCLOSE MATERIAL BABDLXDQ EQUIHSST................. 74 S - ISOLATE DOST? PROCESSES................. 74 P - PROVIDE WET EETECDS OF CP2RAXICH..................... 74 0 - DESIST EQUIH2EBT TO C0S7SGL DOST................. 75 S'. PROVIDE EXHAUST STSTEKS............................. 75 . ? - ESTABLISH MAIST3IABCE ABO QOCD H0DSEXEEPZ3G PROCEDURE... 78 J - PROVIDE RESPIRATORS................. 7...... ........ 78- (a) Air Purifying Types of Respirators....... ... 70.77 (b) Supplied Air Respirators............................ 77 ' The Air Lino Respirator........................ 78,79 .Abrasive Blasting Respirator................I..... 79 (o) Aeoeptanos and Ose of Personal Respiratory Protection by Workaea............................. 79,80 (d) Ose, Maintenance and Care of Respirators............ 80 ' WHAT MEDICAL COHTROL SHOULD BE EXERCISED H i m r r r T m r ACT SUPERYISI03 OP HEB Wolga OH DOST? JOBS1............... 80,81 PHTSICAL ZXAMZHATIQBS............. 80 DESISAB1Z PHYSICAL QUALIFICAIICRS......... 81 RZ-EXAHIHAIIOHS..................................... 81 in urniAnons CCCCLOSIOE.................................................. .......... 81,82 18-0000008 001427 I P '7 Xo JAM 014675 STANDARD OIL COMPANY ( Incorporated in New Jersey ) 30 Rockefeller PUza New Yode, N. Y . MEDICO - SAFETY MEMORANDUM D U ST PRODUCING OPERATIONS IN TH E PRODUCTION OF PETROLEUM PRODUCTS AND ASSOCIATED ACTIVITIES k . irracppcric? - Lose looked upon it objectionable, dust today 1 also reoopiz* ed as dangerous - especially with regard to occupational disease (Pneumoconiosis) and dust explosions.. Since the dust encountered ia the production of Petroleum products and associated operations are non-explosive under ordinary working conditions, no ' further, attention will he devoted to this phase of the dust haxerd. Studies hare revealed that the tine element (exposure) and the concentration and sise of the dust particles are major factors in producing health hazards* Here tofore difficulty has keen encountered in determining actual dust oonoeatraticus and sises of the particles, hut recently developed in*trimeat* suoh as the Zeiss Xeoimeter and the Bausoh * Look Oust Counter make it possible to obtain dust counts and estimate slso of dust partlelos which, while net absolutely aeourate, are indicative of the dustiness of the area. The data presented in this.memorandum are based upgp material taken from the available literature on the subject, upon field investigations and eoafarenees with technical specialists and upon 1008 actual dust counts aadt with a Zeiss Xonlaeter, using a 20 to 10 micron (a mioron is about l/25,000 of an Inoh) poroelaln filter. In the report of the Preventive Engineering Committee of the Xlr Byglene Foundation, Professor Philip Drinker of Harvard, chairman, and other technical specialists on the Committee write* . "If the breathing of dust causes disability of any sort - silicosis is only one manifestation - then it follows that there must be seme degree of air oleaallmoss from which no disability will result to the average m a during the average working period* . " "There is no satisfactory medloal answer at present to this question, but the engineer is naklng a bad mistake if he lets men breathe heavy dust oonoaa- traticos of any material* Zf no' other reason for dust control oaa bo found, then coo should read, transcripts of same of the recent suits at eastern las in which fantastlo damages for alleged sllioosis were granted to men she breathed dust containing little or no silica. The Courts and Compensation boards are not impressed with subtle distinctions between dusts with 1CJ{ sad 40 quarts, especially when medical experts are reluctant to make definite statements as to the comparative significance of suoh differonoos* ` __ lB-0000009 "It would be well to realise that men working in dusty trades suffar far more from respiratory -troubles of all kinds than do men who work in eleaa air* The evidence that exeessive dustiness of any kind ia harmful ia beyond argu ment". 001428 184 JAM 014676 -2- PART I-D U S T AS A HEALTH HAZARD ' I - NET IS THE BUST PR0BLE1 SO DIPOKXAHTt - Although the subject of tho health of worker* da dusty trades has boss receiving oonsldorablo attention from students of' industrial hygiene for a nunber of years, the seriousness of this problem was not fully realised untij* it was brought sharply to our attention by the constantly groie- lug countrywide wars of lawsuits instituted in behalf of the victims is our oeesean law courts, by the magnitude of the generous Terdiots awarded by the juries and by a recent deoision of the Federal Circuit Court reversing the substantial award of .a juxy in a hew Jersey ease (PeansylTania Pulverising Company vs* Eldred 0. Butler), Oifeng to these developments, the problem cannot be Ignored or brushed aside as merely another form of "racketeering" by unscrupulous lawyers and oonsplrlng doctors, Dodging the issue cannot provide the needed solution because even tho most unscrupulous lawyers cannot create a patholegio lung at will and, furthermore, even the most sleep tie of ooroners frequently finds himself corroborating a diagnosis by his postmortem examination. Enlightened industrialists and tho medieal profession as well as the beach and bar, have come to tho realisation that exposure to certain kinds of dust, suoh as those containing considerable amounts of quarts, (silioa), has increased the unhealthy bodily condition and death rate from respiratory diseases) fell* netallio dusts, suoh as lead and its ocopounds, have been associated with general systemic poisoning of workers, "Silioosis* is now a definitely reeognised disease which is' . destined-to become one of the foremost and most serious of occupational diseases of the future because the number of workers is dusty trades is larger titan almost say other group exposed to a single'known Industrial haxard. She McCaffrey Aot, which . became effective September 1, 1935, amending the Jfew Tork Compensation law, included silioosis as an occupational disease subject to compensation, Sixteen states, as well as those of the Federal Cforerpneat amj.ofHawaii, Puerto Sioo, and the Philippine Islands (U.S.Dept, of Labor Bull.Ho.025,Bur.Labor Sta tistics), have Workmen's Compensation Aotswhlch Include compensation for occupational diseases, cither expressly or by Judicial interpretation, or speoifio occupational disease aot*. ^ . XX - WHAT IS KEABX VC rfDBST"1 - Aeeording to Webster's Unabridged Dictionary, "Dust" may be defined as fine, dry pcrtlolea of earth or other matter eo eoaoinated 1 that they may be raised and wafted by the wind) that which -la onmbled to minute portions) fins, powder. As pointed out by Hillip Drinker in a paper read before the Chsmioal Section of the Batlocal Safety Congress (held in Atlantis City, October, ' ' 1930), dusts include all types of dry earthy particles small enough to be blownabout . by ordinary air ourrents. Dust suspensions may be generated as the result of grind lng blasting, or owealanting process) or they may result from the handling of fine ly divided materials as in misting.processes, in sweeping, or the blowing-abeub of wood flour, plant pollens, or common reed dust, There is no ehemioal limitation im plied by the tors "duet" while the range in also of dust particles extends from the sUb-mlerooeople. to small sand grains, Mr. XL Barrington, Chief Health and Safety Branch, XLSiBureau of Mints advises that dust as applied to health and respiratory conditions stay be wet as well as dry. Under acme conditions, suoh for example as in wet drilling in mines, the escaping air from the drill hole may (in fact generally dees) contain a certain amount of entrapped solid material whloh undoubtedly is wet rather than dry, yet it remains in the air sufficiently long in some lnstanoes at least to be breathed by the workers to contribute to possible health trouble. Xbe siso o^ dust of importance from a byglenlo standpoint are those under ten microns. In foot, the slxe< found in industrial atmospheres are under two microns for the larger najority of particles, say 90 to 95 per cent. Hysiologioally, there are al most as nany different classifications of dust as there are authors on the subject. However, aeeording to Professor Drinker ("Dust, Fanes end Smoke", Internatiessl La bor Office, Occupation and Health 7ol.l, 930, P.003) all of these olasslfleatlene 0 0 1 4 2 0 18-0000010 185 JAM 014677 -3- ar* without suoh praotioal importance, sinoe in daily practice la Industry the harmful effect la exeroised nor* frequently by dusts mostly o nixed origin. Besides, what la Best important is the physical and ebeaioal constitution of the dusts and consequent ly thsif action on the system. . H Z - WHIT ABB IBB FHTSI0L0GICA1 EFFECTS PRODUCED BT THE ZBHAIAIZQB 07 DUSTT - To b e hamful from* respiratory viewpoint,-dust aust he of sufficient finesa to pass through the nasal filters and he retained la the alreoli (minute air saos) of the lungs* Particle's found In autopsied lungs are of the order of one miaron (s aloran is 1/OOO of a millimeter or about 1/25,000 of an inoh) or less la sise - about the sise of the oonon baoterla. Some dust particles found in lungs are as large as h fir* or six niorons although these sites are rather exoept&anal. ' Bureare fire distinct types of reaotlonproduoed la man as the result of lnhal- lag dust. These reactions may ho broadly classified, based on the primary cause, me follows* . . (a) Those vdiioh result la lung fibrosis, ooaaonly referred to ae pacts* . aooenioeie* These dusts oentain freo eilioa, aebeetoe, oto* Bow- i erer, it is not noooesary for fibrous tissue to bo formed la order for the disease to be classed as "Faeumoooalosis"* ' (b) Those which ere texlo aad arc absorbed into the blood stream suoh as load, oadmita, oto* . (o) Those which result la what is emanly referred to as metal fuse fereri suoh as sino oxido, oto* - ' . (d) Those whioh are alltrgio la eharaeter, such organio dusts ae pollen, pulverised wood sad flour, eto* The breathing" of pulrerixed wood- * end flotir is frequently associated with tuberculosis* (o) Those eeaaaenly referred to as "aulsanoe dusts". Those may oasse lx** ritation of the respiratory traot or passages and may oatuo eonsiderablo discomfort, also headaohes of the dry "naaal" passage or sinus typo aad exposure to them may bo associated with a high laoldeaee of respiratory illness. The rata and extent of these reactions are dependent upon the resstanos of the indi vidual, the exposure period (concentration of partiles .and length of exposure) tem perature and humidity of the air,* rate of work, and the pfroentage of ingrediente - whioh art harmful. Owing to the length of time required to obtain a reaction by meth ods, the United States Bureau of Hines and the Public Health Service adopted about twelve years ago* a method of injecting small quantities of the-dusts to bo studied late the peritoneal cavity of guinea pigs. ("Response of Peritoneal Tissue of Dusts Introduced ae foreign Bodies* by Dr. John U. Hiller, Dr* R.S.Sayers and ttnP.Tamt* Jcur.Amer.Hed. Assoo. Sept. 22*1934 - Te3U lOS.pps* 907-911). It was found that iden tical reactions oeour in each animal injected with the same dust under tile same com- dltieae end examined la the same time interval after Injection. Those reactions wore essentially the same mioroteopioaHy as that produoed in the lungs and the gross up- pearanos of the dust nodules was sufficiently differentiated to.afford a acama of classifying the physiologies! response to the dusts* There arejthree typee of reaotlon An absorption or dissolution of the dust* X proliferative reaction. An Inert reaotlon. 18-0000011 001430 IB 6 JAM 014678 Tn the Inert reaction, the durt neither caused en inoreose is the lixe of the nodule* sor disappeared fren-the tissues) instead there me* sore or less a ohangs is its dis tribution. Soapstone, earborunda (Sillocm Carbide), jeweler's rouge (Ferrio Oxide), anthraoite ooal, bitumiaou ooal and oertain filter clays hare inert reaction*. Cal cits limestone, precipitated oaloius oarbonate, gypsum, sad Portland Cement exhibit ed an absorption reaction. Quart*, ohat, oertain filter eleys and flint produoed a proliferative reaction. ` .' * .. The physiologioel response to the injeoted dusts were found sufficiently well narked in 90 days to determine the type of reaction, particularly tero the reaotien mas one of absorption or proliferation. Sinos the reaetlon elioited by dust mas oonstant and uniform in all of the animal* lnjeoted with the dust, it is beliered bthat this response of peritonsal tissue to various dusts oan be used as a test to de termine the possible harmfulness of industrial duets. The flbrosls-produolng properties of e Georgia filter olay (30-60 nash grade) a sample of Amerloan contact clay and a German contact clay mere tested by the Xntra- perltoned Method, under the direction of Dr. R. R. Seyere, Med loti Offioer in Charge, D.S. Publio Health Serrloe. The Georgia filter olay ehomed an inert reaotion with a slight tendency towards a proliferation in the 90-day test. She Amerloan eca- taot olay (homed an inert reaction with erldenes of seme (light absorption or die appearance of sene part of dust in the 180-day tests. She German ocataot d a y caneed the formation of light yelloxlsh-bromn nodules end as the intsrral between the ire Jeetion and the examination inoreaaed the nodules beoame caer&at flattened, bub the amount of duet *nd the approximate else of .the nodule remained the same throughout the entire period (90-day*) of the test. This oan be considered .an inert reaction) but as the dust does not disappear fren the peritonea it should bo considered as po tentially harmful though not as dangerous as pure silica. . ' Tn cementing on the results of'the'teste with the-Georgia filter olay and the . American eonteot olay, Dootor Sayers advised that the resulte of the test indicated that the filter d a y is more harmful than the American oontaot olay because the.dust remains Inert in the tissues as this was the largest portion of the dust end the in ert appearance of the lesions was the most prominent. The modification of the reao tion in the filter pley oan be attributed to the prsenos of 5-10 per cent, quarts (Petrographio), Gypsa in the Amerioen oontaot olay may aooount for the alight ab- orptlTe reaction. Doctor Sayers ad-rises that an inert duet. If breathed in suffi cient concentration, may be harmful. These tests were made in aeordanoe with the procedure desorlbed in Eoprint #1808, Public Health Reports, Y d, 49, Ho.3, January 19, 1934, pps. 80-89. ' * The inhalation of dust gires rise to "Pneumoocnlosis" a term derlred fren the Greek gneumon, loga and Vonit, dust", and used to designate a 'pathologloal Condition of the lags caused by the inhalation of any dust. It lnoludes SILICOSIS, a ohrunio disease of the lungs oaused by the inhalation of minute partiles of free eilioa (SO2) dust mhieh produoes a permanent inoapacitating alteration of the lung tisane) ANTERACOSIS, the black lung of the miner d m to ooei duet) ASTHRACOuSXLXCOSIS, the newest f or sdnerd dust affeetlone end istroduoed by the United States Publio Health Serrloe as a result of their studies la the Anthraoite District of Penmyl--- raaia. This affection is the result' of breathing anthraoite o o d dust that 0attains sillos. The oemaon name for the affection is "iliaere* Asthma") CHALICOSIS, the gray-black lung of the stene-outter due to atone dust) ASBESTOSIS; in asbesto* workers due to asbesto* dust) SIDEROSZS, d m to breathing dusts of I r a ere- (She lunge are yellow or red iron metallic oxides generally of iron, )| BISSXROSIS, d m to cotton partidos and vegetable fibre dust, end PHHmOHODlJRAHICSOSCOncSILICeiVOL- CAD0X0NI0SI3, a special form of silloosl* oaused by dtrm-aiorosoopio partiles of siliceous vdoanlo dust. Silloosls, Aabertoels, and SUleo-Anthraoosls are th# only three form* of pneaoeoniosis whioh require praotioal attention. ' _ 18-0000012 001431 13 JAM 014679 While the type of pulmonary legion depends on the particular dust Inhaled, the underlying pathological prijmiple is the suae in 11 forms of the disease, namely, an ultimate fibrosis and replaoement of the elastio lung tissue by a hard unyielding fi brous tissue, dll occupations that expose men to large amounts of dust msy giro rise to pneuaeooniosia but not necessarily to silloosls. Zt Is now generally agreed that In order to produos the latter, (silloosls) Inhaled sllloa dust must reeeh the lungs in s chemically unoembinod condition, in very fine partloles not more than ten ai- orone (10/25,000 inoh) in diameter end in sufficient amount and'error a sufficiently long period of time. In relatively reoent literature it appears that the proponents of the idea that only "free sllloa" is harmful are beginning to have seme doubts and to have the thought that possibly acme silicates may under some conditions be h a m ful. Generally speaking, the necessary length of exposure to produos sllidesls is in direct proportion to the sits of the dust partloles and inverse proportion to the * dust concentration and the amount of free eilioa in the dust, Silloosls Is ohar- notarised snatomioally by s generalised fibrosis of the lungs and.ellnlonlly by short ness of breath, decreased ehest expansion and a progressively lessened eapeoity for work whleh is out of proportion to the objeotlve physio1 findings. The effeot of am posurs to dust suoh as sllloa Is cumulative, the rapidity of development of the die- ease depending upon the time and amount of inhalation. Silioosio say develop to the point of causing symptoms only after siereral years exposure to slllolous dust, but it may be progressive in seme eases even after exposure has ceased and may cause symp . toms or beoome disabling long after the workman has left the environment that caused the oondltlcn. Seme may improve or at least remain stationary in the absence of im feetien. Vrtkini-Pltohford (J.lad.Ryg.2,109 - 1927) tells of Welsh miners who passed the physical examination for enlistment in the British Amy, fought through the World War, then earns bade to England, and died of silloosls. Unfortunately, it is not stated whether these persona died from silicosis complicated with tuberculosis. Brit ton and Bead (J.Am.Med.Asaoo. J, 1928 - 1931) give more detailed descriptions of similar latent eases in the United States. - Slllcoals In General -* Xt is generally agreed that sllieoais may be* defined *JL ehranle disease due to the breathing of air containing sllloa (Slog), characterised anatomically by generalised fibrotio changes and miliary nodules in both lungs, and elialoally by shortness of breath, decreased ehest expansion; lessened capacity for work, ab sence of fever, increased ausoeptlbllity to tuberculosis (some of all of wbloh may be present), and by characteristic roentgenolo gical findings." . In ether words, silloosls is a disease of the lungs in whleh the normal lung tissue is replaoed by sear tissue due to breathing air containing sllloa dust. Un fortunately there is no known oure for silloosls - but SILICOSIS snd'nearly -11, other forms of dust diseases CAB BS PRETESTED, Recognising the wide, interest and even hysteria among apprehensive employers against whoa claims had been filed by alarmed workers, and the necessity of thought ful consideration of the silloosls problem, the Secretary of Labor on April 14, 1938 called the' First Rational Silloosls Conference attended by store 300 persons representing workers, employers. Stats and Federal Agencies, Insurance oampsnles, aad ether interested groups. Four Ccemlttsee were organised to study specific phases of the silloosls problem) and assemble the essential faota about silloosls in a series of reportsi also to present specific suggestions for silloosls' prevention end straighten out ether difficulties that'silloosls has created.- Reports smde by these Ccemlttees wars formally adopted at a second oenferenoe held February 2nd and 3rd 1937 in Washington, from whleh we quotes ' 18-0000013 001432 138 JAM 014680 "While a few persons may still be of the opinion that suoh workars" - (Workers haring s ilioosls )!"are 'through1 end deemed to an early death, every study eonduoted thus far confirms the faet that the great majority of these sen will not neeessarily progress tros bad to worse. Perhaps It say be wise to transfer some workers to other employment, but many say be ooatisued at their regular -occupations If known methods are applied to control the dust end if speoial oars is employed to prevent the development of tuberculosis, pneumonia and other lung ooaplioaticns". * "Contrary to popular belief, silicosis is slow to develop. Usually it takes seven years or nor# of exposure to slllea dust for a worker to oontract the disease. It is said that a few eases have been known to develop in as short b i period as l-l/2 years, but these were under extreme and unusual oenditions. On the other hand, many workers have labored under ordinary exposures to sllioa for more than 30 years without demonstretleg- any troubla whatever that oould be diagnosed as silleosis", . For the convenient diagnosis of silieesis or of sllloosls oomplioated by.ta-, bereulosis, the pulmonary changes are classified in three stages by Drinker k Batch ' ("Industrial Dust" - 1938). In the first stags, tbs disease produoea no diability. The viotim oan work just as wall as ever. In the second stage, his respiration is affeotedj he is bothered by dyspnea or labored breathing, Xn the third stage dye 'pnea becomes severs and he is likely to contract pulmonary tuberoulosis, generally with fatal results. Whether he contracts tuberoulosis or not, the advanced sill* ootio is far below normal and is very susceptible to all respiratory diseases. . . These three stages of sllloosls oan be distinguished by X-ray. A comparison of the X-ray plates of a sllioctio with those of a normal person of Ilk# age and physique shows,, in the first stage, distinctive shadows, evenly distributed in both lungs. These may be missed or misinterpreted by eny but an expertf but the changes in the seeond and third stages are obvious even to a layman. It is, of course, cs- aentlal that the X-ray plates be properly mads. Dr. Psnoost and Dr, Pendergrass of the University of Pennsylvania have given extensive study to the influence of X>ray teehnique on the diagnosis of sllloosls. Pendergrass is of the opinion that shadows and appearances of fibrosis oan bs actually produced by the teehnique employed. Under other conditions, existing fibrosis ean be entirely missed by use of improper 1 teehnique. Silicates as a elass are by no means harmless. It was pointed out by Dr. 8 B. Sayers (U.S. Fublio Beelth Bulletin 221) that Miners' Coneuxption was rather eoe- mon in the Broken Bill district of Australia where the rook contains considerable sillimanlte (Alg SlOg), fibrous silioate, and a rather low percentage of quarts (12.23#). She studies of -Bsdhaa (Kept.Dir. Den. Pub. Beelth, Hew South Wales) giro eon- siderabie support to V. X. Jones' (J.Byg.IS,307-1933) contention that silicates, particularly the fibrous varieties, may well be the cause of pulmonary disability. Badham in 1927 coined the word SILICATOSIS to oover disability from the inhalation of silicates. Other silieates such as Tale (Hi Mg (Sl03)}4) Shale) Kaolin (Bg Al2 312 0g)| Feldspar) Cryolite, (XasAlFg )} end pure Hloe giro much less speoifio changes than quarts. A moderate fibrosis may appear after expooure to numerous materials but this fibrosis is usually not disabling. According to Dr. Lanza, "Silicatosis" la not a reoogalted term in this ooustiy and disability from the inhalation of sili- oates has not been proven, . Dr. Cary F. Mo Cord (lnd.Med. July 1933, pps.4-12) states that all silieates taken into the lungs, of particle slse eapable of passing the oellular membranes, a n likely to indues some fibrosis in excess of normal but the prograss of such silica tosis- is not nearly so rapid as for siliooslo. Tuberoulosis rates are high in ollieate using industries. Antecedent tuberoulosis, quiescent, may flare up as a result 18-0000014 00143ii 139 JAM 014681 of exposure to silicate dust. ' . * . Asbestosls - Acoordin** to authorities olted by Drinker k Batoh in their book "Industrial Dusts", the pathology produoed by asbestos is not like that of silicosis. Sr. ! C> Gardner of Sartnao Lake is of the opinion that the asbestos fibers croup about the seek of an alveolus and shut it off, causing what is known as "Atelootasis". There is no definlts migration or transportation of the dust partiles to the lynph nodes and no fibrous nodules. As the ateleotatio areas increase the reduotion in lung apea causas, parlous dyspnea or laborered breathing. Dr. A. J. lanza (U.S.Health Septs., 60j- 1 - 1935) suggests that the enlarged hearts noted frequently in his oases of seoend stage Asbestosls nay be due to the inereased load on the heart. It takes nore work to puap blood through the fibrosed than through the noxmal lung. Bo fe oent pathologioal studies froa hisaan lungs ikon oases of asbestosls hare lsdloated a diffuse type of interstitial fibrosla with a certain mount of emphysema. IT - MBIT IS THD HUDiUM PZRTUSSABU; DUST COCCEHTHAIIOK? - There appears to be a wide variation in the maxims# concentration- of dust which night be Inhaled without subsequent injury to workmen. Some dusts (as lead) are determined by ohsmloal method# and the concentrations in air are reoorded gravlmetrloally as milligram* per oublo aster. However, the available information on the amount of lead dust that is harmful and the methods of determining lead are better and more aoourate than those for ellioa dust. It is rather well agreed that an Intake of about 1.5 milligrams of lead a day, whether this is acquired by breathing dust or by drinking water that oontains lead, is the maximum allowable quantity. Others (as slllea, whore also Is a factor in determining dangerous partiles), are usually given by count. Holther method tells the whole story, but in both oases It may bo possible to secure the in- formation necessary for the purpose. . The maximum silioa dust concentration considered permissible in the alrbreathed by a workman at any point in the normal breathing some has not*been definitely es tablished. There is eonaiderable dlfferenoe of opinion regarding the range of par tiles that are counted when using the Public Health Sarrioo techniqueiand light, field illumination. Bloomfield of the United States Public Health Service and Brown / of the United States Bureau of Ilines contend that they eouat partiles from one mleren and upward, or erra 0.7 mioroa and upward. The Industrial Commission of Wieooasln and its Advisory Committee, oomposod of both employers and scientists, how- ; ever,' agreed in 1932 on a tentative figure of 15 million oountable partile* under 10 mioroas in longest dimension with free silioa. oentent of 35 per oent la a oublo foot of air as determined by Doited States Public Health Service technique. Varia tions la free slllea content will stake proportional inverso ohaages la this standard. In the ease of practically pure silioa, the permiaalblt dust count should probably never exceed 5,000,000 oountable partiles. By countable partiles Is meant those partiles between 0.6 to 10 mioroas in the longest dimension. Partilos of this size are the ones that are believed to oause the greatest damage and form no visible cloud.' Dust partiles smaller than 0.5 mioroas in the longest ((imession aro not ordinarily oountable. Dust partiles larger than 10 mioroas in longest dimension do not ordinarily reaoh parts of. the lung where thsy can produo# injury of a resplra' tory nature. Host industrial dusts liar brut few partiles above two or throo mioroas in also. They are usually about 90 to 95 por oent. below two or throo aieroc^fe . and 50 per oent. below about 0.5 to 0.7 mioroas. An exoeption to this would bo a *' * dust sample takes close to the point of generation of dust and before the larger partiles had time to settle out of the air. la South Afrioa the figure is 1 milligram per oubio meter (or .500 partile# per oublo eestlmeter. or approximately 8.5 million per oubio fSot.j Sr. found in 1917 in the Joplin, Missouri dirtriot that with good engineering praotioe, a figure of 1 milligram per 100 liters of air could bo attained. This value attrlbut- .ed te Lanza appears too high la comparison with the South African standards. As there 16-0000015 001434 . 130 JAM 014682 are l'OCO liters In a oubio noter, It would indcete that Lanza's estimation reprcsonts something of the order of 60 million partiles per oubio foot* With good on glneerlng practice, lower oonoentvations than this can be obtained. In foot the ex perience in South Africa and also the present experience in this country indicates that it can readily be kept below one-tenth of this Talus by using ordinary good practices. The United States Public Health Serrlee in its recent study in the an thracite region of Pennsylvania, found that SO million partidas per oubio fbot with 5 .per cent, quartz in the coarse dust and 10 million particles per cubic foot with 35 per cent, quarts were apparently satisfactory and often were attained. The figure of 10-20 million particles per oubie foot for granite dust with 35 per sent, quarts content is often quoted from the Veracnt granite studies of the United States Public Health Serrlee. From a consideration of general experience, Cmmings suggests 5 mil , lion particles per eubie foot as a threshold for dusts high in quarts. This figure * is based upon a combination of South Africa, Australian and Amerlosn experience but lacks entirely any published data in its support. According to studies quoted by Philip' Drinker end Theodore Hatch in their book "Industrial Dusts" 10 to 20 million particles per cubic foot by the impinger sampling method, light field eoiating is a reasonable figure for ocmest and limestone. Bee'ot work by Dreessen confirms the universally aoeepted opinion that dusts high in calcita and low in quarts do not produo e disabling fibrosis. The threshold figure of 0.15 milligram per eubie meter is giren for lead dust, presumably litharge and hite lead, or othei soluble lead salts. . It should be noted that mazy of the data were not determined as the Medical requirement, but as being attainable in good praotice and apparently satisfactory from a safety standpoint. It should be further noted that the accepted figures are only relative due to the indefinite powers of resistance of an individual which are an unknown quantity. One individual might resist a proportion of 200 particles per cubic centimeter, while another would react unfavorably to'50 partiles. The- works er's physical condition prior to the exposure is of great importance, sinos A young, healthy individual usually can stand a higher oonoentration or longer exposure before the first stage of silicosis is developed. However, far greater influence than physical condition might be the ability of the nose and respiratory passages to ar rest dust. v " In thslr report to the National Silloosis Conference the Conslttee on Pre vention of Silicosis through Medical Control pointed out that sines standards of safe atmosphsrlo dust oonoentration, based on medical findings have been established for only a*few industrial dusts, and 1m view of the fast that considerable study and in vestigation will-be required te establish standards for other industrial dusts, acm.'. tentative standard would be .useful. It was also stated that this arbitrary standard should be based upen what is believed te be within the limita of'good engineering ' practice provided, it will largely control the silicosis hazard for-most industrial exposures. They, therefore, suggest that "The maximum permissible ocacentratfon of silica In the air breathed might be expressed by the following formula (Determination of dust oonoentration . according to technique described by United States Public Health service in Hsprint Ho. 1520 item FuHllo Health Reports. March 18, 1932)i ' ' Multiply the percentage of fires silica by the total particle duet count. If the result is under 5 million, the condition may-be corn- sidered permissible. If the result is ever 6 million, the_eozdf.tlcu may be considered tec high. Per example, ~ _ ' 10fi freo silica' with an avengo total dust eeneentratiaa f 30 mlllion partidos per eubie foot would gire .10 tinco ie-oooooie ' 0 0 X4 3 & JAM 014683 SO million, which equals 3 million (good praotioe)j 50^, with average total dust ednoentration of 60 million, would" equal ,3 times 50, or 15 million 5 (unsatisfactory). This formula is not applicable to any dust containing loss than free silio^." Theodore Hatch XU his article "Some Fundamental Data on Meohaniesl Dust Traps" (Tech. Put.Vo. 637-A. 60, Amor. but. Min. & Met* Eagrs., Aug., 1936) gives these Safe Dust Concentrations. laolnger Samples - (Light Field, Lon Power Counts.) . . Xind of Dust Maximum Permissible Concentration Containing no Silica. . . . . . . . . . . . . 60 millions per oubio foot Containing any small amount of ailioa. free eembined. . . . . . . . . . . ft ft Containing 20 to 40 per cent. - Free Slllea m i 'll Greater than 40 per seat. Free Slllea .................. * (Preferably as much less as possible) Dr* S. X, Sayers; Medical Offloer in Charge, Industrial Hygiene and Sanitation, H.S. Public Health Serrloe- in anewer to a question as to permissible dustiness writes . 'During recent years, "it has been'customary to- reoossaecod threshold or permissible dust limits ranging trm. fire to ten million partiles por cubic foot as determined by Publio Health Service technique, espeeially with dust in whioh the percentage of free slllea is above five per cent. There is no basis for the application of this criterion to all dusts, but it is generally oonsidered a safe practice and one which oaa be-attained in most industries by exhaust ventilation,'wetting, or other methods of dust control." . . As pointed out by Drinker and Batoh ("Industrial Dust" - 1936) it is unfortu nately impossible to evaluate dust exposures with the arithmetical nicety that we should have liked yet it is cmaonly olaimod - by laymen - that prolonged exposure to lew concentrations is ust as serious as short exposures to heavy eonoezrtratioae. Thie claim is contrary to a fundamental law of physiology* Xn discussing the sub ject dark and Drinker ("Xnduetrial Medicine" - 1935) remark that a sub-thres hold stimulus (dust inhalation) for a long time produces no reaction edteraas a rola* tively brief uper-threshold stimulus may eause a reaction". If workers are exposed to sudden heavy ocnoentratienS, the threshold values suggested previously would bo correspondingly lowered. However, most threshold values are weighed -- an average of the ranges. T - HOW HAT THE CONCENTRATION AND. CHARACTER OF INDUSTRIAL DUSTS BE DETE B U BEDT The properties of a duet whieh determine Its hanofUlneas have been shown to bo Its . composition, concentration (the quantity suspended in the industrial atmosphere), and its partile site. The methods used for the determination of the ooueestratlon and character of industrial dusts vary t r m a routine dust count for the purpose inf evaluating tits efficiency of dust control methods to a detailed study of both the oonoestration and the character of the dust in eon&eotlcn with medieal and engineer ing surveys. 18-0000017 00143l> 192 JAM 014684 The Impingar Apparatus developed et the United States Bureau of Mine), Pittsburgh Experiment Station by Ceorge Smith and Leonard Greenburg, (Desorlbed la Heprint Ko.1526 from the Publie Health Reports Vol.47, Ho.12, Maroh 18, .1932 pp. 064-678)' has .been employed for aore than 10 years as a standard instrument for dust studies. In this apparatus samples of air are drawn into an laplager tube and flask where the dust partiles are thrown or impinged on a prepared wetted glass collectlag. plate. The rate of air'Hoi* is fixed at one oUblo foot per minute while the duration of the sampling period is dependent upon the dust concentration. She air passes through a rifles in the bottom of the impingar tube and strikes glass ooL. looting plat* whloh is submerged in 3 cm. depth of distilled water or some other fluid with satisfactory wetting properties. (If water is used as the fluid in the .impingar, sillos partiles are dissolved-- henoe not available for counting -- unless *the laboratory (counting) work is done within a few hours of taking th sample. )- '* This afford! the means for eoeurately determining the quantity and sise of the partlolea. The liquid Is then thoroughly shaken to obtain a uniform distribution of the partiles) filtered to remore those over 40 mlerons in site and again agitated. Samples of approximately 1 eO* are taken by means of a pipette and placed in Sedgwiok-Rafter counting cells. She use of a suitable mlorosoope equipped with a Whlpplf nieremoter disc to aid in counting, will permit the determination of the noaber of partilas in one quarter of the mieroaeopie field. Fren this figure, the number of . partiles of dust in 1 ou. ft. earn be Calculated. One speeial adrantage of this ap paratus is the faet that analysis of the sample can be determined by counting, by weighing or by ohemloal analysis, the impinger method is neither simple nor extreme ly complex) honorer, reliable results ean be obtained only by well trained, compe tent and experienced investigators. However, owing to the wide use of the impinger in previous investigations that have been correlated with the pathological findings, an impinger should be used for any investigation whieh is to inelude pathological findings or where the results are to -be introduced aa evidence in court. Some state eodes on dust eontrol reoogaixe the_ impinger method. The United States Bureau of Kinos has practically completed the* development ef a "Kidget" impinger whieh has most of the good charaoteristies ef the impinger but lacks most of its drawbacks. This midget impinger will seen be available and will greatly simplify both sampling and o ousting. Other derioos are also available for sampling of dust over a oontinuous period, . namely, the electrio precipitator, tits paper thimble, the elootrostatlo precipitates*, and the hot wire thanaal precipitator. The English are working on a dust sampling instrument whloh preolpltatea the dust from the air by thermal means ("Physical KethOds for the Estimation of the Bust Hasarda in Industry", by H, . brean end H. & Watson, privy Council, Kadioal Reaearoh Counoil, Special Series Ho. 198, Bia Majesty*a stationery Offlee, London, (1938)). The B.S. Bureau of Mines has been ns- ' Ing an eleotrlo precipitator similar to those desoribed by Drinker ("Alternating Current Precipitator for Sanitary Air Analysis) X - An Inexpensive Preoipitator Unit" by F. Drinker, Jour. Xnd. Kjrg., Tel. 14. 1932, p. 364) for collecting samples ef the test suspensions used in testing meohanioal filter respirators for permissibility. . A number ef instruments 'are available fbr making dust determinations for-con trol purposes. Among these is the Konlmotor whloh calls for but little skill in sanpllng. It is light, simple and quick to handle, needs no power for operation and requires only a mlorosoope for counting the particles. She 2elas Xonlmeter oonalata of a.mlorosoope whieh gives a'magnification ef 200K, an air pump, a dust filter to remove very eoarae dust particles, a sample dise and a mlorcmeter ruled in square millimeters. The .air p\np drives a measured quantity ef air against the sample dise* which is covered with a stleky sbatemee (glycerine jelly). This,sample forms.s'dust spot which ean be examined under the mlorosoope for a general idea ef the nature ef the dust and the relative quantities present, or for an actual measure, a "duet count", whloh shews how many dust partilas ere present in ene subie centimeter or in ene litre of the air samples examined. The Konimrter has been used very widely in _q o 00018 0014371 JAM 014695 South Afrioe (Final Report of the Miners* Phthisis Prevention Caamittee, Johannes burg, 1919, p.10) and also in'Canada. The 0.S.Bureau of Mines has also used it in. scat* of its dust studies. In discussing the Talue of the Xcnlaeter in their recent book "Industrial Dust" (MoGra>*-Hill Book Co., Sew York and London - 1936} Philip Drinker and Theodore Batoh of the Sarrard School of Public Health writes .?It .is the aost compact and simple ssapling derloe. Spaoe is prerided for thirty samples on a single dlso and no auxiliary souroe of power is required for its operation. Crab samples can be oollooted with speed and the fluctuations in' dustiness and the drrelopeent of dust floods ean be revealed in a way ' ^ that is inpossible with sore cumbersome apparatus. South African experience involving the collection of thousands of - samples has shown that the figure of nerlt given by the Xoni- - aster is directly related to the amount of phthisis - produo- t ing dust in the air. It is a valuable routine aaapllag in ' . struorat' but because of its low'and selective efficiency, the counts reported are probably considerably below the tree level and they are not easily ocapared with data obtained in ,, England, for example, with the Owens apparatus, or in the United Statee with the iapinger," - . Experience has shewn that contrary to Drinker* s statement, the Xcaimeter if properly used, will give results that agree very well with those obtained by the use of the Zmpinger. The V.S, Bureau of Mines Experiment Station at Pittsburgh la some comparative studies with the Xonlmeter and the Zmpinger found that aa average of five Xonlmeter determinations was within about two per cent, of one Iapinger determi nation. The reason for taking an average of individual results obtained by the Xcnl aeter, for comparison with those of the Zapirger, is due to the fact that tha Ionimeter takes an instantaneous grab sample of'small volumes and owing to the .hetrogene-. ous nature of dust in air grab samples do not represent the average oonditions. The Zmpinger takes a continuous sample of rather large volume# and ia thereby represent*! tive of the average. For these reasons, if it is desired to compare Konimeter re sults with Iapinger results it is neoessary to take several Xonlmeter aempleo during the course of the Zmpinger sample, in order to obtain average conditions. We have no correlating information of the Xonlmeter with the 20 to 30 mioroa porcelain* filter , against the standard iapinger method* A Zeiss Xonlmeter, using a 20 to 30 micron poroelain filter was used in actual dust counts in ear various dust producing operations. The partial# alse'and also classification was estimated rather then aoourately measured and computed. Only partleles ten mioroaa or leas in slse were oounted slnoe it is generally agreed that dust partioles larger than ten microns in else are not particularly pathogen!. . Other methods, ia eenmon use are the Owens jet dust sampler ("Jet Dust Counting Apparatus" by .Owens, Jour.IndUByg.,Tol.lt,1932,P.622), which has reoently'been manufaotured in this oountry and the photographic dust counter, developed by Fieklea end Ott. The Owens jet dust counter is used in this oountry to oolleet samples for particle sise distribution determinations. It is used principally la Australia for determination of number cononitration of atmospherlo dust of industrial hygitnio 1. portanoe. . The latest device for determining dust concentrations is tha Bausoh Lceib Puat Counter which was placed on the market a few months ago. This Instnaaemt oesw slsts of a dark-field mieroaoope magnifying 20CQC, and aa impinging apparatus mounted oa a cornea base. The base is a hollow ohember with the bottom hinged to provide easy aeeess to the dark field oondenser and a circular glass spoolmaa slide. By means of a hand pump, which is part of the impinging devioe, a sample of air is drata 0 0 1 4 3 8 iB-oooooi& 1 9 4- JAM 014686 -12- through a moistening chamber which has at its lower end a narrow slit. The dust is deposited through this slit on to the olrcul&r specimen slide in the form of a ribbon. The slide can be rotated until the sample, oomes into proper position for Tiewing with the mioroaoope, or a maximum of twelve samples can be collected on the slide and then viewed. The slides are quickly removable and replaceable. This dust counter is not designed for aoourate dust determination but rather as an inexpensive devioe for roughly checking .dust conditions. It has not been available long enough for a thorough test in actual practice* b The principal objection to instruments like the Bausoh 4 Lamb Dust Counter nri the Owens jet dust sampler for determining number oonoentratlon is that their dust eolleetlng efficiency decreases with an increase in the atmospheric dust concentra tion and the fact that they take grab samples. ' Sinoe the major portion of dust present in industrial atmospheres is small enough to gain entrance to* the lungs, very little attention need be. given to determina tions of the exaet sixes of partioles. 195 1S_ 0 0 0 0 2 00143a JAM 014687 P A R T II - D U ST PRODUCING OPERATIONS STUD IED j WHAT AR3 THD PRINCIPAL DUST PRODUCING OPERATIONS? - la order to detennlae to what extent if any, workers in the production of petroleum produot* and associated activities are exposed to the hazard of breathing dust, a surrey of all dust produo ing operations was made at the various plants oonoerned. These operations, listed in order of 'their* apparent dogree of dustiness, aret h I . SAND - BLASTING Due to the large amount of finely divided silica dust produoed by the impact of the grains of sand on the surface of the object being cleaned, sand-blasting is the most dangerous silicosis hazard encountered in our survey. Sand-blasting is used rather extensively at oil refineries for cleaning inside soaking drums, bubble towers, tar separators, run-down pans and storage tanks for metal inspection and to permit the application of gunite lining as a means of preventing eorrosion* Reader boxes .or other similar parts, tubes in cracking coil fire boxes and return bends are sand-blasted to permit a detailed and thorough examination for craeks and de fects. Sand-blasting is also employed in the removal of corrosion from under float ing roof tanks; for removing roughness or rust from steel shapes or rods; for clean ing bell caps, bubble plates, trays, and pipe prior to putting them back in service; also on the ends of tubes preparatory to placing them for rolling; and for cleaning castings which are too large or fragile to withstand being tumbled. It has been used, to a limited extent for cleaning buildings and rendering window glass opaque. ' The cracking coil tubes, pipo, bell caps, trays, header-boxes and similar ob jects are usually sandblasted out-doors in the open air or in a more or less open shed, both locations being as far removed as feasible from any shops, prooess1units -or other working places. Coarse river sand is discharged through a one-half to three- quarter inch nozzle with compressed air under a pressure of 30 to 90 pounds per square Inch. The men at the nozzles stand to the windward side of their work and wear a "Healthguard" (Chicago Eye Shield Company) mask, a Sly Sand Blast Belmet or a Fresh Air Bose Mask covered with a canvas hood. The men at the Sand Blast Machines wear "Dust. Safe" goggles and a M.S.A. "Comfo" Respirator. The Mine Safety Appliances Company now has a sand-blast hood that is meeting with considerable approval by in dustry and also by the United States Navy Department. A blower is available for supplying air to these hoods that cleans the air. This same blower can be need in oonneotion with air-line respirators. ` When sand-blasting is done inside of drums having more than one opening, such as soaking drums, an air siphon is placed in the lower manhole which draws out the dust and allows a continuous circulation of fresh air through the drum. In drums where the siphon cannot be used, the air eirculatlon is poor and the m e n work i n shifts ranging from 30 minutes to an hour, depending on the size of the drum and the amount of air circulation inside. They also wear an approved sand-blast helmet. These sand-blasting jobs are not continuous routine operations but are per formed when necessary by men selected from the Common Labor gangs or the Mason's De partment. The work is rotated so that in most eases it occupies less than twenty per bent, of the worker* s time and there is an interval of 15 to 20 days between sand-blasting jobs. Consequently, on the average, no one man is exposed to store than a combined total of -400 hours during the course of a year. In discussing rotation of men on sand-blasting jobs. Dr. Gohrmann, Medical' Director of the du Pont Company wrote* ' - ' * ' . "It must be borne in mind that silicosis is a cumulative disease and. therefore, the rotation of men-in this type of work cannot be considered 196 0 0 1 4 4 0 is-000002; JAM Oldftaa -14- &a entirely preventive. Assuming that a man works in an atmosphere of silioa dust for several months, during whichtime he is bound to absorb a oertain amount of the dust rhich produces permanent damage in his lungsj be is then removed and the possibilities are that the damage which is already done will be sufficient to continue on and progress to the point where in later years he.will develop symptoms. "Therefore, if we take to rotating men in this type of work we are facibg the possibility of, in later years, developing a large number of cases of a moderate silicosis with some permanent disability. The only safe expedient which can be used is complete prevention and thie can only be done by eliminating the dust. " During our survey we found that men engaged in sand-blasting, that is handling the nozzle or attending the sand-blast machine, were more or. leas properly protected while actually doing the work but often times they removed their protective equipacnt before getting completely away from the working area* A large amount of very small particles is produced by sand-blasting. In an analysis of dust samples collected both outdoors and indoors during sand-blasting, the following distribution (Public Health Bulletin No. 217 - p.52) col a size fre quency basis was found* , ' Size Group in Microns Per Cent of Total 0.00 0.50 1.0 0 1.50 2.00 2.50 3.00 3.50 4.00 _ 4.50 5.00 5.50 0.49..... ........... 0.99.... .'........... ......... 1.49................. 1 .99.... ........... . ...... . 2.49........ ....... . ......... 2. 99............... . 3,49..... ........... ......... . 3,99,..... .......... 4.49........ . .......... 4.99.......... ...... 5.49................. .......... 5.99............ . 19.7 20.3 12.6 - 2.8 1.1 0,2 While has been estimated that free silica dust partiles, 1 mioron in diameter, re quire 8 hours to fail 6 ft. In still airj particles 5 miorons in diameter require less than 1 hour to fall the same distanoe. Considering this fact, it is apparent that the dust hazard from a- particular operation may, even though carried out for short periods, be aouto throughout the working day* In view of the fact that the con dition of still air is rarely, if ever achieved* and that dangerous partiles ojdlrfc in sizes below one micron, it is evident that a hazard exists. Fortunately most of the outside sand-blasting is done in more or less isolated locations whieh makes it rather improbable that there will be any unsafe silica dust exposure to other workmen. However, should it become 'necessary for any work to be done in the vicinity of sand-blasting operations either on process units or the sand blast sheds .or yards, it should be remembered that there may be sllioa dust in.the air even though it can not be seen. Dust counts as high as 5,344,160 partiles ten microns or less per cubic foot were found in samples -taken about 50 feet "downwind" (wind blowing about 15 to 20 miles per hour) while sand-blasting-cracking coil'tubes} ,o about 95/1 of these dust particles appeared angular crystalline under the Konlmeter microscope and were about five microns or less in size* Samples taken about 100 feet "downwind" fresa sand-blsting operation had counts as high as 1,812,480 particles per cubic foot. - V 001441 97 JAM 014689 -16- Dust counts as high as 13,933,440 and as low as 453,120 particles per oubio foot were found in samples tak^n during the filling of the Send Blast Machine feed hoppers. The high counts were found when sand was shovelled into a snail olroulor screen and shaken byhand, the lower oounts, when the sand ]nas aimply shorelled in* to the hopper. The average dust produced by filling or charging the Sand-Blasting Machines was 4,950,316 particles, ten micrcns or less, per cubio foot. ' Dust count's as high as 4,964,320 particles, ten microns or less, were found in samples token inside a Sand-Blasting Room while cleaning oastings. The average dust in this room during sand-blasting was 3,873,625 particles per cubio foot* About 80# of these particles were angular crystalline three microns or less in sixo and about 20# appeared rounded, quarts-like crystals about ten mierons in sixo. There were a few rust-like scales over ten microns in sixe and a very large number of minute dark metallic particles too small to be counted accurately. The dustiness of opera tion could bo greatly reduced by the use of steel abrasives exclusively. All of the samples for dust oounts referred to above were token at faoe level i n the vicinity of workmen. 6 ,000,000-dust particles per oubio foot is the tentative maximum allowable limit of dust particles containing free silica of a sixe less than 10 miorons reecto mended for sand-blasting, . H - FILTERING OPERATIONS . . The prooess of filtering is extensively used in the refining of petroleum products to improve the color stability and to remove impurities from motor lubri cants and paraffine waxes.' The three materials most commonly used for this purpose are Filter Clay or Fullers Forth, Contaot Clay and Bone Black. Considerable dust is produoed by the handling, charging and reconditioning of these materials. JL - FILTER CLAY OR FULLERS EARTHr . - What is Filter Clay or Full or Earth? Filter olay cannot b o identified from chemical composition but consists of silica, alumina, iron and alkaline earths i n varying percentages. The distinguishing properties are lack of plastiolty and tho power to remove o d o r from oils. There ore numerous deposits of this olay- and other filtering earths in the United States) the oldest' and among the most extensive ore those found close to the Florida-Goorgia line. One of these, at Attapulgus, Georgia, supples a major portion of the d a y used b y the affiliated Standard Oil Company (Hew Jersey) organizations. At the mine this material oontains on an average approxl- mately 32# silica and 45# moisture. The average composition after being prooessod and prepared for shipment is approximately* - S i 0 2 ............. . A l 2 0 g . ............ F o 2 Q 3 ..... ........ MgO.............. Combined Moisture, Froe Moisture,..-.. 67,46 per cent 10.08 " " 2.49 " * 4.09 " " 5.61" 6.28 The comparatively low dust counts found even in places where there was oleaning and sweeping is no doubt due to the fact that this filter clay is of a rather ooarso na ture and without appreciable amount of fines, ' . There appears to be a wide -variation in the composition and free silica con tent of filter d a y s used in European refineries, "Torrana" a German Filter olay- - used in Poland shows* - ' ' . 0 0 1 4 4 2 i8-0000023 198 JAM 014690 Loss in calcination........... 6.05. per oent . Free Silici (Si02).......... . 83.27 * " AI2O3 1103 F203.............. .*.. 8.27 " " The filter clay used in Rouamnia is reported as haying 60*4 per oent. free silica or 75.3# total silicates. "Granosil" clay used in Belgium oontAins ft total percentage ,of 7.3-1/2 per cent, of*silicates expressed as S102. The peroentage of free silioa was not determined. feow is Filter Clay Mined and Prepared? - The deposit varies from 2 to 12 feet in thickness, probably averaging about 7 feet. There is an overburden of about 35 feet which is removed by.an electrically operated drag line or a steam shovel. The d a y is loaded Into small cars, transported to the wet clay shed where it is diaaped on to the drying floor and dried for three days. It is then pioked up by orange peel buckets, loaded into portable distributors and delivered to belt conveyors whichdis- charge the earth into roller crushers where it is reduo'ed to sixes up to a maximum -of two inches. From these crushers the d a y goes to secondary crushere where it is re duced to a maximum of one inch. Sinoe the clay Is more or less damp very little dust is produced. The d a y is then transferred to tandem oil-fired rotary dryers. SO to 60 feet long and six to.seven feet in diameter. In the 20 minutes required for the'day to pass through the dryers the volatile and moisture content is reduced 40 to 50 per cent, to a maximum of .15 per cent. The averago_dust ten microns _or ' less in size in samples taken at various points around the dryers and oosveyors was 1,564,969 particles per cubio foot. This rather low dust count is the result of the installation of hoods with ducts to exhaust fans placed over the discharge points to the oonveyors or elevators. About 85# of these dust partioles-were angular crystal line in appe&ranoe under tho Korimetor'microscope and about five microns or less in. size) about 15# were over ten microns in size. The larger partloles had rough edges and appeared to 0ontain several small air hubbies. The clay is removed from the . dryers to hot rook cooling tanks, then to a vibrating screen. The oversize is next pulverized in a roller sill and the product conveyed to a sifter. An exhaust system fbr the mills and elevators has been installed. This prooess may be repeated until the desired size material has been obtained end graded to standard mesh sizes, the better known of which are 15-30, 30-60, 60-90, and the 200 mesh. The 6&*90 grade is probably the most commonly used in the petroleum industry when deodaring b y percola tion, and the 200 when contacting. However, the 30-60 is preferred by most of our refining units in the Halted States. The size seleoted is apparently determined largely by the .type of r e b u m i n g equipment. ^ Soreen tests are made hourly to Insure that the sizes are within the specifi cations. H e r e `are two typical screen analyses) ' ' 30 - 60 GRADE FILTER C U T * ~' Mesh Per Cent. Over 30 ....... . ............. 30 - 40.............. ............. 40 - 60.............. .......... 40.3 60 - 82....... ...... .............. Thru 8 2 ...... ....... . 9.7 47.5 1.6 Total - 100.0 199 48- 000002* 00144.5 JAM 014691 -17- FUSES (100 - up) GRADE FILTER CLAY Mesh . Por Cost. Over 9 7 .......... ........ ......... .97 - 157.......................... lfe'7 - 200............................................................................. Thru 200...... 0*6 22.7 8.0 68.7 * Total 100.0 ' There is very little dust produced by the sifting operation. All of the oazw neotions are designed to be dust tight but there is some leakage. Samples of air taken at various points around the sifters while in operation had an average of 2,208,960 dust particles less than.ten microns per cubio foot. About 85# of these dust particles were slightly angular crystalline in appearance and five microns or less in site; about 15# were slightly rounded semi-opaque tenmiorons or over in sise. The larger partiles had small cracks or fissures and several small air bubbles. ' Hen spend about two hours a day cleaning, repairing or replacing silk soreens in the sifters. Samples taken during this operation contained .ah a v e n g e of 2,039,040 dust particles less thsn ten microns per cubio foot. About 97# of these dust partiles were angular crystalline .in appearance and fii'fe miorons or- less "in size) about 3# were opaque over five microns in size. . After being sifted and. graded the clay Is ready for shipment. The 30-60 mesh grade is placed in burlap bags holding 128 pounds and loaded into railroad box oarsj about 400 bags to a ear on an average. Dust counts of samples taken during the fill ing of the bags with the 30-60 mesh grade show that there are frcm 7,589,760 to >,966,640 dust particles less than ten miorons per cubio foot which indicates that all men engaged in bagging and handling bags in this area should wear approved respi rators such as the "M. S.A. Ccmfo". About 80# of the dust particles In samples taken during the filling and handling of the bags appear slightly angular crystalline under the miorosoope and are five miorons or less in size; 2Q# are rounded crystalline, t e a miorons o r .over in size. * Bulk Loading of .railroad box ears with the30-60 mesh grade produces clouds of dust, but a major portion of this dust is apparently larger than 30 miorons in size . as samples taken during this bulk loading had an average of only 6,853,440 partiles, ten zffeercns or less in size per eubio foot. .. The Fines (100-up) grade is put into 128-pound eottcm bags. Dust counts in samples taken during this operation showed that there were Aram 4,644,480 to 14,216,640 dust partiles less than ten microns per oubio foot in the air being breathed b y the fillers, weighers, sewers and truckers. About 80# of these partiles were rounded, semi-opaque crystalline in appearance under the Konlmeter microscope and five miorons or less in sizej 20# were semi-opaque orystalline frcm about seven to fifteen miorons in size. There were also a large number of very small partiles about m s micron or less in size. . . How is Filter Clay Used? - Upon arrival at the refinery, the bags of clay are removed from the box cars by a crew of m e n usually from the General Labor Department| the job being rotated so that the same m e n do not do this particular operation more than perhaps twelve hours twice a year on an average. Goggles and "M.S.A.Gemfe* respirators are generally provided. The olay is either trucked*or dragged to a n elevator or conveyor hopper and dumped and the bags are piled for storage. A t points where the clay is reoeived In bulk, it is unloaded b y a large wooden scoop pulled b y a motor driven drag-line. Unloading-, handling, and dumping the clay is one of the ~ 200 * 001444- i b - o o o o J a M 014692 -18- dustiest parts of the filtering operation. The amount of dust produoed is of eouree dependent on how the work is dctie, the ventilation provided, and the oare used by the )tt.en doing the job* Here are same average dust oounts of partiles less than tea ai " crons in samples taken during the unloading of bags of 30-60 mesh Attapulgus clay Partiles Per ' * Cubio Foot Unloading and dumping bags (128 lbs.).into Hopper at & . Southern Refinery. ........... Dumping clay from Bage into Elevator Hopper at a . Northern Refinexy.................. Handling bags from Storage and Dumping into Elevator Hopper at another Northern Refinery......... Inside Box Car During Unloading........ Outside " " " ' ........... ............ ............. In Filter House Passageway being used to Truck Clay to . . Elevator, hopper............ ........... . Average Dust Produoed while sweeping up inside ear after unloading............. 6,403,466 2,237,260 75^,150 1,110,144 372,924 339,640 651,360 Apparently unloading clay in the bulk is less dusty than handling and dumping of the olay in tegs. Semples taken during the unloading' of bulk clay gave these- average oounts of dust under ten microns in size ' Inside ear during unloading.......... ......... . 962,680 partiles pereubio foot Outside " " '...... ............... 623,040 . * " } Shore is of course more dust produoed in the vicinity of bulk unloading than is proy duoed when handling and dumping cl&y in bags. After dumping, the new elay is taken by elevators and conveyors to storage bins which hold about 20 tons each. This.is also a dusty operation due to the failure t o cover the storage bins or to place hoods over the junction points of elevators belt oosveyors. Semples taken during the filling of storage bins with new olay had these average dust counts of partiles less then 10 miorona in sizes Dust over Bins around elevatore' and conveyors during filling at a Northern Refinery.......... 1,910,432 " 4 Conveyors while filling at another Northern Refinery....................... ......... . 4,275,842 " " " & Conveyors while filling at a . _ Southorn Refinory................................... - 4,531,200 " Face Level on Walkway over Storage Bins Northern Refinexy while Filling Bln.......................... 2,307,776 Dust Counts as high as 8,609,280 particles per cubio foot were found in ssmplcs taken near the discharge of one belt conveyor ixxto the top of a storage bin. About 9QjC of these dust particles appeared angular crystalline under the Xonimeter microscope and were five microns cr less in sizej about 10JS were black, opaque, many scale-like in appearonce and ten microns or over in size. , / ;) "BURNING" CLA.Y - From the storage bins the olay is conducted by chutes and/or conveyors and elevators to gas or oil fired Wedge Burners or Rotary Burners or Kilns in_whleh it is "burned" or roasted, and then discharged into rotary ooolers where it is cooled. Where all openings, chutes and elevator outlet* as well as the ends of- rotary coolers are properly enclosed and an exhaust duot is placed ever the burner, very little dust (an average of only 604,160 partiles, ton miorona or less in size - 201 0014.41) le-ooo JAM 014603 por eubio foot) ia produced and no respiratory protection is neoessary. Throe typos of burners or kilns are used to recondition filter day. Average dust eounts of samples taken during the operation of these burners give & comparison of the amount of dust (partiles ten microns or less per cubic foot) produced by each* Type of Furaaoo -* * Herman-Frasoh Oil or *Gas Firb3......... Wedge Gas Fired,........ Rotary * " Feeding About Furnace Coolers Total General Average___ 2.624.320.. .. 3,700,480..,,2.732.880.. ... 2,990,542 6.399.680.. .. 1,622,469.*. 2.108.590.. ... 2,395,971 2.067.360.. .. 1,070,046....3,115,200.... 1,818,206 The present practloe of using a compressed air hose to clean up the clay on the various floors of the Furnace House at one of the Refineries is particularly objectienable due to the excessive dust (12,687,360 particles ten microns or less per eubie foot) which is stirred up. . ' ' About 90# of the dust particles in samples taken during the burning of filter clay were angular transparent crystalline in appearance and five microns or less in aizej S% were round opaque, ten microns or over and 6% were rounded semi-opaque, -ten. microns or over in size. Exposure to dust produced by burning or reconditioning clay is .rather limited Usually there is one fireman for each shift of eight hours, three shifts per 24 hours and a porter for the day shift only. Since one of the porter's main Jobs is to "clean-up? ho is exposed more continuously to dust than are the firemen. CEARGIHG FILTERS - The cooled, burned clay (30-60 grade) is conveyed to the filters by means of elevators and belt conveyors and charged through chutes from the 'conveyor belt tripper at a rate of from one and a quarter to eight tons per hour -These vessels hold from seven to fifty tons each. The amount of dust produced during the oharging operation depends upon the grade of clay being handled, the'rate of charging, the position of the clay on the conveyor belt, the condition of the convey or belt, tripper and charging chutej also whether the top manhole of the filter Is loft open.during the filling. A general average of 54 dust eounts made of samples taken during the charging of filters at all of our plants using 30-60 mesh Atb&pulgus Filter Clay was 3,717,884 particles ten microns or less in size per eubio feat The amount of dust produced b y the charging operation varies considerably at the various planjjg as is shown by these averages * Refinery Baton Rouge Bayway Bayonne Eagle Works Charging Rate 8 tons per hour 1-1/4 " 3-1/2 " " g e t n Particles per cubic foot 4,271,413 2,435,520 2,42,944 1,042,976 It is the general belief that the more -times a clay has been used and reconditioned, the leas dust is produced during its handling. Our study does not confirm this be lief as applicable to dust produced while charging filters* Averages of dust counts in samples-taken during this operation were - . * # 1 Clay... . . . . . . 2 , 2 4 2 , 9 4 4 particles per cubic foot # 3 " .................. 4,604,832 . " " " # 10 * ..... ;........... 3,896,832 * " " " 202 001448 18-0000027 JAM 014694 According to an analysis of p&rtiole site made by the Bayonne Laboratory of a sample of Raw (30-60 grade Attapulgus Clay) No. 1, -No. 3, and No. 8 Wedge clays, the following is t b s site classification or distributions Haw Clay #1 Clay #3 Clay M Clay Coarser than 100 n o . . 98.5#.......... 9 9 . . . . . . . . . . 98.7#..... .*. 98. 3# ----- --- W~----- Diameter of Particles Raw Clay #3 Clay #8 Clay Millimeters Microns Per Cent Per Cent Per Cent .149 to .074 .074 " .044 .044 " .035 .035 " .025 .025 " .015 .015 " .005 .005 " .001 149 to 74 74 t 44 44 IV 35 _ 35 1 25 25 It 15 15 It 5 5 It 1 0.14355 . 1.00750 0.55095 0.17186 0. 29760 0.05369 0.21555 a 03887 0.17550 0.01729 0.11640 0.01027 0.00045 0.00052 0.54159 0.08449 a 04585 0.01603 a 00847 0.00336 a 00021 About 85# of the dust partiles in samples taken"during'the charging of -#3 olay were slightly angular in appearance and five microns or less in site) 15# were rounded semi-opaque, ten microns or over in site. About 75# of the partiles In samples taken during the charging of #10 clay were slightly angular crystalline, fire microns or less in sisej about 20# were over ten microns in site*and were semi-opaque about 5# were round semi-opaque between fire and ten microns in size. All of the larger particles appear to contain small bubbles. There are numerous small black specks about one-quarter micron in size. Charging of filters is usually done b y one man per shift for eaeh filter * house. There are three shifts a day. These men hare a n average aerrioe of about 20 years and work eight hours a shift, nine shifts out of fourteen. Ventilation is provided in the newer filter houses by ei^itoen-inch roof ven tilators extending about twelve Inches aberro the roof and also by windows which oocupy about 80# of the wall space in front of the top of the filters. JUMPING FILTERS - After the filters are charged w ith clay they are plated up and the oil is allowed to percolate through the clay for several hours, -the length of time depending upon the nature of the oil run and the "yield" of the olay. The oil is all drained off and the clay is then washed with naphtha or "Varsol,rand steamed, to remove all traoe of the naphtha. After this the filter is dumped an to a canvas belt conveyor and the clay returned to the kiln for burning or reoonditioning. Filter clay is used as many as fourteen times before it is finally discarded. In order to determine what effect the reconditioning of filter olay had on its free silica con tent samples were analyzed by the New York State Department of Labor, Division of In dustrial Hygiene with this results . Tiir.es Burned # FTee Silica Considerable steam Raw Clay................ Once.................... Three..... ............. Eight................... 6.30 8.50 9.20 9.30 i s usually given o f f during the dumping which 18-0000028 00144V probably 203 JAM 014695 explains the smaller duet oount (a general average of only 2,518,781 partiles tea micron* or less in sise per cubic foot) than would "be expected. The dustiest part of the filter dumping operation Is sweeping up the floor under the filters after dump lag is completed. Samples taken during this sweeping or cleaning up had as high as 16,638,880 partiles per oubio foot, although the general average of samples taken during dumping at the various refineries was 2,514,816 particles per oubio foot, About 95# of these dust partiles are slightly angular crystalline in appearance under the Konimeter miorosoope and are above five mlorons or less in size; about 6# are rounded semi-opaque over five microns in size. Occasionally the olay doesn't f l o w " when the filter Is opened* and must be started "flowing" by means of an iron bar. This aotion causes some dust (2,888,640 particles per cubio foot) but not as much as pounding the bottom and lower sides with a sledge (4,248,000 partiles per oubio foot) as is some times done. After the clay has run out, the inside of the filter is swept out with a broom whioh produo es a little dust (an average of 792,960 partiles per oubio foot). The filter is then plated up and is ready for reoharging. The work of dumping filters is done by one man per shift, for eaoh filter house. These men have an average servioe of about ten years and work eight hours a shift, nine shifts out of fourteen. They are exposed to dust less than 60 per cent, of their working time. Spent olay is used to a limited extent for packing around valves.and fire hy drants to prevent freezing} also for certain other small absorbing ob suoh.jn on the ' warehouse floors of seme of the larger bulk sales plants where lUbrioatlng oils are transferred from barrels or drums to smaller oantainers, or loaded into five gallon cans from bulk. Most of the spent clay is disposed of, however, by dumping it on 'nearby Company property and, to a lesser extent on railroad property near river banks. Composition of Filter House Air Borne Duati Samples of dust from Attapulgus Clay, whioh had settled on the tops of elevator housings and on girders ever the storage bins in filter .houses, were submitted to the United States. Bureau of Mines E x periment Station for petrographic examination. Ordinarily positive results are not obtained in petrographio tests for the identification of minerals in atmospheric dust. However, the samples submitted were ooarse enough to give results in moist oases. In studying the results of the petrographio examinations it should be borne in that the samples submitted were settled dust, and that they are not representative of the composition of the dust that would be breathed generally owing to the differential settling rates and the ease with which the various mineral constituents oan be crush ed to a powder. ' "Montmorillonite" ((Mg, Ca) O.AI2 3. 5Si 02 nH20 7- n-5 to 8) is the miner al that is characteristic' of many types of fullers earth. Hot all of the less 1m- portant minerals found were fully identified, . - Clay dust from top shell of elevator - Top #2, Herman-Brasoh Furnaoe, Quartz - 10# Montmorillonite - 80# Calolte, Microcline and Unidentified - 10# Dust from accumulation on girder over clay storage bins - #4 Filter House. . Quartz - 10# Montmorillonite - 70# - Possibly other clay minerals present, opaque - 20# Dust from accumulation on girder ever clay storage bins --#1 Filter Housa. Quartz - Over 2# Opaque - 40# Montmorilloni-be - 55# Unidentified - 5# -10^0000029 29* JAM 014696 001448 -22- Control of Filter Clay Dust Dust in a filter plants results principally from the operation of the clay handling machinery. The condition is aggravated by the present practioe at some refineries by using an air hose to blovt accumulated dust and spilled clay from equipment, walls and floors. Handling a fine light dust producing material, such as filter clay, in a system which inoludes open belt oonreyors is in herently a dusty operation. (12,687,360 partioles, ten miorons or less in size, per cubic foot). It .is difficult to prevent some dust from being generated at unloading points where the^olay falls into chutes or bins, but it can and should be controlled by means ^of hoods, enclosures, and adequate exhaust systems with effective dust oolleo- tors. . There will always be an irreducible minimum of spillage and dust settlement wherever dusty material is handled in systems such as exist in most refinery, .filter houses. This is an economic waste and increases the difficulty of the dust -control problem. Unless the present practioe of cleaning dust spillage b y blowing with oem press ed air is changed, the necessary periodic oleanlng will oontixme to be.a very dusty and unhealthful operation even though all precautions have been taken to pro- ' vent the escape of- dust from clay handling equipment. A modern industrial vacuum cleaning system would do the job efficiently, without ereatlng any dust. ' The principal source of dust in filter buildings is the belt conveyor whioh ia usually located at the top of the building. .Gusts of wind from the monitor blow the d a y and dust from the belt. A certain amount of dust is also generated by d a y fall ing into the tripper chute (6,060,460 particles per eubio foot) and discharging from the tripper chute into the chute leading to the various filters (7,306,660 partiles per cubio foot). This eould.be considerably reduoed by inserting canvas or sheet iron connections between the ends of the tripper chutes.and the chutes to the filters, and by using a properly designed belt tripper on the conveyer belt. ' . Bins for the storage of filter d a y should be closed with Steel decks having the smallest possible openings in the form of ohutes to receive clay from the oexrvey- ers. 'If care were taken not to overflow the bins, the dust and spillage oould be greatly reduced, - For complete control of dust, an exhaust system equipped with dust odleotor, fan, duets and hoods should be Installed to remove dust from the points of origin, such as, all unloading points (except movable trippers) of each belt conveyer in the building, new clay bins and burned clay bina. One estimate which has been prepared for such an installation calls for an exhaust system with a capacity of approximately 15,00$*cubio feet of dust laden air per minute, and is based on maintaining an Inward flow of air at openings into hoods and bins at a reoosmended velocity of 200 feet or more per minute. In considering dust collectors, it should be borne in mind that the oyolone type will not remove the fine dust partioles (ten miorons or iess in size), which are most injurious to health, and that the cloth bag type filter has been proven to be more successful in removing these fine partiles. Under existing conditions at most plants it is almost impossible to keep the plants clean, regardless of how carefully the equipment la operated. However, the in stallation of a vacuum system and adequate dust collectors should encourage operators to exercise more care in the operation of equipment and thus cut down the amount of dust and spillage. .. B - CONTACT CLAY* - - . Host oorrfcaet clays, particularly in the United States, are sold treated "Ben- tc&ite". Bentonite is a non-refractory clay, a double silicate of iron and aluminum, derived from the shale of the Fort Benton formation in the upper Missouri valley. 205 001449 1 8 --0 0 0 0 0 3 0 JAM 014697 There appears to be a wide variation in the composition and free ailloa con tent of American and European contact or activated clays. "Filtrol" an extensively need .American ocatact olay ii reported to oontain about 67# free ailloa (allioa which is insoluble in concentrated hydroohlorio acid). "Milwhite'1, another extensively used Amerioan contaot clay, contains 65% tree silica. The oontaot d a y s listed are those most extensively used in Europe Insoluble in Insoluble in Conoentrated Concentrated HCL HCL and 5% KA.? CO3 . ^Ivry" Clay {French).... . "Terrana Extra" (German).... "Clarit" (Italian)......... 75,0#............ 64.4#........... . 49.5#........... .* 64.6# 27.2# . 60.6# "Tonsil AC", another French oontaot clay, has 61.75# free silica*. . The main constituents of "Petrisil", a German contact elay, are* ' Total Silica................ 61.57# Lime (CaO)............. 0.63# Aluminum and Iron Oxides.... 18* 83# Loss on ignition (Water)..,. 23,62# 'The balance probably consists of' potassium and sodium oxides. The following is the result of a petrographic examination of "Petrisil" which was made at the United States Bureau of Nines experiment statlonr , Quartz........................ 6# Kontmorlllonite.......... 90# Unidentified Minerals.... . 6# The use of oontaot olay for improving the oolor of lubricating oils is a re cent development* At present the price of oontaot olay is so low that it is used only once and then discarded. . ^ Although there are many oontaot d a y s on the market, a large percentage of that used by the Standard group is known as "Filtrol", consequently this was inoluded i n our dust studies. _ _ . What is ''Filtrol'* and How Is it Produced? wFiltrolw is a pulverized aoid treai ed Bentonite, used as a decolorixer, absorbent and deodorizer in the refining and preparation of both organlo and inorganlo oils. It oomes from "open out" mines in Mississippi and California,'and occurs in beds about two and one-half feet thlolc under an over-burden of some eighteen to twenty-five feet. There has been same, doubt as to its origin, but it is now believed to have been volo&nio dust transported b y the air and deposited under the waters of either a lake or a sea. Haw Bentonite is mined and loaded onto trucks with steam shovels, and then taken to the preparation plant. A traotor sooop lifts the raw material from the storage shed floor and plaoas It in a hopper out of which it is fed into an elevator b y means of a steel pan feed er. The elevator discharges into a crusher which breaks the material dora\sufficient ly to enable it to pass through a screen (three meshes to an inch) onto a belt con-- veyer which takes it -to a pre-mixer where it is mixed with water to fora a ''slurry'** This slurry is passed into large wooden tanks and treated with dilute sulphurio acid 206 18-000< 00141 JAM 014698 ' agitated with air and oteam. It is then dumped into thick oner8, washed, and deliver. ed to an Oliver filter. From .there it goes in turn to a pug mill, drying tower, oage ) -and imp mill, and olassifier. 'The finished product is plaeed in a bib where it is ^ put into fifty pound Bates Valve paper bags by means of a Bates Bag Packer. It is shipped in railroad box cars, each haring a .capaoity of from 1600 to 2000 bags. The three grades of "FlltTo!" in greatest demand are* GRADE ^# (Per oent. thru * 200 mesh)* Per cent, of Total Production Coarser Than 200 Mesh 200 - 325 Mesh Finer Than 325 Mesh 65 -- 88 76 - 88 90-93 * 80 .16 6 4.# 23.# 8.# 16.# 24.# 23.# 70.# 63.# 69.# -- ;________ j The only real dust pfoduoing operations in the production of Filtro! are the filling, stacking and handling of the fifty pound bags. Samples of dust taken during these operations, revealed the followings Operation Particles per cu ft. Average dust filling bags with '85-86 grade " " .packing room while filling bags " n produo ed in handling of filled bags 10,416,096 9,572,180 5,845,246 A n exhaust system has been Installed to reduce and oontrol the dust produced ) during the packing of Filtrol. This consists of a metal hood above the filling tubes / A n front of the machine, with a basin below. A seven*inch duct leads from the basin and a six-inoh duot to a. canopy in back of the paoker, both connecting with a ten- inch ma i n duct rhioh runs to a Sturtevant Fan (1750 R. P.M. ) designed to handle. 1,620 oubio feet of air per minuto against four-inoh water statio pressure. A cyclone dust oolleotor removes the larger partiles from the air before delivering it to a tubular d o t h dust, oolleotor. About sixty per oent. of the* dust' partiles of samples taken duringthe fil ling operation are slightly angular orystalllno in appearance under theKonimeter ml- orosoope, and are about two miorons or less in sisej approximately twenty per oent. appeflo to bo rounded crystalline, glassdiko, but with rather smooth edges, and over ten miorons in siso. There are a large number of very small gray-partiles (about twenty per oent.) too minute and too numerous to oount accurately, . Whatis the Chamloal Composition of wFlltrolwT Below is the result of an a n a l y s i s by a ocamneroial cBraioal laboratory in Los Angeles, California, of a sample of Filtrol from the Jackson (Mississippi) plants ' * Per Cent. Silica (S102)........ ...... Alumina (A1203)......... Forrio Oxid (F02O3 )........ Titanium Oxide (T102 Calcium Oxide (CaO).... . Humaftliim fhride fMrO^ Carbon Dioxide (COg)........ - 18-0000032 -001451 207 t J A M 014699 -- i>-- \ V Per Cent. Sodium Oxide (N&20)......... ......... . Chlorine (Cl)......,........ ........... Phosphoric Anhydride (P2O5 )..... ....... Sulphuric Anhydride (SO3 ),............. 'Total ignition loss.................... . Ihree Moisture.-.......................... 0.04 ' 0.63 20.00 12.23 k "It is customary to separately report materials such as Silica (Si02) and Alumina (AI2O3 ) in ultimate analysis although the elements are known to be in combination with one another. It is difficult to get as analysis of free Silica, and since the quantity contained in Fil- trol would be very small, we have not attempted to hare this par- ' ticular analysis made," The following is the result of an analysi-; of "Super-Filtrol" which was made in- France* Per Cent, Moisture at 120 degrees C ........... . 16,6 Loss on ignition..................... 7.. 33.5 Insoluble in conoentrated ECL...... . 55,0 (Total Silica and unattached crystals) . Insoluble in ECL and in a 5% Na2C03 solution. 15,0 . ' (Siler, quartz' and unattached crystals) . ` ) ' ' A microscopic examination shows a few particles with . "aoute angles". ' An examination made by the United States Bureau of Mines Experiment Station i Pittsburgh, Pennsylvania showed that Filtrol contains more than 2% quarts, 95 Hontmorillonit ((Mg, Ca) 0.Al203-5S102-nEzO--n*5 to 8) and 5% unidentified mineral A similar examination of Attapulgus Fines (200 mesh) showed 5% quarts and 95% Mont- morillonite. . . . Contact Clay Used? The d a y is mixed with oil, agitated and heated, e d t h e r allowed to settle or run through a filter press. It is then discarded. The d a y is either dumped directly into the oil or placed in a hopper from, whioh it flor into Inductors or mixing chambers where it is mixed with the oil and then pumped t o filter tank. The only dusty operations are the unloading of the .material and dumpii it into the hoppers or mixing chambers. The higher dust counts with the contact oil as compared to filter clay in probably due to the faot that it is a finer material, or at least disintegrates more easily than the filter clays studied. . Samples taken during the dumping of Filtrol and Attapulgus Fines into a re&o* tlon chamber gave the following dust counts. * .Operation Particles per cu. ft. f / . - A v o m g e dust produced while dumping 50 pound bags of "Filtrol".............. ....... . 6,768,480 Average dust produoed while dumping 100 pound" . bags ef "Attapulgus Fines".......... 9,260,640 208 JAM 014700 18-0000033 ,00145 26- i ./) 4 Under the Konlmeter Microscope the particles were rounded in appearanoe. The "Attapulgus Fines" appeared more crystalline and angular, and had a greater proportion of : particles fire microns or less in size than did the "Filtrol". The counts indioate that more dust results from dumping Attapulgus Fines than from dumping Filtrol aotivated clay. Dumping fifty pound hags of "Milwhite" (90# through 200 mesh), a Texas contact clay, into the feed hoppers to the inductors or mixing chambers is an exceedingly dusty operation. .Samples taken during this operation had as high as 14,046,720 par ticles ten microns or less in size per cubic foot. Samples taken in the middle of the room just after thirty bags had been dumped into the hopper had 55,847,040 par ticles per cubio foot. Under the Konlmeter Microsoope, about 90# of these partioles appeared slightly crystalline, and were five microns or less in size; 10 # were round, semi-opaque, ten to twenty microns in size. There were also a few scale like partides. Fourteen men with an average servioe credit of six years are involved in this operation. Three men are exposed to the dust during six hours of each eight hour shift for nine of the fourteen shifts during the 85# of the time the filtering plant is in operation. They wear M. S.A, "Comfo" respirators. After extensive study and investigation the local management has made arrange ments to receive the clay in tank cars similar to thosemanufactured by the Gnral American Tank Car Company, These cars are self-unloading and will discharge into an enclosed hopper, -The clay will then be transported to storage bins by means of a screw conveyor, completely enolosed in ten-inch tubing. It will.be withdrawn from the bottom of the bins, passing through weighing scales, into the inductors where it will be mixed with the oil. This will provide a completely closed system and should eliminate all air contamination. . C - BONS BLACK OR CHARRED BOlIEt . Refined wax is filtered through bone blaok or charred bone* to improve its oolor. This material is obtained from various meat packing firms in finely woven oof- fee bags that hold about 150 pounds each. A n open belt conveyer and elevator carry the bone dlreotly from the reactivating furnace to' the covered filter charging hopper. Metal chutes lead directly from hopper ixrbo filters whieh hold about 3,000 pounds of bone black. Upon complqbion of filtration the bone is washed with "Varsol", steamed for about 24 hours, washed with hot water, steamed for two hours more, and then Stamped upon belt oonveyers whieh carry it to the reactivating, furnace which is gas fired. The bone goes through the furnace at a temperature of about 4100. degrees Fahrenheit and at the rate of about 250 pounds per hour, Bose black pain be used over and over again. Three men one on each shift, with as average service eredlt of ' fifteen years, are engaged in this operation. Their period of exposure to dust is ' about one hour per shift. The greatest amount of dust produced results trm the open conveyers, particularly In dumping the material fraa the furnace onto the conveyer belt. Samples taken during this operation had as high as 11,044,800 particles of ten microns or less in size per cubio foot. Considerable dust (14,273,280 particles per cubio foot) also arises from the open hatch, of the filter charging nopper during filling. An eight-inch motor driven exhaust fan has been installed to suck back the dust from where the elevator buckets dump the reactivated- bone into the chute to the charging hopper. The dust loss from this filtering operation is estimated to be about 1500 pounds per month. - - . < _ -- Under the Konlmeter Microscope about 65% of the dust partioles of samples taken during the reaotivetion of bone black appear to be black, opaque, scot-like, and are five miorons or less in size} 5# are rounded; ami-opaque, ten miorons.or more in size. The angular crystalline and light grey partioles which constitute about 30#. are probably JAM 014701 18-000 001 v -27j bone ash. m INSULATING OPERATIONS Insulation plays an important part in the processing of petroleum produote. The two types of insulating material moat frequently used are "Sponge Pelt" (asbes tos with groundl'sponge to ire dead air spaoe and thus increase the effectiveness of the insulatiop) and a mixture of 85# magnesia and 15# asbestos. Rode wool is used to a considerably lesser degree. In the ordinary commeroial form, Rook Wool, as used at o u r refineries, does not present a dust hazard. It is also used .for house Insulation, and is.available in small nodule form which oan be blown into plaoe. "85# magnesia" is a mixture of magnesia and granulated asbestos and pressed into blooks o f various sizes and shapes (usually 16" x 18" x l-l/2"). Thd.sibst dust oomes from dismantling old insulation and grinding scrap material for use as a plas ter or "ganister". The average servioe of m e n engaged in insulating operations is about fifteen years. Most of these men have been transferred from the Common Labor Department, They work nine out of fourteen eight-hour shifts, in gangs of from two to six men, and are actually exposed to dust for less than sixty per cent, of their . working time. Goggles are sometimes provided, and oooasionally MSA "Comfo" Respira tors, but this equipment is not used as muoh as it should be. Generally speaking, about 85# o f their work is with sponge felt.and 15# with 85# magnesia insulation. At one of the larger southern refineries about 300,005 square feejt of sponger felt SO,000 square feet of 85# magnesia are handled a year, . A - What Physiological Reactions are Provoked by Instilating Materials? Aooording to Dr, Leroy W, Gardner (Jourm Indust,Hyg. Mar, 1937,Vol. 19, No. 3, P. 121) asbestos dust with its fibrous particles does not seem to be readily handled b y the protective meohanism of the lungs. Quoting from his article "They are not removed the lymphoid' tissue but remain in ooataet with the delloate walls of the air spaces. They become surrounded b y as iron-containing ooatlng that fractures and gives rise.to the peon- . liar structures known as 1 asbestos is bodies. The fibers are irri- * tatlng, perhaps because of their form, and they exoite a fibrosis whloh begins about the terminal bronchi olea and spreads to form dif fuse patches in the parenchyma. Often the distribution is sub-pleural. Is the presenoe of infection, the reaoticn to-asbestos dust is muoh _ more severe than that oaused by.the dust alone," ' . There is nothing in the pertinent literature, nor does the Bureau of Mines know of any evidenos, which would demonstrate magnesite (a natural magnesium oarboavate) to be harmful. It would fall in the class of "nuisance dusts" suoh as gypsum. While many of the eo-oalled "nulsaxtos dusts" have never been found-to be harmful, it is the opinion of most investigators in the field of industrial hygiene that no work er should be exposed to any dust In a concentration exoceding 75 or 100 of partiles per eublo foot of air. B - What are the Principal Insulating Operations-and How Muoh Dust is Froduoed During Such Operations? There is,- of oourse, a wide variation in the amount of insu lation work and the amount of dust produced, A few examples, however, will give a good general ideas INSULATING 12" STEAM LINES* 6" x 18" x 1-1ft* bloola of 85# mag- ' * nesla are tied on the steam line with 14-gauge galvanised wire and - covered with roofing paper to make it waterproof. Often this work is performed on scaffolds twslve to fifteen feet above the ground, ~ with men lying on their backs under the line part of the time, . . ~ 18-0000036 JAM 014702 001454 210 Considera-ble dust (as high as 18,124,800 particles of less than ten mlorone per oubio foot)* results from tapping the blooks into plaoe. Samples taken during the entire operation had an average ocooentration of 6,881,760 particles per cubio foot. About 90jC of these dust particles were slightly angular, crystalline in appearanoe and above five microns or less in site (as seen under the Konimeter Miorosoope)) 5% were rounded opaque, ten microns or more in size) and 5% were opaque scale-like, five microns or more in site. Samples taken while applying asbestos sponge felt to a 1 2 " steam line had a dust oonoen-* -^ration as high as 23,-788,800 partiles of ten microns or less in size per cubic foot. The average 1703,12,574,080 partiles per oubio foot. These dust concentrations are .considered too high for work ing without adequate protection. INSULATING A 750-POUND CRACKING COIL ACCUMULATOR* 6" x 36" blocks of Johns-Manville "Fire Felt" are first applied and plastered with extra A A Rubberoid Asbestos Cement and waterproofed with Johns . Manville "Insulkote". The dustiness of handling these materials has been considerably reduoed slnoe the manufacturers began shipping the "Fire Felt" in oardboard cartons containing thirteen or twenty blooks, and the plaster in hundred-pound paper bags. Samples taken during this operation had an,average dust concentration of 4,602,8.80 particles, ten microns or less in size per oubio foot.* About 75> of these dust partiles were slightly angular in appearanoe, five mi- orons or less in size) K # were scale-like; opaque) and 15^ were rod-like and fibrous. _ . . . INSULATING TREATING PLANT ACID SUCTION LINE* Sections of "Sponge ' . Felt Pipe Cover" are out to fit pipe lengths with an ordinary carpen ter's hand saw. This operation produces on an average 821,280 par tiles of dust, ten ailerons or less in size, per obio' foot. Under - the Konlmeter Microscope all of these partiles are slightly angular, crystalline in appearance, and five miorons or less in size. The blooks or sections of the pipe oover are held in place b y wrapping - #16 gauge galvanized wire about eaoh one. . INSULATING CRACKING COIL EOT OIL LINES* All hot oil lines at eraek ing coils are insulated with 2" asbestos tubing (85# magnesia and 15# asbestos) held in plaoe by fine oopper wire. Seotlons of the tubing i^are cut to fit particular areas b y means of an ordinary carpenter* s hand saw. This produces 7,788,000 partiles of dust} ten miorons or less in size, per cubic foot. Under the miorosoope, 90# of these * dust partiles appeared to be rounded crystalline and about three mi crons or less in size. Eaoh section of tubing is pounded into plaoe with the open hand so that it fits snugly against the pipe, and then wired into position. The dust produced from both of these operations averages about 3,379,520 particles per cubio foot. Under the micro scope, approximately 80# or 90* o f the dust partiles appear crystal line, more or less angular, and five microns or less in size) the re- malnlng 10# or more are rounded in appearanoe, and over ten microns in size. . * DISMANTLING OR RittOTOG OLD INSULATION*. As a general rule, the . dismantling or removal of old insulation is a more dusty operation \ than the application of new insulation. The old insulation is chopped or out with a hatchet or small hand-axe, and pried loose and pulled off with the hands. This produoes dust concentrations as high ae - 5,890,560 partiles, ten miorons or less in size, per oubio foot. In . ' * . - 211 JAM 014703 18-0000036 001455 i dismantling an old cracking ooil 4" tar lino, the average dust comoea- tration was 2,322,240 {partiles per oubio foot. In appearanoe those partiles were olear crystalline, rather rounded, and five miorons or lesa in size. Ho fibres were observed in any of the dust samples from dismantling operations. After a few weeks or months servioe, insula tion on hot lines dries out and appears to disintegrate. This is prob ably due .to the fact that suoh insulation is usually oovered with a weather-proof material whioh prevents absorption o f moisture from the air. . - CRUSHING SCRAP ASBESTOS: Scrap asbestos insulation, usually the BS?. magnesia type, -is crushed in a belt-driven Williams orusher to pass through a soreen with one-inch holes or slots, and is then mixed with new asbestos to make Insulating plaster. This operation, whioh la a very dusty on, is performed by two men, with an average aervioe oredlt of about twelve years. Goggles and. USA. "Comfo" or Willson Dust Respi rators are w o r m Considerable dust is produoed in breaking up the sorap insulation b y hand prior to orushing (10,195,200 partiles, ten miorons or less, per cubio foot), and also When feeding the orusher whioh is done b y shovelling the broken-up pieoes into the hopper and poking them down with a short wooden stlok (14,839,680 partiles per oubio foot). Dust counts as .high as 27,527,040^particles per oubio foot were found in samples taken-from over the hopper," These dust oon-= ~ oentratlons are dangerously high. About 95% of these partiles are . sharply angular, crystalline in appearanoe and five miorons'or less in size) 5% are opaque scale-like, six miorons or more in size. Crushing sorap asbestos is not' a steady routine operation, the exposure varying from eight hours a month to about twelve hours a week. . 1 CRUSHING OLD CORK INSULATION: This operation is performed approxi mately twice a year and takes about twenty or thirty minutes. The in sulation is orushed on a belt-driven Williams orusher, b y the same men who orush the sorap asbestos. This crushed oork is used for insulating lines in the old settling plant. The average amount of dust produced is 20,016,178 partiles, ten miorons or less in size per oubio foot, About B0% of the partiles are slightly angular, crystalline, in ap pearanoe, and five miorons or less in size) 20% axe round, semi-opaque, ten miorons or more. There are also a large noaber of very small bl&ok or dark grey speoks, . IV - GUNITING OPERATION , * I What j Gunite and How is i Applied? -- Gunite is a mixture o f approximately one part (one 94 pound bag) of Portland Cement and two paxts (twelve sooop shovels) of olean sharp sand. The sand and cement are mixed dry, shoveled into the hopper, of a Gunite machine, using water under about 40-pounds per square inch pressure azid compressed air at thirty to ninety pounds per square lnoh. It is applied under pres sure, as a semi-fluid, against the surface to be protected (usually prooess equipment, such as, oracklng ooil soaking drums and storage tanks). In praetloally erezy ease where gunitlng is done, it follows -immediately, after the sand blasting job used to olean the auraoe. In most eases, the work is performed b y the same crew. The indi vidual holding the gunite nozzle is provided with the same protection as is the operator of the sand blast nozzle, and the m en tending the gunite machines are pro- . Tided with respirators and are required to use them while aotually handling .the aazid and oement. This involves mixing the materials and charging them into the machines (the two dustiest parts of a gunitlng job). Samples taken during these operations showed the following dust counts of partioles ten miorons or .loss in site 212 JAM 014704 18-000003' 001451 -30- Opcr&tlon Partiles per ou. ft Screening and prior to nixing with oement.... Mixing batoh................................ Shoveling n i x i n t o hopper.................. 2,493,160 1,699,200 6,485,280 About 40# of the dust partiles in samples taken while mixing the batoh and. filling the hopper were erystalline, quartz-like in appearaaoe, and about five miorons in *ixe. The remainder were dark grey in color and below one micron in sise* The dust partiles in air coming out of the bottom manhole of a soaking drum being gunited averaged 528,640 partiles per cubic foot, and were slightly angular, crystalline in appearanoe and four miorons or less in sise. A gunlte crew consists of six menu The average servioe oredit of thei m e n in the Crews studied was eight years. Two "nozzle-men" who "spell" each other every two or three hours apply the gunite. There is one man at the gumite maohine, and three m e n soreen the sand and mix it with cement. Only about 25# of their working time,,..or nine hours per week per man, is devoted to gunlting. Hem oval of Gunite Lining* Pneumatio ohisels are used to remore gunite lining. Samples taken from inside a cracking ooil tar separator during this operation had as high as 16,595,520 partiles of dust, ten microns or less in size, per oubio foot, and an average of 10,804,080 partiles per cubio foot. 'About *75# of these' partiles were rounded, angular, more or less opaque, in appearanoe, one adoren or less in size, and 25# were angular, quartz-like, about ten microns or less in size. A oheai- cal analysis of the gunite lining showed that it contained 68.2# free silloa. Four men from the Plant Labor Department, with an average servioe of seven years, spend about twenty hours per week removing gunite linings from prooes a equipment. A n air syphon provides ventilation, and the m e n are required to use the goggles and respira tors which are furnished them. V - WELDING A N D CUTTING OPERATIONS * Voiding has never been considered a dust-producing operation. However, our studies and those of others indioate that the use of the modern coated eleotrodes or rods produoes a large amount of dust in addition to the fumes whloh are evolved. A n eloctrio arc is used for most of the welding around refineries. There are a number of welding jobs, however, for which oxy-aoetylene is used. Qxy-aeotylene is also used gr practioally all burning or outting. A. - WELDING OPERATIONS - 2. ELECTRIC ARC WELDING Electric aro welding is used oo all types*of oca- struction and repair work. The average servioe of the eleotrio. welders is about two years and most of them came from the Labor Department, having been developed into welders at the individual plants. They ere exposed to ' particulate matter generated b y the welding operation on an average of six hours per shift, nine shifts out of fourteen. This particulate matter is ordinarily referred to as "fumes or smokes". The particles when found have a muoh smaller size range than that of dust, suoh as sllioa. With some operations there may also be seme dust present, but the product formed from volatilizing the metal and rod ooatlngs is oommonly termed a "feme". All welders are provided with approved hand shield or helmets equipped with ^ 10 Noviweld lens. Welding in shops is done is nasvas or wooden booths. A _steam or air syphon is installed when any aro welding is done Inside of olosed vessels suoh as drums or towers. - * * - What ire Coated Electrodes?. Coated electrodes are metal welding rods covered 91 X JAM 014705 18 -0 0 0014 Tvith & composition which prevents oxidation and permits the formation of stronger store uniform welds. What Do These Electrodes Contain and What Products Result From Their Use? la. general, the coatings used in modern coated welding electrodes are patented or trade secrets, with special virtues attributed to each. Obviously, it is Inadvisable to put into these coatings materials which might produce products h a m f u l to man. Nevertheless, chemical analyses of both the coatings and their products indicate that the oontinual use of seme of these rods might possibly lead to oamplioations. Most of the arc welding at our affiliated plants is done with #5 Fleetweld coated electrodes which come in two sires (5/32M and 3/l6") and with General Eleotrio W-20 5/32" coated rods. Other rods sometimes used are ^4 Stainweld EagS alloy welding rod, 5/32" Stainweld A rods for stainless steel, and Murex Niokel Steel oDat ed rods. Among the constituents of some of these electrodes coatings arcs - Coated i Electrode Brand SiQg Per Cent. Fluorine Calcium Fluoride "Fleetweld"., Linooln Electric Co....... . 30.28 "Murex". American Metal & Thermite Co..... 28.05 "USS Cr-Hi 18-8", Amer.Steel & Wire Co.... 37.20 "Stainweld", Lincoln Electric^Co..... . ... 12.101 "Reristal K-A-25", Crucible Steel Co...... 24.03 * 21.20 13.40 - . - ' 14.50 43.50 - present . All of the above coatings also contain Iron Oxide (Fe203) Manganese Oxide, . . either M112O3 or MnO or both, and Aluminum Oxide (AI2O3 ), JLn varying per centages. ' . - ' . The oompesition of the fluxes or coatings used in G & E types W-20, W-22 and W-23 is not available, but it' is known that they contain amounts of free silioates and free silica. According to determinations made by the General Eleotrio Company, the maximum concentration of free silica on any of their electrodes under a particular set of conditions is 1,575,000 particles per oubio foot of air pith W-20, 778,000 with W-22, and 1,093,000 with W-23 loader other conditions the concentrations might be higher or lower than those given. The maximum permissible concentration as listed . b y the Metropolitan Life Inaurano e* Company is 7,000,000 parti d es per oubio foot of air. Coatings also contain cotton fiber, cellulose, or other organic pulp which er elftes fumes, but sinoe we are only concerned with dust in this study all fume pro ducing materials will receive no further consideration. ~ Welding oorr osion-resisting s+eel w ith coated corrosion-resisting steel elec trodes forms a slag, among the major constituents of which ares ' ' "Stainweld" USS CR-Ni 18-8 "Resista!" Fluorine (F).............. ........ . Silica (S02)........ ............... Iron, Chromium and Manganese .Oxides. . Calcium Oxide (CaO).............. 1251...14***....................386...56***............................1134...39*** 5202.73*........2284.02*........ . * 15 2 28 7 * The major constituents of dusts separated from atmosphere by gravity and ool- leoted from the bottoms of welding chambers after welding oorrosior-resisting steel plates with ooated corrosion-resisting steel welding rods are*- ` 214 JAM 014706 jB.0000039 . 00145 "Stainweld" PSS CR-Nl 18-8 "Rexlstal" Silica (SiO )......... .............. 1 1 . Q & . '...* 196 % ....... 10.QJC Calolum Fluoride (CaF )......... . 40,5?.......... 11,4% 23,4% Oxides of Iron, Aluminum and Kiokel* 30,2%..,.,..., 52.1%....... 36. 6j The following is an interesting comparison between the compositions of dust formed vhen using bare mild steel electrodes and then using coated electrodes for weldinggalvanized steel* . Brand "Fleetweld" "Wilson" "Mur ex"- t Bare Electrodes % ZnO % FO203 79.2 62.6 60.5 20.0 60.6 40.0 Coated Electrodes % ZnO % F0203 67. 5 78.8 72.0 31.9 21.5 28.0 ' " Investigations hare shown that there may be as much as a five per cent* varia tion in composition of dust produced by the same make and kind of electrode when used under oonetant conditions but by different operators* Ferric oxide (FeD3) which emanates from all welding aros, regardless of-the type of coating, is disagreeable but not harmful* Concentrations of iron oxide of about ten milligrams per cubio meter are said to be entirely nan-injurious to the respira tory organs. Breathing the dexfse clouds of fumes of zinc oxide, formed whoa the sine of the galvanized coating is boiled off by the heat of the welding aro, onuses what is oobv- monly known as "fume fever". This is evidenced by nausea followed by chills and uxv- pTeaeant fever. The fume fever does no lasting harm except after prolonged exposure, and the effects are not cumulative. Ordinary ventilation, which is neoessary in any welding operation, is considered adequate to prevent fume fever*.. _ What Is The Amount And What Are The Characteristics of gust Produoed gy The Various Electric Aro Welding Operations? There is a wide variation in the amount and charaoter of dust produced by different types of rods on different materials under different operating conditions. ` FEME. OR DUST PRODUCED BT ARC WELDING Material Being Electrode Welded Used Rivets inside Cross Coil Drum. G-E W-20 Coated Mild Steel Blanks Inside Booth. G-E W-20 Coated . Size of Electrode S/S2* . 5/32" Partiles Per otu ft. 20,050,560 Characteristin s_ of Dust Particles. (Sizes and Per- e eatages Estimated) About 98% angular crystal line. 5 microns or less in slzej 2% rounded semi-opaque, 10 microns or more in size. 14.839.680 About 80% round black or red dish brown spooks, 1 microns or less in size) 20% slightly angu lar crystalline, 10 microns or .less but mostly about 5 miorans and large number reddish brown, specks too small and numerous tcoount. . - -- ------------------- - - lB-OOOOO. 215 JAM 014707 0014 /n --33-- . r FUME OR DUST PRODUCED BT ARC WELDIKG (Continued) Material Being Yielded Electrode Used Size of Electrode Particles Per ou* ft. Charaoteriatloa of Dust Partiles. (Sizes and Per* 1 oentagea Estimated) 1 l/4" Boiler ~ P l a ^ Inside Booth. 7?5 Fleetweld Coated 5/32" 11,441,280 About 80# angular crystalline, 1 3 microns or less in size) 1 10 # round semi-opaque, 10 1 microns or more in size; ip# 1 opaque scale like, 10 ai- 1 crons or leas in size. Count- 1 less number of minute par- 1 t i d e s , reddish brown smudge. 1 1-1/4" laid Steel Expan sion Joint !naide Booth. #5.Fleetweld Coated 1/2" Rolled Steel (55,000# per sq. in. Tensile strength) 1In-; aide 6+Foot Dia, drum near head, of closed end. #5 Fleetweld Coated Welding Flange Hurex on 4 n Steel Coated Line-Pipe, In aide Booth. . 5/8" Boiler Plate Inside Booth. #5 Fleetweld Coated 3/16" 3/L6" 19,861,793 2,265,600 About 95# angular crystal- 1 line, 3 microns or less in I slzej 5 # rounded semi-opaque, .1 10 microns or less. Count- { less number of partiles 1 reddish brown smudge. 1 All partiles 6.miorona or 1 less in size) about 10# . I angular_ semi-opaque. I 3/32" 5/32", 2,756,480 490,880 * * 1 All particles' 2 miorons or 1 lesa in size*-slightly 1 angular, glass-like) dark 1 grey smudge. . 1 About 75# round, metallic 1 opaque, 6 .miorons in size) 1 25#- semi-opaque, crystal- I line. Countless number of 1 minute partiles . 1 Welding Riv ets in Courtney Edge Inside Crack ing Coil Soaking Drum. #5 Fleetweld Coated 5/32" 6,456,960 About 90# sharply angular 1 crystalline, about 1 micron I or less in size) 10 # 1 rounded semi-opaque, 5 mi- 1 orons or more. Countless | number of minute particles. 1 0 - 216 18-0000041 JAM 014708 00146 FOIE OR DUST PRODUCED BY AJ WELDING (Continued) Material Being Welded > * * Electrode Size of Used Electrode Partiles Per cu. ft* Characteristics of Dust Partiles* (Sizes and Per centages Estimated) 18-8 Stainless 'Steefc Band at Top of Soaking Drum flanhead Stainweld A Coated 5/32" 849,600 About 60# slightly angular semi-opaque, 5 microns or less in size; 20# rounded, crrer 10 miorona; 20# very glass-like, 10 mi- ^ crons or less* ... * 1/2" Boiler Plate to 6" Pipe Inside * Booth. ` 1/2" Boiler Plate to 6" Pipe Inside Booth. G-E W2 0 Coated Roebling' Iron Rod 3/L6" 5/32" 23,222,400 About 80# semi-opaque, red dish brown rounded, crystal line, 5 microns or less; 20# round globules of metal 5 microns or more in size* Countless number of 11 partiles. 26,592,480 ' About 90# black opaque, 1 micron or less in size; 5# rounded metallio globular, S microns or less; 5# slight ly angular, semi-opaque, orystalline, 3 microns or less. Countless number red dish brown partile?** Back Welding' a Flange on 6" Standard ' Pipe in Out side Welding Shop* Jleetweld #T Coated 5/32" 362,496 About 95# black opaque metallio, 2 miorcns or less; 5# angular'crystalline , 5 miorons or less* Count less number df reddish brown particles* JJjok Welding a Flange on 6" Standard Pipe Inside Booth* Jleetweld ft Coated 6/32." 1,000,640 About 95# blaok opaque metallio, 2 microns or less; 5 # angular orysta lline, 5 microns or less. Countless nuiber o f . ` blaok partiles* Welding Rir eta Inside Cracking Coil Vapor izer (Mild Steel Alumi num Coated). Jleetweld ft '* Coated 5/32* 6,253,056 About 95# angular crystal line, 5 microns or less, mostly around 2 mlcrons;5# semi-opaque, round, 5 mi crons* Countless number of black partiles* ' 18-0000042 217 JAM 014709 ff01461 FUME OR DUST PRODUCED BY ARC WELDING (Continued) Material Being Welded % Eleotrode Size of Used Eleotrode Particles Per evu ft. Charaqteristios of Dust Particles. (Sizes and Per centages Estimated) Welding 2" Ring on 1" Mild ~ Steel Boiler Plate * ** Inside Booth. Fleetweld ft Coated .Mild Steel * Sorap Plates Inside Booth. Xa2S Steel `Inside Booth. Stainweld A Coated Stainweld A Coated 3/16" 5/32" 27.662.976 2,605,440 All partiles less than 2 microns. 70# rpuhd, opaque) 30# slightly angular, crystal line. Countless number of black particles, reddish brown smudge. All partiles blaok opaque, 2 miorona or less in size. 5/32" 12-,460,800 About 8Q# angular opaque, -2 miorons or less) 20# slight ly angular orystalllne, 5 microns or less. Countless number black partiles, -brownish grey smudge.__ The U.S.Navy recently conducted some extensive tests with coated electrodes, and found that the quantity.of dust or fumes developed while welding on galvanised steel plate was greater than vfcen hare steel plates were used and the dust remain ed in suspension for far longer periods of time. It was' also found that the average size of the dust particles was 0.27 microns and that there were 130.000 par't i d e s under four microns diameter per oubio oentimeter. Quoting the Navy reports - "It Is apparent that considerable quantities of dust are found in any aro welding operation. The dust formed when operating on plain mild steel* or oorrosion resisting steel is largely derived from the flux coating on the eleotrodes, as is shown b y the composition of these dusts". What Physiological Effect on Welders is Produoed by The Use of Coated Electrodes. According to a study made by Doctors A.T. Doig and A.P.G. McLaughlin on ljggs of Eleotrio Arc Welders (Lancet - V.20j 771 - 775 (April 4, 1936)), defi nite pulmonary lesions' which gave rise to striking X-ray changes in the appearance of the lungs were found in welders whioh had breathed the dust or fume from ooated eleotrodes. Quoting Doctors Doig and HoLaughllnt - ' "The electrodes or welding rods whioh o ontain a core of metal aui outer covering are consumed gradually b y the heat generated (about 1500C. ) during the welding operation. The metal la the oore of the rod becomes molten and. assisted b y the flux contained in the covering, spreads over the surface of the metal which is being welded. The fume is therefore made up of the volatilized constituents of the coverings of the rods together with fine particles of oxidized metal, usually in the fora of iron oxides. In addition the fumes probably contain gases auoh as nitrogen peroxide and ozone whioh are formed by the action of an electric spark on the air. The composition of the ooverings of the electrodes' or welding rods becomes. ..in ' the oircumstanoes. a matter of seme importance.. Many substances, all of ' _ whioh we do not propose to enumerate, are used. The basis of the majority . of the coverings is- sodium silicate whioh acta as a flux. Again, the /2-.-jelro*' 00142 18 -000004: JAM 014710 -36- coverings of a certain type of electrode contain asbestos. The rods are emetines dipped in a mixture containing powdered asbestos and sodium sili cate, or asbestos yarn is'wound round the rod and fixed b y sodium silioate. In some cases the asbestos completely oarers the rods, and in others it is merely a cord whieh is wound spirally about the rod "The composition of the fumes arising from electric welding eleotrodes has hot yet^been fully investigated. Mr. L.C. McNair, H.M. Engineering In- spec^pr of Factories, has however had partial analysis made of the fumes evolved from an asbestos-covered electrode and some asbestos fibres were found. When the particulate matter of the fumes was oollected in an Owen1 s dust-oounter, it was seen that a large proportion consisted of iron oxide particles, with an occasional asbestos fibre. "The X-ray appearances in the well-marked cases differ from the usual picture of asbestosis. In none of the positive cases and in only one of the suspicious cases was there any blurring of the diaphragmatlo shadow, . and In no ease was the heart outlined blurred. The line of the interlo bar septum (a feature present in a number of films of eases of asbestosis) is seen in only one positive case. The opacities in the films are not ac centuated at the bases of the lungs, but on the contrary the upper lung fields appear to.be the earliest, and in. established cases, most markedly affected. Before asbestosis can be eliminated from the differential ' diagnosis it. must be remembered that the asbestos fibres are being subjected -to intense heat and are not in the same physioal state as the fibres whioh are inhaled by workers in an asbestos faotory. It is possible that a typical picture of asbestosis might be produced by the inhalation of alt err ed asbestos. Merewether. says that - 'the radiographic appearances of the developed or advanced states of asbestosis are distinctive, although they are not specific.. While, as is the case with silioosis, certain radio graphic appearances may be looked upon as typical of the disease, frequent l y modifications of and departure from the typioal picture ooour*. The X-ray appearances in our cases most closely resemble those of a fine sill- oosls, but the elinioal features show two important differences. In the first plaoe, the electrie welders whom we examined are all in good health and are fit to Work. The only .symptoms observed pere slight oougfr and morning expeotoration, and in the first case a small haemoptysis ooourred. This man has not been away from work even for- a day sinoe he was first seen In June, 1933, and-his health at the present time is good None of tilt men suffers from dyspnaea. Secondly none of them has concomitant pulmonary tuberculosis* ' "Miliary tuberculosis can be ruled out of the differential diagno sis for clinical reasons, and to sane extent on the radlologleal appear- anees. None of the cases shows the dyspnaea, cyanosis, and tachyoardia of aoute or subacute miliary tuberculosis Chronlo or healed miliary ` tuberculosis is rare and.it is diffloult to Imagine that a condition of such rarity would be found in 6 out of one group of 16 men. In the X-ray films of the welders' chests the fine opacities are irregular in sise and shape, whereas in miliary tuberculosis of the lung the shadows are more uniform, . "A further possible explanation of the X-ray appearanc.es in this * series of eases is that the inhalation of small quantities of nitrous , fumes together with the.svperadded effect of fine iron oxid dust m i g h t set up small ar eas of ehrenle Inflammatory change, congestion, or fi brosis in the lungs. Again, the iron oxide partiles might be opaque to the X-rays and produoe the picture without the associated presence 210 00146.1 18-0000044 JAM 014711 of fibrosis and congestion." * ' * Z, OXY-ACETYIIHE t&LDTIJOt Ckcy-acetylene yielding ia more or leas oonfined to Sm . n yepnir jobs or to oertain emergency operations where aro welding ia not available or practical Exposure of men doing welding ia more or leas irregu lar. They usually wear American Optical Company or Willson Welding Goggles with #4 Noriweld lena. The amount of dust produced by oxy-aoetylene welding is considerabty less than that caused by the use of coated electrodes in aro welding, and varies considerably with the style tip and welding rod being used as^well ab the material welded, as is shown by the following table . Hat-trial Being Welded DUST PRODUCED BY QXY-ACETYLENE WELDING Welding Rod Tip Used Particles Per Cu. ' Ft. . i Characteristics of Dust ' Partioles (Sizes and Per centages Estimated) - Galvanized lietal Hood Welding Shop. Norway 5/32" Airoo #4 396,480 1/4" sc 2" Bar Iren, Welding Shop. Oxweld cop^ perised steel 3/L6" Aireo #0 509,760 l/Z" Boiler Plate, Soft Steel, Weld ing Shop. Oxweld oop- perized steel 1 / 8" Oxweld #6 1,019,620 1/8" Galvan ized Sheet , Ir<flf, Weld- . ing Shop. Oxweld oop- perized steel, 1 / 8" Oxweld #6 - 1 ,359^60 About 70# slightly angular, semi-opaque, greyish, 6 mi crons or less; 20# rounded semi-opaque, greyish crys talline, lOminrcns or more j 10 # amorphous, soale-liko) 10 microns or more in size. About 80# blaok opaque, 1 micron or less in size) about 2C# rounded, crystalline) 6 microns or less in size. About 80#round, semi-opaque, 5 microns or less in size) 10# angular crystalline Countless number of small blaok partioles. * About 80# rounded, semi opaque, dark grey,l micron or less in size) 10# slightly angular crystalline, 3 mi crons or less) lp# sharply angular crystalline, 5 mi crons or less) eountless ' number of small dark grey partioles. ' Welding Teeth on Band Saw. % Simmons Saw Welding Rod. 3/64" Aero plane #2 - * 1,472,640 About 98# round blaok opaque, about 1 micron or less in size) 2# slightly angular, crystalline, `3 microns or less in size. B - BURNING OR CUTTIUG OPERATIONS . . , 1. WITH QXY-ACETYLEHEt The ooy-aoetylene torch is used both in the qonatruotian 18-0000045 001464 9 on JAM 014712 -38- nH the demolition of process equlpnent and works structures. It also plays an important part in emergency and resoue work. Goggles with shade #5 Kcrriweld lens ere provided and their use is required. At the larger plants men with an average service credit of six years spend about three-fourths of their working time on outtlng or burning operations (about half their time is given to "burning steel" for new construction). The amount of dust, pro duced is usually greater than that caused b y oxy-aootylene welding. b " DUST PRODUCED BY OXY-ACETYLEKE BURNING ----------------------------------------------------- ~ Material Being Burned Tip Used Particles per cu. ft. Characteristics of Dust Partioles (Sizes and Percentages Estimated) Burning 6" Flues (1-1/2" thiok) Out of . Shell Still. Oxweld #2 1,869,120 About 75# round blaok, 2 microns or less in size; 20# slightly angular, crystalline, 2 microns or.lessj 5# opaque, scale-like, various sizes* l/2" Boiler Plate (soft steel) Oxweld #4 2,718,720 About 90# semi-opaque, black, 2 microns or less 10 # round, dark grey, over 5*microns in size* * ~ " 2* WITH NATURAL GAS A large part of the burning or cutting at one of the larger southern refineries is done with oxygen and natural gas (60 pounds per square inch pressure). .A special torch with a l/l6" x 5?,16" tip made in the refinery shops is used. Two men'with an average servioe of thirteen > years spend a major portion of their working time on this natural gas. They wear goggles with $5 shade Kcviweld lens. Samples taken while burning holes in 3" standard pipe in the yard outside of welding shop with oxygen id natu ral. gas had a concentration of 471,811 partiles, ten microns or less in size,, per cubio foot. About 75# of these partiles were slightly angular crystal line in appearanoe under the Xonimeter mlorosoope, and were five microns or less in slzej 25% were rough scale-like, opaque, ten microns or lesa in size. There were also mazy minute particles* .- HEALTH HAZARDS PRODUCED B Y WELDING AMD BURNING OPERATIONS Although our study was confined to the fumes or dust produo ed by Welding aid Cutting operatiosi^he possibility of lead poisoning from welding or outtlng iron plates that have been previously coated with red lead should be pointed out* Lead poisoning from this source is rather common, especially in outtlng uphold so rap, bridges, tanks, and other iron structures that have through mazy years ' of use reoelved protective ooatings of red lead* The action of the flame . volatilizes this lead material and creates a smoke that is poisonous* The same hazard exists in outtlng out rivets In new structures* 'It should also be pointed out that seme of the welding rods oentain manganese which is very poisonous when taken into the body. There is an ap parent hazard from volatilizing this material, or rather changing it to tho oxide of manganese, and breathing the fumes produo ed* There are further dangers from carbon monoxide and oxygen deficiency owing to the "use of gas-cutting or welding flames inside small tanks or similar confined spaoes* ; It is beoamlng more, and more reoognlzed that persons engaged in outtlng j m d welding operations, either-by are or flame, should have respiratory proteo- . ti.on, in all work where there is a possibility of the workmen breathing fumes and dusts created. . ' . - 221 JAM 014713 001465 18-0000046 **o-- ' , I VI - GRINDING OPERATIONS Power grinders are perhaps the most universally used of the snail power* driven tools The usual power grinder, commonly known as the emery wheel, ocnsists of a oast metal stand and two abrasive wheels mounted on a through shaft wfaioh is either belt or motor driven. There are also several grinding wheels, suoh as are found on machine tool equipment where grinding takes the plaoe of lathe and planer work, AJ1 grinding operations produce dust to a greater or lesser degree, depending on the composition and construction of the wheel, the material being ground and the ventilation or exhaust hoods provided* ; ! . What is the Composition of Grinding Wheels? Grinding wheels are made of . either bauxite which is mined, or silicon carbide which is made by heating-a m i x ture of quartz sand, coke and cannon salt in an eleotrlo furnaoe. She bauxite or silioon carbide are orushed to the desired grain size, mixed with an adhesive sub~ stance called a bond, and formed into wheels, disos, cones or cylinders There are many wheels In whieh'the binder is shellao, rubber, bakelite and other organio oao .pounds. Bauxite wheels are known in the ehop as "Alundum" and "JLloxlte", while silioon earbido wheels are known as "Crystolon" and "Carborundum" Alundumwheels should be used on material of low tensile strengths suoh as oast iron brass, alumimum, oopper and marble i5 Abresive Dust Harmful? According to Dr. W, Irving Clark In a paper read at a meeting of Government Officials in Industry (Boston - Hay 21,1931) the artifical abrasives, aluminum oxide and silicon carbide do not contain free silioa and their dust cannot, produce silicosis The dust, like any other inorg&nio dust, oan, however, if breathed for a long period of time in large quantities, produce an I t ray picture similar to that of early silicosis, This pioture ohanges very slightly as years of exposure increase, and at no time are the nodules, eharaoteristio of sill* oosls, evident Dalike silloosis, there is no progress in the prooess after expo - cure oeases and there appears to be no marked physioal disability. Although there is no silioosis, the X-rays do show signs of pneumooordosis ,, Carborundum dust, chemically, is silioon oarblde. According to Hiller and . Sayers (U. S. Pub. Health Hep, Yol. 49 #3 of Jan 19, 1934) oarborundum dust when la Jeoted into the peritoneal oavlty of guinea pigs produced no reaction and was termed "Inert" Dusts such as quarts and flint - silicosis produoing dusts - produoed & proliferative reaotion. _ - - __ _______ Leroy U. Gardner (D.S. Pub. Health Rep. Yol. 50 #21 of Hay 24, 1935) reports that carborundum produces praotioally no reaction when Inhaled b y guinea pigs in. high concentrations over a period of time Quoting from Dr Gardnera article, the. part pertaining to oarborundum dusti "The dust which does reach the tracheobronchial lymph nodes apparent ly laoks the proper physiochemioal properties to stimulate any but a very slight proliferation of connective tissue. In the lungs, there* is prao- tieally no fibrosis." . * The Journal of the American Hedioal Association (Notes and Queries 103, 1472, 1934) makes this statement regarding the health hazard of breathing dus$ from artl flclal abrasives* _ . _ "Only silica (Si.02) is capable of inducing ailiooaisj but any other mineral dust under conditions of prolonged ad gross exposure stay cause . . some increase in pulmonary fibrosis --If the relative potential h a m of silica is rated as 100, these'other non-toxio mineral dusts may be rated - * . ' ' 18-0000047 222 001466 * JAM 014714 40- - only on the order of 5 or 10." ' * v Despite this comparatively low rating of harmfulneaa of these dusts it la w generally considered advisable to use dust hoods and exhausts wherever practical as there is cllnloal evidence that workers exposed to heavy conoentrations of dust of any kind are more liable to develop diseases affecting the nose, throat and chest during the winter months than those not exposed to dust. Dr. Clark believes that an effort should b'e made to keep the dust count below twenty million particles of less than ten microns per cubic foot of air. .. k ** . .. . 1* What are the More Frequently Used Types of Grinders, the Quantity and Character of the Dust They Produce? The grinders most, commonly found in the refineries and as sociated aotivities are* A - TANDEM FLOOR TOCL GRINDERS* Tandem floor tool grinders, the most' fre quently used type, are in most cases motor-driven and operate, at. a speed of from . 1450 to 1850 RITL The type of yrheel or grinding media selected depends upon the ma terial, to be ground. Generally speaking, the wheels found in most of the machine . shops and wood working shops around our refineries used* l-l/2w x 10" Norton Aluadum (Grade P, Grit 46) wheels for sharpening .tools and for general service grinding. l-l/2" to 3" x 14" Carborundum wheels for miscellaneous grinding. 3" x 16" Carborundum (Grit 30, Grade I) wheels for grind ing lathe and other machine tools. , Sometimes-two different wheels are used on tandem tool grinders; for example, a 2" X 14" grain 24, grade Q Norton Aluadum vitrified wheel on one side and a 2" x 14" grain 44, grade 11 Alundun wheel on the other side. * - The amount of dust produced by the operation of tandem tool grinders depends primarily upon the composition of the wheel and the hardness and charaoter of the objeot being ground. Theoretically, the operating speed and the pressure should also be determining factors, but these were not studied. The following are average `"`dust counts of particles ten mlorons or less per cubic foot in. samples taken in the breathing zone of the person using the grinder during the grinding of various ob Jects jjg various wheels of tandem floor grinders* Operation Particles per oubie foot Grinding Cast Iron on 2" x 12" Aloxlte (46M Grit) Wheel......... " a Steel Sleeve on a l/2" x 10" Carborundum Wheel....... " " Bard Steel Chisel on a 5/ 8* x 8-1/2" Alundum Wheel... " " ' * " 1 / 2* x 10" Carborundum Wheel.. n n n n 3^11 x n " " Pneumatio Tool Steel Chis el on & 3-1fz" x 14" Norton Alumdum (3836 - 0.5B) Wheel...................... . " " Chisel Ear on thesame wheel(3836 - 0.5BAluadm). " " Tool Steel Chisel on a 1" x 10"Carborundum (Grain 46M) Wheel............................. '.............. " Tmool Staeel 1on na 2" x 14" Alundum ((4244 gr"ainy grade MQ)) WKbel " a Lathe Tool on a l/2" x 12" " (Grade P) Wheel....... `n n i l M an n - w fH n A/ n 11,648,960 8,127,840 7.476,480 1,670,880 906,240 1,869,120 4,134,720 2,594,112 396,480 1,019.520 339,840 1,331,040 223 0014F 10-0000048 JAM 014715 Operation (Continued) Partile per oubio foot Grinding a Lathe Tool on a 3" x 16" Carborundum (grit 30,grade K) Wheel........ " Mild Steel on a l-l/2" x 10" Alundum Wheel......... Steel Dies on a 3" x 14" Carborundum Wheel.............. Squaring Shear Bladee on a 1-1/2" x 16" Carborundum Wheel. 562.496 6,655,200 56,640 2,577,120 b *' Dust Produced By Operation of Tandem Floor Grinders. As would be expeoted, there is a wide variation in the appearance of the dust partioles under the Koni meter microscope. These examples however, will give an idea of the charaoterlstlos of the dust produced during the operation of Tandem Floor Grinders* Material Being . .Ground Size of Wheel Type of Wheel Characteristics of Dust Partiles. (Sizes and Percentages Estimated) " X 3" M i l d Steel Bar 1-1/2" x 10" Alundum (Grit 46, Grade P) About 70# angular crystalline, 6 miorons or less in size) 30# metallio shreds') 10# white opaque, slightly angular, over IQ microns} many small blaolc specks* . Tool Steel 2" x 14" Alundum vit rified (Grit 44,Grade M) About 90# angular orystalline, 2 microns or lesi in size) IQ# opaque, 1 micron or less in size.. . Tool Steel (Same m a terial as above) Lathe Tool 2" x 14" ' Alundum vit rified (Grit 24, Grade Q) 3" x 16" Carborundum (Grit 30 Grade K) About 60# round, semi-opaque, 10 microns or less in size) 40# angular opaque, 6 miorons or less in size. __ About 75# round, ozystalline, 5 miorons in size) 25# slightly angular. Chisel Bar 2-1/2x14" Alundum (3836-.5B) About 70# slightly angular, 3 miorons in size) 30# blade, .. opaque, metallic. - Fheuoatio Hand Tool Steel Chisel . . . Lathe Tool 2-1/2" Id" Qundum (3636-0.5B) - 1-1/2"x 12" luiidum (Grade P) About 98# round, black', opaque, ' ' one micron or less in size. About 50# angular crystalline, 2 microns or less in size) 50# round, black, metallic, 1 mi- . oron or. less in size. Lathe Tool (Same as above) * 1-1/2" x 12" lundum [Crade R) About 75# angular orystalline, 2 miorons or less in size) 25# round, blaok, metallic, 1 ml- . oron or less in size. 224 0 0 1 4 6 8 " i8 - 0000049 JAM 014716 DUST PRODUCED BY TANDEM FLOOR GRINDERS (Concluded) Material Being Ground Cast Iron b < Size of Wheel Type of Wheel 2" x 12" Aloxite (Grit 46, Grade M) Char&oteristios of Dust Partioles. (Sizes and Percentages Estimated) About 85# sharply angular, crys talline, 5 microns or. lessj 10# rounded angular crystalline, over 10 microns} 5% opaque scalelike metallic, 10 microns or less} large number of black metallio spooks. Where "hard" wheels are used for grinding soft cast steel, about 9E# of the dust part i d e s are metallio and less than one-half micron in size. With the exception of a very small number of men who devote about 95#. of their working time to actual grinding, there is a very wide variation in the number of men exposed and the length of suoh exposure to dust produced b y the operation of tandem floor tool grinders. In only one case was-a respirator worn. Goggles have been provided and their use required in most cases. ' ' - " --- - ' B - TANDEM BENCH GRINDERS These grinders are small in site and are used for sharpening small tools and light grinding. They are all motor* driven and operate at about 3400 R.P.H. Different grade wheels are used, usually l-3L/8n x 8n Carborundum (Grain #80) on one side, and on the other a 1" x 8" Carborundum (Grain #90). tThe amount of dust produced by the operation of tandem bench grinders varies with the ma terial being ground and the composition of the vdieel, but these-average dust oounts are fairly representative* Operation Particles per ou. ft. Grinding Cold Chisel on 1-l/S" Grain #80 Carborundum Wheel.... 6,909,440 " " " 1" x 8" " #90 *. * .... 8,401,600 " l/2" Boiler Plate on 1* x*8"#90 * 'n 12,460,800 " Hard Steel Chisel on x8-l/2" Alundum (Grain 46,, Grade P).........................,-*v-~7,476,480 **Dust particles in samples taken during the operation of the tandem bench grinder have the following oharaoterlstiosi .. * Material Being Ground Size of Wheel Type of Wheel Characteristics of Dust Partiles. (Sizes and Percentages Estimated) Medium Steel Cold Chisel l-l/2"x8" 'Carborundvm (#80 Grain) About 75% slightly angular crys talline, 5 microns or less in size'} 20# round opaque, metallio, one mi oron or less) 5% semi opaque, over 10 microns and look like chips of glass. Medium Steel Cold Chisel TSame tool as Above) 1" x 8" Carborundum (#9P Grain) * 225 About 80# rouatkopaque, 2 miorons . or less in sizej 20# slightly angu lar orystalllne, 5 microns or less in size. . ' * 18-0000050 0014R9 JAM 014717 -43- D'U1S"T' PRODUCED Bi TANDEM BENCH GRINDERS . 9 f Conni i Material Being Ground Size of Wheel Type of Wheel Charaoteristios of Dust Partioles, (Sizes and Percentages Estimated) l/2" Soft ' 1" X B" Steel Boiler ** Plate iTaking" ^ off rough * * edges) Hard Steel Chisel 5/8" x 8-1 / 2" Carborundum (#90 Grain) Alundum (Grain 46, Grade P) About 90j round, black, metallio,. 2 microns or less in size} 10% slightly angular crystalline, 5 microns or less in size. About B5% round, black opaque, 2 microns or less in size; 15% . rounded crystalline, 10 microns or over. ' ' C - SINGLE FLOOR TOOL GRINDERS* There are only a few sinrle floor grinders in "use They tenge in eize from 1" x 10" motor-driven (1750 W W J to 2-2/Zn x 20" belt-driven (1250 RIM). The larger size is used for heavy grinding suoh as blanks and large tools} the smaller sizes for sharpening tools and miscellaneous grind ing. The wheel on the large grinder is Carb'orundum (#9C Grain) For the smaller size class Grain 46, Grade M Carborundum wheels are used on the 1" x 10" and Grain 24, Grade'Q Alundum wheels in the 1-1/2" x 14" size. .Samples taken during the opera tion of Single Floor Grinders had dust counts as follows* * ' . s -- _ Operation * Particles per c m ft. - Grinding Tool Steel on 1-1/2" x 14" Alundum Wheel (Grain 24, Grade Q),........ " Chisel on 1" x 10" Carborundum Wheel (Grain 46, Grade M)......... " l/2" x 4" Mild Steel Bar on 2-l/2 x 20" Carborundum Wheel (Grain 90), 679,680 2,594,112 4,451,904 " The hoods which almost ocmpletely enclose these wheels act as praotioal dust oolleo- tors. .. - .......... . . . Dust partiles produced b y the foregoing grinding had these charaoteristios when examined under the Konimeter mio rose ope* . Material Being Ground Size of Wheel Type of Wheel Charaoteristios of Dust Partioles (Sizes and Percentages Estimated) Hard Steel Tool Bit 1-1/2" x . Alundum *. 14" ` (Grain 24, Grade Q) A ll partiolee were 2 microns or less in size About 60j were aa- gular crystalline} 40% were rounded opaque . l/4" x 2" Mild 1* x 10" Steel Bar Carborundum (Grain 46, Grade H) About 98jwere black opaque, 2 mi- erons or less In size} 2% slightly angular,5 microns or less in size. - l/2"x4" Mild Steel Bar 2-l/2nx20" Carborundum `(Grain 90) About* B5%were slightly angular - crystalline, 5 miorone or leas in eizo} about 15%black semi-opaque, ~ angular metallio, 2 microns'- or less in size ' 18-000005 226 JAM 014718 001470 -44- ' D - nrr-THSAL GRIIIDERS* Aa the name would indioate, universal grinder are . used for a wide variety of purposes and therefore are in more continuous opera i tion than are the other grinders, with the exception of the tandem floor tool grind ers* There ore two types or makes, the Brown & Sharpe Universal Grinder which has an operating speed of 3750 RIM. and the Grand Rapids Universal Grinder which operates at about 3850 RIM. The following abrasive wheels are usedt l/p.^x 5" Horton Co. 3846 J 5B Alundum wheel for grinding ^ hardened carbon tool steel. 1/2" x 7" Horton Co. 3846 I 8B Alundum wheel for grinding high speed tool steel. 2" x 3-1/2" Carborundum Co. grit 401-P-25, type 12 Aloxite wheel for grinding case hardened steel. . l/4" x 10" Carborundum Co. wheel used for cutting. 1" x 10" " " " " . tools, reamers, dies and drill bits. " sharpening . Samples taken during the operation of the various Universal grinders had dust counts as follows* " ' ' Operation Partiles per cpu ft. Dressing l/2" x 7" Alundum (3846 I 8B) Wheel with a . "Diamond'Point".......... ............... .................. 1,397,120 (Evidently the clouds of dust which came off during - dressing have particled larger than 30 microns) Grinding High Speed Tool Steel on 1/2" x 7" Alundum Wheel * (3846 I 8B)...... ..................... . 1,846,464 " Hardened Carbon Tool Steel on l/2" x 5" Alundum Wheel - .(3846 J 5B)......... .................... 6,683,620 " Case Hardened Steel on 2" x 3-l/2" Aloxite (Grit 401 - P - 25 Type 2)......... . 84,960 Cutting off Tool Steel with l/4" x 10" Carborundum Wheel.... 1,416,000 Dust particles in samples taken during the operation of Universal grinders have trifee characteristics* . . Material Being ' Ground : Sise of .Wheel Type of Wheel Dressing Wheel With a ^ "Diamond Point" l/2" x 7" Alundum (3846 I 8B) High Speed Tool Steel (a Landis Pipe Chaser) . 3/2" x 7" Alundum (3846 I 8B) Characteristics of Dost Particles (Sizes and Percentages Estimated) About 80# slightly angular crys talline. About 3 microns in size* 20# black opaque, round, about 1 micron or less in size. About 60# opaque angular, about 2 microns or less In sizes 40# slightly angular, crystalline, 5 microns or over Incite. \ . 227 18-0000052 OT1471 JAM 014719 . ' / Duat pertioles in samples taken during the operation of Universal grinders ` have these characteristics (Continued)* * Material Being ' Ground Size of Wheel Type of Wheel Characteristics of Dust Partiles. (Sizes and percentages Estimated) . Hardened .Car-,bousted Steel (Pipe Grip foVPipe Machine) 1/2"x 5" Alundum (3846 J 5B) About 30# angular crystalline, ' about 2 microns or less in sizes 70# round black opaque, less than 1 mioron in size. Numerous black speoks too small to count. Several large oblong black opaque par ticles about 20 microns wide and ' 35 or 40 microns long. ' Case Hardened 2" x 5-1/2" Aloxite Steel (Plung-_ (Grit 401-P- ' ers for Fill 25 Type 12) ing Naohine) All particles blaok opaque, 1 mlcron or less in size. E - SURFACE GRIHDERS* Surface grinders are used almost exclusively on valves and dies. They are equipped with either l/2" x 8" Norton Alundum (1-946H*) wheels or l/2" x 4" to 6" Carborundum (Aloxite) wheels* No dust collectors are provided* the dust being thrown out into the atmosphere. Samples taken during the operation of surface grinders had the following dust concentration (10 microns or less)* Operation , Part-1oles per cu. ft. * Grinding Soft Cast Steel Valve on l/2" x 6" Carborundum . Aloxite Wheel................ . " ' Tool Steel Die on l/2" x 8n Alundum (1946H) Wheel...... ........ ...**................ Dressing Surfaoe of l/2" x 8" Alizadum Wheel with a "Diamond Point".................................. 666,400. 1,019,520 1,132,800 About 70# of the pertioles from grinding the steel die were metallic, 3 mi crons or less, whereas 98# of the particles from grinding the soft steel valve were metallo. Many of the particles were too small to identify or count aoeurately. F - LANDIS TOOL GRINDERS* Landis tool grinders are-usually equipped with two different types of,wheels-, one for side grinding and the other the ordinary type. 1-1/2" x 12" Carborundum Aloxite (Grit 40, Grade H, Bond 33) is used for general . purpose grinding such as bull ohlsels, diamond points, oold chisels, flanges and scrappers. The Side Grinding Type is usually k 2-1/2" x 1-1/fe" x 12" Grit 46A-P P678 Aloxite brand A A wheel used for grinding Landis dies. At one plant the wheels . of the Landis tool grinder are enclosed by hoods at the rear of each of whioh is attached a two-inch pipe connected to a three-inch pipe which discharges into a sewer. Suction is induced by a stream of compressed air Crea a half-inch pipe in serted in the two-inch pipe just back of the hand. This arrangement &ots as a sy phon and pulls the dust away from the person using the grinder. Samples taken dur ing the operation of Landis tool grinders had dust concentrations as follows* 29Z 18-0000053 _ ` 01472 JAM 014720 -46- Operation ' * Particles per otu ft. Dressing l-l/2" x 12" Aloxite Wheel (Grit 40,Grade H, Bond 33).,............. 226,560 (Evidently particles in the cloud of dust thrown off by the 2-1/2" x 6" Metcalf Bnery Wheel Dresser are larger than 30 microns in site) Grinding "Diaaond Point" Chisel on l-l/2" x 12" Aloxite Wheel (Grit 40, Grade H)....... ................................. 2,067,360 Grinding 2-1/2" x 6" Landis die on 2-l/2" x l-l/2" x 12" Aloxite Wheel (Grit 46JUP P678)............................ 755,203 Under the Konlmeter microscope dust particles in samples taken while dressing the 1-1/2" x 12" Aloxite Wheel appeared slightly angular with a yellowish tinge and were fire microns or less in .size. About 75# of the particles from grinding the Landis die were round, opaque, and less than 1 aileron .in aizej 25# were alightly angular crystalline, less than 2 ailerons. Partiles from grinding the diamond point ohisel were less qurtz-like than those from grinding the die. This difference is, of course, due to difference in the composition of the two wheels. On an average, Landis tool grinders are used about twenty hours a week, usually by different men. G - YANKEE DRILL GRINDER* Deed for grinding all-types -of drill bits, 2a* a side grinding type 1" x l-l/2" x 9" Carborundum Aloxite (Grit 30, Grade H, Band 28) Wheel. Operating speed 1735 RBI. On an average a Yankee Drill Grinder runs about three hours a day and is used by four different men with an average servloe of twelve years, : .. - } Samples taken during the grinding of a 2-5/16" high speed drill had an ave- / rage of 1,000,829 particles, ten microns or lesa, per cubic foot; About 70# of these dust partiles are slightly crystalline in appearanoe, five miorans or loss'll* size} 30# were rounded, semi-opaque,, over ten microns in size. There were also a few small metalllo shreds. No exhaust or dust collector is used in this grinding* . H -- AUTOMATIC CIRCULAR SAW SHARPENING MACHINE* There are a number of- these grinders in use in the wood working operations - such as in the production of wooden barrels, boxes and orates - closely assooiated with-the refining of petroleum pro- duots. Since they are automatic when cooe put in operation, there is very little dust hazard except where no exhaust or dust collectors have been installed and'"the dust p &duoed is thrown into the filing room atmosphere. Automatic Clroular Saw Sharpening Machines are equipped with l/4" x 8" Norton Alucndum Wheels (Grain 60, Grade N), 3/8" x 8" Norton Alundum (1946 M) wheels, or l/2" x 6" Carborpidum wheels*. The average dust produoed during operation of these machines is* ` - Wheel Particles per cu. ft. l/2" x 6" Carborundum...................................... . 1/4" x 12" " ....................................... 3/8" x 8" Alundum (1946M).'................................. 1/4" x 8" " (Grain 60, Grade H)............ . 1,923,280 3,568,320 2,095,680 1,461,312 -About 98# of dust particles in samples taken while sharpening oireular saws on the Carborundum wheels were black metalllo in appearanoe, and one mioron or less in size. About 76# of the particles from the Alundum wheels were rounded crystal-- - line, 5 miorans or under in size, and 25# round black metallic, about one mloron or y less in size,- There were a number of small metallic shreds in the samples from the - - thicker (3/8" x 8") wheel, * . I - AUTOMATIC BAND SAW GRINDERi o on After the Band Saw has been inserted and the JAM 014721 . 00147. J 16-00000E -47- machlne adjusted, this grinder works automatioally. The wheel ordinarily used is a l/2n x B*1 Grain 50, Grade IT Norton Company Alundum. The wheel ie refaoed or dressed with a Metcalf finery Wheel Dresser about twioe a day. The average dust produced by this dressing operation is 2,284,480 partiles less than ten miorons per cubio foot* About 95# of these dust partiles are sharply angular crystalline in appearance under the Xonimeter microscope, and about five miorons or less in sise. The dust produced during the sharpening or grinding of the band saw blade is on an average only 877,920 partiles per cubio foot. About 50# of these partiles appear angular crystalline and .about 50# round blaok opaque. All .of them are about two miorons or less in sise. J - AUTOMATIC BAND. SAW LAP GRINDERi -Used to grind ends of band saw prepara tory to welding them together. The grinding wheel usually used is 6/8n x 10" Grain 46, Grade M, Norton Company Alundum. No dust oolleotor is provided although a dust oount as high as 16,142,400 particles, ten microns or less, was found in one sample taken In front of the. wheel vdiile it was in operation. The average dust produced ' b y this lap grinder was 4,964,320 partiles per cubio foot. About 80# of these dust particles were semi-opaque, slightly angular in appearanoe, and two microns or less I n size} 20# were black opaque, about one micron pr less in sice. . ' X - PLANING KNIFE BLADE GRINDERt Uses a l/2" x 8" Grain 46, Grade N, Norton Company Alundum wheel. Operating speed 3000-RFM. No hood o p any other protection. Average dust produced while sharpening a Planer fioife Blade was 566,400 partiles, ten miorons or less per cubio foot. About 60# of these dust partiles were slight ly angular crystalline in appearanoe and about two microns or less in size) 40# were opaque of various sizes from about seven miorous or less. There were a few small metallic shreda^ . *' ' x ___ L - LINDERMA1T CUTTER GRINDERt Sharpens cutters from the Lindoraan maohine for tonguelng and grooving. Grinder uses a l/2n x 6" Norton Alundum (Grain 60,Grade N) oup wheel. Operating speed 3000 RFM. There is a hood guard over the top of the grinding wheel, but no exhaust or dust oolleotor, although dust counts as high as ~ 14,386,560 partiles, ten microns or less, were found at the fToht of the grinder i n ... operation, and 12,574,080 particles per oubio foot in the back. The average dust produced was 9,137,920 particles per cubio foot. About 70# of these dust partiles are round semi-opaque in appearanoe under the Konimeter mierosoope, and three ad-' - erens or less in s x ^ > 2 0 # a r e round, globular like partiles, seven miorons or less in size; and 10# are metallic shreds about two microns wide a n d - `twig- ' There $e many minute orystalline partiles too small and too numerous to oount ao- curately. . M - GANG SAW BLADE GRINDER* Uses a 5/8" x 10" Grain 50, Grade'll, Norton Company Alundrum wheel, operating at 1800 RPM. `A rather orude dust oolleotor V f been installed, but the average dust (8,760,320 particles per cubio foot) produced b y this grinder in operation isdioates that it is inadequate. About 90# of the dust particles in samples taken during the grinding of a Gang Saw Blade wore semi opaque in appearance and about two microns or less in size;. 10# were black round, opaque, one micron, or less In size. There were numerous minute black speoks too small to oount accurately. * * N -- EDGER SAW GRINDER* Uses a 3/8" x 8" Grain 60, Grade H, Norton Compeny Alundum wheel, operating at 1650 RFM. No hood or any other dust oolleotor for this grinder. The low dust count, an average of only 453,120 partiles, ten miorons ,or * less per cubio foot, indloates that there is very little real need for such equip, ment. The dust particles produced while grinding an Edger Saw Blade are crystalline, about two miorons or less in siso. . . 0 - CIRCULAR SLAB CUT-OFF SAW' GRINDER* Uses a 3/4" x 10" Grain N, Norton 230 JAM 014722 001474 18-0000C *4 8- ompany Alunduo wheel operating at 1650 RH1* A rather ineffective dust oolleetor has 'en installed, but the averageOiigh dust concentration (10,931,521 particles per ^Jbio foot) shows that it is inadequate. About 80# of the dust partioles in samples taken during the sharpening of a Circular Slab Cut-off Saw were opaque in appearance, two microns or less in sise) 20# were slightly angular crystalline, five microns or less in sise. There were also a large number of minute black opaque partioles. P - "BOG KNIFE" GRINDER Uses a 1-1/2" x 24" Carborundum wheel operating at 300 RIM. Thisfc grinder is completely enclosed b y a metal hood, bub the dust 8 dis charged onto the floor through an opening in the lower part of the hood. The average dust produced by the operation of this grinder is 1,869,120 partioles per cubie foot. About 75# of these dust particles were angular crystalline in appearanoe under the Xonimeter microscope and four microns or less in size) 25# were round, blaok opaque, two miorons or less in size, ' , Q - CUTTER GRINDER* Uses a 3-1/2" x Z-l/Z" x l/2" Norton Alundum wheel (3846 X B 5). The amount of dust produced depends upon the material being ground as is shown by the following ' * __ Grinding a steel counter sink........... 736,320 partioles per cu. ft, .. " ' " " reamer............. *...1,019,520 " " " " The dust particles are about 98# opaque metallio in appearance and about one mioron____ or less in size. . ` What Precautions Should Be Adopted For Safeguarding Those Who Use Grinding Wheels? Authorities generally agree (Jour.Indust.Hyg.Vol.VII No.8 August 1926 ' ip. 35l)" that workers who habitually use grinding wheels will ru n but slight risk of 'developing pneuaooosiosis if they use certified abrasive rather than eandstopewheels -for all grinding operations and if the machines upon which the artificial abraeive . wheels are mounted are properly hooded and exoessive dust removed by suotion. _ ' ' Control of Dust From Grinding. Polishing and Buffing Wheels. .Exhaust systems for grinding, polishing and buffing wheels vary widely in design. In the case of grinding-,*the-hoods used serve not only to provide means for capturing the dust but also aotto:protect the worker in ease the wheel bursts. The chief difficulty to be crerccme in grinding wheels, .according te-U* S.Publio Health Bulletin No. 217. "The Determination and Control of Industrial Dust" (1935), is the outward ft, fan aotiojJf due to the revolving wheel. This effect is very marked with high speed and rough wheels and is so strong that in many instances it is sufficient to counter act the normal Inward flow of air. The same effeot exists with polishing buffing wheels but to a less marked degree. - " Practically all Industrial States have codes regulating the construction . dust connections for grinding, polishing and buffing wheels. They also regulate the air required for wheels of various sizes in terns of static suction In the connect ing ducts ''These codes possess no uniformity. However, the requirements designat ed by State codee must be followed. In States where no codes have been adopted it is desirable to provide exhausts on all grinding wheels with a suction at the con nection to the hood sufficient to produce a difference of level of at-least two inches of water'between the two sides of a U-shaped tube. ' * A number of .the wheels have been'provided with suction exhaust produced b y a motor driven fan or a hood, with a two-inch pipe one end of whio is immersed i n `a bucket of water. The dust is drawn in b y the rapid revolution of the wheels (17S0 . BBM). This simple arrangement is particularly effective. Three samples taken near the discharge of a motor driven suction fan connected with the hood of 1-1/2" x 10" 001475 ia-ooooos6 231 JAM 014723 lundum (Grit 46. Grade P) wheel while a tool was being sharpened had an average of . 2,076,989 partiles per cubio.foot whioh would have' otherwise been thrown into the machine shop atmosphere. ` * As pointed out by Dr. W. Irving Clark in his paper "Dust Hatards and the Pre vention of Injury from the Same" read at a meeting of Government Offioials in Indus try at Boston, Haas, on May 21, 1931, the most effective method of removing fins particles of duqt is by suction applied as close as possible to the point where they are generated and the amount of this suction is great .enough to overeme the dis persing action upon the dust of the work being done.' : The velocity at the air duots of an efficient dust removing tube* should be 1500 linear feet per minute. Quoting Dr. Clarkt "No matter how well a workman is protected he should be kept under medical supervision and have a periodio examination of his heart 1 and lungs. In addition, the X-ray should be employed freely in order to detect early signs of fibrosis in the lungs and to show ary signs of early pulmonary tuberculosis. In my experience with workers exposed to inorganic dust, ncn-silioous in eharaoter, a yearly physical examination with an X-ray every second year after ten years exposure is sufficient but it must be remembered that this is the result of work in a factory where the eharaoter of the dust is relatively harmless and vhere excellent dust remov- - ing devices are installed on every machine where it is possible. Where free sllloa is present in large quantities the examinations should begin after two or three years exposure and an X-ray should ' be taken every year. Dr. Clark also states thiat men who are asthmatic, who suffer from ohronio ' bronchitis, or who have had pulmonary tuberculosis should not work at a dusty job. V JI - HANDLING POWDERED OR PULVERIZED MATERIAL A large amount of powdered or pulverised materials are used in the treatment of petroleum produots and boiler water and in the manuf&oture of greases insee . tioidesr " In most* oases approved respiratory protection is provided and its use re quired when handling the materials. Exposure to dust is usually intermittent and of short duration. Among the powdered**or~pulverised materials,xwed^inJshe refining of petrole\^products and associated activities are '.uTM. A - LIME lime is extensively used in the hydrated form and.to a muoh lesser de gree as lump quioklime. . . . * . - " ` ' 1 Hydrated limet Deed in the preparation of lime soap grease and the m a n u facture of pressure gun and oup grease; also in the treatment of boiler feed water to "soften it". It comes in fifty pound paper bags by railroad, usual ly about 1,000 bags to a ear. According to a ohemioal analysis of a typioal * sample, hydrated lime container . . Fe203Al203........... 0.30 per oest. CaO.......... ....... 73.64 " " HgO.............. . 0.93 * " Insoluble Silloa Residue..... 1.01 " * _ (Remainder mostly Moisture and Volatile Matter) . . Iom ISO to 350 pounds of lime are used per batch in the manufacture of greases. 2 32 00147K is-o000057 JAM 014724 Re ancles of lino aro usually opened end dumped into the mixing kettle. Con- \ siderable dust (as high as 34,890,240 particles losa than ten microns per ou- tic foot in one sample) is produced by this operation. The average dust pro- dueod is 4,733,305 partiles per oublo foot and the average exposure per batoh is about five minutes. The number of batches made per week varies from one to . twenty-five. Ho respirators are worn by men dumping hydrated lime at any of . the points.where it is used with the exception of Baton Kouge where the wear* ing of the HS^l>,Ccmfo" respirator is required. About 85# of the dust partiles in aamplest taken while dumping lime in mixing kettles are slightly angular, slightly opaqu, crystalline, in appearance under the Xonimeter microscope,and five microns or less in size; 15# are rounded, semi-opaque, with a metallio greyish color, ten microns, or over. There are also a countless number of very small particles. . Only a small quantity of hydrated Lime is used in the treatment of boiler . feedwater. About 70 pounds of lime is mixed per batch and about six batohes - are made every day (24 hours). The mixing is done by one man' on eaoh shift. Although the exposure is 'very short, the men at Ingleside Refinery wear Willson "Dust-tite" respirators while dumping lime. .The average dust produoed during this operation is only 657,024 particles, ten microns or less, per eublo foot. _ This low dust concentration is the result of a spray of water from a two lush pipe aoross the hatch of the mixing tank Just below the opening while saoks* are being dumped. Consequently, the material is wet almost as .soon as the lime is__ introduced. About 95# of the dust partiles in samples taken while the lime was being dumped into the mixing tank were semi-angular crystalline in appear- anee, and from five microns or less in size, and 5# were round opaque, two ml* orone or less in size. * ~ , ) 2. Lump Quickllmet Used to "soften" boiler ifeedwater. The lime used for this purpose is Oyster Shell-Lump Quicklime (97# GaO). It comes in fifty pound paper-lined burlap bags, and eight bags are usually used per batoh. One batoh is made per shift. The dumping and mixing requires* about ten minutes per batoh, and the man doing this work is protected b y rubber type goggles, but no respi* . rator. The average dust produced by handling the bags of lump Oyster Shell Qulokllme is 2,605,440 particles per oubie foot. The average duet produo ed while-dumping, tiie bags -of lump Oyster Shell Quicklime into the mixing tank is ^ ""294;628 particles, less than ten microns-, per cubio foot. The handling and dumping of this Oyster Shell Qulokllme produoes less-dust than Isproduood by the hydrated lime usually used. .About 95# of the dust partiles, in samples taken Bring the d uaping of Oyster Shell Quicklime into the mixing kettle ap> _. , pear slightly angular, crystalline under the Xonimeter miorosoope, and are five microns or loss in slzoj 2 # ere round, semi-opaque, over ten ailerons in_ size; and 3# are black opaque scale-like, five microns or loss in size, ~ Whet Physiloglcal Effect is Produo ed b y Lime Dust? According to the Inter national Labor Offioo (Occupation and Health, Yol. II, 1934) partiles of lime mix with the sweat of workmen handling it and irritate the unoovered pores of the skin; lesions of the muoous membranes are also set up. W are told that* "The action of quicklime is due partly to its avidity for water (dehydration), to the heat given off in its reaotion with water, - and partly to the peculiar causticity of the alkalipe oxides or alkaline earths. Qulokllme exerts essentially a local action (on the skin and muoous membranes) irritating and caustic, which - __ is naturally less marked in the ease of slaked lime. Ttllk of . lime is a feeble caustic acting only on the muoous membranes, . The dilute lyes are only caustic t o the skin after prolonged ac tion and especially when they are warm. * 233 00147V ooooo JAM 014725 ' ) J "In practice it is the dust of quiokllme and slaked lime, given. ' off in the course of- manufacture and manipulation, whioh gives rise to the well known lesions. This very fine dust is deposit- ed readily on the mucous membranes and skin.' When inhaled it . may penetrate as far as-the respiratory tract*" .Although lime has a tendency to irritate the mucous membranes of the respira tory tract, it. is not considered particularly hazardous when breathed in small quantities at intermittent intervals* However, complications may result when a large amovbt of*the dust is breathed more or less regularly* Therefore, it is desirable to wear an approved respirator suoh as the MSA "Camfo" or the Willson "Dust-tite1!. . . J2. - METALLIC ZINC constituent in Pipe used per batch, and . DUST* Metallic zinc dust (90# through 300 mesh) is an impo. cant Thread Coating Compound. About 1500 pounds of this material is about fifty batches are made per month. The zino dust oames in 400 pound wooden kegs or 500 pound steel drums. According to a ehemioal analysis, this zino dust is 99. 20#metallio zino and 0.80# zino oxide (ZhO). The partiole size distribution of a typical sample as determined b y a standard screen analysis 1st All through 120 mesh soreen .3*76# retained on 200 mesh - 2.04# " " 250 22.24# * " 325 The zinc dust is dumped from the keg or drum onto a metal sheet in ft-coat of the ket tle end shoveled into the kettle b y two or three men (with an average servioe of > about three months) from the General Labor Department.' This is a very dusty opora ) tion* One sample taken during the shoveling of zino dust had as high as 68,760,960 particles per cubic foot of air the average concentration being 28,351,328 par ticles, less than ten microns, per eubio foot* The workmen are exposed to this dust about thirty minutes per batch or approximately 2-l/2 hours per month. They wear dust respirators* About 95# of these dust particles are dark grey, opaque, awgniaw ' In appearanoe under the X ocimetcr mierosoope, end about five microns or less in sizej 5 # appear slightly angular, crystalline, t e n microns or less in size. The . crystalline material is -probably zinc oxide* . , _ What Physiological Effect~ls' Produo ed b v Zlno Dust? Although zino oxide (ZnO) produo indefinite physiological effects, metallic zino: dust does n the person b r e a k i n g it other than that eaus ed by the inhalation of any inert dust* Nevertheless some investigators are of the opinion that zino is not entirely inert; and harmless* Certainly it is not as harmful as lead or arsenio, but the- Dnited States Public Health Servioe has certain limitations on the amount of zinc that is ' permitted in drinking water. According to Nude, E. Hemy, and F* Foltzmann (Jour* * Indust. Hyg., Vol*12, 1930, page 171 Ab* ) Zino-dust can cause lung trouble after being inhaled in large quantities* Zinc dust is also very definitely explosive* * * Si - ASBESTOS "FLOAT" Float asbestos is used in the manufacture of tractor lubri cants. It comes in 150 pound cloth bags b y railroad, about 2000 bags to a oar* From 200 to 3000 pounds are used per batoh and from two to fifteen batches are made per month. The bags of asbestos float are dumped into the mixing kettle b y three men with an average service of twelve years. These laborers are exposed to dust about forty minutes per batch. Dust concentration as high as 8,269,440 partioles, ten microns or less in size, per cubic foot sure produo ed during the dumping of as bestos float, the average being 3,056,560 particles per oubio foot* About 98# of these particles are slightly angular, round, transparent in appearance under the * - Xorimeter.mierosoope. and two microns or less in sizej 2# are round, semi-opaque, * . 00 1478 18-0000059 JAM 014726 -52- ' plat like, five microns or error la siso, - ' . > - Recent investigations hare indicated that the inhalation of asbestos particles ten microns or less in size is cron more hazardous than was originally- belleved, and that in order to prerent harmful effeots concentrations should be kept below U t o million partiles (10 microns or less) per cubic foot. The physiologioal effects hare already been discussed under "A5BEST0SIS" so need not be giren any further con sidoration, liten handling asbestos float should be required to wear approved respi rators. ^ .. ' D - GROUND MICAt Ground mica (80 mesh) is used in the manufacture of axle grease. It comes in 100 pound burlap bags. About fifty pounds ,of ground mica is used per batch and an average of fire batches are made per month. The period of exposure will not exceed ten minutes a batch. Handling ground mica produces an average of 2,577,120 particles ten microns or less in size, per cubic foot. About 60J of these particles arc transparent irregularly shaped scale like in appearance under the Konlmeter microscope, and five microns or less in size) about 40J{ are over ten ml- crons in size. The transparent plates have small lines or fissures and appear to . oontain small air bubbles, - Although ground mica' has never been considered a hazardous dust, seme recent studies made among the workers in North Carolina Indicate that oantinued exposure to large quantities of ground mloa over a period of years will produoe a fibrosis. Hese- ever, there is very little probability of any trouble where ocnoeatrations are kept below 10,000,000 particles per cubio foot of air and where the exposure to jaioa dust is such a small percentage of the employee's working time, . 1! ** SULPHURt Sulphur flour is used for sulphurizing outting oils and in the, preparation of special lubricants for hypoid gears. Crude sulphur is used in the manufacture of sulphuric aold and in the treatment of gasoline and naphtha for re moral of impurities such as the mercaptans. - - Sulphur Jlourt Sulphur flour comes in paper-lined wooden barrels, 100-pound cloth bags, or 150-pound burlap bags. About 2500 pounds of this sulphur is ` * dumped into the melting kettle b y two m e n with an average servioe of twelve years,, ones a day,_*Their, exposure to the dust which results freos handling and dumping the bags, an "average of 1,540,60*8 partiles, ten microns or ;-U85s, per cubic foot, is aboufc fifteen minutes per m a n per shift on an ave rt-ge. No goggles or respirators-are worn. '''About 90# of the dustpartiolea....._ . in**ampies taken during the dumping of the sulphur flour were slightly angu lar crystalline in appearance trader the Konlmeter mi oroso ope, and five ml-' ' crons or less in slzej 10J were semi-opaque, rounded, and over five microns in size. The larger particles appear to contain small air bubbles^ There ' were also a number of very small spooks. About 370 pounds of flour sulphur is used per batch in the preparation of hypoid gear lubricant. Two batches are made per week an an average. The exposure t o the sulphur dust is only about two hours per week on an average. Sinee the sulphur is dumped into drums of oil being agitated by a rapidly revolving propeller type mixer more dust is produced than where the bags are simply dumped into a kettle. Samples taken during this opera tion had-as high as 6,-910,080 partiles, ten microns or less in size, per oublo foot. The average was 3,783,552 particles per cubio foot. The dust partiles had the same characteristics as those given in the preceding paragraph, . ~ Crude Sulphurt Crude sulphur comes in box oars holding about 90,000 pounds, * usually from Rreeport, Texas, Towers are filled with this sulphur by four ~ ' ' 235 001470 i 6 - o o o 0 6 < JAM 014727  -53- jaen with a average service of eight years. It requires about two hours to fill a tower with about 1(1,000 pounds of crude sulphur. Two towers are oharg- ) ed erery week. Consequently, the men are exposed-about four hours a week t o the sulphur dust caused by breaking up the lumps (4,304,640 partiles, t e n ad orons or less, per cubio foot) and shoveling the erude sulphur into the tower el orator (an.average of 3,357,640 particles per oubio foot). The amount of dust produced by this operation is somewhat reduced by the steam turned on in side the elevator shaft to prevent dust explosions. About 6C0J of the dust particles in samples taken while the tower was being filled were slightly angu lar orystalline in appearance-under the Konimeter nlorosoope and five microns or less in sirej 35# were rounded semi-opaque, ten microns or over In sire) and. :S% were opaque eoale like, between five and twelve microns in sise. Sulphur dust particles are explosive but otherwise are not oon*idere4 harardous any more than any of the other "nuisance" dusts, although they will irritate the auoous membranes and the eyes after alight exposure. Consequently, it is advis- . able to. wear rubber type goggles and approved respirators, such as the U S A Ccmfo type. In an artiole b y Aldo Cestarl (Aroh. Intern. Pbanaacodynamie, .1933, vol. 46, pp, 300-314) it is stated* "Intratracheal injection of sulfur suspensions brings about eso* ereti on of hydrogen sulfide in a period of 60 hours. There are - slight exudative and infiltrative reactions in the lungs. It is supposed that a substance similar to glutathione reduoes the sulfur to hydrogen sulfide." * , . . * i i T - LITHARGE* Litharge is added to the Flumbite. or "Lootor" Solution to assist in / the removal of mercaptans, other sulphur compounds and unsaturated hydrocarbons from gasoline and naphtha. From one to five 600-pound drums of litharge are used in a batoh, depending upon the stook to be treated and the oondltlon of the "Doctor So- lutlon". The litharge is removed from the drum a shovel at a time, and about fifteen minutes are required to dump one batoh. A batoh is made onto a week on an average. The average serrioe of the men involved in this operation is seven years. They wear MSA Ccmfo respirators with an ^approved lead filter and rubber type goggles. All of -- -- the work of adding litharge is done in the open air an a platform at the tops of the solution tanks. ' ' ... .-.................. ^ h e Average dust produoed during the. dumping or shoveling of litharge into the solution task is 3,077,480 partiles, ten mlorons or less in sire, per -oubio foot, although there were as high as 9,288,960 partiles per oubio foot jduring the -, operation. A rough estimation of this litharge concentration indio ates the presence of from five to fifteen milligrams of lead per ten oubio meters -- the amount that a n average person doing moderate work would b r e a r e in one day. This is in excess of 1.6 milligrams in tern oubio metere which is the maximum allowable limit set b y the Doited States Public Health Servioe. About SO# of these dust partiles were.rounded, transparent, orystalline In appearance under the Konimeter mloroaoope, and five miorons or less in slzej about 15# were over ten mlorons and appeared to ecntaln small air bubbles} 6 # were dark opaque scale-like, from U v e to ten microns In sise. . -Necessary Precautionary Measures When Handling Litharge. Litharge is a ocaa- pound of lead, and consequently there is the possibility of lead poisoning unless a # few simple precautions ar$ observed to prevent the entrance of lead into the body * * b y swallowing minute partiles cf the litharge dust, b y inhaling the dust, or b y ' absorption from the skin when handling the litharge. A n effort should be made to - ' oause as little dust-as possible. Instructions issued by the Medical Department re quire that* - " 236 0014 at) le-oooooi M M 014728 -54- "1 , No employee shall handle litharge until he has been examined and certified as j^ysioally qualified b y the Company Dootor. "2. Employees must be sent to the Company Dootor for physical ex animation at least every six months or at the first sign of ill health. . "3. Bespibators - An approved type of lead dust respirator, proper t y adjusted, shall be worn when handling litharge. All respi rators shall be thoroughly olearned with soap and warm water* "4. Clothing - Unionalls, caps or some head covering and gauntlet gloves shall be worn when handling' lithargo. Upon the comple tion of this operation the outer olothing must be removed and placed in a locker used for this purpose only. Unionalls should be washed at least onoe a week. "5, Bathing and locker facilities A conveniently located looker and was h room shall be designated for use of employees hand ling litharge. Separate lookers should be provided for street clothes, work olothes, and one for Unionalls worn when hand ling litharge. In plants where m e n are handling litharge throughout the shift, only two lookers need be provided. The floors of the looker rooms where the m e n change their dust oovered Unionalls and the benohes shall be thoroughly moisten . ed before -being cleaned* "6. .Personal cleanliness - General personal cleanliness la of first importance. ' J / (a) Hands must be thoroughly washed on the completion, of the litharge handling operation. Hands must also be thoroughly -wished before'eating or placing anything in the mouth. A special effort should be made to olean the finger nails ao . aa to remove any litharge* * * . (b) Never eat" until litharge covered clothing has been removed and the hands washed.___ _ ^ (e) Teeth should be brushed at least twioe a.day and the teeth and gums kept in good condition* ~ (d) The mouth should be rinsed thoroughly before eating. " (e) Never use tobaoeo in a n y form rhile working in and around litharge*" The-responsibility for the careful observance of ALL of these instruc tions should be placed upon the foreman* G -- SODA ASHt Soda ash (58# NagO) is used to form a solution for neutralising aoid oil. Thirty 200-pound cloth .bags o f soda ash are dumped .into a tank of water per batoh b y six men, with an average service of five years, from the General Labor De partment! three batches a week. Men exposed to dust resulting from opening and \ dumping the bags of soda ash about five hours a week. Sight men-spend about half a' day a-month unloading bags from railroad b o x ears* The men ho do tiro unloading wear MSA Ccmfo respirators and are not the same men as those doing the mixing who do not wear any respirators or goggles* The average dust produoed by the dumping, and 0014 8X Le _ o o o o o 6 2 JAM 014729 sdodng operation is 1,003,337 partiles, less than ten microns, per oubio foot of ) air, -These partiles are all slightly angular, orystalliae in appearance under the /' Koriiaeter miorosoope and about five microns in sire. Many are transparent, glass lilce. There are a* number of small blaok specks, H - TALC or -"SOAPSTONE"t Pulverised talc or "soapstone" is used as a filler in the manufacture of*"hot neck" greases used in the steel mills, Acoarding to R. B, Ladoo (U.S, Bureaulof Mines Bui, No. 213, 1919) ordinary talc or soapstone is Steatite (hydros Aagnesium silicate 52^ 53(2 10 3 )4 ). In the form of powder, the talo is greyish white. Associate Chemist Frederick Goldman of the U.S, Bureau of Mines, who made a chemioal analysis of samples of talc as marketed, reports 5102........ . 46.04 per oezrt CaO...... ......... 4.39 " " , . MgO................ 26.20 . ' Combined Oxides.....16.64 " " Grease makers usually consider the composition of "soapstone" which they use as ap. proximately 90% magnesium silicate and 10# oaloivm carbonate. It eases in 90-pound paper bags, 700 bags to a box car. About 7200 pounds are used per batch and one batoh is made a day on an average. The "soapstone" is dumped into the mixing kettle by two men with an average service of ten years. This dumping which requires about an hour per batoh is a rather dusty operation. One sample taken at face level Just after a bag had been dumped had as high as 22,995,840 partiles, ten microns rlese in sise, per cubic .foot of air. The average dust produoed was 13,064,960 dust par tiles per cublo foot. About 98# of these dust partiles were transparent, crystal line, irregularly shaped plates and rods, in appearance under the K animeter mioro- * soope. Most of these partiles (about 96#) were five microns or less in size,1 the - remainder being ten microns or overj about 2# were scale-like, semi-opaque, five mi crons or less in size. Physiologioal- Effects Produoed By Talo Busts. About two years ago Br. W. C. Breeesen, Passed Assistant Surgeon, and J. M. Balia Valle, Assistant Sanitary Engi neer, United States Publio -Health Servioe, made a study to asoertain whether there is a connection between tale dust exposure and the relatively high "tuberculosis j death'rate in'Murray County,'Georgia, where two. talo mills and, mines are located They found (Reprint No. 1669 from the Publio Health Reports Vol. 60, No. 5, Feb. ;1, 1935, pages 131-143)t ...... ...... ^ _ .. .. "Physical and roentgenologle examinations were made of 66 men and . women who were exposed or had been exposed to talo dust.' In the ' ' higher dust groups comprising 33 men, 8 were found to have Pnexsao- - coniosis I and 8 to have Fneumoooniosis U or III Six of~the thirteen examined were diagnosed, as having Pneumoconlosis I. No ' advanced stages of the disease were found in this group. In the group exposed to lew concentrations of dust, no Pnemoooniosis was found." The final conclusion of this study was that although Georgia talo appears to be "more injurious than tremollte talo" the high tuberculosis mortality rate in the County "oould not -.be attributed to the talo industry". .. Investigators have suggested, however, that for more or less continuous expo- sures concentrations of talo or "soapstone" dust sh<iald not .exceed 15,000,000 par- tioles, ten microns or less in size, per oubio foot of air ' * I - GRAPHITE Powdered graphite'(80# to 85# graphitio carbon and 15# probably magnesium sllloate) is used in the manufacture of spring, and pressure lubrloants. It 238 001482 la-Q poooe JAM 014730 -56- ornea In metal drums or 100-pound paper lined bag.' About 3700 pounds of pondered raphite is used per batch and tone batch is made per day on a n average. The ^graphite is dumped into the mixing kettle by men with an average servio of aoven years. This operation requires about forty minutes per batch per man on an average. Three men are usually engaged in this dumping. They near respirators nhile hand ling and dumping graphite, which is not a particularly dusty operation. The average dust produced is '1,603,080 particles, ten miorons or less, per eubio foot of air. All of these dust-particles are rounded or slightly.angular, black opaque, amorphous, sooty or dar grey in appearance under the Konlmeter microscope, and three microns or less in size. . - -- SLATE FLOTO Slate flour (300 mesh) gives rigidity to asphalt on "fast sur faces" such as steep roofs and pipe lines, and prerents its running off. It also produces desirable weathering properties. Mixtures as Ion as 10% slate flour and . as high as 40% are used. An average of two tons of slate flour is used to each still which averages about 800 barrels of steam reduced asphalt. Since the slate flour is introduced by the use of closed pipe lines and centrifugal pumps, the only dust produced Is that which' results during the unloading of the saoks and dumping them into the hopper. The slate flour comes in 50-pound paper bags,. 760 bags to a railroad box ear. Four men with an average servloe of about a year, open the bags and dump the slate flour directly into a hopper from whioh it is siphoned b y oaa- pressed air to a storage tank holding about 15 tons. About four carloads a.month are reoeived and an average of about 6-1/ 2 hours is required to unload each oar. About one and three-quarter million pounds were dumped during the last quarter period. The men wear J1SA Ccmfo respirators. A screen analysis of this slate flour showed that 99.7% passed through a 200 mesh soreen and 96,6% through a 325 mesh soreezu Due to the fineness of slate flour and its low bulle density (1.04) ooiw side rabie dust, an average of 12,007,680 'partiles, ten miorons or less in size, 1 per eubio foot of air, and counts as high as 1 6 538,880 partiles per eubio foot, are'produced during dumping the Backs and filling the storage tank. About 96% of these dust partiles are slightly angular, transparent, crystalline in appearance under -the Xonimeter microscope, and five microns or less in size; 2% are semi-opaque, . slightly angular. There were a few plate like partiles which appeared to oontain small air bubbles, and a large nizaber of small black partiles. ... A'petrographio examination made of .a slate flour sample at .the United States Bureau cf Mines Experiment Station In Pittsburgh, Pennsylvania showed that it oon- tained more than 1% Quartz (SQ2 )*.30JC Serioite (X20~3Al23-6 SiOg^HgO), 40% opaque aqg 50% five different unidentified constituents. A chemical analysis"b f .. . slate granules and flour (Jour. Indust. tyg.Vol*XV. ,No. 2,Mar. 1933,p. 87) reports these . constituents Silioon Dioxide .... Titanium Dioxide.... Aluminum Oxide...... Ferric Oxide........ Ferrous Oxide ....... Managanous Oxide...., Calcium Oxide....... Barium Oxide..... ... Magnesium Oxide.... Potassium Oxide.... Sodium Oxide....... Water below 210C. " above * Phosphorio Oxide... Carbon Dioxide..... Ferrio Sulphide.... Ot 3ZjS ' Speoiflo Gravity - 2.795 "The silicon found, though expressed in the chemioal analysis as sllieaa dioxide. Is not differentiated chemically as to the ' forms present in the original minerals, whether free silioa or silicate." . 239 * -.J.8-0000064 00143,) . . JAM 014731 -57- ' , Effect of Slate Flour on The Lunge * In his paper "Effects of Certain Silicate Dusts in the Lungs" read befgre the Industrial Hygiene Section of the American Public* Health Association at Washington, D. C. cm October 27# 1932, Dr. Waldeoar C. Dreessea J the United States Public Health Service, reporting the results of his studies of workers exposed to slate dust, wrote "Of the 48 cases of pneumoconiosis observed, all were in the first stage,.except 5 cases*' In general, the pneumoconiosis observed in ; the early or first stage cases resembled that induced by cement ust.,, The bronchial striations, however, were somewhat more prctmi- nent. There was always a moderate bilateral increase in the sise and density of the hilar shadows with accentuations of bronehial striations which-extended well out into each lung field. The linear striations seemed "softer" in appearance and lacked seme of the sharpness of detail which is visually observed in the X-rays of' individuals who have inhaled silica dust. This diffuse, fine generalized fibrosis was chiefly confined to the lower two-thirds of the lung fields. .... "In the seoond stage an increased prominence of the above mention- ed characteristics was present with the appearanoe of flake, like, . dappled,areas of increased density in both lung fields. In the - . third stage these dappled areas .seemed to conglomerate, and in this manner gave way to massive, clouded areas of increased density.".. . Dr. Dreessen found that although the silicate dusts of slate "induce' a fine diffuse, bilateral fibrosis of the lungs which is definitely demonstrable in the X-ray" - . workers exposed to slate dust do not begin to show definite first stage pneumooonlo- sis until after more than ten years' exposure. He did not find any evidence that . ) the resultant pneumoconiosis had led to disability. S " GRHIDHTG PERRIS ROOT Dorris root is used in the manufacture of insecticides. It comes in 500-pound tales from the Dutch East Indies. In order to reduoe dust, - the bales are thoroughly wetted with white oil. The root is ground at the rate of 500 pounds an hour to pass through a 3/8"-soreen. One m an with three years' servioe is exposed to an average dust oone entrati on of 1,604,800 particles, ten microns or less, per cubic foot of "air. About 80/C of these dust particles are rather round, `"" ""^ c r y s t a l l i n e in appearanoe under the Xonimeter microsoopo, and about five microns in size] 20% are sharply angular, five r d o r o n s o r l e s s i n sizo. The partiolesap- pear to*J>e more inorganio than organic in character. Evidently the lighter root dust particles are either larger than 30 microns and were, therefore filtered out by the Xonimeter filter or were carried out b y the exhaust ventilation, thus leaving the dirt or soil whioh had adhered to the roots. The grinder is located in a room well ventilated b y means of a 30-inch motor-driven fan. This explains the low dust concentration In the samples taken during the grinding operation. She operator wears rubber gloves, cover-alls, and is provided with a fresh air hose type- of ipe - while grinding. . ; . i j What Extent is Perris Toxic7 According to recent studies by the Halted States Department of Agriculture (Indust. & Eng. Cham. Vol. 28, Ho. 7, July 1936, pps. 815-821) -Perris is a possible health hazard to those .engaged in milling, grind ing, and diluting it (Derris) without the use o f suitable protective measures. Pharmacological studies show that Derris and its ...water extraots affoot the respira tory center whioh is initially stimulated and then, .after fatal doses, completely * depressed, with death resulting. Derris dust when applied to -the armpits was also' found to provoke a "mild evanesoent irritation." - . 1 - CRIZIDXHO rYRTHR8K FLOWERS Pyrethrum flowers are an important source of one ~ . 240 001484 18-0000065 JAM 014732 -58- p f the essential ingredients of insecticides. Thdy oome from Japan in mat oovered jjales weighing about 450 pounds. On an averago, about ten bales are ground per. ^shift. Opening the bales of compressed flowers is the dustiest port of the opera tion, producing on an average 2,039,040 particles, ten microns or less, per ctibip foot of air. About 85% of these particles are angular, crystalline in appearance under the Konimeter microscope, and three microns or less in size; about 15% are flat round particles and discs and shreds, ten miorons or less. The crystalline appearing dust Jprobably originates from the soil whloh has blown on the flowers or plants. One man. is exposed per shift for about four hours a day during a nine month period. He wears & Willson dust respirator. The grinder is enclosed in a metal housing connected by a fourteen-inch duct to a sixteen-inch motor driven exhaust' fan. Pyrethrum dust seems to irritate the skin of some individuals and not. afen.t others in the least; as a matter of fact it causes an allergio type of reaction in some individuals to such an extent that it is inadvisable for such persons to work in pyrethrum dust. K - MIXING AND PACKING "FLIT" POUDERt "Flit" powder is a mixture of pulverised derris root, pyrethrum flowers and other ingredients. It is mixed in a special room provided with exhaust ventilation by a man wearing a respirator. The dustieat part of this operation is sifting the pulverized derris and pyrethrum ihich produces an average of 8,722,560 particles, ten microns or less, per eubio foot of air. About 95$l of these dust particles are angular, crystalline in appe&ranoe under the Xonimeter microscope, and about three miorons in size; about 5% are less crystalline ... and more opaque, five microns or less in size. . Filling Cans? Three-quarter and two and one-quarter ounoe t i n cans are fill ] ed by automatic machines, the filler ends of rhioh are enclosed in a metal housing f with a four-inch exhaust duct to a fourteen-inoh motor-driven fan. That this ex haiist arrangement is fairly effective is shown by an average dust concentration in samples taken at face level of the operator during the filling operation of 1,755,840 partiles, ten microns or less, per eubio foot of air. The girl at idle . Sealer wears a bag-type dust respirator. . VIH - CLEANING TUBES AND DRUMS C O N T E N T S Cleaning .tubes and drums of boilers and process equipment is a routine opera tion which produces considerable dust belonging more to ^ e "n\iisanoe^e|ajBs,Jhiui to . the flb^gsis causation group. Nevertheless, consideration should be given'" f c c T - such dust down to a minimum of not more than 1 0 ,000,000 particles per eubio foot due to the number of men engaged' in this- work and their more or less continuous ex posure . . _ -" " ' I. - CRACKING COIL SOAKING DRUMSt Cracking coil soaking drums "coke-up" about once a month, so that in many cases they are almost completely filled with the ex ception of an opening down through the center no greater than twelve inches in diasvter. At.most plants, this -coke is removed b y a special machine; at the others, men with an average service of ten years are regularly engaged in cleaning these drums by means of & concrete buster type of pneumatio chisel, starting at the top of the drtn. One man works Inside and two outside at the top manhole. The temperature inside the drum is about 90 degrees Fahrenheit. Each man works half sin hour inside and is then relieved for about an hour. On an average, each man works about two and a half hours per shift, two shifts a week. A "boatswain" qhair is used to get in and out of the * ' drum. They wear "hardbolled" hats and life-belts. Excellent ventilation is provided bjr~i steam or an air syphon placed in the bottom manhole of the drum, as -a result of which samples taken at face level of men during the operation of the pneumatio chisel had an average of only 311,520 dust particles, ten microns or loss, per euble foot* of-, air. About 60J- of these particles were sharply angular, crystalline in appearance oh , 001485 is-0000 JAM 014733 -59- under the Konlmeter microscopes, and about fire microns or less In airej 3EX were . -ouad, a ml-opaque, oryatall^ne, about ten microns or over] and about 5% were small \aok'particles. There were also a few blaok scale-like partiles orar tea mioraas '^'a sise. The major portion of this dust is probably colee or carbon and the seale- like particles are, no doubt, metal from the sides of the drum or from the ohisel. IX. - CRACKING COIL TUBESt There are 183 tubes in a high pressure craoking coil unit. After running from twenty to twenty-fire days, depending upon the ohar- aeter of the stock being run, the temperature and pressure, the petroleum eoke whioh is deposited on* the tubes must be removed. Liberty air-driven tube cleaners with cone and star cutters operated by men with an average serviee of six years are used for this purpose. The men work in gangs of six to eight and are exposed to dust about six hours every two shifts on an average. They wear neither goggles nor respi rators although a dust samle taken immediately after reversing the oleaning machine while In a tube contained as high as 9,062,400 particles, ten microns, or less In sise, per cubio foot. About 3QX of these dust partiles are blaok, opaque in appearanee under the Konlmeter'microscope, and two microns or less in sitej 40# are angular, transparent, .plate-like, ten niorons or larger] and 3QX are angular, transparent crystalline, five microns or less in sise. ' Samples taken on the Cleaning Platform while oleaning Craoking Coil F u m a o e tubes at a Northern refinery had an average of 113,280 particles per cubio foot. Ninety-eight per cent, of these dust particles were rounded crystalline in appearance under the microscope and five microtis or less in site. Samples taken in the passage way back of the furnace while tubes were being cleaned had as high as, 1,076,160 .... particles, ten microns or less in size, per cubio foot of air. This indioates that the m e n in the passageway, baok. of the furaaoe are exposed to more dust than those on the cleaning platform. ' ) . ' ' / - III. -- WATER HEADERS AND BOILER TUBESt Tubes and headers are oleaned twioe a year by means of air-driven turbines. It has been found that oleaning an be done more effectively if done dry rather than wet beoause the dust can be blown out. If ~ water were used, the loos ened material would soon form a paste whioh-would be smear ed baok on the tubes b y the action of the cleaning turbine. Regardless of the dust which is produced in concentrations-as high a* 30,359,040 partiles, ten mioron* or less in .site per. cubic foot of air, workmen refer working in dry drums rather than -- v i n wet ones. Eight men "(two on each turbine) are* engaged in this oleaning operation which requires about twelve days ,,a year. H e n with an average service of fifteen years are assigned to this job from the Labor Department. The temperature inside of the drums ^headers is about 70 degrees Fahrenheit. In accordance witS"'th'usuaI*prao*itee tiee, mat operating the turbines, inside the drum or header, work about ten minutes and are relieved for ten minutes b y their eo-workers who assist in handling. the air . hose in and out of the drum manhole. Respirators have been provided iq. most oases ` but are not always worn. The average dust produced while cleaning water-headers and boiler tubes in samples taken from* ' Lower Platform, Front Water Header...... ........ .18,306,048 part, per otu ft. In #2 Drum While Cleaning Water Kail and Tubes.... 5,664,000 " " " Inside Manhole frum #3 While Being Cleaned....... 28,320,000 " " " ' / / / About 40j of the dust particles in the samples taken on the lower front water-header platform, while-'header was.being cleaned, were rounded, dark red in appearanoe under the Konlmeter mioroseope, and about two mlorons in size] 50X were opaque, store or less angular, and about five microns in site] 10% were crystalline, slightly angular,* * and ever ten microns in site. About 65% of the partiles in idle sample taken'inside '^2 '*drum during cleaning were black, opaque, angular, less than two microns in sis] and about 15X were round, more or less opaque, over ten mlorons. She concentration * of dust INSIDE the drum during cleaning appears to decrease with the distance tram 242 0 0 1 4 8 G 18-oooooi JAM 014734 -60- the manhole as is demonstrated by these oounts in samples from Drum $2 (Riley Boil- 9T)t J . t* Looatlon ' Particles uer cu. ft. About 8 ft. Inside Drum.. n . . . K __ 18 " " " R n 24 N* **" It .................. 2,265,600 The dust particles from inside the drum appear black, angular and were less than two microns in size. The dust from these cleaning operations are supposed to be largely the results of metal corrosion and sediment (largely Caloium Carbonate and Calcium phosphate) deposited by the treated Boiler Feed Water., A petrographlo examination of a sample of dust from the Front Water Wall header was made by the United States Bureau of Mines Experiment Station at Pittsburgh, Pennsylvania, who reported* . ' . Quartz (Si02 )..... .................. .. 1 per oent. Opaque or Coated with Opaque Material.. 90 " " Unidentified Clay-like. ..... . 9" " According to a chemical analysis of this same material made by a regular re finery chemist vising the method of Adolph Knopf, U.S. Public Health Service, the dust-- . oontained* Free Silica................ ........... 0*70 per cent. Combined Silica........................41.01 " " j Although the analysis of the dust shows a low free silica content, the high dust'concentrations found and the possibility that at times such concentrations may be higher than those found, demonstrate the desirability of wearing respirators re gardless of the kind of "dust encountered. . IX-FO U N D R Y OPERATIONS . During* recent years considerable attention, his been focused' upon the health of foundry workers by the operation of.the so-callod "Silioosis Packet" whloh has ex tracted large sums of money from the Foundry Industry. It is diffioult to i 8olate^--~~TM. this t y p e ^ f work which gives rise to a very general exposure to dust whloh may in volve all workers employed in the foundry. In many oases the worker is in suoh close oontact with the duty atmosphere as to cause serious exposure. Muok progress has . been made in reducing the dustiness of our foundry'operations and plans are"now being considered whloh will further safeguard our foundry workers. The following is a - brief outline of foundry dust producing operations* A. - POURING MGLTEN METAL INTO SAND MOULDS - About 19-1/2 tone of metal are poured per.."heat". Thirty-five* men with an average servioe of twelve yeare spend about one and a half hours pouring and six and a half hours moulding per day, five days a week. Goggles, asbestos leggings and congress-type shoes are worn by the men handling the molten metal. About 60% of the moulding send, whloh is the principal souroe of dust, .is free silica (S10 2 ). During the pouring operation the foundry air appears to be full of dust and smoke, however, samples taken during this work aver- .. aged only 396,460 particles ten microns or less in size per cublo foot of air. Prao- tically all of these dust particles appeared angular, crystalline under the Kocimeter ^ microaoope and were about two microns or less in size. . ' A sample of dust from the top of the crane rail over the moulding floor was - .. . o/t o 001487 ' i 8_000006B - JAM nU7?e -61- riven & petrographio examination by the U. S. Bureau of Minos Experiment Station in Pittsburgh, Pennsylvania who ireported 50# quartz (Si02)| IS% Clay Mineral not com pletely identified. Kaolinite is AI2O3 . 2 SiO 2. 2^20) 5% Caleite (Ca CO3 ) and 30# Opaque. B. - "SHAKING OUT" CASTINGS - After pouring, the castings are allowed to cool, then the moulds are liberally sprinkled with water from a hose. The bands or elemps are removed and the flask is thrown over and broken open. The rough easting are pulled ut, piled up and trucked to the Cleaning Room. "Shaking Out" is con sidered one of the serious occupational disease hazards encountered in industry and the dustiest operation in founderies but due to the thorough wetting and careful handling by the men, samples taken during the- operation had an average of only 658,230 dust particles ten microns or less per cublo foot of air. The impingar method would no doubt reveal much higher counts. About 98# of the dust partiles were slightly angular crystalline in appearance under the Xaaimeter microscope and were one micron or less in size. , "Shaking Out" is rather hot work, the men per spire freely so that it would be difficult to enforce the wearing of goggles and res pirators. Twelve men with an average service of eight years work oh this Job, eight hours per shift, five shifts per Week. * ' After the castings have been removed the moulding sand is again wetted and thoroughly woiked over with a motor-driven sand cutter which is a series of -revolv ing blades, similar to those on a lawn mower,' operated by an eleotrlo motor, mounted o n a rubber-tired four-wheeled carriage which moves back and forth over the moulding floor. Moisture `tests are made and when. these tests lndioate 4.6 to 5.6 moisture the sand is considered ready for the moulders. During the operation of this sand cut ter, the operator is exposed to an average dust concentration of 1,529,260 portioles ten microns or less per cubic foot. These particles were less than two microns end were slightly angular crystalline in appearance voider the Konimctor microeoope. / C. -- CLEANING CASTINGS -- Various methods are used to clean eastings depend ing on their size and -shape. All of these methods produce more or less dust sme of which can be taken care of by exhaust ventilations, others cannot. The methods swot commonly employed are? . (X Preliminary Cleaning"- Castings are brought from the moulding floor during* the night and deposited in the Cleaning Room, The following morning the oores are knocked out, the sprues and gates^are broken off and seme scratch cleaning is done. This wojjk produoes considerable dust especially when the sand an^^d^^'eliurt'^ "'' - - shovelled through the ;*rating into the oar or buoket below (3,455,040 partioles -ten miorons or less per oubio foot of air), tinder the Kanimetor mierosoope about 70# of the dust partioles appear angular, crystalline, three microns or less, in Isei. 20# < were rounded crystalline, five mlorons in size and about 5# were seale-like send- , ' opaque with a roddish-brown tinge and over ten microns in*size. Pulmosan Respirators have boen provided hut are not always worn by men doing this work. NO attempt . been made to control dust from preliminary cleaning although seme study has been given to the provision of a special air-tight roam with a grating floor and a hopper underneath With a screw conveyor at the bottom to convey the debris to the disposal car or bucket and thus eliminate the dust-producing shovelling and handling, Under this plan exhaust ducts with a series of outlets around the top of the hoppor carry off the dust. . Air is also introduced into the room about a man's breathing level and the amount of air taken out' is greater than that introduced so that a negative pres sure is maintained and a complete air change is made about every three minutes. * _ (b) Tvanblast - The Tunblast is a machine which combines tumbling with air blast ing. Trom 400 to 1500 pounds of eastings are put into a drum which revolves about ' 10 REM. They run from about 20 minutes to four Hours, depending upon the type of _ eastings and cleanliness required. While the eastings are being tumbled they reoelve * 244 001488 le-oooooi JAM 014736  ft blast of #20 Steel ahot through throe 5/l6 inch nozzles under an air proasuro of 05 pounds per square Inch. This machine is operated by three men, with an aTorage jervioe of eight years, for a period of two and a half hours per man per day, fire -- flays a week. Pulmosan Dust respirators are provided but are not always worn. i. ten-inch exhaust pipe has been installed at the top of the machine and a six-inch exhaust pipe over the screen. The suction on these exhaust pipes is said to be about 2-1/2 inches- water. Samples taken during the operation of this machine aver* aged 1,200,760 duSt particles, ten microns or less in size, per cubio foot'whioh in dicates that he dust control measures which have been provided are getting results although there is still room for improvement. About 98# of the dust particles ap pear quartz-like under the Eonimeter microscope; about 60# are five microns or less in size and are angular crystalline in appearance; 40# are ten microns or over in size, and rather rounded in appearance. There are also a large number of minute blaok metallic speoks entirely too small and numerous to count aoeuratoly. , (o) Sly Tumbling Mill - Cleans brass castings by a combination of tumbling and air-blasting with jj$ Sand Blast Sand and 85 pounds per square inch air pressure. The Kill holds from 100 to 1500 pounds of castings and cleans five loads a day. Two m e n , with an average servioe of 15 years, operate this mill which runs about five hours a day. They wear Pulmosan Dust respirators and roggles when opening the machine. This Kill is hooded with an 8-inch exhaust pipe having a 2-inch water suction, also a 10-inch exhaust pipe over the sand screen at the rear of the machine. Samples of dust taken during the operation of the Sly Tumbling Hill had as high as 2,492,160 particles ten microns or less in sizo per eubie foet of air and an averjage o f . .~.-- . 1,393,344 particles per, eubie foot. About 90# of these dust partioles were rounded crystalline in appearance under the Eonimeter microscope and two microns or less in size; 5# were black, opaque scale-like and 5# were rounded crystalline about five microns in size. .... .. .. ' J -(d) Tumbling Barrels - 36" x 42" Whiting Tumbling Barrels remove sand from east ings. They hold from 1200 to 1500 pounds of castings per load and revolve at 10 BPK. ~ .. The eastings are tumbled-about two hours with about 700 pounds of one-inch unanneal- ' ed east malleable iron stars and jacks. A n exhaust system with a 6-laoh pipe through the trunnion having a suotion of 1-1/4 inches water. This suction has been found in adequate to give the desired results consequently the suction is to b e increased to 4-inohes -water; Samples taken during the operation of the Tumbling Barrels had an *~>~-^average of l,34B,032 dust particles ten microns or less in size per cubic foot of air. About 90# of these particles were angular crystalline in appearance under the Eonimeter Microscope and three microns or leas in size; about 10# word kounded"semiTO'w ^ "-" crystalling, ten microns in size. There were also ft few triangular-shaped opaque ' * metallic particles. Three men, with an average service of twelTe years, operate these tumbling barrels eight' hours a shift, five shifts a week. Pulmosan Dust Proof ' respirat.ors and goggles have been * provided but are not always worn. . The type of Tumbling Barrels being used has been condemned b y a major com pany because it is impossible to ventilate it properly. The holes in the end liners clog up when the barrel starts revolving, thus preventing circulation of air through the barrel. This condition bus been remedied, in a new design now on the market, by the use of two sheila - an inner perforated and an outer solid shell. Both trun nions are hollow, and are connected with the air ehamber between the two sheila. Air under pressure is introduced through one trunnion and exhausted through the other; (e) Air-Blasting - Castings which cannot be tumbled due to their size and fra- ' * girAty are cleaned by air-blasting (85 pounds per square inch) with mixture of ap- . , | prxma-fcely half end half sand and #40 Steel Grit. Syracuse Core sand is used when ^ a special finish is desired. There are three men, with an average servioe of three ' years*, on this job who work 45 minutes of every hour, eight hours a shift, for one . week out of three weeks. This work is done in a special tight, air conditioned room 245 00143 -I 18-000007C JAM 014737 while wearing a Sly Sand-blast Helmet supplied with outside fresh' air provided by a epeoial blower used for that .purpose only* Samples taken inside the room while a easting was being air-blasted had an average of 3,738,240 dust partiles ten microns or less per oubio foot of air* About 60# of these dust partiles were sharply angu lar crystalline in appearance under the Konimeter microscope and three microns or less In sise; 20# were rounded quartz-like orystals about ten microns in size* There were also a few rust-like scales and a large number of black metallio particles too minute too numerous to be counted accurately. The silioosis hazard of this opera tion ooult^ be greatly reduced by the use of steel abrasives exclusively* (f ) Rough Snagging Wheels - These machines are used for removing projections suoh as sprues, parts and gates from castings. There are two types of these wheelst the DOUBLE END using either 19-1/2" x 3" Carborundum and Vitrified or 24" x 2-1/2-" Redmanol (Bakelite bound) Wheels; and the HORIZONTAL DISC Grinder having a ,50" ' diameter vitrified wheel. These wheels are used by seven men having an average service of nine hours per shift, five shifts per week. Eaoh wheel is hooded and has a four-lnoh suction pipe. There is an eight-inch suotion pipe on the Horizontal Grinder. Goggles and respirators are provided but the latter are not always worn with the exeeptlon of the men on the Horizontal Grinders* Vitrified wheels are run at a slower speed (1800 RBI) than the Bakelite Bound Wheels which operate at 3400 RFti. Samples taken during the operation of the Rough Shagging Wheels had the fol lowing dust concentrations. * Double End Snagging Wheelst ' Average Dust from Vitrified Wheels...... * n n carborundum " ...... * " " Bakelite Bound Wheels. 3,653,280 particles per eubio foot 3,322,820 - . * 2,662,080 * Horizontal Piso Grindert Average Dust from 50" Vitrified Wheel....* 2,124,000 partiles per oubio foot The average dust produced by all the Rough Snagging Wheels was 2*322,820 partiles, tea mierons.or less in size, per oubio foot of air. . About 80# of the dust partiles-from the vitrified wheels appeared black angu lar opaque under the Konimeter mierosoope and two mi orone or less in size; 20# an guiar crystalline about one miaron or less. There were also a^la^ge number of blaek minut^partiles too small end numerous' to oount* The dust p a r t i e l e F ^ W S ^ f ^ o r i ^ * zontal (Vitrified) wheel were approximately 90# angular, crystalline and 10# blaek opaque* All of these particles were about two microns or,108s in size. :`-About 60#. of the dust partiles from the Bakelite bound wheel were black angular two miorons. or less in size; 25# were angular crystalline, less than one micron in size and about 15# were rounded crystalline about five miorons in size. (g) Vine Snagging and Polishing Wheels - These wheels grind off small projeotions and remove rust from stock which has been in storage. There are three typest DOUBLE 4" x 14" POLISHING EMERY WHEELS - Wheels after being made up are dipped in glue and then rolled in Alundum Grinding Grain, sizes 60, 80 and 120 mesh. DOUBLE DISC GRINDERS - 36" discs covered with $46 Cast Iran Grain or Silioon Carbide (am eleotrio furnaoe product) end WIRE SCRATCH BRUSHES - made up with four 12" sections* Exhaust hoods with a suotion of from three to five inches water,. have been Installed . . on the Polishing Wheels and Disc Grinders. There is NO hood on the Wire Soratch, Brushes. Those wheels are used by four men with an average sorfloe of two years* They wear goggles and gloves but no respirators. Samples taken at face level during the operation of this equipment had the following average dust ooneentratione * _ 246 . * * 16- 0 0 0 0 0 7 : 001400 ~ JAM 014738 -64- * Dust Produced by 36" M a o Grinder............ 1,416,000 particles per cubic foot it " 12" Wire Scratch Brush...... 736,320 * " " " n " 4" x 14" Polishing Wheels.. 461,440 " " " ' These comparatively low dust counts indicate that the dust eontrol measures which have been provided are either effective or the dust particles produced are error 30 microns in size and were thus filtered out by the Konimetor filter. Under the ml*. orose ope dusjf particles from the Polishing Wheels appeared all round crystalline and about one micron'ln size. About 40# of the dust particles produced b y the Double Diso Grinder were sharply angular, opaque about three microns or less in size* 60# were less angular crystalline about one micron in size. The dust particles produoed b y the Wire Scratch Brush were all rounded, crystalline and about one micron in size. There were no metallic#particles in any of the samples examined. Pew exhaust hoods h&ve been installed on Wire Scratoh Brushes because it has been generally assumed that these brushes did not produce any dust. This assumption, however, is untrue as one sample from a wire brush at a Southern Refinery had as high as 6,683,520 pan tielcs ten microns or less per cubic foot of air. (h) Cone Grinding Wheels - These wheels are operated with oimpressed air and are used to do miscellaneous, grinding on castings by four men, with an avorage ser --- vloe of twelve years, about two hours a day on an average. The eones are 5-l/4" x 3-1/4" vitrified and produce an average dust of 1,869,120 partiles ten micron or less per cubic foot of air. About 80# of these partiles are sharp angular crystal line, In appearance under the Kanimcter microsoopo they are five microns or less in size; 20# are round opaque but non-metallio in appearance and five microns or over .. i n size. There tyre no hoods over these wheels and the operators'wear no respirators. .. . \ i Average Dustiness of Cleaning Room Air - A series of five samples were j taken between 9i30 and 9t40 A.1- to determine the average amount of dust in the air ^ of the cleaning room while the various cleaning operations were in full blast. A&- other series of five samples were taken about .3*30 P.M. in the afternoon after the roam had been given its regular clean-up. There was quite a difference in the amount of dust in the air during the morning (2,166,480 partiles ten microns or less per cubio foot of .air) and during'the afternoon toward the elose of the shift (338,272 partiles per cubic foot). About 95# of the dust partiles In the evening samples -- ii TTT.T crystalline in appearanoe and about two microns in size. There were a few large semi-opoque or scale-like particles about 20 microns in size. About 98# o f the dust particles in the morning samples were angular orystalline two-miorcos^or less in $Lzo and about 2# were round, crystalline over five mlorons in size. A sample of dust from top of one of the larger Exhaust Ducts in..the center of the cleaning room was given a petrographic examination b y the U.S. Bureau of Mines Experiment Station at Pittsburg, Pennsylvania and found to contain 40# Quarts (SiOg), 20# Clay Mineral not completely identified! 40# opaque. . D, - CORE MAXIEG - A large number of oores are made b y the Dcmmler Air Opo- rated Core .Machine which uses'a mixture of two-thirds sea sand, one-third river sand and one gallon core oil per 60 gallons sand. There are three souroes of dust in the operation of this machine (1) Shovelling Sand to fill the Machine Hopper. .1,019,.520 particles per cubic foot (2) Blowing out Core-boxes...... ............ ... 736,320 " m h n (3) Blowing sand into the Core-Moulds........... 755,200 " N N *N ~~ About 96# of the dust particles from blowing out the core boxes are dark, opaque in appearanoe end about one micron in size. The dust particles Area.-blowing sand into the core moulds are angular rystalline less than one micron in size. 24? 00149 i. 18-0000072 JAM 014739 -65- Cores are "smoothed up" after being baked in the core oven b y soratohing . ^he rough .edges with an. ol-d hacksaw blade. This operation produoea an average of / 906 240 dust partioles ten microns or less in site per cubic foot of air. About 9B$C of these partioles are angular, crystalline in appearance under the Konimeter mi- crosoope and are less than one micron in size. E. - SEPARATION OF BRASS FOUNDRY SKUtilNGS - A Steinlein Separator, ing about $5 RHI) separates brass from about 100 pounds of skimmings an hour. The separator has a .4-inch exhaust duct to a 12-inoh fan which produces a suction of about four inches water. Samples taken during the operation of this machine had an average of 1,231,920 particles ten microns or less per cubic foot of air. About 95% of the dust particles in samples taken above the charging chute appeared opaque angular black in color under the Konimeter microscope and were less than one micron in size. About 80# of the dust particles in samples from the trunnion were more crystalline and rounded in appearance and less than one micron in size. This was also true of the samples taken in front of the machine where the slag drops down into a bucket. The dust particles in samples from the .metal being discharged from the saohine were about 50% metallio in appearance about 50% angular crystalline. Both crystalline and opaque particles were about two miorons or less in size. Six men, with;an average service of seven years, take turns operating this machine which runs about two hours per day on an average. revo X - MASON'S OPERATIONS ' ' - -- I. - TEARING OUT STILL FIRE BOXES - Two men with an average' servioe of ten years, spend two days a month on an average tearing out slag-covered bottoms of crack ing ooil furnace fire boxes. Temperature inside fire box is about 85F. The bob toms which are composed of fire brick are broken up with "Bull Point" Pneumatio chisels. Samples taken inside the fire box while this work was in progress had dust concentrations as high as 1,019,520 partioles ten microns or less per oubio foot of air. These particles were glassy sharply crystalline in appearance under the Kcoi- meter miorose ope. About 90# were five microns or less in size and 10# were over ten miorons. The larger particles were semi-opaque. There were also a large a m b e r of round black opaque particles about one micron or less in size. After the bottcos had been broken up by the pneumatio chisels they are shovelled out through the fire box door and then reshovelled into truoks to be hauled away. This operation naturaly produoes more dust than the breaking up inside the fire box. Although no wind was blowing samples taken at facelevel dur i n g t h o s hovelling and loading had dust ooncentrftians as high as 2,435,520 particles ten microns or less per oubio.foot of air and an average of 1,345,200. Goggles but no respirators were worn b y the 12. -- CHIPPING OR CUTTING CONCRETE - A large number of employees with an average service of three years, spend at least ten per cent, of their time dismant ling or cutting oonorete structures with pneumatio ohisels in the removal of old * foundations, oonorete supports and bloeks and in cutting holes in walls and floors Samples taken during the cutting or ohipping of ooncrete had as high as 6,910,090 partioles ten microns or loss in size per cuble foot and a general average of . 1,591,051 particles per cubic foot. All of these dust partleles are slightly angular crystalline in appearance under the Konimeter miorOsoope. About S5% of the dust par ticles -- ere five micrcms or less 'in size) 10% between five and ten miorons snd about 5% over ten miorons in size. In many cases neither goggles or respirators were worn, by the workmen. Regardless of the rather low dust counts found, men engaged in ohip ping or cutting concrete should wear oonorete due-to the high silica oontmrt in the usual aggregate used in oonorete. . III. -- CHIPPING HQRTAR FROM BETWEEN BRICK -- Chipping Mortar with pneumatio chisels from between bricks in walls of structures preparatory, to weather-proofing is a particularly dusty operation. Semples taken during this work had dust ooneentratiohs 248 0 0 14 9 2 18-000007. JAM 014740 -66- * as high as 20,956,800 particles ten microns or less per cubic foot of air and a general arerape cf 13,848,480 particles per cubic foot. All of these particles were enrular crystalline in appearance voider the Konlmeter microscope and about sijemi- crons or less in sire. There were also a countless number of minute reddish-gray particles. This work was done by an outside contractor whose employees wore goggles but no dust respirators, . # IV, * . . - CRUSHING FIRE BRICK - Fire bricks are crushed in a belt-driven Williams or a Motor-driven, Sturtevent Brick Crusher so that 80# will pass through a 3/8" or a 150-mesh soreen - much cf it is powdered during the crushing. This material is then mixed with fire clay, crushed asbestos and cement to make "Ganister" whioh is.used in tube sheet linings, packings or as mortar in building fire boxes of furnaoes. Samples taken during the crushing of fire brick had dust concentrations as )iigh as 11,554,560 particles ten microns or less in size per cubio foot and a general average of 2,562,960 particles per cubic foot. Crushing new fire briok produces about six times as many dust particles (4,375,733 per cubio foot) as is produced when crushing old, used fire brick'(736,320 particles per cubic foot). Under the konlmeter mi croscope about 94# of the dust particles produocd by orushing new fire briok appear angular crystalline, one micron or less in size; about 5# re opaque orer ten mi crons and about 1# are dark opaque, scale-like about five microns in sise. The dust partiles from crushing old used fire brick are more rounded crystalline in appearance and are about five microns or less in size. 'An analysis of Alamo Flre-olay Brick, ' which is'oosnonly used and was the new unused fire brick being crushed at the time our samples were taken, supplied by the manufacturers (Harbisan-Walker Refractories Company) reports: * Silica. ................ Alumina and Titania..... Ferric Oxide...... . Lime.................... Magnesia........ . Alkalies..... . per oent. n tt It n It It n Fire.brick is crushed by two men assigned from the Labor Department, the aver age service of these men is about 14 years. Two to three tons are crushed per day. The total length of exposure per month depends upon the demand for erushed fire brick and will vary from a general average of fifteen hours per m a n per month to as muoh as twelve hours a week. Goggles and M. S.A.Ccnafo dustrespirators-are^worxuw ,.,,*,,** V. - SHAPING TIRE BRICK OR EMERY WHEEL - Fire briok are ground to a specified shape and size on a 2" x 24" Carborundum (Grit 16, Grade 1, Bond 6C) Whebl which re volves 900 RFK, This wheel* is almost completely enclosed by a hood whioh has a 4- . lnoh duct to a 24-inoh motor-driven fan operating at 1750 RIM., but this exhaust is evidently inadequate as samples taken while rounding off the edges of a fire elay fur- naoe block had a dust concentration as high as 4,078,080 partioles ten microns or less in size per oubie foot, of air. The general average was 2,001,658 partioles per cubio foot... All of these dust particles were slightly angular and slightly opaque in appearance under the microscope and five microns or less in size. One man wearing , goggles and a M S .A. Comfo respirator, with about 15 years service, spends an average' of about two days a month shaping fire brick and blocks on this wheel. * VI. - DISMANTLING HASCNRX - Dismantling Masonry structures such as old boiler and still settings is a very dusty operation but was not Included in this dust study as there was no work of this type in progress at any-of the plants at the time of our' survey. ' . . . . ' 240 001493 * 18-0000074 ' JAM 014741 -67- - XI * WOODWORKING OPERATIONS >' / Woodworking op#rations, a# performed in oonnection with tho refining of pe troleum produota and aasooiated activities, are used in the production of pattern, box shook, oontainer, and construction or maintenance work. These woodworking operations produoe more or less dust whioh is largoly organic and although it may hare some spores, and have an allergio offeot on some individuals, it is not consider ed harmful* Mr*'D. Harrington of the U.S. Bureau of Mines advises that the TJ.S. De partment of Lbpr in a recent bulletin indicate that workers breathing wood dust are far more definitely afflicted with tuberculosis than the general run of industrial workers. In large quantities, however, wood dust belongs in the "nuisance" class and may also be an explosion hazard ' i, - BOX SHOOK MANUFACTURE - All pine lumber used in the manufacture of box shooks is "kiln-dried" and all gum lumber is "air-dried". Men work eight hours a shift, fire shifts a week. 1 ' (a) Resawing - Band saws, twenty-five feet four inohos in oircumferenoe, re saw four-quarter and five-quarter lumber into 3/8-inoh and l/2-inoh shooks respeo- tively. Samples taken during this resawing had an average dust concentration of 155,760 particles ten microns or less per oubio foot of air when sawing pine and 996,864 partiles per oubio foot when sawing gum. These low-ooust* .Indicate, that the exhaust and dust oolleotlng system which has been provided is functioning. This exhaust system inoludes hoods over each saw with 8-inch ducts to a belt driven A a with five-foot blades revolving 3500 RPtU About 60# of the dust partiles in samples taken while resawing pine were crystalline, rather glass-like-in appearance - prob ably resin - under the Konimetor mlerosoopo and over ten microns In sizej 40#,were round with* rough edges gray and opaque, five microns or less in size. About 80# of -the dust partiles from cutting gum lumber were round crystalline semi-opaque in ap- pearanoe, five microns or less in size) 20# were over five miorons in size. Gun lum ber is resawed only about four days a month. - . (b) Ripsawing - Rip saws. 14 inohes in diameter out end's from four-quarter gum lumber. An exhaust system has been provided with a hood over eaoh saw and four inch metal ducts to a belt-driven fan with six-foot blades revolving 3500 RIM. Samples taken during this operation had an average dust concentration of 169,920 partiles "'ten mlorons or less per cubic foot of 'air. All of those partiles were angular crys talline semi-opaque in abearance under the-Konimeter miorosoope and about three m i c r o n ^ in size. . . * (o) Cut-Off Sawing - Saw four-quarter lumber to make box ends.. --About 85#. of the time gum lusher is sawed, and 15# pine lumber is sawed. Semples -taken While saw ing gum lumbar had an average dust oonoentration of 877,920 partiles ton miorons or less per oubio foot of air. About 50# "of these particles were round crystalline semi opaque, gray in oolor and from five to ten miorons in siz) 50# were slightly angu lar crystalline In appearance under the Xonlmeter mi roso ope and three microns or less in size. There were also several very small blaok speoks. The low dust count indi cates that either the partiles were mostly over 30 miorons in size were thus filtered out b y the porcelain filter or that the exhaust system was effective. . (d) Planing - Planers or double surf&cers resurfaoe the four-quarter five quarter lumber to give it the proper finish. There is an exhaust hood over eaoh ma chine with an eight-inch metal duct to a belt-driven fan with six-foot blades revolv-- * ing 3500 RIM Samples taken during the operation of planers or double surfabera had . general average dust concentration of 509,760 particles ten miorons or leas per oubio foot of air when planing pine lumber and 415,360 partloles per cubic foot when planing gum lumber. Partloles of-dust produced while planing pine lumber wore - crystalline rather round in appearance under the Konimeter microscope, about 75# were 001494 l6-000 250 JAM 014742 -68-- ti"T9.micron* or lea* in size; 25% were larger than two miorons and rather opaque* fast partiolea from planing gud lumber were round opaque in appearance and one' mi- roroa or leaa in aire* Dustineaa of Shook Factory Air - A series of fire samples were taken at fire strategic points to determine the average dust concentration of th faotory air. These samples'gave an average concentration of only 141,600 dust partiolea ten mi crons or le|s per" cubio foot of air which indicates that either the major portion of the dust is over SO miorons in size or that the ventilation system is proving effec tive. The latter is probably the more logical explanation although the excellent hous ekeeping is undoubtedly an important factor. About 98% of the dust partioles in the faotory air samples were slightly angular crystalline in appearance under the Xonlmetor microscope and about five microns or less in sisej 2% were round, opaque dark gray in color and two microns or less In size, 1 B. - BELT SANDERS, SAND DISCS AND SPINDLES OR CYLINDERS - This equipment is used, for "squaring up" and smoothing surfaoes of wooden patterns, -olearning and finishing barrel-heading and stave* and general mill work in the Carpenter Shops. ' Sanders are a notorious souroe of fine wood dust*. They are also oontaminated with * an appreciable amount of silioa, if a sand-type of abrasive is used, consequently either hoods for the machines or respirators for the men engaged in operating these machines should be provided. He appreciate that it is rather -difficult to-properly hood a sandor to prevent the fine dust being carried around b y the abrasive member, particularly diso senders. Our attention has been called to a ease where a man ea-. gaged in the use of senders suffered recurring respiratory illness and ultimately * death from pneumonia. H i s 'attacks of illness seemed to oorrelate with extended use of the senders. , .) (a) Belt Sanders - A n 8" x 28-1/2 ft. Belt Sander (Lightning Adalox Cloth . l-l/2 - 40 X Grit Norton Abrasives) runs on an average of two hours per day and is used by eight-different men with an average servioe of fifteen years. Sample^ taken while finishing #1 Pine lumber had a dust oonoentratlon as high as 15,519,360 par tiles ten miorons or less per oubio foot of air and a general average of 3,443,712 partioles per. oubio foot. About 90% of these partioles were angular crystalline in. appearance under the Konimeter mio rose ope and five microns or less in sise; 5% were over five'm iorons in sise; 5% were opaque scale-like, ten miorons or less in sire. There wasIre hood181e v e r t h i s sandog_and the dust produced was thrown into the shop . air. , - A 6 in. x 18 ft. Belt Sanding machine (#3 PToduotion Cloth Minnesota Mining Company) runs on average from four to six hours a week and is used b y four different men, with an average servioe of four years. This work was formerly dcae b y on a lathe with sand paper. Semples taken while finishing the outside o f a barrel had a n average dust oonoentratlon of 481,440 partiles ten miorons or less per oubio foot. These partioles were largely angular crystalline in -appearance under the Kaai- meter mlcroeoope. About 50% were five microns or less, and 50% were over five mi orons in size. ` ' (b) Sand Discs or Wheels - These disos run from 40% to 6C0S of the time are usually used by everybody in the shop in wfaloh they are located. Samples taken during-the operation of sand disos or wheels had the following dust concentrations* 251 001495 18-0000076 JAM 014743 *W w ' No. Sise Abrasive (Lia. ) Used Work Being ' Done I 7" #24 Sand Cleaning Paper Minn. heads . Mining Co. . Finished h Barrels r M II #i-l/2 Gar Squaring net Paper. Wood Minn. Min Pattern ing Co. III 30" 17 30" #40 Grit on Bristol Board. Gardner Ma chine Co. Smoothing off Pat tern, #2 Garnet Net Back. Gardner Machine Co. Squaring Wood Pat tern Partiolee Per Cublo Foot 604,160 623,040 1,925,760 3,624,960 ~ Charaoteristios of Dust Partiles (Sizes and Per centages Estimated) t Angular crystalline * about 50$ five miorons or less and 50% larger than five miorons. About Z5% angular crys tallise two miorons or laser 5% quarts--like rounded about 10 mi crons in size. About 90% angular crys talline three miorons or less; 10% opaque angular one mi oron in size. About 9B% semi-opague, sand-like, one micron or less, 2% opaque 6 microns or over in size. The said diso in No* I was used in a well ventilated cabinet oonneoted to a 48" motor driven fan by a 7-inch duot. The men wore goggles and "Ccmfo" respira tors. The sand wheels in No. II and He. Ill had hoods with about S-l/2 lnohes water snotion connected to a 24" motor driven fan b y 4-inoh duets. Tho m e n w o r e neither goggles nor respirators. The wheel in Ho. 17 had an exhaust hood with & 6-- inch duot oonneoted to a 24-inch duot whioh in turn was oonneoted with a 36-inch. mo tor driven fan. ..(e) Sand Spindles fly Cylinders - Sand spindles or oylinders are used on a n average of about two hours per man per--day..No hood or suotion exhaust has been pro- vldedefor. this equipment. Men using it do not wear gcggles or Tespirators^althpugh. ^ the dust partiles produced are more angular in appearance than those produoed by sand disos or wheels. " ' . _ ' Samples taken during the operation of Sand Spindles or cylinders had the fql*> lowing dust concentrations Size (Dia. ) Abrasive Used .Work Being Done Partiles Per Cublo Foot ?" #3arnet Paper Cutting Inside Gardner Machine Core Boxes Co. 2,322,240 Charaoteristios of Dust Particles (Sizes and Percentage Estimated) About 60j quartz-like in appearance, ten mi crons or over in size} 4 Q semi-opaque five, miorons or less in size. * -3 S 2 - 001496 18-0000077 JAM 014744 -70- DTJS? PRODUCED BY SARD SPIHDLBS OR CYLINDERS (Conoluded) Size (Dio. ) Abrasive Used Work Being Done 3-l/* #l=l/2 Carnet paper Minn. Mining Co. ` Putting Taper on Pattern. Partiles Per Cubio Foot 877,920 Characteristics of Dust Partiles (Sizes and Peroent&ge Estimated) About 90# angular crys talline two microns in size) 10# opaque five miorons or less in size. . C. - KAXIHG WOODEN CRATES -- Two type of sawa are used in preparing lumber making crates for gasoline pumps and tanks * * * ' . (a) Band Sows - Samples taken during the operation of Band Saw had a dust concentration of- 453,120 particles ten miorons or less per oubio foot of air* All of these dust particles were round, opaque in appearance under the Konimeter miorosoope and three, miorons or less in size. . (b) Railroad Saws - Samples taken during the operation of am 18" Railroad Saw had a dust concentration of 3,964,600 particles ten miorons or less per oubio foot of air. All of these partiles were round, grayish opaque in appearonoe under the Konimeter microscope and about fire microns or less in s*ize. There were also nu merous minute gray specks too small to count accurately. .. t * X n ROCK EXCAVATIO N Rook excavation is. usually a dust producing operation which is limited to con struction activities in the petroleum industry. The haz&rdousness of rook excavation depends entirely upon the nature of the rook being excavated, the length of exposure and the methods being followed. The principal sources of dust are rook drilling blasting, mucking and handling of the rook. Of these, drilling probably produces the greatestamounj:c)fdxis t. - . ^-^t'-"*******^ .. A. - DRILLING - The pneumatic ^rook drill operates essegttal&yM^-a^crushln g device which shatters the rock to a powder at the point of impact. Aooording to Theodore Eatoh of the Harvard Sohool of Fubllo Health (K.Y. Ind. Bull.Yol. 15, Ho. 9 - Sept. 1936) the partiles of dust thus generated vary in size from, end-quarter jnoh or larger down to sub-miOroscopio diameters. The dust is removed fren the drill hole b y a stream of air or water or a combination of the two introduced through the hollow drill steel. In the case of jack-hammer drilling a considerable amount of rook dust ejected from the hole falls back to be orushed further before it is removed again. Quoting Hr. Bitch "The amount of dust produced b y a rook drill is surprisingly large - a jack-hammer., operating at the over-all rate of 100 * . . feet of drilling per day, actually crushes more than 200 pounds ` of rock in eight hours. C f this, at least five per cent, is in ' the form of particles smaller than ten microns) hence, more than - fifty grams of dust small enough to be air floated is generate^ * per foot drilled. In terms o' numbers -of partiles the figures ' are enormous - it has been found that a jack hammer produbos os - much as one billion particles, of hygienio interest during one * minute of operation".' . ' , ~ 001497 18-000007 JAM 014745 -71- B. - BLASTING - It is often said that blasting produces the greatest amount of dust in rook- exouvation. This statement is contradicted by some authorities who refer to the faot that the blast dislodges, a great deal of dust from the rock sur faces deposited there from earlier drilling operation in addition to that actually generated by it* Under this condition blasting is undoubtedly followed by a higher dust concentration than in the case when all the dust produced by drilling is eap- tured and eonveyed to a remote collector so that only that actually generated b y the explosion^eeoapee into the air. While it is undoubtedly true that if drilling is done dry, there will bo de position of some of the dust on the surfaces of the excavation and later be raised by blasting, however, dust from this source'is minimised if drilling is done wet, beoause the slushed out particles tend to form agglomerates, which are not so readi ly raised by the blasting operation. Also, when good practioe is followed; the faoo and sides are wet down with water before blasting, and in mining work, there is a continuous water spray that is started onto the heading before the blast takes plaoe and continued for some time after to help allay the dust and to wet down the material, so'that dust raised during mucking will be at a minimum . C. - MUCKING - The amount of dust produced by mucking and other rook-handling operations varies greatly with the nature of the operation. On open excavation it ' is probably of liVtle importance, but in confined sources as-in tunnels -and mip.cs ' the dust eonoentratlon associated with rook handling may reach dangerous levels* D, - DUST CONTROL - Methods for the oontrol of dust in rock excavation as . suggested by Mr. Hatch include* - (a) -- Wet Drilling and Wetting Down Rook Walls and Muck Piles -- In general it may be said that water is less effective against quartz-bearing rock than against silioa-froe material such as lime-stone. The usefulness of water is limited when freezing temperatures are encountered and it produoes objectionable working conditions . especially for overhead drill operators and is oertaisly to be avoided if a pneu monia hazard exists. A fundamental objection to the wet method'is that the dust is not removed from the eoene of operation but simply suppressed near Its souroe where it remains to be thrown into the air by a subsequent disturbance suoh as blasting. - general Ventilation - The purpose of general ventilation is to dilute the dusty air with sufficient olean air^to^brlng-the. oonoentratlcn down to a satis factory level. Two precautions are required* ,,..... 1st. - the fresh air Itself must be froo from dust and- 2nd - it must be properly distributed through the work- lags to Insure maximum mixing with 'the dust laden * air. (o) - Dust Exhaust Hoods on frills and Other Mucking O perations and Looal Sources of Dust - Effectlvo dust control can be secured by means of & dust trap whloh surrounds the drill steel at the rock surface. The dust-laden air is captured as it mer g e s from the drill-hole by the inflow of clean air into the trap. To bo offeo- tive, the inlet velocities must be` great enough to prevent the outward movement of the dust and sufficient yeloolty must be maintained at all points within the trap t o prevent settling and clogging. The oolleeted dust is'oonveyed by the air-stream through hose and piping to a suitable dust separator in which the air is freed from . its dust load and thus is discharged from the apparatus as clean air. .Traps 'of dlf-- .feroat designs are required with various drilling operations and special supporting devices are necessary to hold the trap in propor alignment with the several operat ing positions. (NOTE* The dust trap is satisfactory under many conditions, but again, under many other conditions has not proved satisfactory. RSB) . 254 0 0 1 4 9 8 1-` 00c JAM 014746 -72The dust dispersed during mucking, as well as that arising from rook drill iing oan be controlled by local' exhaust Tentilatlon and requires no elaborate ap paratus (d) - Personal Protection By Keans of Respirators and Positive Pressure Masks An effective respirator or a positive-pressure mask supplied with an adequate quantity of dust-free air provides the wearer with protection when it fits the faoe properly and is worn continuously in dusty atmospheres* Respirators and masks have a legitimate place*in the field of silicosis oontrol, especially to provide pro tection against infrequent unexpected dust concentrations but cannot be recommended as a substitute for dust control in continuous operations. 5 . I f ) 255 001499 18- ooooobo f JAM 014747 -73- PART III - M EASURES FOR REDUCTION OF TH E D U ST H A ZA R D . * . HCW CAN THE DOST HAZARD BE REDCED7 - The quantity of duet inhaled may be . mininired"b y the employment of these four methods outlined b y Dr. M. JCummel In "ffedi- oal Reoord"*- .- Bl* ' Suppression of Dust Near It* s Origin, by the use of exhaust draught, * dust fraps or water. The water has the advantage of a fly-paper effect on the silica particles, but the humidity created tends to favor infection by prolonging the life of pathogenic organisms outside the body and faoilitat- ing their entranoe into the body. ' "2. Admixture of Adulterant Dust with the silica whioh may assist in the expulsion of silioa from the lungs, retard the prooess of the disease or prevent the development of tuberculosis. However, the introduction of ^ an additional foreign body into the lungs is of doubtful value fraught * with potential danger and should be regarded very cautiously and oon- aervatively. "3. Proper Ventilation, in connection with other methods. ^ "4. Masks should be an ideal preventive measure but,' unfortunately, -- most of the masks stopping the dust also stop the respiration, thus ne- .. ... . cessit&ting their frequent removal. They should be of an approved type, *. properly maintained, strictly supervised and their use rigidly enforced." We do not believe that the use of water would have any outstanding offCots on raising the humidity-in most of the dust producing operations in the Petroleum In- dustry, any more than, for example, sprinkling one* a lawn would have. We believe it remains to be proved beyond doubt that the hum!difioation of air actually favors ' bacteriological growth to the extent that the incidence of disease from pathogenic organisms is raised signiflo&ntly. There has been muoh discussion an this subject, but little has been preven. Theoretically, it m a y be admitted that these organisms live longer in a moist atmosphere than in a dry atmosphere, but it is rather hazard ous reasoning to conclude that for the reasons stated, the use of wet methods in dust controlcaus es an inorease in disease. Sfcr Runnel s statement that most masks (we presume h e means respiratorel~that stop dust also stop respirations; is a little strong. There are available today respirators that adequately remove dust, without creating a* resistance to breathing in exeess of ,15 to 30 millimeters of water oolumn, and the tendency of-progressire manufacturers of swoh devioes is to further lower the resiatanoe. Urn during the war actually did fighting vhlle wearing respiratory protective devioes that had as much as 50 to 75 millimeters resistance. The resistance figures given for respira tors are measured at a rate of air flow of about three oubio feet a minute which is equivalent to the amount of air breathed by a person doing hard physical work* . Dust Respirators and Air Masks - Respirators- and masks of various types have been used since the days of the alchemists and are mentioned by Agrcola, Ramazzini and others.; Control of the dust hazard by means of respiratory protective equip ment is effeotive, provided* - (1) the protective equipment is .effioient, and - ' * " ' (2) it is worn continuously. , * 18-0000081 - Efficient equipment is available, but for continuous use, day after day, -this method 2ot> 001500 JAM 014748 -74- * of control cannot b e depended upon to provide the first line of defense) In this re ject It nay be likened to the use of personal immunisation as a primary safeguard against the spread of typhoid fever. bust respirators and air masks do, however, hare a definite plaee in the field of dust eontrol, especially as an emergency measure, as a means of protection on infrequent dusty occupations and as an adjunct to other more fundamental methods of prevention. Repoqts made to the National Silicosis Conference, called by the Secretary of tabor in February. (1937) to -study specifio phases of the silioosis problem and pre sent suggestions for its solution, oontained many recommendations by qualified au thorities on the subject which have been successfully employed under actual operating oonditions. Briefly summarised measures for the control of dust and the prevention of pneumoconiosis include A. - DESIGN PLAN! FOR DUST CONTROL - Much can be accomplished through design, when new buildings are contemplated or when old buildings are to be remodeled For instance, structural projections and ledges may be minimized to prevent the accumu lation of dust 'tiiat might later be released into the atmosphere by air ourrenta or b y building vibration caused by travelling oranee, vibrating machinery, and equipment that have large reoiprooating parts. The Engineering Committee recognized the faot that our present day engineering and structural materials for faotorles* do not per mit elimination of dmnvmerable ledges and projections without -prohibitive building and roofing ooets. However, -building interiors should be so eontructed that they m a y be easily cleaned by washing, hosing, vacuum cleaning or brushing. In some eases---- operations may be lcoated over gratings, beneath which equipment is provided for re moving -the materials and dust that fall through " * ' B -- 'PROVIDE BUILDING VENTILATION - Natural ventilation should usually be' considered only an adjunct In removing or reducing dust in the air Even though it is possible to*have high roofs in one-story structures which will give the greatest benefit from natural ventilation, such methods cannot b e relied upon to provide ccom plete protection in dusty operations. Where mechanical ventilating systems are pro vided, care should be taken to prevent strong drafts from open windows and doors de stroying the -effectiveness of the system. Guards and shields should be placed in -the vicinity of hooded and partially enclosed processes to prevent such a condition. . UJ DUST-TIGHT BINS - Dusty materials should be stored in dust-tight bins, ta3MT~or~"sneiosures,.but -each structure of this -type should 9b provided with a breather or vent stack -- perhaps ... the stack -- to permit the air displaoed during loading to be carried outside the building* Basements may be used'for storage purposes but should not be used for dusty manufacturing operations -. ; " D - ENCLOSE MATERIAL HANDLING EQUIPMENT - Excessive dust created b y mechan ized material* - handling equipment can usually be controlled b y provision of adequato housing and application of exhaust systems Some materials can be kept in a moist condition while being handled,* but when this is done, the material may dry out and b o dispersed 'into the atmosphere as dust, . E, - ISOLATE IAJSTY PROCESSES - Where possible, several or all dusty prooesses may be-isolated from the rest of the plant. This sometimes permits the installation of a more oompact exhaust system resulting in more efficient operation and loner main-, tenanoe coat. * ` - F. PROVIDE WET METHODS OF OPERATION - Water, oil, and other liquids may be used effeotivelyt - 0 0 1 5 0 1 ie_00 0oa2 257 JAM 014749 -75- 1 To suppress dust at the point of origin in such operations, as rook-drilling)* handling, pulverizing, and milling rook and crej grinding metal on grindstones) abrasive-wheel outting of granite and sandstone. 2. To prevent the re-dispersion of dust that has settled on the floors, walls, and other surfaces such as in the granite indus try and" in foundries. . G. - PESIUK EQUIPMENT TO CONTROL DUST - When new machinery or other equipment is contemplated, the manufacturer can frequently he encouraged to include dust con trol features such as exhaust hoods as an integral part of the design and construc tion. ' . H. -- PROVIDE EXHAUST SYSTEMS - In some operations, exhaust systems may he installed to remove dust at its point of origin. In many cases several n systems are preferable to a larger system. Any mechanical ventilation system should he de signed to meet at least the minimum requirements of local State laws or industrial codes, or lacking such requirements, should he installed aooording to the host ac cepted praotioe. .. . Dust.Arresters - Provision of dust arresters will prevent', hazardous dusts from being circulated Into" other "parts of the- - - plant or into the neighborhood. The location of dust arresters ... is very important, particularly if dry types of arresters are . used. Provision should he made for removal of the_oollected . dust without its 'esoape into the area where the arrester is loqated. , ; ) ' - ; y ' I.- - ESTABLISH MAINTENANCE AND GOOD HOUSEKEEPING PROCEDURE - Good housekeeping is unquestionably the cheapest single method of controlling dust. Maintenance goes . with it hand in hand. The best equipment in the world will not control dust if su perintendents, foremen, and workers are careless and disorderly A n their work. Eight suggestions, are advanced b y the Conference Committee* . 1. If dust-tight equipment is installed it should be inspected at regular and frequent intervals and all defects should be cor rected m s o ^ .... . Operations should be perfomed in a manner that will create the minimum amount of dust. - ' 5. Use water under pressure where possible to clean building in teriors* . 4 If praotloable, ocobine water with air for eleaning purposes* All cleaning should.be done, if possible outside of working - hours and men engaged in this operation should be provided with dust respirators. . B, Vaouum cleaning removes dustwithoutdispersing, itelsewhere, 6.. Brushing is particularly adaptablefor cleaning buildings of the older type of construction. . 7. Low-pressure steam can sometimes be used to -advantage. -- t 258 18-0000083 ooif)n2 JAM 014750 -78- 8, A responsible, person should be assigned the task of supervis- ing maintenance and housekeeping activities. Among other things he should make tests from time to time to j&ake sure that the dust control program is achieving the desired re suits. . . J. - PROVIDE RESPIRATORS - The Conference Committee was of the vtnaminous opin ion that "dust elimination must be given primary consideration in solving the sili cosis problem", Nevertheless, when known methods of elimination are not applioable or are ineffective, respirators should be provided as "a last resort and for oc casional exposure only. Rotation of personnel under these conditions is advisable." The report definitely states that there will always be places where other methods will be inapplicable and ineffective, and respirators will be required for doing the work, also that there will be situations where respirators will be the primary means of protecting the workmen. The scope of good use of respirators is consider ably beyond that of occasional exposure. The need of rotating personnel depends on the typ of work done and the supervision given the workmen. In same operatins, respirators are as much a part of the workman's equipment as his tools. Certainly, it cannot be expected that a person can wear a respirator for several.hours con tinuously - but how many jobs si* there that would require a person to keep the res pirator on continuously for an extended period, of time. The common practice in the majority of industrial occupations is* that the person is Intermittently exposed-and is afforded many opportunities for the periodic removal of the respiratory protec tive devioe. The two general types of respirators which the Committee considered suitable for protection against silica dust are _ ' . (a) Air-purifying respirators that filter out the dust particles. ' ' * (b) Supplied-alr respirators In which dust-free air breathed b y the worker comes to him from an uncontaminated outside aouroo. H o s t respirator manufacturers have submitted their devioes for testing and approval, b y the U,S.Bureau of Hines, and only those which have been approved should be used. (a) Air-Purifying rpes of Respirators - O f the air-purifying class, the type moatlcpnanonly used is the mechanical filter respirator for mechanically-generated dust. These respirators give no protection froa gases.and vapors._They generally consist/^* h alf f&oepieoes to which are attached an exhaust valve and a filter medium that removes the dust from the inhaled air; seme are equipped with a filter medium that removes paint mists and same fumes. They are light in weight -and inex-- pensive. Filter pads must be changed at certain intervals, depending- on t h e oonoen- tration of dust. Some 'types restrict the field of vision. The general requirements o f a safe and suitable Heohanical filter respirator are (l) adequate protection, (2) reasonable oomfort and convenience, (3) an acceptable service life period of protec tion, (4) easy eleanlng and sterilisation, and (5) low cost of maintenance in good serviceable condition. . . Studies of mechanical filtration by fibrous materials made b y such ageaeiea as t h e United States Bureau of Hines (U.S. Bur. of Hines, Tech. Paper Ho. 394 (1926) and U.S. Pub. Health Bull. Ho. 177 (1928)) and the Harvard School of Publio Health (Jours. Indust. Byg. 9,26 (1927)) revealed that filtering efficiency varies with the partiole size and the amount-of solid particulate matter retained; also that the resistance to , a i r flow varies with the amount of solid particulate matter .retained and.the rate -of * alr_flow. After all, the fundamental basis for judging the suitability of a respi rator is whether or not the amount of dust that is unretained or escapes, through the filter under conditions of practical use is below the amount that would be harmful .. t o breathe. This is not related to achy percentage efficiency. - In order to meet the `Bureau of Hines requirements for approval, a respirator must satisfactorily remove 00150.* JAM 014751 dustB Of the following size characteristics* 90 91 9 fi 80 it n 9 70 *nit titi 60 50 n it it 1.40 " 1.00 " " 0,85 " " 0.72 * " 0.60 " It will be noted that 80 per cent of the dust used in these approval tests is below one micron (l/25,000th of an inch) and SO per cent is below 0.6 microns. Canister* will not remove dusts of these characteristics and should not be used as dust respi rators. . In order to obtain the desired protection, it is essential that the faoepieees of the mechanical-filter respirators fit the face of the workman snugly but with a minimum of head-band tension. A simple practical test, suggested b y Carlton . Brown of the U. S. Bureau of Hines Experiment station in Pittsburgh, Pennsylvania (Jour. Indust. Hyg. Feb. 1937 Vol.19, No. 2, p.98), that anyone can run to determine whether a respirator fScepiece is making a tight seal, is to wear it in a high con centration of coal dust. The time of the test can be shortened b y blowing stream of air containing a high concentration of coal dust around the edges of the faoepleoe. The location and approximate magnitude of the'leaks are shown by''streaks of coal dust on the part of the face oovered b y the facepleoe. Another test, according t o Hr. Brown, consists of plugging the intakes of the respirator and then attempting to inhale. This type of test could well be supplemented by thp Coal dust test. .(b). Supplied Air Respirators - Industrial processes such as pneumatic drilling,ab rasive blasting and spray coating have introduced atmospheric conditions for which th air-purifying type of respirators are not particularly suitable. Certain kinds of pneumatic drilling are responsible for dust concentrations so high that they would rapidly overload a dust respirator. The operator of an abrasive blasting outfit must be protected not only against the inhalation of air containing high oonoestra tions of dust, but also against impact and abrasion of the head and.shoulder b y the rebounding abrasive and loosened abraded material. Spray ooating is responsible fre quently for pollution of the surrounding atmosphere b y a combination of partloulate matter (mists that .are liquid partleles or a combination of solid end liquid par ticles) and harmful vapors resulting-froa tho evaporation of the liquid vehiole of the cutting used in the spray gun. . ' -- Slnoe these operations are oarried out frequently in isolated plaoes and at different locations at various times, they do not lend themselves always*-to general oontrol measures. Therefore, supplied air respirators perform a definite serrioe.* The types in general use are those cranonly known as hose masks, air-line respirators, and abrasive blasting respirators such ss sand blast masks, helmets, and hoods. Supplied-air respirators have the following advantages for routine non-emer gency use over those of the air-purifying respirators such as gas masks, mechanicalfllter respirators and the combination of gas mask with a mechanical filter* - 3* NO resistance to inhalation. .. 2. Freedom from inward leakage of contam inated air. ~ 3. Protection against all kinds of contaminants and even against at mospheres deficient i& oxygen which will not poison or irritate the- skin, - 8-0000085 oO JAM 014752 001 SO* -78- 4. The Inflowing air reduces exoessive perspiration and tends to cool the face. . ` > - ' 5. When a hand-operated blower is used a second person la always present (With an approred mask, provided the facepiece is tight, the wearer o&n inhale enough air through the hose to ea- cape if the blower should stop). ' The filr-Lino Respirator consists of a tight-fitting facepiece, a loosely fit ting facepiece or "even a helmet or hood covering the head and extending down over the neck or shoulders. The air supplied to these respirators has been largely that ob tained from the ccapressed air source used in. the performance of the work, as in sand blasting, pneumatic drilling and spray painting. This air is frequently con taminated with objectionable and, In some instances, harmful substances whioh, to some extent, can be removed by means of air-purifying appurtenances. In discussing "Res piratory Protective Devices" in the February (1937) issue of the Journal of Indus trial Hygiene and Toxioology, Mr, C. E. Brown of the Uhited States Bureau of Mines wrote "Using air from the ordinary compressed air system found in industry to supply respirators is not to be indiscriminately reoanzsended* These compressed air. systems are usually bf the high pressure,"internally lu- ~ ~ bricated, reciprocating-compressor type. The air supplied b y these ... systems is contaminated frequently with malodorous constituents, euoh as vapors, mists and products of decomposition of the oempressor lu- briosst, slugs of water,'and rust from the pipe line. All or most of these contaminants oan be removed probably b y some of the ocmmeroial ' air purifiers sold for this purpose. A. pres sure-reducing meohanlam should be used also in the line to prevent any possibility of sudden aeoidestal blasts of higjh-prossure air from injuring the lungs of the wearer of the respirator. With a compressor of this typo there is always the possibility, however rare it may be in well-kept systems, of the generation of oarbon monoxide due to overheating of the compressor In- brioant. (Jour. Indust. fyg. 18,461 (1936))* This danger can be minimized or eliminated b y the use of temperature controls or oarbon monoxide alarms on the compressor whioh, of oourse, should b e so maintained as to pre vent the generation of oarbon monoxide* *>"The tread in suppliod-air respirators is to use speolal low-pressure, externally lubricated, positive-pressure air-supply devices. Most of the objections to the high-pressure reoiprooating-type oampress.or^do not apply to an sir-supply of this kind. Sinoe these devioes are not ooraaon in industry, however, it is usually neoessary to purchase a special one for use with the respirator* Sinoe air purifiers, pres sure-roduoing meehanisms, and special comprossor-control or alarm me chanisms are not neoessary, the prloo of this respirator ocmplete with air-supply device should not exceed that of the other type of respira tor without the air supoly system. . "The use of a special air-conditioning unit to regulate the tempera- turo and humidity of the air supplied to the respirator wearer is de sirable. " ' The minimum air supply for a respirtes* designed-to use all-the alr_for res piratory needs at a high degree ef efficiency is generally agreed among Industrial ' Hygienists to be at least four to six times the air breathed per minute. As 'a _ general class, respirators with loose-fitting faoepieees, hoods,*or helmets .require - . . 281 JAM 014753 18-000008 . 00151 nor# lr than those Tilth tight fitting faooploocs. There Is ease diffsrcno'b of opinion among veer* of respirators u to vhether or sot adjustment* should he prorlded whersby the wearer own. vary the flow of elr to aeet variation* in his requirements. It mss the opinion of the national Siliooais Conference Ccnaittee that definite reocnm'endation* for ell situations oannot he sade, hut for many situations, and particularly where tight-fitting faoepleoos are used, an adjustable flow is desirable and nay even be necessary) also, most workmen ean learn to adjust the air properly. On the other hand fixed-flow procedures re quire a slnlntes amount of Instruction and superrieiea and arc the most oonduoivs to safety under all conditions. . While Eose Masks and Alr-Llne Respirators hare many definite advantages the area of trarel of the wearer Is limited to the length of the hose, and movement* are handicapped to some extent by the hose. Manifestly, the air for the hose and the mask should be fresh and purs, but unfortunately this Is not always so. Abrasive Blasting Respirator - Abrasive blasting respirators eons 1st essen tially of a hood, with windows, that fits loos sly orsr the head and shoulders and , designed to withstand and protect the wearer's head, neck and shoulders from abra sion by tie rebounding of partiolea of sand or grit) and a supply of fresh air, at. least six euble feet per minute, blown Into the hood. Only equipment nhloh has met the United States Bureau of Mines test requirements and nhloh la approved by the Medical and Safety Departments should be used. ' (o) Aeoeptanoe and Use of Personal Rsspiratorv Proteotlon by Workmen - As stated ' in a paper by 6. M. Xints and B. C. Fowler of the United States Bursau of Mines (X.C.691S ftovl936) presented et the International Petrolew fccposition and Congress, Tulsa, Oklahoma, Hay 21 1936, selecting respiratory protective equipment is simple compared with'getting men to wear it after it Is supplied. Generally workmen wiXL _ _ wear masks readily in plaoes where they have seen ethers asphyxiated, or la some ~ "7 similar trouble, but they are likely to resist wearing protective equipment where * the dust cannot be seen or where the fumes and mist have no objectionable odor. There are three main reasons for such resistance* ' * First, inbred objection .to any new idea) Second, the feeling that the individual is a superman and oaa "taka It" without protection) and. ' .i .. .. Third, the inooorenianoe of wearing the equipment. In a aurrey conducted among the employees of the Colgate-PalmaULre-Pert Cam* jmny by Mr. 7, H. Vellaer of that Company's Insurance Department, It was found tint .. the men didn't like the disfiguring appearance of a "Bustle" over their fhoes. t m q survey also dlselosod that acme workers objected to the respirator beoause they thought it made breathing difficult when the real trouble was that they wera not breathing correctly. Breathing through a respirator should be demo deeply end slow ly end after the proper habit has bssm aoqulrsd muoh discomfort may bo eliminated. Quoting Mr. Uallnert "Foremen should appreciate that tho position of the straps that * : I bold tho respirator in plaoe has much to do with oemfort. They should * * learn *4iothor tho straps should bo worn ever the head on around tho ' aeok. Sate types hove two straps, one to bo worn around the nook,, t h e " . ^ other around the head.* , . ' ~ Probably the most effective plan in getting respirators worn la first .to "soil" * 0 0 1 5 0 6 18-0000007 282 JAM 014754 -Bo th* supervising personnel who la turn should "**11" the worker by education, possibly .* ' vi aoocnpanled by strlot sad fair supervision sad discipline. Employ* exposed to dust hsxsxds requiring the wearing of respirators should bo ocorinoed that it is essential to saerifios sons oonfort aad dignity to avoid serious eases of disability and suffer ) aindgj.ustEtvheirsy wporrokteerctsihvoeudledrihoaeveshoisitocwonntraecsptisrtathoer.faoeItsnrueqguliyrwesitthina*miannidmuefmfoorfthetaod band tension. It.cannot ba expected that the average workman will readjust a dif- . ferent respirator-eaoh day. Also, the psychologies! effeot of using a respirator worn previously by'another workman is not unimportant.* Although ha nay not say any thing about it, It Is naturally revolting to most men's principles of bodily sani tation to have to olaap over his fees a devloe that has been soaked with sweat .and Slrt of another man's fees and Into whleh one or more men hare breathed day after Lyl It is too muoh like' using the other fellow's tooth brush. Die beet praetioe is to mark every respirator so each workman can identify his own. (d) TJse. Maintenance and Care of Respirators - Personal respiratory proteotiv* de- viees must be maintained in a condition substantially the same as when reoelved from the manufacturer.. Depending m the density of the dust replaceable filter* should be changed frequently to prevent their beoenlng elogged and usually it la desirable to us* a respirator without a faoelet. However, if they are considered necessary, ' the faoelst* should be ohanged often to avoid akin irritation. A clean faeelt give* ,the respirator a clean appearanoa and remove* on# objection to wearing it. ` The Colgate-Palmolivs-Peet Company found that the habit of some worker* of removing their respirator* at Intervals caused skin irritation. Erexytim* they did this,, dust settled on the surfsoes that lay next to the'worker's fsoo and irritating partielos were transferred to the skin when the device was replaced. It is, there- fere, best to have the employe* wear his respirator constantly while under exposure. In sea* oases, ointments or petroleua jelly has helped to oreream* the irritating of feot of points that contact the skin. . ' ' - - . Whore a considerable nisaber of respirators are used, it is good praetioe to have a "Heeplrator Room" with an attendant who issues the respirators aad cleans, . sterilises and otherwise keep* them In good condition. Respirators may be oleanSed by washing aad brushing thorn with an antiseptic soap and warn water. " they should be eheoked for damaged or Improperly functioning parts such as rubbar valve seats and bead-bands. If defective, these should be replaced by mew parts. * WHAT MEDICAL CONTROL SBOPLD BE EXERCISED TH THE STNERTIQH AHD SOFEKTISIOW OP WEE WQR1CIHC ON DUSTY J0B3T - It la essential that adequate medical oontrol be ex ercised. Such control should include the examination, prior tq Initial working on dusty jobs of the worker to* insure that he Is a suitable physloal subject. This an amination should preferably Include X-ray examination of.the lungs whiqh pansits oleser oontrol with subsequent X-ray test* as well as being a protection to the em ployer la the event of aiqr later legal action. . A worker, to be classed as physioally suitable, should be in addition, daterained to be a nose-breather rather than a mouth-breather and the natural filter ing oapaolty of the hose should be found to be satisfactory. G, Lehaann (J.Ind.Hyg, 12,57 - 1955) indicates that th* "Sillootlo susceptibility of workers with poor amsal filtration is muoh greater than that of men with good nasal filters". Ho ad vises that jobs with a silioosls hatard bo hold only by mon with good nasal filters" and that mouth breathars are an eapeoially bad risk. Ho suggests that th* "dust re taining capacity of the nose be 'used as an index of the individual* qualification for working in a silioosla producing atmosphere". It is possible that 5ternst*in's taehniqu* for measuring nasal resists* ("Industrial Dusts - p.W ) eould bo develop ed into a simple procedure for scleetlag men boot adapted to dust exposure. According to R -inker and Hatch ("2ndustrial Dust" p.52) it is wise to eoleot 001-07 18-0000088 263 JAM 014755 ' ' >. tor durty Job men who are past the ago ot 40 and not young men Just tricing up a trad* n i worker engaged la hamful dusty operations should he periodically thorcughly re-examined, inolading X-ray tests. Particular emphasis should he placed ca any Indication of shortness of breath and chest palas Regulation* should he enforced concerning the time limitation of work of any maplcyees involved in a dust producing operation. Such Ccnpany regulations ooncom ing sandblasting calling for a fixed slx-nonth maximum period on such work, after whioh a minim* slx-nonth period away ikon dust produolng work should ho followed sore closely. h ' For protection frets a legal angle, tho worker should ho glren a Anal then* ough examination Inoludlng X-ray before being permanently transferred to s a c other type of work, laid off or discharged. * CONCLUSION . \ There is still a tremendous amount to he learned about jmeuaooonlosis and dust-produoing operations. One thing, howerer, is oertaln -there is a very definite tendency to require compensation for Industrial or oooupational diseases. Xf the compensation costs are to he kept to a minimum and the health and safety of workman are to he promoted it will he necessary to make further studies and to promptly adept adequate precautionary measures. Many of those are now In effect, tho others should ho put in force as soon as posslhls. After years of study and direct content with the Dust Problem, hr. Dan Barrington, Chief, Health and Safety Branoh, United States Bureau of Mines, has earns to this conclusion (Eng. A Min. Jour. March 1937' pp*. 119-21) with whioh wo are heartily in accord _ _ . "In the maseiof uncertainties connected with almost all phases of .. ' 'the causation and diagnosis of dust disease, about the only really will-determined fact available is that breathing largo quantities of duet (or possibly of certain dust) ever extended periods is likely under some conditions to he harmful to health and that subsequent al leviation or cure is difAoult "or impossible. Therefore, it would teem to he logietl to try to prevent duet fermatlco thus preventing..... ... it from harming workers through respiration or otherwise. Here is a real Job for the engineer, and little or no help oaa ho oxpeotad in these vital fuaotloss Ikon any agency except the engineers and operat ing officials. . "The meet harmful of the ordinary dusts to breath is probacy ___ silica duet, but, on the other hand, net even free ellloa, supposed ly tho most detrimental of the ellloa duets, is harmful unless it is breathed, in oeaaldareble quantities and over extended periods. Bo htaaan being ever lived any considerable time on this earth of ours without breathing sllioe dust (free silioa dust), yet by no means all of tits people of the world hare or have had silloosls. In ether words, the Quantity of dust taken into the respiratory organs is a oontroll- . ing faster In dust respiratory harmfulmess. * "One ocumon-sense answer is that any atmosphere in whioh dust is __ " visible to the naked eye is certainly too dusty to bo bkeathed with - ~ safely by h m a n beings, and the wise, farsighted, human employer will" . Immediately start to decrease the dust content in any atmosphere there duet is risible. After he has eliminated visible dust, there may 00150 1 18-000089 i SS`l JAM 014750 still remain enough very small invisible dust to cause harm to the health of those who breath it but in any event if he has exerted suf ficient well-direoted effort to remove the visible dust it is oertain that muoh of the smaller invisible and probably most harmful dust has also been removed " . "Manifestly, if dust is kept out of the air breathed b y workers the latter oannot aucoumb to dust disease of a respiratory character," e ' i * ' In olosing, we acknowledge with gratitude the support and oooperation of Dr. W. J. Denno, General Medical Director, Standard Oil Company (Hew Jersey) whose.:' , vision and active interest in Medioo-Safety problems made this Dust Study.j>onrible. We also appreol&te the advioe and assistanoe rendered by ' Mr. W. P. Taut, Direotor of Researoh & Development, N Mine Safety Applianoes Coiapany, Pittsburgh, Pennsylvania. . i " ` " Dr. Leonard Greenburg, Exeoutiye Direotor, Division of Industrial hygiene. Department of Labor, State of Hew York, Hew York, H*Y. Dr. R. R. Sayers, Senior Surgeon, - - ... ..1_ G, S, Public Health Servioe . " Chief, Division of Industrial Hygiene, national Institute of Health, Washington, D. C. Mr. Daniel Harrington, Chief, Health and Safety Divio ion Halted States Bureau of Mines, Washington, D. C. Dr, A. J. Lanza, Assistant Medical Direotor, . Metropolitan Life Ixmtronoe. Company, Hew York, H.T. jjL j-: . .. . . . ^ ....... "rit- . . :isj-.; . Mr. E. H. Barlow, Chief Engineer, ' .. .. < Standard Oil Development Company, Elizabeth, Hew Jersey. ' ' . ' /V iV * Mr. H. H. Blakeslee, Department of Aooidesb Prevention, ^ r. Amerioan Petroleum Institute, H e w York, H.Y, -f: : Hew York. H.Y. July Fifteenth 1 9 ' 3 7 285 R. S. Bonsib Chief Safety Inspector Standard Oil Co. (H.J. ) 18-0000090 001509. . *M**VtA 6 SoMdOnt rfNifi.HornH* JAM 014757 k