Document km9ZLYZDB2aw7Mxq2QDOo2YLn

\ DUST PRODUCING OPERATIONS IN THE PRODUCTION OF PETROLEUM. PRODUCTS; and Associated "activities: MEDICO-SAFETY SURVE.Y. BY Roy 5. Bwuib,U.A.,E.W 1 enter evtrrnsrfcTb* . 1TAMO**0 at MMMK ; rORCWOKO T- ' willifi J. DiniU, U.D< ecncM. utotetL oetrat : iTJMa*ro at coupmT.tH.Jtr. le&kssi STANDARD OIL COMPANY^N. jj. 30 ROCKEFELLER PLAZA; ' NEW YORK.N-Y. - | PLAINTIFF EXHIBIT! JULY -- 193.7 nous' fastys t . KTUBtftwmWWIOUWB . fMT f IMS huin4 to*r K MtXitO *~v--^ iir/.jn ^02rOOOOO<).L_ J, *001420BfS 176 SC-API-0950 FOREWORD Btoiiut It is the doty of Industry to protect it* employee* usd booaus* no ocoprahanslv* survey ofth* hazard* Incident to oc cupation*1 dust problems had yet been cede, It was felt that har* mi an opportunity to render a serlva* to tho potrolaua Industry - and Its eaployaas by pairing suoh a survey. It la hoped that tha information priaantad In this bullatIn will assist In finding propr answers to sons of tha many questions sdiloh ban recently arlsan coneeraing the health hatards of amploy- aas whosa work lnTol-rse exposure to dusts of various origin. In attempt has batn sad* to oansolldato opinions from th* most experienced studantt of occupational-dust problems to thorn tho ralatiyr hsxxrds -of-daets -and h duration of*xposura which any prove harmful to tho worker. . rurtharaora, a study of tha praralaaoo of dust partloloo oo- ourrlng In various operations In tha prtrolaua industry has hocn asdo and included in this reportj also a description of tho pro- tootivo dovleas and equipment provldad for tho protaction of tho workmen- ' . This raport should ssrrs as a gulds to operating executives and safety engineer* in handling personnel and In providing adequate protection In dusty oooupations. It should also resolve many of tho fears and questions of industrial workers in these occupations. . Tha study confirms an opinion that dusty oooupations, thaw oughly understood and Intelligently handled should result In no serious disability. _ Hillard J. Dane. H.D. General Medical Director Standard Oil Company (K J. ) 16-0000002 001421 177 MEDICO - SAFETY MEMORANDUM DUST PRODUCING OPERATIONS IN THE PRODUCTION OF PETROLEUM PRODUCTS ' AND ASSOCIATED ACTIVITIES CONTENTS PICE IHTR0D0CTI05 PART I - DUST AS A HEALTH HAZARD I - HHT IS TES COST PROStXH SO IMP0HIAHT7........................................................... 2 11 - WHAT IS MEAHI BI "DOST"!.............................................................i.................... 2 TTT _ WHIT ASS THE FHTSIOLOOICAL EFFECTS PSCCOCEO IT The Inhalation of Cost.................... 3 Slliooola In Gatnl......... ......................... 4 First Ihtloul SUlooiU Conforonoo.......................... 4 - --SAHaatoola...................... 3 Asb*jto*i*......................................... T XT - WHAT T& THE KUXHOl PBOOSSABtS DOST COVCOniXXOn Formula Tor Determining ttadam Ftrai*title Coao entratlon of.SlIloa la Tha Air Hreathed... ............ .. 7.. S - Safa Dost Conoentratloaa, Iaprlnger Saaplte...T....9 T - SOU HAT TES COECOTSAIICS ASD CEASACTZB OP 1HD0STRZAI, COSTS BE PSTSHHTHEPt.......................................................................................... . 9 . Tha mplngar Apparatua..................... .......................................................... 10,11 Tha Zeiaa Ionian!er.'....................................... ............................. ............... 11 Tha Bavaoh A Loot Dost Counter....................11 PART D - DUST PRODUCING OPERATIONS STUDIED WHAT ARE TES PRINCIPAL DOST HtODOCIHO OFERATXOSST I SATO-BIASTIIO................................................................................................................................ 13-15 n PILTZJilRO OPSRATIOIC............................................................................................................ 1S-2T A - mtar. Clar or Fullora Eartht What 1* Plltar Clap er Follara Eartht........................ 15,IS Hon la TITtar-Clay Hlnad and Tra^arodt....................... IS,17 ' Hon la mtar Clay OaadT............ ;....................................................... 17,15 . Burning" Clay...................... 18,19 Charging Plltar*......................... 19,20 .......... Duaplng Plltar*........................................... 20,21 Competition *f Plltar Hou** Alr'Borh4~D<rc................... --21 Control of Plltar Clay Dust......... ............................................ 22 ) -- Contact Clara . _ Main Can*tltotat* of Cootaot Clays........................... What la "Filtrol" and Hon is It Protaadl...................... What la tha Chemical Conpoaltloa of Plltrolt................. Hon.la Contact Clay TJaadt........................ --............................. 22,23 23,24 24,25 25,28 18-0000003 001422 173 k -2- pagi C - Doe.* Black g- Charred Boaei Hew da Boat Sleek Bnd*#****M*#**************** Zl OT - rHStgATPR? bpS*AttOESi ' "' ' " A- What Initiating Matsrialst. ......................................... ............................. 2T. B - Whet Art the Principal Insulating Operation! end * How Much Dust It Produced During Such Operational........... 27 Insulating 12" Steue Lint*...................... ...................................... 27,28 Insulating a 750-?ound Cracking Coil Accumulator........... 2# Insulating treating Plant Acid Suction tine........ ....... 28 Insulating Cracking Coil Hot-Oil Linas............. ................. .. 28 Slscantling or amoving Old Insulation.................... 28,29 Crushing Scrap Asbestos............. ..................................... ................ 29 Crushing Old Cork Insulation,................... .......................... 29 n - snrrrro OrS>jt;:c:s _ What Is Outita and How Xa Ik Appliedt. .29.39 3eaoval of Cunita'Llntlrj...... o'o ' .(tVl'eti * -------30 4* WEUHBI a cortnio OPStATIOXS, X - Welding Operational 1. Elcotrle Are Welding..................................... * 30 What ara Coated Usetrodesl.................... 39.31 What do Xh*se Electrodes Contain and What - Products Result Prom Their Heat................................. ... 31,32 What is The Amount and What Are the . .- . Charaotaristlcs of Fuses or Oust Produo ad '' Bp the Tarlous Elsotrio Are Welding Operations....... 32^5 What Physiological Effects on Welders is Produced hp The Use of Coated Electrodes............. 3S-3T - 2. Ctty-Aortylene Weldiag.,.................................. 37 runes or Dust Produoed by Csy-Aoatylens Welding........ 37 ; * turtrine oj- Cutting Operational .* X. With Osy-Acetylsue....................................... 37,38 - Fumes or Dust predueed by Qxy-Aastylaas Burning,......... 38 * 2. With Batumi Gas........... 38 C - Health Retards Preduoed by Welding an# Cutting Operations.... 38 ^ TL - 0M3PCT0 OPSUlTIOgSt * What Is The Composition of Grinding Whsslst.***.* 39 Is Abrasive Dust Hushdl.............................. ...a......... 3J9.40 1 - Hhi* ire, the ttKS faOTfgtly KM TTVSi Ktettge . the Ouaatltr and Charaoter of the Dust they Prodooft.-------------- 40 10-0000004 001423 179 1 ' 3- - PAGE 1 . uumol FLOOR TOO/ CRIHDERS................................... . Dtt*t Produood by Tula Floor Grladors...................... 40,41 41,42 B r tAHpErt BE3CH CRIHDERS........ ............................................................. - - '^asryTi'Bduuod'tytoadoaAsnah. Grindors......................................... 41 41 Chsrsetorlstlos of Dart produood by tsiido* Wtodow...... . ....... ...... .42 t. . C - SIHGLE FLOCK TOOL ORJXDEXS................................................................... Dust Produood by Slnglo Floor Grinders.......................................... Ounctirlitlti of Dust Produood...................................... . - 43 43 43 D - TOIYERSAL GRISDSRS........................................................................... Dust Produssd By Oairorssl Grinders........ ....................................... Chsreetersitie* of Dujt Produeod............................ 44,45 44 45 2 - SURFACE GR1SDERS............................................................................... Dust produod by Surfsao Grindors.............. ........... .. 45 45 7 - LAHDI3 TOOL GRX3SES5. ................ .................................................... 45,45 ~ part~f^oduo*d-by Ltmlls.Jool Grindors.............. ..................... . 45 o.m3imaina........................................ '................................... 45 Dust froduood by Tohkoe Drill Grinder..............44 2 . AOTGKAIXC CtRCGLAX SAW SHA3PEBX30 HACHIKS................................... . 44 Dust Produood by Tank## Drill Grinder......r........-i....... _ 44 I - AUTCHA11C BAUD SAM GRINDER........................................................ . 44,47 Dust Froduood by Ivtntlo Bead So* Grind#r................. 47 j - Asrotttxxc aunt saw up grxsder. ...................................................... .. Dust Preduood by Up Orludor................................ 47 47 X - PLAKIHG miX BLADE CRUDER................................................................ Dust Produood by Blsdo Grindor.................... .......... L - LUDESMAA CUTTER CRUDER.................................................................. - Dust Produood by Cuttor Oriudor....................... 47 47 47 47 K -- GABO SAM BLADE CRUDER.............................. .......................................... - Dust Produood by Gone S* Blsdo Criedor........... 47 47 X - EDGEA SAW GRINDER.......................... ....................................................... 47 Dust Produood by Edgor Ssw Grinder.......................... . 47 O ..JCUluuUR SLAB. CUT--OFF SAW CRsdi/H............................ 47,45 Dust Produood by Cut-Off'Ssw OHMor. * * i ...........45 P . "BOG I21IE? GJUBDEB......................................................... ................. . Dust Produood by "Hog Khlfo" Griador........................ 44 45 Q - CUTTER GRIBDER................................................... 18-0000005 ~ 45 Duot Produood by Cuttor Griador........... . ......... 45 - Wat Froosutloas Should Bo Adoptod For Ssfofoordlog Zhooo Who Vso Grinding WheolsT.............................. 00J. 42 4 45 130 i Control of Oust roa Grinding Wheels.................. . ra - maat.TM fowdemsd ok poltehizsd materials PACE 48 (1) .Hydrated Liao................................................................................. .. ... (1) liaf QiilfttSai...................................... 50,51 . What Physiological Effeot 1 produced by tine Boot......................... 51 ^ 1 - METALLIC ZH>C TOST, ... . Typical Serin Auljriii............................ ...................... .........................SI hut rreduoil.................... .............. ................................................... 51 '.That Physiological Effect 1* Produoed by Zina Dust........... 51 C - ASBESTOS *FLOAT"i Dust Produced.................. 51,52 Physiological Effeot of Asbsstos Psrtlolss................... 52 D - C20C3D niClt Dust Produced.................. .......... .............................. - -fty*4slug4sal-Efust.-of411aa_Duat^.................... 62 52 2 - STOPHORi - . (1) Sulyhur'n.our............................................ 52 (2) Crodo Sulphur.........^.................................. 52,63 Physiological Effect of Sulphur............................. 53 . ?. LITHARGE Dust Produood................................................ lTecessary Precautionary Measure* When Hand!Ing Litharge.......................................... 33 53,54 a - SOU. ASH* ' Dust Produeed............................... .... 64.55. H - IA1C or "SOAPSTOXE** . Duat Prodused............................... Physlologloal Effects Produoed by Tele Dust. .... 65 .... 55 X - GRAPHITE, . Duet Prodused.................................55,58 J . SLATS FLOOR, ' Dust Prodused................................................... " Effect of Slate flour os the lusgs........................... 55 57 K - GRIDDING tORIS ROOT, Dust Prodused................................................................. To Uhat Extent is Derrls XaxialL.................................................... -87 57 L - GUDDCtO PXSETHMH ILOUEBSi Dust Prodused.................^ ................ 57,58 _ ' U . taxon Duet AMD PAOUEO BPUX* POUDEIs Prodused.................. .......................9'0oooa rilling Cane................... . ` 001425 181 -6- PAGE rax - ciaanaw totes asp EBBS* z . aucxim coil soaezvo ntotisi MM4JM*******MMI**t* 59.89 n crack no coa. tubes* Dost Produo*4............. ...................... ....................... . 59 nz WATER HEADERS ACT BOILER TUBESi . k Butt Produo*d.......... ............ ........... ..................... Caopo.it lan of Duat Iran Front Water Wall Etadar. 59 <0 IX - FOtHDHT OPERATORS i A potmbro moiter keial mo sard moulds. B "SHAxno our" CAStnes................................. U CLEA3I30 CASTnCSi Pr*llnlnry Cliulog.......................... Turtleit........................... lly-lwmo; mu.... ............... Tartling Barral*................... Alr-Blartlng..................... loiflt Su((b( Uheela......................... Flc* Sala( end FoUtMaf I&hIi. Con* Grinding Wi**ls............... XTtrt[< IkutlaNi of Cleaning Boo* Air.-- 0 CORE KAXiaO..................................................... . E SEPARATION OF BRASS FOUHDRT SIEIOTCS, 60,81 61 61 61,62 62 .... -ti . 62.63 63 63.64 64 . 64 64.65 65 I - HASOmS OPERATIONS* I II _ hi it T TI - XEASXUO OUT'STILL FIRE BOXES;................................................................... CHIFPIEG OR CUITIBS CONCRETE.................................................................... - csurnta mortar from beiweer brick............................................... - causHno ms brick.................... - SHAPIRO ms BRICK OR EHEET WHEEL........................................................ . DISKAXtURG ............................................................... 65 ' 65 65,es 66 66 66 H . WOODWORgnO OPERATIOSS. A BOX SSOOK KUUFACIUSE R*t axing...... Rip*awing. .... Cut of Suisg. Planing....... Dilation* of Shoofc-Faetory Air, 67 67 67 67,66 --68 B - BELT RASTERS, SARD DISCS AID SPXXUXS OR CILHDGRS* (a) Balt Sandart................. .....'........................ ............. . ft) Sand M*o* or Uli*ele.................... ............ (e) Sand SpIndia* or Cylinders........................... 69 99,99 69,70 C - MAXI3G U00DE5 CRATESt (a) Band Saxo............................................ 18-0000007 (t) Railroad Sans................................... TO 70 00142G 182 PACE XII - RCCK EXCATATIOWt .. . . b A-DHHXXm.................. ............................... ................................................................. B - BLAST333..................................................... ............................................................. C - HTOEE....................................................................................................................... 70 71 71 ~ (ft) Wot Drilling and Wotting Coxa Rook Wall* usd " Mask ............................................................................................................ (b) General Tentllatlon.................................. (a) Dust Exhaust Hoads oa Drills sod Other Muoking Operations sod Loosi Sources of Dost................................. (d) Personal Protection by Means of Respirators sod PosltlT* - Pressure Ktski................................................... 71 71 ' 71,72 72 PART HI - MEASURES FOR REDUCTION OF THE DUST HAZARD . ROM CAK IS DUST HAIAjU) BE REDUCED! A . DESIST PUTT 701 DOST C03T2CL................................................. 7+ B - 73CTI3E BCHDm> TESTHATIOH...................................... 74 .........-0 -- .MOKi-sPsrjAaiaaAis la-sctt-Ticgans.----44 . D - E3CL0S2 KAISRIAL BAHDLIEO EQUIHSar....................................... 74 - ISOLATE DUSTY PROCESSES..... ............................ T4 P - PROTIDE WET KETECD3 OF CPERATTCH........................................... 74 C - DESX'V TWXrtSn TO C03TSOL DOST.....'................................... 75 H - P2C7ES EEia: STSTHIS.................................................... 73 f . ESTABLISH HU3RJDA1ICE AHD QOOO 30USEEXP130 PROCEDURE... 75 J - F30YDE RESPIRATORS........ ........................... '..............".............. - 75- -- is) Air Purifying Types of Respirators............. ;........ 78,77 b) Supplied Air Respirators.............. 77 ' The Air Llue Respirator........................... 78,79. .AbraslTe Blasting Respirator................!..... T9 (o) Aeoeptsnee sol lit of Personal Respiratory Protection by Workaes............................. 79,80 (d) Use, Itslctensnoe end Core of Respirators............ 80 WHAT MEDICAL COHIROL SHOULD BE EXERCISED IW THE SELECTIOlf ab> supsansiog or heh wohcpp ox aosrr jobst................................ so.bi PHYSICAL EXOZRUXIOHS........................... DESIRABLE FHTSICAL QUALI-XCAIICSS.......................................... RZ-EXlHUmiOHS............................................................................ TUX LHCIAIZOHS 80 81 81 CO3CLQSI0C..................................................................................... 81,82 18-0006008 001427 133 STANDARD OIL COMPANY (Incorporated in New Jctxy) 30 Rockefeller Plw. New York. N. Y. MEDICO. SAFETY MEMORANDUM DOST PRODUCING OPERATIONS IN THE PRODUCTION OF PETROLEUM PRODUCTS AND ASSOCIATED ACTIVITIES k 12I3C3TCTICS - Lose looked upon os objectionable, dost today Is also reoomlx- t os dangerous - eepeololly with record to occupational disease (naousoooalosls} sad dust explosions. Since the dust encountered in the production, of Petroleum products snd oss00loted operationsore non-explosive under ordinary working oomlitiocs, no further, attention will be deroted to this phase of the dust haxard. Studios hare rcreeled that the time oleaeat (exposure) and the eonoastratloa and else of the dust particles art major footers in produoing health hasards. Here tofore difficulty has been encountered, in dstsrnlnlng actual duet ooooontratlons and sites of the pertiolet, but recently developed instruments suoh as tho Hsiss'Xeniw mstar sad the Jansoh k Lomb Dust Counter sake it poosiblo to obtain dust counts and 0Stloote sits of dust partiolos whioh, while not abeolutely aacurate, are Indicative of the dustiness of the area. - the data presented in this.acmoreadum are based upjri material taken from the available literature on the subject, upon field investigations and aonfaroaoss with taohnloal specialists end upon 1008 actual dust counts node with a Zeiss lonimeter, using a Z0 to 80 micron (a micron is about l/l5,000 of aa Inch) porcelain filter. In the report of the Preventire Engineering Coraaittoe of the Ur Hygiene Foundation, Profeesor Philip Drinker of Harvard, ohaimaa, and other teohaiaal specialists on the Committee writes "If the breathing of dust causes disability of any sort - silicosis is only one manifestation - then it follows that there must bo torn* degree of air cleanliness from which no disability will result to the average man during the average working period. . * "There Is no satisfactory aedioal answer at prssent to this question, but the engineer Is naklag a bad mistake if he lets men breaths heavy dust eoasen- tratlons of say material. Zf no'other reason for dust control oea bo found, then 'one should read, traasorlpts of some of the recent rults at aomens las* in ----which faminetle-deangoc-for-alleged eiliswli memo granted-to..seen-she,breathed dust sontainlng little or no silica. The Courts and Compensation boards an ' not ispvsieed with subtle dletlnations betneea dusts with 10)( sad 40g( guarts, ospooislly when nedioal exports are reluotant to aake definite itatCMflbi as to the oemparative ilrniflcence of suoh differences. ' . 18-0000009 "It would bo well to realise that men working in dusty trades suffer far uore from respiratory troubles of all kinds than do non who work in clean air. The evidonoo that oxsoaslva dustiness.of any kind is harmful is beyond argu ment*. 001428 184 -2- PARTI - DUST AS A HEALTH HAZARD X - VSX IS T3E Best FR0BLB1 SO mPORmni - ilthough the subject of th health of workers la tarty trades ha* been receiving considerable attention from student* of' lpdtoial frylane far ^ ymlnr rf jiui, the seriousness of thla problem ni not fully realised until" it was brought""fhtypiy'to'1'out "uttaatdoe'by-thc saseAanlily.gpow .. . Inf wave of Umolti Instituted la behalf of tho victims la our seaman, law oourto. hy tho magnitude of tho generous verdlota awarded by the jurloo cad by a reseat doololoa of tho Federal Circuit Court reversing the substcstlol award of .a Jury la n Few Jersey eue (Pennsylvania Pulverising Caopany vs. Hired 0. Butler), oJtng to these developments, the problem eenaot be Ignored or brushed aside os merely another fora of "raoketeerlng" by unscrupulous lawyers and ooasplrlng dootora, Oodglag the Issue cannot provide the needed solution because even the aost tmsorupulous lawyers eenaot create a pathologic lung at will and, furthermore, even the most tkeptio of ooroners frequently finds himself corroborating a diagnosis by his postmortem examination. Enlightened Industrialists and the mediecl profession as well as tho bench end bar, hare ease to the realisation that exposure to eertaln hinds of dnst, sunk as those containing considerable amounts of quarto (ailloe), has Increased t&e unhealthy bodily condition and death rate firoa respiratory diseases) idiUe aetalllo dusts, such es lead and Its aeapounds, hare been associated with general eystemlo 1 poisoning of workers. "Sllioosis" is new a definitely recognised disease which Is' destined to become one cfthyTerBaoifaBd-noct.-ccrdcus-of eeeupatlonal.diseases-of the future because the mmher of workers In dusty -trades It larger than almost any other group exposed to a Ingle'known Industrial haxard. tho KoCaffrey let, which beeerne effective September 1, 193$, emending the Hew Fork Compensation lew, inoluded allioosls as an occupational disease subject to compensation. - . 'Sixteen states, as -mil as those ef the Federal Corerpacnt amtof Eanall,. - Puerto Xiao, and the Philippine Islands (0.S. Dept, of tabor Bull, Bo. 62S,Bur. Labor Sta- tJsties), hare Workmen's Compensation lots' which inolude compensation for occupational diseases, either expressly or by Judicial Interpretation, or specific occupational disease acts. _ . . XX - WHJLX IS HEIST 8T rfDtJST"T - looordlsg to Webster's Thm.brid gad Dictionary, "Boat" may be defined ae fine, dry particles of earth, or other matter sc oossainuted that they may be raised and wafted by the wind) that rhloh Is oroahled to minute portions) fine, powder, la pointed out by HillIp Drinker In a. paper reed before the Chemical Section ef the Xatlord Safaty Congress (held la Identic .City, October. ' 1934), dusts include dl types of dry earthy particles smell enough te be blown about by ordinary air currents. Dust suspensions may be generated sc the result of grind* lag bleating, or ooxslautlng proaess) or they nay result fron the headline of fine ly divided materials as la mixing .processes, la weeping, or the blowing-about of wood flour, plant pollens, or loon rood dust. There la no chemicel limitation law piled by the ten "duct* while the range In site of dust partloles extends from the sub nlerosooplo. to smell sand grplsa Hr. D. Barrington, Chief Health and Safety Branch, TJ. 3. Bureau of Ulnae advises that Aunt as applied te health and reeplratery conditions may be wet as well as dry. Coder sene eoodltlens, cash far example as la wet drilling dm-evU>ear-thc-escaping.mlr.frpn the drill hole nay (la fact generally does) contain a certain amount of entrapped solid material WUohnadoiibtedly'liwen rather this dry, yet It remains In the air uffielastly long in some lartanoe* at least to be breathed by the workers to contribute to possible health trouble. Xhs also of dust of importance from a fayglenlo standpoint are those under tea microns. In fact, the else< fovml In Industrial atmospheres are under two microns for tho larger majority ef pertleles, say 90 to 95 per seat, Physiologically, there are al most as nany different classifications of dust so there are authors em the sihjeet. However, according to Professor Drinker ("Doit, Foies end Smoke". International Le ber Office, Occupation and Health ToX.1, 930, P.603) all of these classiflaatloos ' 001420 ia-0000010 185 -3- ar without auoh fnotlstl lmportanoe, lUofladUly practloa la ladmtty thi bioftl ,f'*ot la exarolsad more frequently by dust* aaatly af nixed origin. Besides. wha.t la sort Important la the physical and ohamioel constitution of tho dusts sad oonaequent- thel action ea tha aystma. . 'u - * . Ill - WHAT JLRE TEE PHISIOWOICAL EJTECT3 PRODUCED BT TEE ZXSUJISK> OP DOSIT To --twtinmPul-ftiewia reapirahncy rlRKPotat,' dust must ha of suffloleat flaesa to pass through tha nasal filtars aad ha ratalnad ln*th*ll*WIilnifltTrt -mirewae) 'f.Aha luata. Partialn* found in autopsled lungs art of tha ardor of ona mloroa (a mioron la 1/1 cf * lUUatar or about l/25,000 of an ladh) or 1** la alia - about tha slit of tha oecaon baoterla. Sane dust particles found la lungs ara aa largo aa b flra er ala nlerons although that a sisas ara rathar aaoeptlonal. ' Thar a ara flra dlstlaat types of reaotlen produced In nm aa tho rarult of iahsl- lag dust. Ihasa raaotlons nay ba broadly classified, based on tha primaryeauso, as foiloust . . - (a) Those whioh result la lung flbrosla, scanonly referred to aa jnauaoooaloaia. Thaaa dusts aoatala free sllloa, asbaatoa, eta. BOww ' rrar, it Is not aaoossary for fibrous tissue to ho formed la order for tha disease to ha olassed aa "PaeuBooaaioils"* '' * (h) thoaa vdiloh ara toxla and ara absorbed into the blood stream rush aa lead, eadalta',ote* . ' - (o) Those which result la shat Is eenoaily referred to aa ssatal flats fcrarj auoh aa lino oxide, oto* -' . (d) Thos a whloh ara allargla la eharaetar, such orgaalo dusts aa pollan, _ pulTarltad wood end flour, oto. Tho hreathiag'of pulrdirltod wood- ' and flour If frequently associated with tuberculosis. ' ' (a) Those comonly rsforrsd to as "aulsaaoo dusts". Those nay oans a Ir ritation of the respiratory traat or passages and nay osuso eoa- sidarsbla disaasfert, also haadaohes of tho dry "nasal" jmssago ar sinus typo aad exposure to than nay ho assooiatad with a high 1* oldanoa of respiratory Illness. . Tha rata and extent of those raaotlons are dependant upon tha raalataaso of the indi vidual. the exposure period (oonosntration of partiolos .and length of exposure) ternporntura and humidity of tha air,- rata of woric, and tha pqroantago of lngradiasta wfaloh are barmful. Owing to tha length of tine required to obtain a reaction by twhai< netboda, tho United States Bureau of Minas and tho public Health garrlao adopted about twolTa years ago, a method of Injecting snail quantities of tha dusts to bo studied Into tho peritoneal cavity of gulnoa pigs. ("Response of Peritoneal Tlaaua of Ousts Xntrodueed as Porolgn Bodies* by Dr. John W. Millar, Or* LB. Sayers aad Wk P.Tast, Tour.Anar.Mad. Assoa. Sept, 22,1934 - ol*103*ppa* #07-111). It was found that ldcoHaal.raact.iAns jeonr la saoh animal Instated with .tha same dust under tha aana eon> - dltlens aad raalail la the aaao tint Interra! tttBTU)Wthk " Those- rsaotlauawsre nsstisUytkt aaao nlorooooploally sit that produced la. the lungs aad tho gross appaaranoa of tho dust nodules was aufflalantly differantlmtad to. afford a aooaa of classifying tho phyolologloal raiponsa to tha duata. Thors arojthroo types ofraaotloas An absorption or dissolution of tho dust. A prollfsratlTo reaction. An inert raaotloas. 001430 18 G 1 In th Inert reaction, the durt neither caused an Increase in the sis* of the nodule* nor disappeared from -the tlssui'sj Instead there era* nor* or less a change la It* dis tribution. Soapstone, carborundum (SlUeon Carbide), jeweler'* rouge (Terrlo Oxide), asthraolt* ooal, bituminous oo*l and oertaln filter days hare Inert reactions. Cal- olta, limestens, precipitated osloivm earbonate, gypsum, and Portland Cement sxhlbib- ed an absorption foaotieeu Quart*, ohat. oertaln filter olays and Hint produoed a proliferative reaction. * * ` .. the physlologloal response to the Injected dusts were found sufficiently well narked In 90 days to determine the -type of reaction, particularly W*ere the reaction was one of absorption or proliferation. Since the reaction elloitsd by dustwa* oonetaat and unlfona in all of tha animal* Injeotad with th* dust. It Is bslloTod hthat this responta of perltonaal tlssus to various dusts oan bt used as a tsst to de termini the possible hamfulnej* of industrial dusts, the flbrosls-produolng properties of a Georgia filter olay (10-80 a*ah (rads) a simply of American oontaot clay and a Gorman oontaot olay wore tested by the Intra- peritoneal Method, under th* direction of Dr. R. R. Sayers, Medloal Officer la Charge, H.3. Public Health Serrloe. Th* Georgia filter olay showed an Inert reaction with a alight tendency towards a proliferation in tha 90-day teat. The inerloan soa- tact slay showed an Inert reaotlon with erldeno* of a me (light absorption or dis appearance of acne past of dust in the lBO-dey testa, Th* German contact olay oauaed tha formation of light yellowish-brown nodules and as tha interval between tha la ' jeetioa and the -ramination Inoraaaad tha nadulae -banama jqaevdULt flatteoed, .hut the amount of dust and th* approximate alt* of .tha nodult remained th* same throoghout th* entire period (90-day*) of th# test. This earn be Considered am Insrt reaotlon) ' hut as th* dust does not disappear froa th*. peritoneum it should be considered as po tentially harmful though not as dangerous as pur* silica. . ' In consenting on th* results of the -tests with the -Georgia filter olay and th* . Amerloan oontaot olay. Doctor Sayers sdrioed that th* raaulta of th# toot Indicated that tho filter olay is more harmful than tha American oontaot olay because the.dust remains inert In th* tissues as this was th* largest portion of tho dust and th* 1m ' art appearena* of th* lesions was th* most prominent. The modification of tho rota tion In th* filter olay oan ba attributed to tho presonoe of 8-10 per sent, quart* (Potrographic), Cypsta In th* American oontaot olay may aoeount for th* slight ab sorptive reaction. . Doctor Sayers advises that an Inert dust, if breathed In suffi cient concentration, may be harmful. Thee* tests were mad* In aoeordeno* with th* procedure dosorlbod In Reprint #1808, Public Health Reports, Tel. 49, He, 3, January 19, 1934, pp*- #0-89- ' - - Th* inhalation of dust gives rise to "PnetsMoaalesls* a term derived fra the Creek pneumon, lunge and konld. dust", and used to designate a pathologioal Condition f th* lungs caused by th* Inhalation of any dust. It laoludo* SILICOSIS, a chronic disease of th* lungs caused by th* inhalation of minute partlolos of Arc* silica (SiOj) dust whloh produees a permanent lnoapaoltatlng alteration of tho lung tissue* AHIHRAC0SI3, the black lung of the miner due to eoal dustj AXTHHAC0-3ILIC0SIS, the newest of cur mineral dust affsetlos* sad lntroduoed by the Halted States Public Health Ssrrio* a* a result of thslr studios la th* Anthracite District of PsmnsyL-- vanla. This affsotlon 1* the result" of breathing anthracite eoal dust that contains alllca. Th* common asm* for tho attecifXoair'^W^th^pCHttltOSIS.'th# gray-blank lung of tho stcae-eutter duo to stone dust] ASBESTOSIS; la asbestos workers due to asbestos du*t| 3IDER03I3, duo to breathing dusts of Iron ore- (She lungs are yellow or red from metallic oxide* generally of Iron. )j ST33XH03X3, duo to oottoa partlolss and vegetable fibre dust, sad ITfEtltOHOTLTAAHICIOSCOPICSILICOVCC- ' CUKK0H10SIS, a special form of sllloosls caused by ultra-mlsroeeopi# partleles of Uleoous voloaalo dust. Sllloosls, Asbestosis, and SUloo-Anthraoosls are th* only three form* of pneusoeonlesls which require practical attention. ' 18-0000012 001431 187 While the type of pulmonary lion depends on tho particular dust Inhaled, tho underlying pathological principle is ths ssas In nil forms of tho dlssoso, namely, on ultimate fibrosis oad replaoemeot of tho olostlo lung tlssuo by o hard unyielding fi brous tlsius. Ill occupations that cxdss.non to largo amounts of dust nay giro rlso to pneumooooiosIs but set nooossarlly w illlooila. Zt is non gsnorally agrood that la ordor to produce tho letter, (tilloosls) lahCod sllloa dust Bust rtaoh tho lungs la a ehemloelly unooBhlaod condition, la Tory fins partlolss not mors than ton al~ oroas (10/25,000 lash) la dlaastsr and la snfflslaat anount end'over a sufficiently JLnat jsrlod of tin*. In rolatlrsly rsoent lltsraturo it appears that tho proponents ^fths idea ifcat only *freety'tsgfaartng-tm trrro -acma^dwfcts-aad tho thought that possibly sons sllloatss nay undsr some conditions bo ham- fnl. Generally spasting, tho aooossary length of exposure to produoo sUloosls is la dlreot proportion to the site of the dust particles and inversa proportion to tho dust concentration and the amount of free sllloa in the dust, SUloosls Is ohar-- notarised eaatoaloally by generalised fibrosis of the lungs and.ollalaslly by short ness of breath, deoreejed cheat expansion and a progressively lessened oapaolty for work whioh is out of proportion to the objective physioal findings. The effeot of ex posure to dust suoh as sllloa Is eVnulatlra, the rapidity of derelofmeut of the dis ease depending upon the tine and anount of inhalation. Slliooela nay develop to the point of causing symptoms only after several years exposure to elllolous duet, but It Bay bo progrssslTO in sen# oasos even after exposure has oeasod and nay oauao symp- . tons or beoene disabling long after the workman has left the environment that caused the condition. Son* nay improve or at least remain stationary la tho aboeaoo of In fection. Watkins-Fltohford (J. Ind. hyp 9,109 - 192T) tolls of Welsh miners its passed the physical examination for enlistment In the British Army, fought through the World War. then caaia hT<hctd~ErfglA)ld.' Sag ~sa Iff-vUlcnels. --gnfortunatsly. -1-t la -not stated whether these persons died frsa elllooeia eomplloated with tuberoulosia, Brit ton and Bead (J.Aaultad.JUsoo,S9, 1926 - 1931) give more detailed descriptions of slallar latent oases la the Cnltsd States. - SUloosls In General -`It la generally agreed that (lllooals may be*defined as *1 ohronlo dleease due to the breathing of air containing sllloa (3102), charaoterited anatomically by generalised flhrotlo ehangee and miliary nodales in both lungs, and olinloally by shortness of breath, decreased chest expansion; lessened oapaolty for work, ab -- senoa of fever, lnoreaaed susceptibility to tuberculosis (soma of all of which may be present), end by eharaoterlstlo roentgenolo gical findings.* , In other words, ellloosls Is a disease of the lungs In echloh the normal lung tissue is raplaosd by soar tlssuo duo to breathing air containing aUlaa dust. Un fortunately there le no known sure for slllsosls - but SILICOSIS and'nearly ail other forms of dust dlssasss CAB BE PHCTEfTED. Recognising tho wide. Interest and even hyatsrla among apprehensive employers against idiom claims had been filed by alarmed workers, and tho neeesslty of thought ful consideration of the sUloosls problem, the Secretary of labor oa April 14, 193d oalled the' first Rational SUloosls Conferees# attended by more then 300 persons representing workers, employers. State and Fedaral Agendas, Xnsuranoe companies, end ether -interested 'groups,--fae.niaiHfcin -- --gealsad nf the sUloosls problem] end assemble the essential fasts about silicosis in a series of reportsj also to present ipsolfje suggestions for slUsoais* prereatlan and straighten out ether difficulties that'sUleocls has created.- Reports made by these Ccemltteea were formally adapted at a second confercnee held February 2nd end 3rd. 1937 In Washington, Aran whioh wo quotei ' 18-0000013 001432 138 -6- "While a few persons any still be of the opinion that suoh workers" - (Worker* having t lliooi)5'"are through' end doaied to en eerly deeth, every study oonduoted thus for confirms the net thet the greet majority of these sen will not neoesserlly progress from bed ho worse. Perhaps It nay ho wise to transfer seas workers to other employment, hut neny any he ooatlmed at their regular-occupations if fajoro nethods ere applied to oontrol the dust and if spoolgl sere is employed to prerent the development of tuberoulosis, -and'.ofchcK-I.ung.coapllftat.lnrn?.. * "Contrary to popular belief, -silicosis ie elow to develop. Usually It takes seven years or more of exposure to sllloa dust for' a worker to oontraot the dieetie. It is said that a few easee haTe been known to derelop in ae short k m. period ee 1-1/2 years, but these were under extrema and unusual conditions. On the other hand, nany workers hare labored under ordinary exposures to eillea for wore than 30 years without demonstrating any trouble whatever that oould be diagnosed as ellieoels". . For the convenient diagnosis of sllioosis or of silloosls ooaplloated by to- beroulosis, the pulmonary changes are elasslfled in three stages by Drinker A ("Industrial Dust" - 193d). In the first stage, the disease produoes no dlability. The victim can work Just as well ae ever. In the eeeond stage, hie respiration is affeeted) he is bothered by dyspnea or labored breathing. In the third stage dye- ` pnea becomes eerere and he Is likely to oontraot pulmonary tuberoulosis, generally with fatal results. -Whether_he-onntraota tuberoulosis. or not, the advanced sill- . ootio it far below nomal and is very susceptible to all respiratory diseaeee. . These three stages of silleosil ean be distinguished by X-ray. Aooaparleoa of the X-ray plates of a silicotic with those of a normal person of like age and physique shows,, in the first stage, distinctive shadows, evenly distributed In both lungs. These may be missed or misinterpreted by any but an expertf hut the changes in the isoond and third stagas are obvious even to a leyman. It Is, of course, es sential that the X-ray plates be properly made. Dr. Panoost and Dr. Pendergrass of - the University ef Pennsylvania have given extensive study to the Influence of J^ray technique on the diagnosis ef silicosis. Pendergrass is of the opinion that shadows end appearanoes of fibrosis out be actually produced by the technique- employed. Under other conditions, existing fibrosis oan he entirely missed by use ef improper technique. Silicates aa a elaas are by no means harmless. It was pointed out by Dr. K, 'X. Sayers (0.3. Public Health Bulletin 221) that Miners' Conatscptioa was rather com mon in the'Broken Hill district of Australia where the rook oontalne considerable sllllmanlte (Alj SlOg), fibrous silicate, and a rather low percentage of quarts `(12.23#). The studies ofXadham (Kept. Dir.Can. Pub. Health, Hew South Wales) give con siderable support tcU.IL Jones' (J.Byr. IB. 307-1933) contention that silicates, particularly the fibrous varieties, may well he the cause of pulmonary disability. Badham in 1927 coined the word SILICATOSIS to oovor disability from the inhalation of silicates. Other sllloates suoh as Tale (B Mg (9l0j))(| Shalej Kaolin (lg Al2 212 0p)| Feldsparj Cryolite, (Has AIF5 )l and pure Mloa giro much less spooiflo changes than quarts. A moderate fibrosis may appear after exposure to amorous materials hut this fibresle is usually net disabling. Aooordlag to Dr. Lanza, "Silicatosis" is not a recognlrta tif*~ia*Tiiii bbdtttry-and'disability -ftum- the itAnksttum'-vf tti- sates has not been proven. . Dr. Cary P. McCord (lnd.Hed. July 1933, ppa.4-12) states that all silicates token into the lunge, of particle else capable of passing the oellular membranes, an likely to indues seme fibresle in osaess of normal but the progress of suoh eilleatools is mot nearly ae rapid a* for elllooels. Tuberculosis rates are high in sili cate using Industries, Antecedent tuberculosis, quiescent, may flare up as a result 18-0000014 00143a 139 i of xpQur to Jlllonto dujt* * Asbestosls - According* to authorities altad by Drinksr 4 Hatch In thelr back "Industrial Dusts", ths pathology prodooad by asbestos la not Ilk* that of sllloosis. Or, L. U. Oardnor of Ssrtnao Laka is of tho opinion that tho asbostos fibers group about tho naek of an alroolns and shut It off, oaualng what la known aa "Atelectasis". . There la so dsflnlto nlgratlon or transportation of tho dust partlolas to tho lynph " ' nodes and,hV'rrfif(W6MH*ilii,`'^fca-4ho-ataJoatatt-.axaaa.lnoroaao the reduction In lung ayea e.auses .parlous dyspnea or labororod breathing. Dr. A. J. tanxT (U, S.Hoalhh, Septs., SSt- 1 -~1935) suggests Uwt tho enlarged hearts noted frequently la hla . eases ef seeond stage Asbestosls nay be due to the lnoreased load on tho heart. It takes nor# work to pump blood through the fibres ed than through the normal lung. Sa fe ont pathologies! studies from human lungs from oases of asbestosls hare lndioated a diffuse type of Interstitial fibrosis with a certain amount of emphysema. IT . bHAT IS THt tUXSfJM PERM1SSABU,- DOST COCCEfTRATIOK? - Thors appears to bs a wide variation in the maxlmus concentration- of dust which slight bo Inhaled without subsequent injury to workmen. Some dusts (as lead) are determined by ohamioal methods and the eonocatratlons In air are reoorded grastmetrloally as mllllgrama per oubla netsr. Bonersr, ths arallable information on tho amount of load dost that la harmful and ths methods of determining lead are better and more aoourato than those for silloa dust. It it rather well agreed that an Intake of about 1*8 milligrams of lead a day. whether this Is acquired by breathing dust or by drinking water that eontains 1tad," is~the-srajclittim-ellewmVle-quantity, -Others. (aa silloa, where also Is a factor in determining dangerous partloles), ars usually given by count. Xeither method tells tho whole story, but in both eases it msy be possible to stours the In- formation nooessary for the purpose. ' . The maximum silloa dust concentration considered permissible in the air breath ed by a workman at any point in the normal breathing tone has net-been definitely tabllihed. There Is considerable difference of opinion regarding tho range'of par tlolas that are counted when using ths Fublis Health Service technique end light field 111vmination. Bloomfield of tho United States Public Health Service wd Bronx ' '. ' of the United States Bureau of Ittnea contend that they count partloles from one <cron and upward, or even 0.7 mloron and upward. The Industrial Commission of Wlsconsin and Its Advisory Committee, composed of both employers end scientists, how ever.' agreed in 1932 on a tentative figure of 15 million oeuntable particles under 10 microns in longest dimension with free silloa. content of 35 per cent In a oublo foot ef air as determined by (blted States Public Health Service technique. Yarlatlone in free silloa content will make proportional inverse changes in this standard. In the case of practically pure slllaa, tho permissible dust count should probably ' never exceed 6,000,000 oountable particles. By countable partloles is meant those partloles between 0.6 to 10 microns in the leagast dimension. Partloles of this is* are the ones that are bellrred to cause the greatest damage and form no visible aloud.' Dust particles smaller than 0.6 mlorocs in tho longest dimension are not ordinarily oountable. Dust particles larger than 10 mloroai in longest dimension do - not ordinarily reaoh parts of. ths lung where Ussy can produce injury of a resplra' tory nature. Most Industrial dusts have but few partlolas above two or three mi crons in else. They ere usually shout 90 to 95 per cent, below two or three sderaq^k . ' --en4-60-per~ee*h,-Vdgw-ahattt.0.5..oJ)..7 microns. An exeoptlon'to this would be a * dust sample taken dess to the point ef generation of dust'ahJT>eTaFe~thif'larger * partloles had time te settle out ef the air. la South Africa the figure is 1 milligram par aubio meter (or 300 partloles per eublo centimeter, or approximately 6.6 million per eubie foot. f Dr. Lanxa found in 1917 in ths Joplin, Missouri district that with good engineering praetioe, a fignrs of 1 dillgram per 100 liters of air oodd bs attained. This value attrlbufc. ed to lanxa appears tee high in comparison with the South Afriaan standards. As there . 18-0000015 00,1434 130 -V- ara 1,000 Uteri In a oublo neter, it would Indicate that Lanza'a estimation ropreentz something of the order of 80 million partioles per oublo foot. With good on- . glneerlng praotte*. lower conoentvztiohs then thii can be obtained. In fact the ex perience In South JLfrloa and alio the preaent experlenoe In thli oountry Indicate! tint it can readily be kept below one-tenth of thii nlue by using ordinary food practloei. The United Stats* Public Health Service In it* reocat study In the aathrf.lt". region of PexiRgylvenia, found that 50 million partlelea por oublo fbot with 5 pr oent. quartz in the eoarae durt and 10 million perfidies per bubVcTTodf with 3S,,p*r cent, quartz were apparently latlzfactory and often were attained. The flgun* of 10-20 million partlelee per oublo foot for granite duzt with 35 per eent. quartz content ie often quoted from the Yanaont granite itudlee of the United State* Publlo Health Serrlea. From a eonilderatlon of general experience, Cummings euggeeta 6 *11lion partlelee per oublo foot a* a threehold for duete high In quartz. Ihla figure Is based upon a combination of South Africa, Australian and Amoriean experieno* but lacks entirely any published data in it* support. . Aoeording to studies quoted by Philip' Drinker and Theodore Hatoh In their book "Industrial Dusts" 10 to 20 million particles per oublo foot by the Implnger sampling mathod, light flsld counting is a reasonable figure for oment and limestone. Seoeat work by Creesssn oonflras the universally aooepted opinion that dusts high In salolto and low In quartz do not produo. disabling fibrosis. The threshold figure of 0.15 milligram per euble-meter is given for leed dust, preeuaably litharge end *hlt* lead, or othei soluble leed salts. . . It should be noted that many of the data war* not determined as the Medical requirement, but as being attainable In good praotio* and apparently eatle feotory from a safety standpoint. It should be further noted that the aooepted figure* cm. only relative due to the Indefinite power* ef resistance of an Individual whleh are an unknown quantity. On* individual might resist a proportion of 200 partial** per cubic centimeter, while another would reset unfavorably to'50 partible*. The- work-* er'a physloal condition prior to the exposure la of great Importance, alno* a young, healthy Individual usually can stand a higher eonoentratlon or longer exposure before the first stag* of sillsoala Is developed. However, far greater influence than ..physical condition might be the ability of the nos* end respiratory passages to an. rest dust. -- In their report to the Rational Sllloosls Conference the Ceraitte* on fro- -rentlon of Sllloosls through lledleal Control pointed out that since standards of safe mtmosphsrie dust eonoentratlon. based on medical findings have been established for only o'few Industrial dusts, and in. view of the fast that considerable study *nl In vestigation will -be required to establish standards for other Industrial dusts, some tentative standard would be .useful, it was also stated that this arbitrary standard should bs based upon what la believed t* be within the Units of good engineering * practise provided. It will largely control the slllcosla hazard for moat Industrial exposures. They, therefore, suggest that ` "The maxlsnaa permissible eonoentratlon of slllaa In the sir breathed might be expressed by the following formula. \Determination of dust oneentratlon aoeording to teehnlqu* described by Malted States Publlo Health aerrlec In Reprint -Ho. -HtO ft un' futiUv'-Heatth Rcpwrtsttaruh'lfl,~1132)i Multiply the percentage of free sllloa by the total particle duet count. If the result Is under 5 million, the condition may be cen-~ sldered permissible. If the result Is over 5 million, the_oond:'.tlaa may be considered toe high, for example, * 10jS ike* silica' with an average total dust oono entratlon of 30 million particles per euble foot would give .10 tines 18-0000016 00145.5, 191 SO Billion, which equal* 3 million (good praotloe)j 5Cif,, with average total dust odnocstration of 60 million, would' equal , 3 times 50, or 15 million 9 (uajatlifaotory). This formula Is sot applicable to any dust containing loss than 6jC free silica.-" . jhacdor* Betoh 01 his artlol* *3cae Fundamental'Deta"'d}l'TfWhrnleai-ttavbtraps!'*.(lank Pub, Jo, 437-A, 60, Xmer. last, Ttivu * {tot. Zngrx.. lug,, 1936) gires these Safe Dust Concentratlone. Impingr Seasiest (Light Field, Low Power Counts.) . . Xlnd of Dust Maximum Permissible Concentration Containing no Silica.................................... 60 allllons per oubio foot Containing any small amount of sllloa, free combined. ............. SO * ** Containing 20 to 40 per sent. * . Free Sllloa................................................... 10 * *" Creator than 40 per cent. Free .... B* . . .....(frcfei^ly * -mooh-l'eee-as .possible) Dr. B. X. Sayers, Medical Officer la Charge, Industrial Hygiene and Sanitation, 0,3. Publlo Health Service- In answer to a question ns to permissible dustlneae wrlteet . "During recent years, `It has bsen'oustomary to-reccoaend threshold or psraltslble dust limits ranging from firs to ten million partioles per oubio foot a a determined by Public Health Serriee teahnlque, espeotally with dust In which the percentage of free sllloa Is abors firs per cent. There Is no basis for the application of this criterion to all dusts, but It It generally considered a safe praotloe and oaa which can be-attained _ In most Industries by exhaust ventilation,' wetting, or other mathode of dust central.* . . As pointed out by Drinker and Hatoh ("Industrial Duet". - 193d) It Is unfortn- - nately Impossible to evaluate dust exposures with the arithmetical nloety that it# should hare liked yet It Is eooesonly elalmed - by layman - that prolonged exposure to low concentrations is just as serious as short exposures t heavy oonoantratlana. This elalm la contrary to a fundamental lam of physiology. Da diecuesing the sub ject Clark and Drinker ("Industrial Kedlolne" 1935) remark that a sub-thres hold stlmslns (dust Inhalation) for a long time produces me reaction whereas a relax lively brief super-threshold stimulus may causa a reaction*. If workers are exposed to sudden heavy concentration!, the threshold values suggested previously would be correspondingly lowered. However, most threshold values are weighed -- an average - of-the-ranges. T i HOW HAI THE COKCEHTBAXIOH AID. CHAfiACTEX OF XXBUSTXIAX. HOSTS BE feTEHttlEPt The properties of a dust which determine Its harmfulneis have been shown to ho its composition, concentration (the quantity suspended la the industrial atmosphere), aad its partlele site, The methods used for the determination of the scncestratloo and eharaeter of Industrial dusts vary (ros a routine dust teuat tor the purpose sf evaluating the efficiency of dust control methods to a detailed study of both the concentration and the eharaeter of the dust In connection with medical and engineer ing surreys. 18-0000017 00143W 192 The lmplnger Apparatus developed at the United States Bureau of Mines, Pittsburgh Experiment Station by Georg* Smith end Leonard Orosaburg, (Deaoribtd la Reprint Bo. 1528 from the Publie Health Rtports Tol.iT, Ho. 12, March 18, .1982 pp. 654-875? haa .been employed for more then 18 yeara aa a ataadard laatnaunt for duat studies. In thla apparatna aaaplaa of air are dram Into aa lmplnger tub# ead flask nharr -"""i"ar^aplnted.joa.ajrapajnedjaattad.^laan,sol3 ant ing, plate, The rate of air'flow la fixed at oaeoubio foot per minute while the .duration of the sampling period la dependant upon the duat oonosatiation. The air paaaaa through am-orifice in the bottom of the lmplnger tube and strikes glass ooL- leotlng plate whloh la submerged In 3 on. depth of diatilled water or tone other fluid with satisfactory wetting properties. (If water la ueed aa the fluid In the lmplnger, allloa partiales are dlssolved--hene* not available for oounting -- unleoo 'the laboratory (counting) work la done within a few houre of taking the sample, )- " Thla afforda the naans for aoourataly determining the quantity and alia of the per- tlelee. The liquid la then thoroughly shaken to obtain a uniform distribution of the partlelei) filtered to remove those over 40 miorons In site and again agitated. Samples of approximately 1 od. are taken by means of a pipette and pitoed in Sedg- wlok-Rafter eountlsg oells. The use of a suitable adoroaoope equipped with a Whipple micrometer disc. to aid In oounting. will permit the determination of the number of partlolea in one quarter of the mleroseoplo field, from thla flgura, the number ef pertlolea. of dust In 1 on. ft. eaa be oaloulated. One speolal advantage of this ap paratus la the, .ftat..tMfc.Analysis .of.-ihs .sample .eta be deterai^edhycixmtiRg, by weighing or by ehemloal analysis. The lmplnger method la neither simple nor extreme ly complex) however, reliable results earn be obtained only by well trained, ecmpe- tent and experl ended Investigators. However, owing to the wide use ef the lmplnger la previous Investigations that have been correlated with the pathological findings, an lmplnger should bo used far any Investigation whloh la to Include pathological findings or whore the results are tote introduced as evidenoe In court. Some state codes on dust control reoognlie the_ lmplnger method. The Halted States Bureau of Mines'haa praetleally completed the* development of a "Midget" lmplnger whloh haa moat of the good eharaotarlstles of the lmplnger but lacks most of its drawbacks. This midget lmplnger will soon be available and will greatly simplify both sampling and o ousting. . . -* Other devises are also available for stapling of duat over a ocatinmens period, namely, the eleotrla preoipitator, the paper thimble, the eleotroetatio preoipltator, and the hot wire thermal precipitator. The English ere working on a duat sampling Instrument whloh precipitates the dust Aram the air by thermal means ("Rqrsloal ' Methods for the Estimation of the Rust Baxarda in Industry", by K,'L, Green and H. H. Uatson, Privy Cousoll, Medleal Seaearoh Counoll,; Speolal Series Hew 198, His Majesty's Stationery Office, London, (1938)), The U.3, Bureau of Minos has boom us ing aa eleotrlo precipitator similar to those described by Drinker ("Alternating Current Precipitator for Sanitary Air Analysis) X - Aa Inexpensive Preoipltator Dolt" by P. Drinker, Jour. lad. fyg., Tol, 14, 1932, p.364) for collecting samples ef the test suspensions used la testing meehaaleal filter respirators for permissibility. A ntsaber of Instruments' are available for making duet determinations fOr-eeotrol purposes. Among these Is the Konlatter which calls for but little skill in sampling. It' Iflight',- simple and qulok toThandle, n4ids no power1"Tor operatioa fbd requires only a mloreseope for counting the partlsles. The Zeiss Ioniastar consists of a. microscope which gives a'magnification ef 20GDC, am air ptmip, a dust filter to remove very Coarse dust partloles, a staple diso and a jelorcsaeter ruled In square nilHaotore. The .air puap drives a measured quantity of air against tho staple diso* whloh It covered with a sticky subatanoe (glycerine Jolly), Thla.sample formsj^durt . spot which can bs examined under the mierossopo for a general Idea of the nature of the duet and the relative quantities present, or for aa actual measure, a "dust eount", edileh shone how many dust partlsles are present la one oubio centimeter or la one litre of tho air temples examined.' The Xoniaeter has been used very widely la 18-0000010 001437| 193 -11- South Africa (Final Report of the Minora* Phthisis Prevention Committee, Johannes burg. 1919, p.10) and alao 1 Canada. Tho O.S. Bureau of tUnoa baa alao used it In <na of lta duat studies. In dis our sing tha rain* of tha lonimeter la tbolr raeamfc book 'Industrial Duat* (HoQraw-Klll took Co., Hew York and London - 1994) Philip Prinkar and Theodora Batoh of tha Harrard Sohool of Publio Haaltb writes - 1 ..It.la tha ada't la provided for thirty taaploa on a single dlao and no auxiliary souroa of powar la required for its oparation. Orab aanplaa can ba oollsotad with spatd and tha fluotuatlons in du*tines* and tha development of duat floods oan ba roraalad In a way that la laposslbla with nora emberjob* apparatus. . South African axparlanoa Involving tha collaotion of thousands of aanplaa has shown that tha figure of aarlt given by tha foal- star la dlraatly ralatad to the amount of phthisla - produo ing dust In tho air. It la a valuable routine stapling In- . itruamt' but because of Its low'and soleotlTo offlolenoy. tho oounta reported era probably considerably below the true lerel end they are not easily compared with data obtained in England, for example, with the Owens apparatus, or In tha United States.with tha Implngar." - ' - Experleno e has ihowri~thtt'~0'Pgtrary to ~Prlnh-r*s -atatoTeont. the Ioalmeter If properly used, win giro results that agree eery wall with thoie obtained by tho uaa of tha Implngar. The U. S. Bureau of Hlnoa Experiment Station at Pittsburgh In *H"; some comparative atudlaa with tha lonlmeter and tha Implngar found that an average of five tonineter detoralnatloaa was within about two per cant. of on* Implngar determlw nation. Tha reason for taking an areraga of individual results obtained by tha leal- meter, for eompcrlaoa with those of tho Implngar, Is dus to tha foot that tha toni-- meter takas an instantaneous grab semple of'small volumes and oaring to tho.hatrogene- eus nature of dust In air grab samples do not represent tha avsrage conditions, the Implngar takes a continuous sample of rather large voluaei and la thereby represents^ tlva of tha average. For these reasons. If it le desired to eompure lonimeter re sults with Impiager results it Is neoassary to take s ovarii Konlmetar samples during the course of tha Inplngsr sample, in order to obtain average conditions. Us have no oorrslatlng information of tha lonimeter with the 20 to 30 mloroa porcelain* filter against the standard Implngar method. A Zeiss Toalmeter, using a 20 to 30 aileron poreolaln filter was used In .Mg aotusl dust counts la our various dust produoing operations. Tho partlolo ils< and slso elassifleatlon was estimated rather than aeourately measured and oomputed. Only partloles tan microns or lass In slsa wars oorntsd slnoo It Is gonorally agreed that dust partloles larger than tan miorons in else are not particularly pathogonlo. - Other methods. In common use are tha Owens Jet dust sampler ("Jet Duet Counting Apparatus* by 1.3.Owens, Jour. Iod.Hyg, ,Tol.H,1932,P.622), which has reoestly bean. manufactured In this country and the photographic duat counter, developed by Flcklaa and Ott. The Owens let dust epunter la uaed la this oouatry to oolleot aanplaa for partlSle Sira idlxtrlbutlen determlnatlrms. . .Jtlauaad..pJinolpelljr la Auatralla for determination of number concentration of atmospheric dust of lndnetrial"hjrIrole"1- portsnoe. . The latest derlos for datarninlng dust eooocatratloas Is the Banach bomb Dust Counter which waa placed on tho market a few months aga._ This Instrument eon- . elate of a dark-field microscope magnifying 200X, and an Impinging apparatus aounted on a oomen base. She base la a hollow chamber with the bottom hinged to provide - easy aooaas to tho dark field condenser and a circular glass specimen slide. By moans of a hand pump, which la part of tha Impinging device, a sample of air Is drawn 001438 18-00000i 194 -12- through a moistening chamber which ha* at its lower end * narrow slit, the duat la deposited through this alit on to the circular specimen slid# la the fora of a rihh*. Th* alide can he rotat^until the sample. comes Into proper poaitloa for viewing with tfc ieroaoope, or a maximum of twelve samples can he eolleoted ea the elide aS 'desl'gaed for accurate dust determination but rather aa aa inexpensive derlee tor* roughly ohecklhg .dust conditions. It hat not been available long enough for athorourh teat la actual practice, . rouSn The principal objection to instruments liko tho Bausoh & Lamb Dust Counter and the Owena jet dust sampler far determining number concentration la that their duat collecting officiary decreases with an Increase in the atmospheric dust concentra tion and the fact that they take grab samples. Since the major portion of duat present in Industrial atmospheres is small teinoonusghotfothgeainexeancttrasnicteestoofthpearltuionlgesa, .very little' attention need be 6given to due*oteerrmaiinnaa- 195 i8_0000020 Ddl430 -J.O- PART II - DUST PRODUCING OPERATIONS STUDIED VHAT AR3 THS PRINCIPAL DOST PRODOCIHO OPERATIONS? - la order to determine to Tth&t extent if.AJjy., workers in the production of petroleum produots and assoolated activities are exposed 'to'.*;ur,*y,,nf.Jill. duatsJtt'Qduq ing operations was made-at .the various plants oonoerned. These operations, listed in order of their apparent degree of dustiness, are* h I - SAND - BLASTING Due to the large amount of finely divided silica dust produced by the impact of the grains of sand on the surface of the object being cleaned, e and-biasting 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 gunlte lining aa a means of preventing corrosion. Header boxes .or other similar-parts* .tubes JLn cracking coil fire boxes and return bends are sand-blasted to permit a detailed and thorough examination. Tor cranks "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 aervioe) also on the ends of tubes preparatory to placing them for rolling) and fdr cleaning eastings 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, pipe, 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, process units -or other working places. Coarse river sand is discharged through a one-half to threequarter inch nozzle with compressed air under a pressure of SO 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 Helmet or a Fresh Air Hose Mask covered with a canvas hood. The men at the Sand Blast Hashinea wear "Dust. Safe" goggles and a M.S. A." Coinfo" Respirator. The Mine Safety Appliances Company jjow 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 o onneotioh witli air^llne resplr*tors. 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 droms where tho siphon cannot be used, the air oiroulation.is poor and the men work in shifts ranging from 30 minutes to an hour, depending an 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 Conation Labor gangs or the Mason's De partment* The work is rotated so that in most eases it occupies less than twenty perueitW**wf'-fehc^wcmltsrlsJbime.and.there is an interval of IS to 20 days between, sand-blasting jobs. Consequently, on the average^ no 'dhSCmsar^'MWiposed tOTwr-e *than a combined total of 400 hours during the course of a year. In dlaeuasing rotation of men on sand-blasting jobs. Dr. Oehrmann, Medical'Director of the du Pont Company wrote* .' -' . "It must be borne in mind that sil.leosis Is a cumulative disease and, therefore, the rotation of men-ln this type of work candot be considered .. 196 001440 18-0000021 ns entirely preventive. Assuming th&t a man works in an atmosphere of all ies dust for several months, during whichtime he is bound to absorb a cer tain amount of the dust vhich produo es permanent damage in his lungs j he is then removed and the possibilities are that the damage which is already dome-will -be...sufficient to oontinue on andprogress to the point where in later years he.will develop symptoms. ...................... ' "Therefore, if we take to rotating men in this type of work wo are facing 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 this can oily 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 less properly protected while actually doing the work but often times they removed their protective equip* ment before getting completely away from the working area. A large amount of very small partioles is produced by sand-blasting. In an analysis of dust samples eolleoted both outdoors and indoors during sand-blasting, the following distribution (Public Health Bulletin No. 217 -- p.52) on a size fre quency basis was found* *- Size Group in Microns Per Cent of Total 0.00 - 0.49 0.50 - 0.99.1...;..................................... 1.00 - 1.49.............................................. 1.50 - 1.99........... <.................................. 2.00 - 2.49.......... 2.50 - 2.99................................................ 3. 00 * - 3.49................................................ 3.50 - 3.99.................... 4.00 - 4.49................................................ 4.60 - 4.99............................................... 5.00 - 5.49................................................ 5.50 - 6.99.............................................. 1.4 19.7 34.7 20.3 12.6 5.2 - 2. 8 1,6 ' 1,1 0.2 0.2 0.2 While has been estimated that free~jniica au3t partTdlesf"''I-Tttliflfrntt 'in'-diamter, re- quire 8 hours to fall 8 ft. in still airj partioles 5 mlorons In diameter require . less than 1 hour to fall the same dlstanoe. Considering this fact, it is apparent that the dust hazard from a- particular operation may, even though carried out for short periods, be acute throughout the working day. In view of the faot that the Con dition of still air is rarely, if ever achieved, and that dangerous partioles exist 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 lsolatod locations which makes it rather Improbable that there will be any unsafe siliea 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 *strods"or -Bay hn *11 Inn air evbn though it can not be seen. Dust counts as high as 5,344,160- partioles tea mlorons or less per cubic foot were found in samples -taken about SO feet "downwind" (wani blowing about 15 to 20 miles per hour) while sand-blasting.oraoklng coiltubes | about 9SX of these dust partioles appeared angular crystalline under the Komlaetor microscope and were about five microns or less in size. Samples taken about 100 feet "downwind" from sand-blasting operation had Oounts as high as 1,612,480 partioles pox* oublo foot. -7 001441 18-000002 -16- Dust oounts as high as 13,933,440 and as low aa 453,120 partloles par oublo foot wars found in samples tai^en during the filling of the Send Blast Haohlne feed hoppers. The high counts were found when sand was shovelled into a small oircular screen and shaken by hand, the lower oounts, when the sand was simply shovelled 4w- to the hopper. The average dust produoed by filling or charging the Sand-Blasting HachinW'tnrs "4yW0>*3M part*ol>e -teo-mior-ens .or,J.aas^par -cubic-foot. Dust coup's as high as 4,964,320 particles, ten nlorona or less, were found in samples taken insj.de a Sand-Blasting Root while oleaning castings, Tho average dust in this room during sand-blasting was 3,873,625 particles per oublo foot. About 80# of these particles were angular crystalline three microns or less in size and about 20# appeared rounded, quartz-like crystals about ten microns in size. There were a. few rust-like scales over ten microns in size and a vory large number of minute dark metallio partioles too small to be counted accurately. The dustiness of this'; opera tion could bo greatly reduoed by the use of steel abrasives exclusively. All of the samples for dust counts referred to above were taken at faoe level in the vicinity of workmen. . 6,000,000- dust particles per oublo foot is the tentative maximum allowable limit of dust particles containing free silica of a size less than 10 miorons recom mended for sand-blasting, . II - FILTERING OPERATIONS . . The prooeaa of filtering is extensively used In tho refining of petroleum, produota to improve the color stability and .to remove impurities from motor lubri cants and paraffine waxes.' The three materials most commonly used for purpose are Filter Clay or Fullers Earth, Contact Clay and Bone Blaok, Considerable dust Is produoed by the handling, charging and reconditioning of these materials. A - FILTER CLAX OR FULLERS EARTH . What is Filter Clay or Full era Eartht Filter olay cannot bo identified from chemical composition but consists of ailioa, alumina, iron and alkaline earths in varying percentages. The distinguishing properties are lack of plasticity and the power to remove oolor from oils. There are numerous deposits of this olay and other filtering earths in the United States} the oldest* and among the moet extensive are those -found--clgoe -to -the-Florlda-Ceongla--line. -~Qaa-nf thnse,-at-Attapulgna, ..Gflnrgia, suppl9fes a major portion of the olay used by the affiliated Standard Oil Company (Hew Jersey) organizations. At the mine this material contains on an average approxi mately 32# silica and 45# moisture. The average composition after being processed and prepared for shipment is approximately* - S102.............................................. 67.46 per cent AI2O3............................................ 10.08 " " Fe20s............................................. 2. 49 " " ' MgO................................................. 4.09 " " Combined Moisture...................... 5.61 " " Ik*ee Moisture................... . 6.28 " " Tho comparatively low dust counts found even in plaoes where there was oleahlhg' and sweeping is no doubt-due to 'the feet that this filter clay is of a rather ooarao na ture and without appreoiible amount of fines. 1 . ~ There appears to be a wide variation in the composition and fees siliea eon- tent of filter days used in European refineries. "Tomma* a German Filter olay - used in Poland showst -* - ' 001442 10-0000023 193 Loss in calcination.................. . 6.05. par oent Fre# Silici (Si02).......................... 83.27 " " AI2O3 and F02O3......................... 8.27 " " . The filtar olay used in Roumania is reported as haring 60*4 per oent. free silica or 75.Z% total silicates. *Granosil" clay used in Belgian oontains A total pereentage?^"7^T^^i^P''erwit';' "'of'-'5lltostea-cxpr ejgod"e-S1Oa ... Ihe .parjcnts.ge offrefl 'silica was not determined. feow is Filter Clay Hlncd and Prepared? - The deposit raries from 2 to 12 feet in thickness, probably averaging about 7 feet. There Is an. overburden of about 35 feet which is rcmerred by,an electrically operated drag line or a steam shovel. The olay is loaded into small cars, transported to the wet clay shed whore it is dumped on to the drying floor and dried for three days. It is then picked up by orange pool buokets, loaded into portable distributors and dolirerod to belt oonTeyors whiohdis charge the earth into roller crushers where it is reduced to sizes up to a maximum-of two inohes. From these crushers the clay goes to secondary orushers where it is re duoed to a maximum of one inch. Since the clay is more or loss damp Tory little dust is produced....-The olay is then transferred to tandem oil-fired rotary dryers, 60 to 60 feet long and six to.seren feet in diameter. In tho' 20"minutes required for the olay to pass through the dryers the -volatile and moisture content is reduoed 40 to 50 per cent, to a maximum of .15 per cent. The average.dust ten microns j>r * less in site in samples taken at -various points around the dryers and conveyors was 1,564,969 particles per cubic foot. This rather low dust count is the result of the Installation of hoods with ducts to exhaust fans placed error the discharge points to the oonveyors or ele-vators. About 85# of these dust partioleg-were angular crystal line In appearanoe under thd Xonlmeter mlorosoopo and about fire microns or less In size* about 15/ were over ten miorons in size. The larger partioles had rough edges and appeared to o ontain several small air bubbles. The clay is removed from the . dryers to hot rook cooling tanks, then to a -vibrating soreen. The oversize is next pulverized in a roller mill and the product oomreyod to a sifter. JLn exhaust system for the mills and elevators has been installed. This prooess may be repeated until the desired size material has been obtained and graded to standard mesh sizes, the better known of which are 15-30, 30-60, 60-90, and the 200 mesh. The 60-90 grads Is probably the most eonmonly used in the petroleum industry when deocloving by percola tion, and the 200 when contacting. However, the 30-60 is preferred by most of our refining units in the United States. The size seleoted is apparently determined largely by the .type of reburning equipment. me Soret'-te5tv -*ra--ntade-heurly'^-iaaujie.Jthat jthe ^iizjes are within the specifi cations. Here *are two typloal soreen analyses! ' SO 80 GRADE FILTER CUT "" Mesh Per Cent. Over 50 30 - 40... 40 - 60... 60 - 82... Thru 82.... 9.7 47.5 40.3 1.5 1.0 Total `"3WS.0 199 iQ-0000024 00144.*. FIRES (100 - up) GRADE FILTER CLAX Mash For Cent. Over 97 ........................... 0.6 .97 - 1S7..................................... .......................... ..'.***. %- * .'a.,o Thru 200--........................................... 22.7 68.7 * Total 100.0 ` There I# Tory little dust produoed by the silting; operation. All of the aonneotlons 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 partioles less than ten microns per eubio foot. About SSjC of these dust particles were slightly angular crystalline in appearande and fire mioroas or less in size; about 15$$ were slightly rounded semi-opaque ten microns or orer in also. The larger partioles had small cracks or fissures and sereral email air bubbles. * Hen spend about two hours a day eleaning, repairing or ripladlhg'silk soreens in the sifters. Samples taken during this operation contained .an arerage of 2,039,010 dust particles less than ten microns per eubio foot. About 97$S of these dust partioles were angular crystalline.in appearance And five aiorons or-lees-in sizey about Zf, were opaque orer firo microns is size. . After being sifted and. graded the clay is ready for shipment* The 30-60 mesh g^-ade is placed in burlap bags holding 128 pounds and loaded Into railroad box oarsi about 400 togs to a ear on an average. Dust oouats of samples taken during the fill ing of the bags with the 30-60 mesh grade show that there are tron 7,589,760 to .9,968,640 dust particles less than ten aiorons per oubio foot fdiioh indicates that ail men engaged is bagging and handling bags in this area should wear approved respi rators suoh as the "tf.S.A.Ccmfo". About 80$$ of the dust partioles In samples taken during the filling end handling of the togs appear slightly angular crystalline under the microscope and are fire miorons or less In sizey Zpj are rounded crystalline, ten mierons or orer is size. * Bulk Loading of. railroad box ears with thaySO-60 mesh grade produo as clouds of dust, but a major portion of this dust is apparteqtly larger than 30 miorons in size, as samples taken during this bulk loading had an average of only 8,853,440 partioles, ten lifccrens "w-i.ss -ia-siee -per-oi^ie-foot. .. The Fines (100-up) grade is put into 128-pound ootton togs. Dust oouats in samples taken during this operation showed that there were from 4,644,480 tol4,216,640 dust partioles less than tea mierons per eubio foot in the air being breathed by the fillers, weighers, sewers end truckers. About 80$$ of these partioles more rounded, semi-opaque crystalline in appearance under the Xonimeter mlorosoope and five mierons or less in sizey 20% were semi-opaque crystalline from about seven to fifteen aiorons in size. There were also a large number of Tory small partioles about one micron or less in size. .. How is Filter Clay Hsedf - Upon arrival at the refinery, the bags of oley are remoajad^fram-.thaJiox^..iSfl|!9. Jjyacrow of men usually frcathe General Labor Department! the job being rotated so that the same men db not dq tKli"aOiler "Bperafion more than perhaps twelve hours twioe a year on an average. Goggles end "US.A. Coofo* respirators are generally provided. The elay is either truekecfor dragged to an elevator or conveyor hopper and dumped end toe beg* ere piled for storage. At points toer.e the elay is received in bulk, it is unloaded by a large wooden scoop pulled ty a motor driven drag-line. Unloading, handling, and draping the elay is one of the " 001444 18--ooooQ 200 -18- dustiest parts of the filtering operation. The anoint of dust produood la of oourse dependent on how the work is ddie, the ventilation provided, and the oare used by tha nen doing tha job. Here are acme average dust counts of partlolea leas than ten nl~ orons in samples taken during the unloading of bags of 30-60 neah Attapulgus olay Partlolea Per ' Cubio Toot Unloading and dumping baga (128 lba.) into Hopper at a . Southern Refinery...................... ................. Dumping clay from Bags into Elevator Hopper at a . Northern Refinery............................... ..... 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 Truok Clay to , . Elevator, hopper......................... Average Dust Produo ed while sweeping tip'inside eAf"after unloading....................... 5,403,466 2,237,280 755,150 1,110,144 372,924 339,840 651,360 Apparently unloading olay in the bulk is less dusty than handling and dumping of the olay in bags. Samples taken during the unloading^of bulk clay gave these- average counts of dust under ten microns in Bizet ' Inside car during unloading.......................... 962,880 partlolea peroubio foot Outside n " " '...................................... 623,040 * "" There is of oourse more dust produoed in the vioinity of bulk unloading than Is pro duced when handling and dumping olay in bags. After dumping, the new olay la taken by elevators and oonveyore to atorage bins which' hold about 20 tons each. This. is also a dusty operation due to tha failure to cover the storage bins or to place hoods over the junotion points of elevators and belt oesveyors. Semples taken during the filling of storage bins with new olay hd these average dust counts of partloles lass than 10 mlorons in sizet Dust over Bins around elevators and conveyors during " "Jtfem ..... -*/d41Ang-Jit..a.Ncrthem Refinery............. 1,910,432 " 4 Conveyors while fillin--g at another ,w ' ww Northern Refinery................. .......................... . 4,275,842 n " "4 Conveyors while filling at a . Southern Refinery..................... ................................. ~ 4,531,200 * Face Level on Walkway over Storage Bins Northern Refinery while Filling Bin......................................... . 2,307,776 Oust Counts as high as 8,609,280 partloles per oublo foot were found in samples taken near tha discharge of one bait conveyor into the top of storage bln. About 90JC of these dust particles appeared angular crystalline under the JConimoter microscope and were five mlorons or less in slzoj about 1<# were black, opaque, mazy scale-like In appean&aom.smd.tfsn mlorons or over in size, "BURNING" CIAT - From the atorage bins tha clay is conducted by chutes and/or ooxrreyors and elevators to gas or oil fired Wedge-Burners or Rotary Burners or Kilns in_which it is "burned" or roasted, and then discharged into rotary coolers where it la cooled. Where all openings, chutes and elevator outlets as well as the ends ofrotary coolers are properly enclosed and an esdiauat duot is plaoed over the burner, very little dust (an average of only 604,160 particles, ten mlorons or less in sit* - . 0014.45 lB-oooo 201 ptr eublo foot) it produced end no respiratory protection is necessary. Three types ot burners or kilns are used to recondition filter olay, Arerage dust counts of samples taken during the operation of these burners giro a comparison of the amount of dust (particles tea microns or less per cubio foot) produced by eacht . gype of Furnace * . .` Feeding , ........ Total General About Furnace ' Coolers ' - ^TBrage Herman-Frasoh Oil or fc6as Firtd......... 2,624,320..,. 3,700,480.. 2,732,880,,.,, 2,390,542 Wedge Gas Fired............. 5,399,680.... 1,522,459.... 2,108,590..... 2,395,971 Rotary " 11 2,067,360,. 1,070,046*... 3,115,200.,... 1,818,206 The present practice of using a compressed air hose to clean up the clay on the rarious floors of the Furnace House at one of the Refineries Is particularly ob jectionable due to the exoessire dust (12,687,360 particles ten microns or lees por oubio foot) which is stirred up, ' . ' About 90/t of the dust paYtial''tn"sanrples^ -taken -during.-th.oJtmmlng. jpf. filter clay were angular transparent crystalline in appearanoe and fire microns or less in sites 5# were round opaque, ten microns or orer and 6% were rounded semi-opaque, ten microns or crer in site. 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? he is exposed aor.e continuously to dust than are the firemen. CHARGING FILTERS - The cooled, burned olay (30-60 grade) Is conreyed to the filters by means of eloTators and belt octnreyors and charged through chutes &aa the eomreyor belt tripper at a rate of from one and a quarter to eight tons per hour. 'These toss els hold from seren to fifty tons each. The amount of dust produced during the charging operation depends upon the grade of olay being handled, the `rate of eharglng, the position of the clay on the eonreyor belt, the condition of the eonrey-- or belt, tripper and charging ohufccj also whether the top manhole of the filter Is left open during the filling. A general arerage of 54 dust counts made of samples taken during the charging of filters at all of our plants using 30-60 mesh Attapulgus Filter Clay was 3,717,884 particles tea microns or less In size per oubio feat. Mis smouat of >d.ust_produoed by the charging operation Taries considerably at the rarious planftg as is shown by these areragest * . Refinery Charging Rate _Particles par eublo foot Baton Rouge layway Bayonne Eagle Works tonas paer hoaur N . tt n an n 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 less dust is produced during its handling. Our study does not confirm this be lief as applicable to dust produced while charging filters. Arerages of dust counts in samples takeh durlhg"^My uperat1un-werot - * # 1 Clay............ . 2,242,944 particles per euble foot # 3 * ............................... 4,604,832 . * " " # 10 " .......... .................... 3,896,832 " "" " 202 la-0000027 00144b' i Aaoording to an analysis of portiole also made by the Bayonne Laboratory of a . sample of Raw (30-60 grade Atta.pulgua Clay) Ho. 1, -Ho. 3, and Ho. 8 Wedge olaya, the following la the site classification or distribution* Raw Clav *1 Clay #3 Clav CoaTgerthan 100 mos[2i -------------J Diameter of Partloles . 98* . *..... 99* 4^# ..*... 98. Raw Clay #3 Clay 98# #8 Clay Millimeters .149 to .074 .074 " . 044 .044 " . 035 .035 " .025 .025 " .015 .015 " .005 .005 " . 001 Microns 149 74 44 -35 25 15 5 toN N .n . n n ti 74 44 35 25 15 5 1 . ....... - Per Cent For Cent Per Cent 0.14365 . 1.00750 0.54159 0.55095 0.17186 0.08449 0.29760 0.05369 a 04585 -a 21555 ...- -----0.03887........- -----0.-01603 0.17550 0.01729 0.00847 0.11640 0.01027 0.00336 0.00045 0.00052 a 00021 .... About 85jC of the dust partloles In samples taken'during~the charging of '#3 day were slightly angular In appearance and fire ailerons or loss In sizei 15jC were rounded semi--opaque, ten microns or over in site. About 75% of the particles In samples token during the charging of #10 clay were slightly angular crystalline, fire microns or less in site; about 20% were over ten microns in size*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 n blaok specks about one-quarter mioron in size. Charging of filters Is usually done by one man per shift for eaoh filter ' * house. There are three shifts a day. These men hare an average aorrioe of about 20 years and work olght hours a shift, nine shifts out of fourteen. Ventilation is provided in the newer .filter housee by eighteen-inch roof ven tilators extending about twelve inches above the roof and also by windows which bo-- cupy about 80 of the wall space in front of the top of the filters. jjUiPING FILTERS - After the filters are charged with clay they are plated up and the oil is allowed to percolate through the day for several hours, the length of time depending upon the nature of the oil run and the "yield" of the clay. The oil is all drained off and the clay is then washed with naphtha or "Varsol"" and steamed. to remove all trace of the naphtha. After this the filter is dumped on to a canvas belt conveyor and the day returned to the kiln for burning or reconditioning. Filter clay is used as many as fourteen times before it is finally discarded. In order to determine what effect the reconditioning of filter elay had bn its Arse silica con tent samples were analyzed by the Mew Tork State Department of Labor, Division of In dustrial Rygiono with this result* . - ...... - .-T.ln.t.1.Hum4** .. . - , . ~ -.,,^>Fbee~Sillca Raw Clay.............. Once............. Throe............ Eight.................... . 16-0000028 001447 Considerable steam is usually given off during the dumping which probably 203 explain* the smaller duet oount (a general avorage of only 2,518,781 partloles tea mioron* or lesa In size per oyblo foot) than' would be expeoted. The dustiest part of the filter dumping operation is sweeping up the floor under the filters after dump ing is oompleted. Samples taken during this sweeping or oleanlng op had as high as 16,638y8-Trtil*s-psrsuhi*-Xfife.,,%lJAauJgh thejgeneral aTerage of samples taken during dumping at the various refineries was 2,514,818'partloles per IbiiKlo foot.- About 96< of these duet partloles are slightly angular crystalline la appearanoe under the Konimetor mioroeoope and are above fire microns or less In sizoj about 6# are rounded semi-opaque error fire microns in size. Occasionally the olay doesn't flow" when the filterxs opened* end must be started "flowing" by means of an iron bar. This aotlon causes some dust (2,866,540 partloles per cubio foot) but not as much as pounding the bottom and lowor sides with a sledge (4,248,000 partloles 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 produces a little dust (an average of 792,960 partiolos per oubio foot). The filter is then plated up and is ready for recharging. The work of dumping filters is done by cne mam per shift, for each filter house. These men have ah average "servine-of-about-ten year-*-and-work.night-hour* 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 Job suoh.jtq. on the ' warehouse floors of seme of the larger bulk sales plants where lubricating oils are transferred from barrels or drums to smaller containers, or loaded into five gallon cans from bulk, host 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 Dustt Samples of dust from Attapulgus Clay, whioh had settled an the tops of elevator housings and on girders over the storage bins in filter .houses, were submitted to the Halted States Bureau of Hines Ex periment Station for petrograpbio examination. Ordinarily positive results are not obtained in potrographle tests for the identification of minerals in ataoephorlo dust. However, the samples submitted were ooarse enough to giro results in most oases. In studying the results of the potrographio examinations it should bo borne in <wd that the samples submitted were eettled 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 orush ed to a powder. ' "Montmorillonite" ((Mg, Ca) 0.A12 0$, 5S1 02. nH0 n-5 to 6) is the miner al that is oharaoterlstlo of many typos of fullers earth. Hot all of the less Im portant minerals found were fully identified. .- Clay dust from top shell of elevator - Top 42, Herman-Rrasoh Furnaoe. Quartz - 10# Montmorillonite - 80# Caloite, Mlorooline and Unidentified - 10# Dust from accumulation on girder over clay storage bins - Filter House. _ . Quartz -- .10# Moatmoriilonite - 70# - Possibly other olay minerals present, opaque - 20# Dost from accumulation on girder over olay storage bins -~#1 Filter House. Quartz - Over 1# Montmorillonite -- 55# ' Opaque - 40# Unidentified - 6# -18r-0000029 29* 001448 -22- Control of Filter Clay Duati Dust in a filter plants results principally from the operation of the clay handling machinery. The condition la aggravated by tho present practice at seme refineries by using an air hose to blow aocmaulated dust and spilled day from equipment, walls and floors. Hand!log a fine light dust producing material, as Tilter-^!i,gy,~*tg"a^y8te>^ddcvh^laalndnj ,npon,,bolt oonyyyprs ia in. horontly a dusty operation. (12,687,360 partioles, ten miorons or less in sise, per cubio foot). It .is diffioult to prevent eone dust fraa being generated at unloading points where the^-olay falls into chutes or bins, but it can and should be controlled by means p>f hoods, enclosures, and adequate exhaust systems with effective dust oolloo- tors. . There will alv.-ays 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 praotioe of cleaning dust spillage by blowing with oam- pressed air is changed, tho necessary periodic oleanlng will oontinuo to be. a very- dusty and unhealthfMl operation even though all precautions havo boon taken to pro- ` vent tho escape of- dust from clay handling equipment.' " X tfdflerg~industrial~yaouum cleaning system would do the job efficiently, without creating any duat. ' The principal source of dust in filter buildings is the belt conveyor vhich la usually located at the top of the building. Gusts of wind from the monitor blow the olay and dust from the belt. A certain amount of dust is also generated by clay fall ing into the tripper chuto (6,060,480 particles per cubic foot) and discharging from the tripper chute into the chute leading to tho various filters (7,306,660 partioles per oublo foot). .This could.be considerably reduced 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 conveyor holt. : . Bins for the storage of filter olay should be closed with steel decks haring the smallest possible openings in the form of chutes to reooivo clay from the ooarrey-- ers. 'If care were taken not to overflow the bins, tho dust and spillage oould be greatly reduced. - For complete control of dust, an exhaust system equipped with dust oollector, fan, ducts and hoods should be Installed to remove dust from the points of origin, suoh as, all unloading points (except movable trippers) of eaoh belt conveyer in the building, mew-clay-bima- -and burned-elay-Jilns. ..One estimate which has been prepared for suoh an installation calls for an exhaust system with a capaolty of approximately 15,009*cubio feet of dust laden air per minute, and is based an maintaining an inward flow of air at openings into hoods and bins at a reoomaendod velocity of 200 feet or more per minute. In considering dust collectors, it should be borne in mind that the cyclone type will not remove the fine dust partioles (ten miorons or less in sire), which are most injurious to health, and that the cloth bag type filter has hoen proven to bo more successful in removing these fine'partioles. Under existing conditions at most plants It is almost impossible to keep the plants oleon, regardless of how carefully the equipment is operated. However, the in stallation of a vacuum system and adequate dust colleotors should encourage operators to exercise more care in the operation of equipment and thus out down the amount of dust and spillage. ............... .............. , B - CONTACT CLAYi . . Moot contact clays, particularly in the Ublted States, ere sold treated "Ben tonite". 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 001440 j.a-0000030 There appears to he a wide variation in the oexposition and free ailloa ooa- tent of American and European contact or aotiYated days. "Filtrol" an extensively need Aaerioan oontaot clay ii reported to contain about 57# free ailloa (ailloa which la inaoluble in eonoantrated hydroohlorlo aoid). "Hilwhite", another extensivelynaed American contact clay, contains 65# free ailloa. The oontaot days listed are those-moefc-cjBfccnsixdy **d Jn Europe* - Insoluble In Insoluble in Concentrated Concentrated HCL HCL and CO?;. * ^lYry* Clay (French)........... . "Terrana Extra* (German).... "Clarit" (Italian).............. . 75.0#...................... 64.4j{............. 49.5;L............ 64.6# . 21,2% . 60.6% "Tonsil AC", another French oontaot clay, has 61.75# free silica. The main constituents of "Petriail", a German contact clay, arc* "Total-Silica. ~EL.J57% Lime (CaO)............... ............... 0.55% Aluminum and Iron Oxides.,.. IS.83# loss on ignition (Water),.,. 23.52% ' The balance probably c<mslsts ofpotassium and sodium oxides. The following is the result of a petrographio examination of "Eetrisil" which was made at the United States Btxreau of Mines experiment station* Quarts. ............................... 5% Hontmorlllonite,............ 90# Unidentified Minerals.......... 5% The use of oontaot olay for improving the oolor of lubricating oils is a reoent development. At present the price of oontaot olay la so low that it is used only once and then discarded. . ** Although, there are many oontaot olays on the market, a large percentage of that used by the Standard group la known as "Filtrol*, consequently this was included in our dust studies, . Whet is "Ultrol" end How is it Produced? "Filtrol" is a pulreyised aoid treat ed Bentonite, used as a deodoriser, absorbent and deodoriser la the refining end preparation of both organio and lnorganlo oils. It comes firoa "open out" mines in Mississippi and California,'-and occurs in beds about two and one-half feet thick under ah over-burden of some eighteen to twenty-fire fast. There has been some doubt as to its origin, but it is now believed to hare been Yoloanio dust transported by the air and deposited under the waters of either a lake or a sea. law Bentonite is mSawd'tu^'^eedei'^ito tsucka-mUh. ,*teaa_ahoTAlflU apdJ^enjNken to the ^ejaratioa plant. . A traotor seoop lifts the raw material from the storage 'ffibJ fto ind'plabeait in a hopper out of tdiieh it is fed into an elevator by means of a steel pan feed er, The elevator discharges into a crusher which breaks the material down^suffle last ly to enable it to pass through a screen (three meshes to as fboh) onto a belt ooxw --Teyer which takes it to a pre-mixer there it is mixed with water to form a "slurry". This slurry is passed into large wooden tanks and treated with dilute sulphuric acid 206 18-0000 00145 agitated with air and steam. It Is thon dumped into thickeners, washed, and dellrered to an Oliver filter. From .there it goes In turn to a pug mill, drying tower oara and Imp mill, and classifier, 'The finished produot is placed In a bin where lt'ls * put into fifty pound Bates Valve paper bags by means of a Bates Beg Packer, it 1* shipped .in railroad box oars, each haring a oapaoity of from 1600 to 2000 bars. Ww. three grades of "WltroT*'"In^greitt^irtr"demmd^aret grade . (Per oest. thru ` _ 200 mesh) 85 - 88 76 - 88 90-93 Per cent, of Total Production ' 80 15 6 Coarser Than 200 Mesh 14.0j 23. 0j5 8. 0% 200 - 32S Mesh 16.0^ 24.055 23. 0% Finer Than 325 Mesh 70.0% 63.0% 69. 055 . The only red -dust producing. operations in the production of Filtrol are the filling, etaoking and handling of the fifty pound bags. Samples pr~dUst taken durlng these operations, revealed the following* " Operation Particles per cu ft. Average dust filling bags with 85-88 grade 10,416,096 " packing room while filling bags 9,572,160 " " produoed in handling of filled bags 5,645,248 An exhaust system has been installed to reduce and control the dust produced during the packing of Filtrol* This consists of a metal hood above the filling tubes dn front of the machine, with a basin below. A a even-inch duct leads from the basin and a six-lncH duct to a. canopy in back of the paoker, both connecting with a ten- inch main duot rhioh runs to a Sturterrant Pan (1750 K.P.H. ) designed to handle. 1,620 oubio feet of air per minute against four-inoh water static pressure. A cyclone dust collector removes the larger partioles from the air before .delivering it to a tubular doth dust oolleotor. - About sixty per oest. of the* dust* partioles of samples taken during the fil ling operation are slightly angular crystalline in appearance under the Konlmeter mi croscope, and tyy~ttnmt,~bi*D mlcropa-og--L*a-~ln-.alsflj ..spprojdmately^tweutypor oest. appedfr to be rounded crystalline, glass^llko, but with rather smooth edges, and over ten miorons in site. There are a large number of very small gray-partioles (about twenty per osnt. ) too minute and too numorous to ocrunt accurately. -- . What* la the Chealeal Composition of "Filtrol"? Below is the result of an aa- .alyaie by a ocsaneroial efiemioal laboratory in Los Angeles, California, of a sample of Filtrol from the Jackson (Mississippi) plants ' - * Per Cent. Silica (S102)............ 56.90 --......... -**.Ailisalue.-4ll203....................... . . 13.97 . .*Perrie Oxide (P^Qg).......... --1/tt Titanium Oxide tTiOz).............................. a 10 Calcium Oxide (CaO)........................ 2.82 Magpesim Oxide (MgO).................* 3.66 Carbon Dioxide (CO2)............. Potassium Oxide (KgO)--**........ . -_ 0,03* 18-0000032 ,001451 207 --ZS- Per Cent. I* Sodium Oxide (H&20)...................................... 0.04 Chlorine (Cl)...................................................... - Phoaphorio Anhydride (P2O5)........................ - ..w. 0.-33 _ total ignition loss..................................... 20.00 Ifireo Hoisture.-............................................. 12.23 b "It i* customary to separately report materials such aa Silica (Si02) and Alumina (AI2O3) in ultimate analysis although the elements are known to be in o.onbination with one another. It is difficult to get ax analysis of free Silica, and since the quantity contained in Filtrol would bo very small, we have not attempted to hare this par-- tioular analysis made." The following is the result of an analyst? of "Super-Filtrol" which was made in- France* ' Per Cent. Moisture at 120 degrees C ................... . 16.6 Loss on ignition................................. . 33.6 Insoluble in concentrated ECL .......... 55.0 (Total Silica and unattacked crystals) Insoluble in HCL and in a 5% Na2C03 solution. 15,.0 (Siler, quarts' and unattacked crystals) . . . A microscopic examination shows a few particles with . "aoute angles". ' An examination made by the United States Bureau of Mines Experiment Station lx Pittsburgh* Pennsylvania showed that Filtrol contains more than .1% quarts, 95^ , Mantaorlllonite ((Mg, Ca) 0.Al203-5Si02-hH20--n5 to 8) and 5% unidentified minerals A similar eramination of Attapulgus lines (200 mesh) showed 5% quarts and 95% Moot- morillonite. _ -. . How ls Contact Clay TJsedt The olay is mixed with oil. agitated and heated* au either allowed Vo settle br'narthrough -a~filter-pregs*: -It-la theadlacardcd* The elay is either dumped directly into the oil or placed in a hopper from whioh it Horn into inductors or mixing chambers where it is mixed with the oil and then pumped to 1 filter tank. The only dusty operations are the unloading of the.material and' dumping it into the hoppers or mixing ohsabers. The higher dust counts with the oontaot ola; as compared to filter clay is probably due to the fact that it la 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 reac tion chaster gave the following dust counts. Operation Particles per cu. ft. - Avonx^e dust prddwed'VftYl'&'JdASlJ5ing'S6'pOUnd :----bags of "Filtrol"..**..................... *..... Average dust produced while dumping 100 pound- . bags of "Attapulgus Fines"...................... 9*260*640 - . 208 . ' 18-0000033 ,001452 -26- Under the Konlmetor Microscope the particles were rounded in appearanoo. The "Attapulgua Fines" appeared more crystalline atid angular, and had a greater proportion of particles five microns or less in sire than did the "Filtrol". The counts indicate that more dust results from dumping Attapulgus Fines than from dumping Filtrol aoti- rated clay. Dumping fifty pound bags of "Milwhite" (90j 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-* tides ten microns or less in site per cubic foot. Samples taken in the middle of the roam just after thirty bags had been dumped into the hopper had 55,847,040 par ticles per cubio foot. Under the Konimeter Microsoope, about 90jf of these partioles appeared slightly crystalline, and were fire microns or less in sire; lOji wore round, semi-opaque, ten to twenty microns in size. There were also a few scale like par ticles* Fourteen men with an average service 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~85J? of thetlme the filtering plant is in operation. They near H. S. A. "Corafo" respirators. . After extensive study and investigation the local management has made arrange ments to receive the clay in tank ears similar to those manufactured by the General American Tsnk 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 Aron 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 - BORE BLACK OK CHU-KED BOlIEi . . Refined wax is filtered through bone black 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. An open belt conveyer and elevator carry the bone direotly from the reactivating furnace to* the covered filter charging hopper. Metal chutes lead directly from tg>s hopper into filters which hold about 3,000 pounds of bone black. Upon completion of filtration the bone is washed with "Taraol", steamed for,About 2.4 .hour*, washed with hot. water., steamed for two hour*..more, and then efcmped upon belt oonveyers which carry it to the reactivating, furnace wkioh la gas fired. The bone goes through the furnace at a temperature of about -1100 degrees Fahrenheit and at the rate of about 250 pounds per hour. Bose blaek oen be used over and over again. Three men one on eaoh shift, with an 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 from the open oonveyers, particularly in dumping the material from the furnace onto the conveyer belt. Samples taken during this operation had as high as 11,044,800 partioles of ten microns or less in size per cubic foot. Considerable dust (14,273,280 particles per cubio foot) also arises from the open hatch, of the filter charging hopper during filling. An eight-inch motor driven exhaust fan has been installed to suok back the dust from where the elevator buckets dump the reactivated' bone into the chute to the charging hopper. ~ THe'cftist'loSs' mr'thli 'TiTtering 1500 pounds par month. - , C . -- '* Under the Konimeter Microscope about 6G of the dust partioles of samples taken during the reaotlvation of bone blaek appear to ba black, opaque, aeot-like, and are five microns or less in sizej 5JS are rounded; sal-opaque, ten microns,or more In else. The angular crystalline and light grey* partioles which constitute about 30&are probably 9 on 18-0000 0 0X4 4 bene ash. -27- i HI INSULATING OPERATIONS Insulation plays an important pairt "lii `thi prbd`tSslng'1^'p%tTT>ltrtsirprotItKrt yho two types of insulating material mast frequently used a-ro "Sponge Fait* (asbes- toa with jroundlspongs to give dead air spaoe and thus increase the effectiveness of the Hnul atlpp) and a mixture of 85jS magnesia and XSj asbestos* Sock wool is used to a considerably lesser degree. In the ordinary conmerelal font. Rook Wool, . as used at our refineries, does not present a dust hazard. It is also used .for house insulation, and is.available in small nodule form which oan be blows into plane. "85j magnesia" is a mixture of magnesia and granulated asbestos and preseed into blooks of various sires and shapes (usually 16" x 18" x 1-1/2"}. The .Most.dust comes from dismantling old Insulation and grinding sorap material for use as a plas ter or "gsnister". The average aervloe of men engaged In insulating operations is about fifteen years. Most of these men have been transferred from the Common Labor Department. They vfork~n4nc-out rjf.Xoitrean .e.igh.t-hour bAftU ihCi*SSS 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 occasionally MSA "Ccmfa" Respira tors , but this equipment is not used as much as it should be. Generally speaking, about 85} of their work is with sponge felt.and 1SJC with 85^ magnesia insulation. At one of the larger southern refineries about 300,005 square feej of sponger felt 60,000 square feet of 86j magnesia are handled a year. A - What Physiological Reactions are Provoked by Insulating Materials? Acoording to Or. Leroy 0* Gardner (Journ. Indust. Hyg. Mar# 1937,Yol 19, No, 3, P.121) asbestos duet with its fibrous particles does not seem to be readily handled by the protective , mechanism of the lungs. Quoting ftros hie artiolei . "They are not removed to the lymphoid'tissue but remain in a gotact with the delloate wells of the air spaces. They beooms surrounded by an 1ron-eontalning coating that fractures and gives rise, to the peon- liar structures known as tasbestosls bodies*. The fibers are Irri tating, perhaps because of their form, and they excite a fibrosis which begins about the terminal bronchioles and spreads to form dif fuse patches in the parenchyma. Often the distribution is sub-pleural. In the presence of infection, the reaction to asbestos dust is muoh more scver8^'hKn"th:t"ouyed~by;-fee--dust alone. * '. . There is nothing in the pertinent literature, nor does the Bureau of Minos know of any evidence, whloh would demonstrate magnesite (a natural magnesium oarbanate) to ba harmful. It would fall in the class of "nuisance dusts* such as gypstsa* While many of the so>oalled "nuisance dusts* have never been found to be harmful, it is the opinion of most inrostigators in the field of industrial hygiene that no work er should be exposed to aay dust in a concentration exoeeding 75 or 100 millions of partioles per cubio foot of air. ** What are the Prinoinal Insulating Operations and Bow Muoh Dust is Produced Luring Suoh Operations? There is,- of oovrse, a wide variation in the amount of imsu- latlan-week-end. Aha ^oant..ofulnat.produced.. example*, however, will give a good general Idea* INSG1ATIR0 12" STEAM LdESt 6* x 18* x 1-l/Z* blooks of BSfC mag nesia are tied on the stasia line with 14-gauge galvanised wire and oovered with roofing paper to make it waterproof. Often times this work is performed on scaffolds twelve to fifteen feet-above the ground, ' with men lying an their hacks under the line part of the time, - * .1 yB--0000035 o - a 00145a -zn- Considerable dust (as high as 18,124,000 partioles of loss than ten mlorons per eubio foot)' results f*am tapping the blooks into plaoo. Samples taken during the entire operation had an average concentra tion of 6,881,760 partiolos per oubio foot. About 90# of these dust partiolos were slightly angular, orystalline in appearanoe and above Dime.jaitxrona/.or.3ftss.in, siid.X<ts.neen. under he.Jtonim.tr MippospopeJIj 5# were rounded opaque, ten microns or more in sizoj and 6# were opaque sciale-llko, five mlorons or more in slza. Semples taken while applying asbestos sponge felt to a 12" steam line had a dust oonoen-* tJration as high as 23,-788,800 partiolos of ten microns or less in size per eubio foot. The average was. 12,574,000 partioles per oubio foot. These dust concentrations are considered too high for work ing without adequate protection. . INSULATING A 750-POUND CRACKING COIL ACCUMULATORi 6" x 36" blocks of Johns-Manvlllo "Fire Felt" are first applied and plastered with extra AA Rubberold Asbestos Cement and waterproofed with Johns . tianrille "Insulkote". The dustiness of handling these materials has been oonstflerKblyTcdueea vino*'thoTnanufaqturors 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 4,502,8.80 particles, ten microns or less is size per oubio foot.' About 76# of -- these dust partioles were ellghtly angular In appearanoe, five mi- orons or less in sizej 10# wore seala-likej opaquej and 15# were ' rod-like and fibrous. _ . INSULATING TREATING PLANT ACID SUCTION LINEt Sections of "Sponge . Felt Pipe Cover" are cut to fit pipe lengths with an ordinary oarpen ter1 a hand saw. This operation produoes on an average 821,280 par-- . tides of dust, ten mierons or less in else, per oUblo foot. Under . the Konimeter Hiorosoopo all of these partioles are allghtly angular, crystalline in appearanoe, and five mlorons or less in size. The blooks or sections of the pipe oovor are held In place by wrapping - #16 gauge galvanized wire about eaoh one. INSULATING CRACKING COIL HOT OIL LINES All hot oil lines at oraok- Ing oolls are Insulated with 2" asbestos tubing (05# magnesia and 15jC asbestos) held in place by fine copper wire. Sections of the tubing ^are cut to fit particular areas try means of an ordinary carpenter's hand saw. This produoes 7,788.000 partioles of duet; ten mierons or less in size, per oubio foot. Under the mioroaoope, 90$C of these dust partioles appeared to be rounded orystalline and about three mi crons or less in size. Eaoh seotion of tubing is pounded into plaoe with the open hand so that it fits snugly against the pipe, and than wired into position. The dust produced from both of these operations averages about 3,379,520 partioles per eubio foot, Rider the mloro- soope, approximately 80# or 90> of the dust partioles appear orystal line, more or leas angular, and five microns or less in size} the re maining 10# or more are rounded in appearanoe, and over ton mlorons in size, .- . ' ' .DISMANTLING OR RH10V3NG OLD INSULATION* As a general rule, the . dismantling or rev.oral of old insulation is a more dusty operation \ than the application of new insulation. The Old insulation is chopped ' or out with a b&tehet or small hand-axe, and pried loose and pulled off with the hands* This produoes dust oonocntrations as high ** - 6,890,560 partioles, ten mlorons or less in size, per Cubio foot. In . ' - O *1 1 18-0000036 001455 r -29- '_ ' .I - dismantling an old cracking ooil 4" tar lino, the average dust oanoentration was 2,322,240*partloles per otibio foot, la appearanoe thsao P&rtlolea wars dear crystalline, rather rounded, and fire microns or less la size, Ho fibres wore observed in asy of the dust aaaples from dikaaa^4f*^|wktiw., ,.jytar ,a. fieie weeks or months aenrioe, insula- ` .&lon on hot lines dries out and appears to dislntdgrster "Thi* -is-probably due to the fact that such insulation i usually oorered with a weather-proof material which prevents absorption of moisture from the air. - - . , CRUSHING SCRAP ASBESTOS* Scrap asbestos insulation, usually the 85# magnesia type, is crushed in a belt-drlren William* crusher to pass through a sereen with one-inch holes or slots, and is then mixed with new asbestos to make insulating plaster. This operation, whioh is a Tory dusty one, is performed by two men, with an arerage service credit of about twelve years. Goggles and, HSA, "Comfo" or Willson Dust Respi rators are worn. Considerable dust la produced in breaking up the scrap insulatiahby "hASd prior-t~orushing--(10,136,200. portioi,es, ton microns or less, per cubic foot), and also when feeding the orusher . whioh is done by shovelling the broken-up pieoes into fire hopper and * poking them down with a short wooden stlok (14,839,680 partloles per oubio foot). Dust counts as high as 27,527,040_partioles per cubic foot were found in samples taken from over the hopper," These dusteon- " . centrations are dangerously high. About 95# of these partloles are . - sharply angular, crystalline in appearance and five microns or less In siroj 5# are opaque scale-like, six microns 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, . - CRUSHING CLD COM INSULATION* This operation la performed approxi mately twice a year and takes about twenty or thirty minutes. The in sulation is orushed on a belt-driven Williams orusher, by-the same men who crush the sorap asbestos. This crushed oork is used for insulating lines in the a old settling plant. The average amount of dust produoed Is 20,016,178 partloles, ten microns or less in size per oubio foot, About 60# of the particles are slightly angular, crystalline. In ap~ pearanoe, and five miorons or ISss in sizej 20# are round, semi-opaque, - tea microns .,or more. There are also a large ntmber of very small black or dark grey specks. . . IV-GUNJTING OPERATION What |# Ounits and How If ti Applied7 - Gunite is a mixture of" approximately one part (one 94 pound bag) of Portland Cement and two parts (twelve scoop 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 and compressed air at thirty to ninety pounds per square inoh. It is applied under pres-- sure, as a sesd-fluid, against the surface to be proteoted (usually process equipment, such as, eraeking ooil soaking drums and storage tanks). In practloally every oase whore^gunitingis done. It follows -Immediately, after the sand blasting job used to olean the" suraoN,"'wia''&gSt`*tfxscsth'`'werk~d*-fesifk>Bwd-%.-the. same crew, the indl- , -ridual -holding the gunite nozzle Is provided with the same protection a* is the operator of the sand blast nozzle, and the men tending the gunite machines are pro* . . vlded with respirators and are required to use than while actually handling .tb* sand and cement. This involves mixing the materials and charging them into the machines (the two dustiest parts of a guniting job). Samples taken during these operations showed the following dust counts of partloles ten microns or less in size* . 18-0000037 001.4 5 f -30- Qporatlon Partioles par on. ft. * Screening sand prior to mixing with oemonfc.. Mixing batoh..................................................... " iuts v. v 2,493,160 1,699,200 260 About 40jJ of the dust partioles in samples taken while mixing the batch and. filling the hopper were crystalline, quartz-like in appearanoe, and about fire aioroas in Aire, The remainder were dark grey in color and below one micron la size* The dust partioles in air coming out of the bottom manhole of a soaking drum being gunited averaged 628,640 partioles per cubic foot, and were slightly angular, orystalline in appearanoe and four microns or less in size, A gunite crew consists of six men. The average servioe oredit of the men in the Crews studied was eight years* Two "nozzle-men" who "spell* each other evory two or three hours apply the gunite. There is one man at the gunite machine, and three men soreen the. sand and mix it with cement. Only about ZS% of their working time.,,,or nine hours per week per man, is devoted to gun!ting. - Removal of Gunite Lining* Pneumatic ohisels are used to remove gunite lining. Samples taken from inside a oraoking eoil tar separator during this operation had an high as 16,595,520 partioles of dust, ten microns or less in size, per oubio foot, and an average of 10,804,080 partioles per cublo foot. "About "75JC of these'parttolos were rounded, angular* more or less opaque, in appearanoe, one mloraa or loss 2m size, , .and 25# were angular, quartz-like, about ten microns or less in size. A oheaical analysis of the gunite lining showed that it contained 68.2^ free sillea. Four men from the Plant Labor Department, with an average aorrioe of seven years, spend about twenty hours per week removing gunite linings Ikon prooess equipment. An air syphon provides ventilation, and the men are required to use the goggles and respira tors which are furnished them, V - WELDING AND CUTTING OPERATIONS * Voiding has never been considered a dust-produolng operation. However, our studies and those of others indicate that the use of the modern coated electrodes or rods produoas a large amount of dust is addition to the fumes whloh are evolved. Am electric arc Is used for moat of the welding around refineries. There are a number . of welding 3bb*rdwwevervwhieh.mxyaaeigrlene Is used. Oxy-aoetylene is also used fgr practically all burning or outting, . A - WELDIHG OPERATIOKSt 1* moiRIC ARC VELDIHQi Electrio aro welding is used on all types~of eonstruotlon and repair work. The average servioe of the eleotrlo. welders is about two years and meet of them earns ikam the Labor Department, having been developed into welders at the individual plants. They are exposed to * particulate matter generated by 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 partioles when found hava^jmmh.smaller, size range than that of dust, suoh as slUoa. With same operations there mayalsobe aMe dust j^eSiSatr"bm*tfta*prudtwt-fewaod.4kgB , volatilizing the metal and rod seating* is oosnonly turned a "fuse", AH . welders are provided with approved hand shield or helmets equipped with #10 Vorlweld lens. Voiding in shops is done in tianvas or wooden booths. A \ _Steaa or air syphon is installed when *ny aro welding is dene Inside of olosed vessels suoh as drums or towers. ' - What are Coated Electrodest. Coated electrodes are metal welding rods savored * 18-00 0014.' with a composition which prevents oxidation and permits the formation of stronger more uniform wolds. * * What Do These II ootrodas Contain airf What Produota Result ffram Their tfael la general, the coatings used in modern coated welding eleotrodee are patented or trade eeorets; upeelal-'erirtoee-afctnlbuted.Jbo.each. , Qtriously., it is inadvisable to put into these coatings materials which might produce products hairmful 'to man. nevertheless, chemical analyses of both the coatings and their products indloate that the continual use of same of these rods might possibly lead to complications. k Most of the are welding at our affiliated plant a is done with #5 Fleetwold coated electrodes which come in two sizes (5/32" and 3/lS") and with General Eleotrio W-20 S/32" coated rods. Other rods sometimes used are #4 St&inweld lagS alloy welding rod, 5/32" Stainweld A rods for stainless stool, and Murex Kiokel Steal coat ed rods. Among the constituents of some of these electrodes coatings are* Coated Eleotrode Brand SiOa Per Cent, Fluorine Calolum Fluoride "Fleetweld", Lincoln Electric Co..........30.28 "Murex", American Metal 4 Thermite Co.....28. 05 "tJSS Cr-Hi 18-8", Amer.Steel & Wire Co,...37.20 "Stainweld", Lincoln Electric' Co.............. ..12.101 "Reziatal K-A-25", Crucible Steel Co......24.03 ' 21.20 13, 4D 14.60 43.50 presemt- All of the aboTe coatings also contain Iron Oxide (l^Qs) Manganese Oxide, either tfc*203 or MnO or both, and Aluminum Oxide (AljQs), jin varying per centages. ' The composition of the fluxes or coatings used la G 4 E types W-20, W-22 and W-23 is not available, but it ia known that they contain amounts of free eilloatos end free silica. According to determinations made by the General Elootrio Company, the maxlmua concentration of free a illo a on any of their electrodes under particular set of conditions is 1,578,000 particles per cubio foot of air pith W-20, 778,000 with W-22, and 1,093,000 with W-23 under other conditions the concentrations might be higher or lower than those given. The maxlmua permissible concentration as listed . by the Metropolitan Life Xhsuranoe- Company is 7,000,000 particles per oubio foot of air. *. Coatings also contain cotton fiber, cellulose, or other brgaidu'puly'tdiitdi creates fumes, but sinae we are only concerned with dust in this study all fume pro ducing materials will receive no further consideration. - ' Welding oorrosion-res1sting s+eel with coated oorroeion-reoibting steel elec trodes forms a slag, among the major constituents of vfcioh artt ' "Stainweld" CSS CR-HI 18-8 "Bosistal" Fluorine (F)............................................ 12.4*........ 6.6*................ 14.0* Silica (Si02>............ ........................... 25.1*.............38.6*................. 13,3* Iron, Chromium and lianganese.Oxides... 22.3*........24.2*..........16.2* The major constituents of dusts separated from atmosphere by gravity and ool- leoted from the bottoms of welding ehambers after fielding oorrosioc-resiiting steel plates with ooated corrosion-resisting steel welding rods are*" 214 iS-0000039 . 001458 -32- "Stalnwold" U3S CR-Hi 18-8 "Rozlstal" Silica (S10 )......................... ............... 11*0$...............19.6#................ 10.0# Calcium Fluoride (CaF )..................... . 40.6#............... 11.4#............. 25.4# ^Iron7'^nBHlTnaff''aHa. . . . , ; :v ^;'VJ36r6# ' The following la an interesting comparison betweon the eaopoaitions of dust formed riien using bare olid steal electrodes and vdien using coated electrodes for welding galvanized steolt . Brand "Fleetweld" "Wilson" "Murex" 1 Bare Electrodes # ZnO # F23 79.2 62.6 60.5 20.0 60.6 40.0 Coated Electrodes # ZnO # TozOz 67.5 70.8 72.0 31.9 21.5 28.0 ' ` Investigations have shown that there may be as much as a five per cent, varia tion in composition of dust produoed by the same make and kind of eleotrode when used under oonstant conditions-but by different operators. Ferrlo oxide (Fe2D3) which emanates from all welding arcs, regardless of-the type of ooating, 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 dexlse clouds of fumes of zinc oxide, formed when the zino of the galvanized coating is boiled off by the heat of the welding arc, oauses what is earnmonly known as "fume fever". This is evidenced by nausea followed by chills and un pleasant fever. The fume fever doss no lasting ham 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 Charaoterlsties of Oust Produoed By The Various Eleotrio Are Welding Operations? There is a wide variation in the amount and character of dust produced by different types of rods on different materials under different operating, conditions. ` FOIE. OR DOST PRODUCED BT ARC WELDING Material Being Eleotrode Size of Particles Welded Used Eleotrode Per ou. ft. Rivets inside G-B V-ZO Cross Coil Coated Drum. 5/32* 20,050,560 Characteristics, of Dust Particles. (Sizes and Per centages Estimated) About 98# angular crystal line, 5 microns or less in size) 2# rounded semi-opaque. 10 microns or more in sizo. MiW"Steel"'* 'UJE'Wi'20 . .Blanks Inside ... Uoated . Booth. *HA*k xtt*' fdlshtrerospeoks, 1 microns or less in sizes 20# slightly angu lar orystallino, 10microns or . less but mostly about 5 mioroms and large number reddish brown specks too small and numerous -t-o---o--o-u-n--t.-------------- - ia-0000`040 215 00145! -33- FTC-tt? OR DUST PRODUCED BT ARC WELDIHO (Continued) % .' Welded Characteristics of Dust -Partiolas,, .-Xsix0*.and Per centages Estimated) l/4" Boiler _ #5 Fleet- piatfc Inside* weld Booth. C oat ed 5/32" 11,441,280 About 80# angular crystalline 3 microns or less in alee) 10# round seal-opaque, 10 microns or more in site) 10# opaque soale like, 10 mi crons or less In size. Count less number of minute par ticles, reddish brown smudge. 1-1/4* !1U .... .^S^Flest*;. Steel Expan weld sion Joint In Coated side Booth. 19,861,793 About 95# angular orystal~llh ,"^3 "iderons -or -1-esa-in size) 5# rounded semi-opaque, 10 microns or less. Count less number of particles reddish brown smudge. l/Z" Rolled Steel (55,000# per aq. In. Tensile strength) ` In-; ' side 6+Foot Die. drum near head-of closed end. #5 Fleet- wold Coated Welding Flange Hurex on 4" Steel Coated Line 'Pipe, In side Booth. fi/8" Boiler Plate Inside. Booth. #5 Fleetweld Coated 3/L6" 2,265,600 All partioles 5 miorons or less in size) about 10# angular, semi-opaque. 3/32" 6/32*. 2,756,480 490,880 All partioles 2 miorons or less in size)-slightly angular, glass-like) dark grey smudge. . About 75# round,iMftalllo opaque, 6 microns dn size) 25#- semi-opaque, crystal line. Countless number of minute partioles . Welding Bir- ets in Courtney Edge Inside Crack ing Coil #5 Fleetweld Coated .Soaking Dr*** ... 5/32" 8,468,960 About 90# sharply angular crystalline, about 1 micron or less in size) 10# rounded semi-opaque, 5 mi crons or more.Countless number of minute particles. ' 21G . . . 10-0000041 . 00146 -34-- FUME OR DUST PRODUCED BJ ARC WELDIKO (Continued) Heotrode Sice of Partioles Charaoteristios of Dust ^ Welded " . "Dsia""" m'edtfdttir ~ ^Pavtielea, Per centages Estimated) 18-8 Stainless Stainweld ' Stecft. Band at A Top of Soaking Coated Drum Manhoad 5/32" 849,600 About 6Q^ slightly angular seal-opaque, Smicrons or less in size; 20 rounded, over 10 microns| 20?f very glass-like, 10 mi- ^ crons or less, ... % 1/2" Boiler Plate to 6" Pip# Inside Booth. ' G-B W20 Coated - S/L6" 23,222,400 About' 80j seal-opaque, red dish brown rounded, crystal line, 6 microns or leas| 20^ ` round globules of metal '5 microns orsore in sice. Countless number of small partioles. 1/2" Boiler Plate to 6" Pipe Inside Booth. Roebling' Iron Bod ' 5/32* 26,592,480 ' About 90j black opaque, 1 micron or less in sice} 6% rounded metallio globular, 5 miocons or less| 5^ slight ly angular, seal-opaque, crystalline, 3 microns or less. Countless number red dish brown partiolo?, * Back Holding' a flange on 8" Standard * Pipe in Otttaide Holding Shop. Jleetweld #7 Coated 5/32" 362,498 About 95# black opaque metallio, 2 mieross or lessi 5#aagular'orystallino, 6 microns or less. Count less number of reddish brown particles. ||ok. Holding a flange on ' 6" Standard Pipe Inside Booth, flestweld #7 Coated 6/32? 1,000,640 About 95# blaok opaque metallio, 2microns or less; S#angular, oryeta- lllno, 5micrpns'or less* Countless number of . blaok partioles. ' * Welding Rireta Inside Cracking Coil Yapor- Steel Alumi nas Coated), Jlestweld #7 ' Coated 6/32* 6,253,056 _J About 95# angular crystal line, 6 microns or less, mostly around 2 aierons|5# a an!-opaque, round, S mi- orons. Countless number of jg-0000042 . . 217 001461 FU1S OR DUST PRODUCED BY ARC WELDING (Continued) : Material Being Eleotrode Size of Particles Welded Used Eledtrods Per eu ft. V Charac.teristios of Dust Particles. (Sizes and Perooutages Estimated) Holding 2" Ring Fleetweld on 1" Mild - ft - Steel Boiler Coated Plate * ** Inside Booth, 3/L6" 27,662,976 All partioles less than 2 miorons. 70?C round, opaque) 30# slightly anpilar, crystal line, Countless number of black particles, reddish brown smudge. . Mild Steel So rap Plates Inside Booth. St&inwold A Coated 5/32" 2,605,440 All partioles blaok opaque, 2 miorons or less in size. IagS Steel 'Inside Booth* Stalnweld A......... Coated 5/32"' 1Z, 460, BOO About 8C# angular opaque, -2 miorons or less) 20slight ly angular orystalllno, 5 microns or less. Countless mother black partioles, -brownish grey smudge. __ The U.S.Navy recently conducted some extensive testa with coated electrodes, -and'found that the quantity.of dust or fumes developed while welding on galvanized steel plate was greater than when hare steel plates were used and the dust remain ed ill'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 partioles under four microns diameter per oubio oentlmotor. Quoting the Navy report* - "It is apparent that considerable quantities of dust are found in any aro welding operation. The dust formed when operating on plain mild steelor oorrosion resisting steel is largely derived from the flux coating on the eleotrodes, as is shown by the composition of these dusts"* . What Physiological Effect on Welders is Produoed by The Use of Coated Electrodes, --JLccordinr-1o jl .study-made- byJtectora.jL.1* Jolt awd p. on Ijggs of Eleotrio Are Welders! (Lancet - V. 20j 771 - 775 (April 4, 193d)), defi nite pulmonary lesions' which gave rise to striking X-ray ohanges in the appearance of the lungs ware found in welders whioh had breathod the dust or fume from ooated eleotrodes. Quoting Doctors Doig and MoLaughllnt -" ' "The eleotrodes or welding rods whioh contain a oore of metal and an outer covering are eonsuned gradually by the heat generated (about 1500C. ) during the welding operation. The metal in -the core of the rod beoomes molten and, assisted by the flux contained in the covering, spreads over the surface of the metal whioh 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 form of iron oxides* *2ld`'ANa|t'i^'W'*7iiibsn^^^ly' SMtairi gasbsrw&ah k*'hltr'dgeii`pWb*ide and ozone which are formed by the action cf an electric spark on the air. The oanposition of the ooverings of the electrodes' or welding rods becomes, ..in. the eireumstanoes, matter of some importance.. Many substanoes, all of ' _ whioh wo do not propose to emuorate, aro used* The basis of the majority . of the ooverings is- sodiun silicate whioh aets as a flux. Again, the * 001462 18-0000043 -36- coverings of a. certain type of electrode contain asbeetos. Tho rode are sometimes dipped in & mixture containing powdered asbestos and sodium sili- oate, or asbsstos yam la wound round the rod and fixed by sodium ailio&te. In same eases the asbestos completely oovors the rods, and In others it la merely a oord whioh la wound spirally about the rod. . "Tho composition of the fumes arising from electric welding el eotrod os haa hot yetjieen fully investigated. Mr. L.C. MoHair, H.H, Engineering ln- 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 collected in anOwon's dust-oounter. it was seen that & large proportion consisted of iron oxide particles, with an occasional asbestos fibre. "The X-ray appe&ranoes in the well-marlced caaea differ from the usual picture of asbestosia. In none of the positive eases and in only one of the suspicious cases was there any blurring of the dl&phragnatlo shadow, and in no oaso 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 aooentuated at the bases of the lungs, but on the contrary the upper lung fields appear to.be the earliest, and in established oases, most markedly affected. Before asbestosis can be eliminated from the differential ` dlagnoeis it must be remembered that the asbestos fibres are being subjected to intenso heat and are not in the same physical state as the fibre* whioh are Inhaled by workers in an asbestos faotory. It is possible that a 'typical picture of asbestosis might be produoed by the inhalation of alter ed asbestos. Merewether. says that - 'the radiographic appearanoes of the developed or advanced states of asbestosis are distinctive, although they are not specific.. While, as is the case with sllloosls, eortaln radio graphic appearances may be looked upon as typical of tho disease, frequent ly modifications of and departure from the typical picture ooour*. The X-ray appearances in our cases most olosely resemble those of fine ailioosia, but the ollnioal features show two important differences. In the first place, the electric welders whom we examined are all in good health and are fit to work. Tho only .symptoms observed yore slight oough and morning expeotoration, and in the first case a small haemoptysis occurred. This man has not been away from work even for- a day sinoe he was first seen in..June,_1323,-andAla, healtha,the. proscnt. time..is..good.Hone .of tfte men suffers from dyspnoea. Secondly none of them has oonocmltant pulmonary tuberculosis. "Miliary tuberoulosls can be ruled out of the differential diagno sis for olinical reasons, and to seme extent on the radlologioal appear ances. Hone of the oases shows tho dyspnoea, cyanosis, and tachycardia of acute or subacute miliary tuberculosis. Chronio or healed miliary - tuberoulosls is rare and.lt is difficult to imagine that a condition of suoh 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 site and shape, whereas in miliary tuberculosis of the lung the shadows are more uniform. _ "A further possible explanation of tho X-ray nppearane.es in this ' series of oases is that the inhalation of small quantities of nitrous ' fumes together with the. superadd ed effect of fine iron oxide dust might -- set up small areas of chronio inflammatory change, congestion, or fi . brosis in the lungs. Again, the iron oxide partloles might be opaque to the X-rays and produce the plotur'e without the associated presence 210 001463 18-0000044 *. _ of fibrosis and congestion." * 2. OXY-ACETYIEME :aXPT30t tfxy-aoetylene welding is nope or less oonfined to ^iii repair lobs or to certain emergency operations where are welding is not available or practical. Exposure of men doing welding is more or less irregu lar* They usually wear American Optical Company or Willson Welding Goggles - with "#4^ Eoti^ield^Jrana^'H^'eaeeuBrb-ef-dwst.^aso^ftfld Jty,j^^AMfcrlonejn*l14as - is-considerably less than that caused by the use of coated electrodes in aro welding, and varies considerably with tho style tip and welding rod "being used ar well ab* the material welded, as is shown by the following table* . DUST PRODUCED BY OXY-ACETYLENE WELDING Material Being Welding Rod Tip Used Partioles Per Characteristics of Dust . ' Welded Cu. ' Ft. Partioles (Sizes and Per centages Estimated) Galvanized Metal Hood Welding Shop. Uorway -...... . Aireo 5/32" ----- 396,480...... About.TOJ. slightly angular, semi-opaque, greyish, 6 mi crons or less) 20>rounded. seal-opaque, greyish crys talline, 10 microns or more) 10JJ amorphous, eoale-lilcej 10 alorons or more in size. l/4" x 2" Bar Iron, Welding Shop. Oxweld eop-i Airco periled #8 steel 3/16" 509,760 About 8QjC blaok opaque, 1 micron or less in size) about 2Qf. rounded, crystalline) 6 microns or less in size. l/2n Boiler Plate, Soft Steel, Weld ing Shop. Oxneld cop Oxweld perlied steel l/8" 1,019,620 About 80^round, semi-opaque, 5 alorons or less in slzey 10JS angular orystalllne. Countless number of small blaok partioles. 1/8" Galvan ized Sheet Ir<flf, Weld-"' ing Shop. Oxweld o opperitod ' steel, 1/8" Oxweld #6 ....... 1,359^60 ' About 80^ rounded, seal- opaque, dark grey, 1 micron or -lees-in-si*) -1-OjClightly angular crystalline, 3 mi crons or leas) 10> sharply angular crystalline, S mi crons or less) eountless ` number of small dark grey partioles, ' Welding Teeth Simons Saw Aero on Band Saw. Welding plane Rod. 3/64" . ts,n, ^ *f\m ......... B - BumTOO OR CUTTinO OPERATIONS t 1,472,640 About 98^ round blaok opaque, about 1 micron or less in size) 2/C slightly angular, . orystalllne, *3 miorons or less in.size. .. \ 1. WITH QXT-ACSTYISSEi The oxy-acetylene toroh is used both in tho qonstruotlon , 18-0000045 9on 001464 and the demolition of process equipment and works structures. It also plays an important part in emergency and resoue work. Goggles with shade #5 Xcnri- weld lens are 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 cutting or burning operations (about half their time is given to "burning steel" for new construction). The amount of dust produced-is*4isually,.greater than that caused by ojy-aoetylene welding. b ' DUST PRODUCED BY OXY-ACETYLENE BORUIHO ' Material Being Particles Characteristics of Dust Particles Burned Tip Used per cu. ft. (Sizes and Percentages Estimated) Burning 6* Hues (1-1/2" thick) Out of . Shell Still. Qxweld #2 1,869,120 About 75# round blaok, 2 microns or less in size) 20# slightly angular, crystalline, 2 mlorons or.less) 5# opaque, soale-like, various sizes. 1/2* Bollor Plate (soft steel) Oxweld 2,718,720 - About 9C# semi-opaque, blade, 2 microns or less 10# round, dark grey, over 5"micron's in size. ' -- 2. WITH NATURAL GASt A large part of the burning or cutting at one of tho larger southern refineries is done with oxygen and natural gas (60 pounds per square inoh pressure), -A special torch with a. l/l6" x s/l6n tip made in the refinery shops is used. Two men'with an average aerrio# of thirteen years spend a najor portion of their working, time on this natural gas. They wear goggles with 05 shade Eoviweld lens. Samples taken while burning holes in 3" standard pip# In tho yard outside of welding shop with oxygen a^id natu ral gas had a concentration ef 471,811 particles, ten microns or less in slxe,. per oubio foot. About 75# of these particles were slightly angular crystal line in appearance under the Koniraeter stlarosoope, and were Ore microns or less in size) 25# were rough scale-like, opaque, ten microns or less in size. There were also many minute particles* - HEALTH HAZARDS PRODUCED BY WELDING AMP BURKING 0PERATIOKS tAlthough our study was confined to the fumes or dust produoed by Welding and Cutting opera-, tiomjthe possibility of lead poisoning from welding or outting Iron plates that have been previously coated with red leadshould be pointed outT"lad poisoning from this source is rather common, especially in outting up old scrap, bridges, tanks, and other iron strvotures that have through zany years of use received protective coatings of red lead. The action of the flame , volatilizes this lead material and creates a smoke that is poisonous, Tho same hazard exists in outting out rivets In new structures. . ' It should also be pointed out that some of the weldirg rods contain manganese which is very poisonous when taken into tho 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-outting or weltfing-tlBea `'litsWe-small -twnka >VK^4mllar--wwkfimed spaces. It is becoming more, and more recognized that persons engaged in outtihg and welding operations, either-by arc or flame, should have respiratory proteo- . ti.oa, in all work where there is a possibility of the workmen* breathing fines and dusts created, .' . - 221 18-0000046 00146?) - i -ay- VI - GRINDING OPERATIONS .t Power grinders ere perhaps the most universally used of the smell power- drIton tools* The usual power grinder* oonsaonly known as the emery vfaeel, consists of a oast metal stand and two abrasive wheels mounted on a through shaft vfaloh is either belt or Vti/tor^rtnur<f**aL..grJj^ fouxtd -on machine tael equipment where grinding takes the plaoe of lathe and planer work. All 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 Tontllation or exhaust hoods provided, ;i * - What Is the Composition of Grinding Wheels? Grinding wheels are made of . either bauxite which Is mined, or silicon carbide whioh is made by heating-a sulkture of quarts sand* coke and ccanon salt in an eleotrio fumaoe. The bauxite or silioon carbide are crushed to the desired grain site, mixed with an adhesive sub stance called a bond, and formed into wheels* discs, oones or cylinders. There are many wheels in whioh the binder is shellao, rubber, bakelite and other organic ocm* .pounds* Bauxite wheals are known in the shop as "Alundum" and "Aloxito", while silioon esxbido wheels are known as "Crystoion* oi3"^Carborundui*. "TUMndum idreels should be used on material of low tensile strengths such as east iron, brass, alumi num, copper and marble. Is Abrasive Dust Harmful? According to Dr* W. Irving Clark in a paper read, at a meeting of Government Officials in Industry (Boston - May 21, 1931) the artifi- eal abrasives, aluminum oxide and silicon carbide do not contain free silica ed their dust cannot, produce silicosis* The dust, like any other inorganio dust, oan, however. If breathed for a long period of time in large quantities, produoe an X-ray pioture similar to that of early silicosis. This picture ohanges very slightly aa years of exposure increase, and at no time are the nodules, oharaoteristio of siliooals, evident. Tfalike allloosia, there is ho progress in the prooeas after expe- - sure oeases and there -appears to be no marked physioal disability. Although there is no sllioosis, the X-rays do show signs of pneumoooniosis* . Carborundum dust, chemically, is silioon barbide* According to Miller and Sayers (G. S. Pub, Health Rep, Vol. 49 #3 of Jan. 19, 1934) oarborundum dust when in* jeeted into the peritoneal cavity of guinea pigs produced no reaction and was termed "inert". Dusts suoh ms quarts and flint - sllioosis producing dusts - produced a proliferatire reaotion. Leroy 0, Gardner (0. S. Pub. Health Rep. Vol. 60 $21 of May 24, 1936) reports that oarborundum produoes praotioally no reaotion when inhaled by guise* pigs In. high concentrations over a period of time. Quoting from Dr. Gardner4* artlole, the. part pertaining to earborundm dusti - "The dust which does reach the tracheobronchial lymph nodes appareob- ly laoks the -proper physlochomioal properties to stimulate any but a very slight proliferation of connective tissue. In the lungs,, there is prao tioally no fibrosis." . The Journal of the American Medieal Association {Votes and Queries 103, 1472, 19S44'JBakai.thAa-afeaaiwnt..x.qg!r.dj^g the health.haeard of breathing dust from arti ficial abrasivest _ . "Only silica (S102) is capable of induoing sllioosis^ but any other ' ~ mineral dust under eauditions of prolonged and gross exposure may eauae , seme increase in pulmonary fibrosis. If the relative potential harm of silica is rated as 100, those'other non-toxio mineral dusts may be rated . - * .. ' 10-0000047 222 001460 ' only on the order of 5 or 10." a* Despite thia comparatively low rating of hamfulnesa of these dusts it ie ` generally eonaidered adhriaable to use dust hoods and exhausts wherever practical an there is elinieal evidence that workers exposed to heavy concentrations of dust of any kind are store liable to develop diseases affecting the nose, throat and ohest during the wln'ter inb'dtHS"*thmn'*those^Ot'Tpt>sid't^rtiust believes -bha urn -effort should 0 made to keep the dust count below twenty Billion partioles of less tMTM ten nierons per cubic foot of air. b ** 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 activities aret A -- TAKDQ1 FLOOR TOOL GRINDERS* Tandem floor tool grinders, the most fre quently used type, are In most cases motor-driven and operate, at a speed of from . 1460 to 1850 RFM. The type of wheel 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 uaedi 1-1/2" x 10" Horton Alundwa (Grade P, Grit 46) wheels for - sharpening .tools and for general aervioe grinding. _ 1-1/%* to 3" x 14" Carborundum wheels for miscellaneous grinding. . 3" x 16" Carborundum (Grit 30, Grade K) wheels for grind-- lmg laths and other machine tools. Sometimes - two different wheels are used on tandem tool grinders; for example, a 2" x 14* grain 24, grade Q Horton Alundum vitrified wheel on one side and a 2" x 14* grain 44, grade M Alundum 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 eharaoter of the objeet 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 mioroos or less per oubio foot in samples taken in the breathing sono of the person using the-grinder during the grinding of various ob- Sects varioue-wbeelo-ef* tamdem -floar-grindAras Operation Partioles per oublc foot Grinding Cast Iron on 2* x 12" Aloxite (46M Grit) Wheel.............. * a Steel Sleeve on a l/Z" x 10* Carborundum Wheel....... * " Hard Steel Chisel os a 5/8" x 8-1/$" Alundum Wheel... * * * " ' * " 1/2" x 10" Carborundum Wheel.. " * " " ", " 3/4" x 10" " " .. " * Pneuaatlo Tool Steel Chisel on a 5-1/%"x14" Horton Alundum (3836 - 0. S3) Wheel........................... ................. " ". Chisel Bar on the same wheel (3836 - 0. SB Aiuadisa). .. * ... 46H) Wheel...................................... .......___ .......... * Tool Steel on a 2" x 14" Alundua (24 grain, grade Q) WJftel a a " . "(44* " H) " " * a Lathe Tool on a l/Z* x 12" * (Grade P) Wheel........... * "" ***'."- * ( " R) * ...v... 11,646,960 8,127,840 7,476,480 1,670,880 806,240 1,669,120 4,134,720 2,194,112 ' 396,480 1,019.520 339,840 1,331,040 223 0014F 18-0000048  Partioles p*r* * Operation (Continued) _ oublo foot ~ ...... ~ ' Grinding a Lathe foci on a 3* x 18" Carborundum (grit 30, grade X) Wheel,,...,.. 362,496 Mild Steel eo a 1-1/2" x 10" Alundum Wheel........................ 6,855,200 >* ..... -Steel JOlea. JOB 3" x 14" Carborundum Wheel..,56,640 , ' Squaring Shear Blades on a 1-1/2.'* xl5*!Jafb6?tlli8tBrWheWl.` "t;l5Tf^l20 h ** Vast Produced By Operation of Tandem Floor Grindere, As would be expected, there la a wide variation in the appearance of the duat parti ales under the Kamimeter miorosoope. These example# however. will giTe an Idea of the characteristics of the dust produced during the operation of Tandem Floor Grinderst Material Being , .Ground Sire of Charaeterlstle s of Lust Partioles. Wheel Typo of Wheel (Sites and Peroentages Estimated) 1" x 3" Mild Steel Bar 1-1/2* x 10" Alundaa (Grit 46, Grade P) About 70% angular orystalllne, 6 microns or leas in size# 50% me tallic shreds) 10jC white opaque, slightly angular, over IQ mlornnaj many small blaok speaks. . Tool Steel 2" x 14" Alundum vit rified (Grit 44,Grade M) About 90jJ angular orystalliae, 2 microns or lesl Is sizei 10% opaque, 1 micron or less in size. _ - Tool Steel (Same ma terial as above) 2" x 14" Alundum vit rified (Grit 24, Grade Q) About 60j round, semi-opaque, 10 mlorons or less in sizej 40% angular opaque, 6 mlorons or less in size. Lathe Tool 3" X 16" Carborundum (Grit 30 Grade K) About TSJC round, crystalline, 5 mlorons in sisej 25% sli^tly angular. ' Chisel Bar . ... . 2-1/JX.14". , Alundum About 70% slightly angular, 3 (3036-6. SB)...... mlorons "la s'lsej'BOgC'3Uik, opaque, metallio. - Pneumatic Band Tool Steel Chisel 2-1/2" x 14" Alundum (3836-0. SB) About 56% round, blaok'.' opaque, *' ` one aiorcn or less in size, . Lathe Tool 1-1/2" x 12" Alundum (Grade P) About SO% angular crystalline, 2 microns or less in sizei 50% round, blaok, metallio, 1 ad- . oron or less in size. - Lathe Teel (Seme as above) 3-3/J"*12" (Grade R) About 76% angular otystalline, 2 mlorons or less In sizei $6% round, blaok, metallio, 1 mi- . oron or less in size* 001468 i<M>000049 224 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) Charaotoristios of Dust Partioles. (Sizes and Percentages Estimated) About 85J{ sharply angular, crys talline, 5 microns or. less) 10j rounded angular crystalline, over 10 microns) opaque scale-like metallic, 10 microns or less) large nuaber of black metallic* speolcs. ' Where "hard" wheels are used for grinding soft east steel, about 98jS of the dust pazw tides are metallic and less than one-half micron in site. With the exception of a vexy small number'd mod Wh6'detdte About 9SjC or their working time to actual grinding, there Is a Tory adds rariatlon in the masher of men exposed and the length of such exposure to dust produced by the operation of tandem floor tool grinders. In only one case was-a respirator worn. Goggles hare been provided and their use required Inmost cases. ' ' - - ---- ' B - TANDEM BENCH GRINDERSt These grinders are small in size and are used for sharpening small tools and light grinding. They are all motor- driven and operate at about 3400 R.P.M. Different grade wheels are used, usually 1-1/8" x 8" Carborumdm. (Grain #80) on one side, and on the other a 1" x 8" Carborundum (Grain #90r). The amount of dust produo ed by the operation of tandem benoh grinders Taries with the ma terial being ground and the composition of the wheel,but these arerage dust oouots are fairly representative! Operation Particles per ou. ft. Grinding Cold Chisel on l-l/8" Grain #80 Carborundum Wheel.... 6,909,440 " *" " 1" X 8" " #90 V " .... 8,401,800 " l/2" Boiler Plate on 1" x-8"#90 " 12,460,800 " Hard Steel Chi eel on 5/j x 8-l/2" AJunrtum (Grain 46^ Grade p)................. ....................... 7,476,480 ^Dusi particles in samples taken during the operation of the .tandem benoh grinder hare the following charaotoristioss ." Material Being Size of Ground Wheel Type of Wheel Medium Steel l-l/2"x8" Carborundum Cold Chisel (#80 Grata) Medium Steel Cold Chisel Tsana tool as Above) 1" x 8" Carbortmdua (#90 Grain) 225 Charaotoristios of Dust Partiolee, (Sizes and Percentages Estimated) About 13% slightly angular orystalline, 6 aiorons or less In size) 20% round opaquo, metallio, one mioron or less) B% scoippaqoe.-orerIG^mioroma ~aad-JLook like chips of glass. About 90% round-opaque, 2 miorona . or less in size} 2OjC slightly angu lar oryrtalline, 5 microns or ' loss in size. . . ` 18-0000050 0014R9 -43- DUST PRODUCED BY TANDEM BEHCH GRINDERS (Cpnoludad) * Material Being Size of Characteristies of Dust Partioles. "Ground -'""Wheel- -`Trpe-ofiJffcoel'o ~-(-SAaea-and P*mmats gas rstlratxnl-)' l/2" Soft ` Steel Boiler Plate <Taking- off rough '* edges) 1" x 8" Carborundum (#90 Grain) About 90% round, blaok, netallio,. 2 microns or less in slzej 10% slightly angular crystalline, 5 microns or less in size. Hard Steel Chisel 5/0" x 8-1/2" Alundum (Grain 46, Grade p) About 85% round, blaok opaque, 2 microns or less in size; 15% rounded orystalllne, 10 microns or over. 1 ' " c - SINGLE FLOOR TOOL GRINDERSt Thera &re only & few single floor grinders in nso. They range In size from 1" x 10" motor-dri-ren. (1750 RR1) to 2-1/2" x 20" helt-driTen (1250 RFtl). The larger size is used for heavy grinding such as blanks and large tools; the smaller sizes for sharpening tools and miscellaneous grind ing. The wheel on the large grindtfr is Carborundum (#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 l-l/2" x 14" size. .Samples taken during the opera tion of Single Floor Grinders had dust oounts as followsr Operation * Fartloles per on. ft. Grinding Tool Steel on 1-1/2" x 14" Alundua Wheel ' (Crain 24, Grado Q)................. 679,600 " " Chisel on 1" x 10" Carborundum Wheel (Grain 46, Grade M)....................... . 2,594,112 " 1/2" x 4" Mild Steel Bar on 2-l/2 x 20" ' Carborundum Wheel (Grain 90).......... . 4,451,904 The hoods which almost completely enclose these wheels aot as praotioal dust collec tors. . Dust partioles produoed by the foregoing grinding had these characteristics when examined under the Xonlmeter mioroscopot . __ Material Being Ground Size of Wheel Hard Steel Tool Bit l-l/2B x 14" Type of Wheel Alundum (Grain 24, Grade Q) - i/i" * 2" miu 1" x 10" Steel Bar - l/Z*x4* Mild 2-1/2"*20? Steel Bar CArbMiiodin (Grain 46, Grade H) Carborundua (Grain 90) 226 ' Charsoteriatlos of Dust Partioles. (Sizes and Percentages Estimated) All partioles were 2 miorons or less in size. About WA were an gular crystalline) 40% were rounded opaque. About 96%were blaok opaque, 2 mi crons or loss in size) 2% slightly angular,5 borons or less in size. About'B5%were slightly angular crystalline, 6 miorons or less la aizeiabout 16%blackacad-opaquo, - angular metallic, 2 miorons' or less in size. . 10-0000051 0014.70 -A----------- -44- D - lET-'ERSAL GRIHDERS* . As the name would indicate, universal grinders are used for a wide variety of purposes and therefore are in more continuous opera-- ' tion than are the other grinders, with the exception of the tandem floor tool grind ers. There are two.types or makes, the Brown A Sharpe Universal Grinder whioh has an operet4ng~epeed~e.395OiE!L>Md~4h*-&saj^'>a{d.da,Jfai;m0rsal,.Gxdtadar..diiah operates at about 5850 RHL Tho following abrasive wheels aro usodt l/?.*-x 5" Morton Co, 3846 J 5B Alundum wheel for grinding ^ hardened carbon tool steel, 1/2" x 7" Morton Co. 3846 I 8B Alundum wheel for grinding high speed tool steel. 2" x 3-l/2" Carborundum Co. grit 401-P-25, type 12 Aloxite vdieel for grinding case hardened steel. . l/4" x 10" Carborundum Co. wheel used for cutting.. 1" x 10" " "" " " sharpening . tools, reamers, dies and drill bits. Samples taken during the operation of the various Universal grinders had dust counts as followst `' Operation Partloles per op. ft. Dressing l/2" x 7" Alundum (3846 I 8B) Wheel with a "Diamond '-Point"................. ............................................................ 1,397,120 (Evidently the clouds of dust which come off during - dressing have particled larger than 30 miorons) . 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 - .(3646 J 5B).................................................... 6,683,520 " 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 tht&e characteristics* .. Material Being Sixe of Charaoteristlos of Dust Partloles . ' Ground : " .Wheel Type, of Wheel (Sizes and Percentages Estimated) Dressing Wheel 1/2" x 7* Alundum With a _ (3846 I 8B) "Diamond Point" About B0% slightly angular orystalline. About 3 miorons In sizej 20% bl&ok opaque, round, about 1 micron or loss in size. High -- i/r arr** -ntaButt -- Tool .Steal (a . <3846 I SB) Landis Pipe Chaser) . ^Atrotrt'UOjC opaque-angular,`aboutt miorons or less in size; 40jt slightly angular, crystalline, 5 miorons or over in .oil 0. \ J . 227 18-0000052 G01471  Dust ptrtiolos in samples taken during the operation of Universal grinders hare those characteristics (Continued)t Material Being Site of Characteristics of Dust Portioles. ' Smuad J^pe of. Wheel., , (Sires and Percentages Estimated) _ Hardened Car-^. 1/2" x 5" berated Stel (Pipe Grip fo*% Pipe Machine) Alundum (3846 J SB) . About 30jf angular crystalline, about 2 microns or less in sixoi 70# round blade opaque, less than 1 mloron in site. Numerous black apeaks too small to count. Several largo oblong black opaque par ticles about 20 microns wide and ' 35 or 40 microns long. Case Hardened 2"x5-1/2" Aloxite Steel (Plung- . (Grit 401,-P- ere for Fill- " -25fype 12) ing Machine) ' All particles blaok opaque, 1 mi cros or loss la size. B - SURFACE SRIEDERSt Surface grinders are used almost exclusively on Talves and dies. They are equipped with either l/2" x 8* Norton padum (1946H) wheel, or 1 / x 4" to 6" Carborundum (Aloxite) vdieels. Ho 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 lossji Operation Part-tales per cu. ft. Grinding Soft Cast Steel Val*re on 1/2" x 6" Carborundum . Aloxite Wheel................................................ "' fool Steel Die an l/2" x 8" Alundum (1946H) Wheel.,.................... ......................... .. Dressing Surface of l/2" x 8" Alundum Wheel with a "Diamond Point".,........,.;................. . 686,400 1,019,620 1,132,800 About 70% of the particles from grinding the steel die were metallic, 3 mi crons <pr less, whereas of the particles from grinding the soft stool tsIto were motal^io. Mary of the partiolos were too small to identify or count accurately. F - LANDIS TOOL GRINDERSt Landis tool grinders are usually equipped with two different types of .wheels, one for side glinting 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 ohisels, diamond points, oold chisels, flanges and scrappers. The Side Grinding Typo is usually a 2-1/2* x 2-2/2* x 12* Grit iSA-F P678 Aloxite brand AA 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 attaehed a two-inch pipe connected to a three-inch pipe which discharges into a sewer. ' Suction is induced by a stream of compressed air from a half-inch pipe dis serted in the two-inch pipe just back of the hand. This arrangement aote as a ey ing the operation of Landis tool grinders had dust oonoentrations as foilowet 228 10_OOOOO53 _ 001472 Operation Particles per ou, ft. Dressing l-l/2* x 12" Aloxite Wheel (Grit 40,Grade H, Band 33)............................ . (Evidently j*rtT61eifflbOd TITTOrt'-thrcsfcrW "by the 2-1/2" x 6* Metcalf Emery Wheel Dresser *r larger than 30 microns la slie) Grinding "Diamond Point" Chisel on l-l/2" x 12" Aloxite Wheel (Grit 40, Grade H).................................... .............. -....................... Grinding 2-l/2n X 6" Landis die on 2-l/2" x l-l/2" x 12" Aloxite Wheel (Grit 46JUP P678)..................................................... 226,560 '' 2,067,360 755,203 Order the Konimeter 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 micron.in size} 25# were slightly angular crystalline, leas than JZ-mifirms... -Partiole* ..fraaLgrindiag the dismond.point ohisel were less quartz-like than those from grinding the die. This dlfferenee is, of eourse, due to dlfferenee la 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 aUUtypes -of drill bits. Wa a side grinding type 1" x 1-1/2" x 9* Carborundum Aloxite (Grit 30, Grade H, Bond 28) Wheel. Operating speed 1735 RBI. On an average a Yankee Or ill Grinder runs about three hours a day and is used by four different men with an average service of twelve years. . ^ . Samples taken during the grinding of a 2-5/L6" high speed drill had an ave rage of 1,000,829 particles, tan microns or less, per cubic foot; About 70# of these dust partioles are slightly crystalline in appearance, five microns or less'In size} 30# were rounded, semi-opaque,, over ten microns in size. There were also a few small metallic shreds. Ho exhaust or dust collector is used in this grinding. . H - AUTOMATIC CXRCGUR SAW SHARPENING MACHINE* There are a number of these grinders in use in the wood working operations - suoJs as in the production of woodon barrels, boxes and crates - closely associated with-the refining of petroleum pro ducts. Since they are automatie when onea put in operation, there is very little . dust hazard except where pe-exhwst--er -dust--colleotors-have-been lastslled-aad-the dust p#BHueed is thrown into the filing room atmosphere. Automatlo Circular Saw Sharpening Machines are equipped with l/4" x 8" Norton Alundm Wheels (Grain 60, Grade V), 3^8" x 8" Norton Alundum (1946 M) wheels, or l/2n x 6" Carborundum wheels*'. The average dust produoed during operation of these machines 1st . ~ . Wheel Particles per eu. ft. l/j" x 8" Carborundum.,........................................ . 1/4" x 12" * ............................................................. ........... 3/8* x 8" Alundum (3946M).............................................................. 3/4" X 8" " (Grain 60, Grade N)....................................... 1,923,260 3,688,320 2,095,680 1,461,312 -About 98# of duet particles la samples taken whno 'sharprtlnglBlrOttlar earn m the Carborundtm wheels were 'black metallic hat appearance, <*nd one mioronor less in size. About 76# of the partioles trcm the Alundum thesis were rounded orystpj*- liae, 6 mioroas or under la size, and 25# round hlaok aetalllo, about one aloron or lees in size.. There were a number of small aetalllo shreds in the samples ikon the * - thicker (3/8" x 8") wheel. -. I - AUTOMATIC BAND SAW GRINDER* '' - ??n After the Band Sew has been inserted and the . 18-0000054 00147.} - ..-L-47- aachina adjusted, this grinder works automatically. The wheel ordinarily used is & l/2" x 8" Grain 50, Grade H Horton Coaps&y Alundun. The i"fceel is refaoed or dressed with a Metcalf Emery Wheel Dresser about twioe a day. The average dust produced by this dressing operation is 2,284,480 partioles loss than ten microns per oubio foot. About 95?S of these dust partlolos are sharply angular crystalline in appearanoe under theTWaifcetW'merosoopef,' "toia''`abdtft 'Ti*re microns' or'lesa~itr-Alae. '~Thrdus(t .produced during sharpening or grinding of the band saw blade is on an aTerage only 877,920 particles per cubic foot. About 50# of these partioles appear angular crystalline and .about 50# round black opaquo. All.of them are about two mlorona oaf less in size. J - AUTOMATIC BAUD. SAW LAP GRINDERt -Used to grind ends of band saw prepare/-' tory to welding them together. The grinding wheel usually used is B/s" 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 vdieel while it was in operation. The arerage dust produced ' by this lap grinder was 4,984,320 partioles per oubio foot. About 80# of those dust partioles were, soai-opftque., -slightly.Angular in .appearanoo,, .and .two.miorxna nr-loas in sizej 20# were black opaque, about one micron or less in size. ' I - PLANING KNIFE BLADE GRINDERt Uses a l/2" x 8" Grain 46, Grade N, Norton Company Alundum wheel. Operating speed 3000- RHi. No hood or any otljer protection. Arerage dust produced while sharpening a Planer Knife Blade was 566,400 partioles, ten microns or less per oubio foot. About 60# of these dust partfoles were slight ly angular crystalline in appearance and about two miorons or leea in size) 40# were opaque of rarious sizes from about seren miorons or less. There were a few small metallic shreds. .' ' 'v ' L -- LINDZRMAN CUTTER GRINDERt Sharpens cutters from the Linderman maohlno for tonguelng and grooving. Grinder uses a l/2" x 6" Horton Alundum (Grain 60,Grade V) cup Wheel. Operating speed 3000 RIM. 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 partioles, ten miorons or less, were found at the front of the grinder in operation, and 12,574,080 partioles per oubio foot in the back. The average dust produced was 9,137,920 partioles per oubio foot. About 70# of these dust partioles are round semi-opaque In appearanoe under the Konimeter miorosoope, and three mi-' - crons or less in zizj^J 20# are round, globular like partioler, seven miorons or less in sizej and 10# ere motallio shreds about two microns wide and 20 to 50 miorons long, ' . There |ge a&ny-edaufre-crystalline-partiolos too email and too numerous to^oonnt ao- - curat ely. ." ' M - GANG SAW BLADE GRINDERt Uses a 6/8" x 10* Grain 50, Grids'll, Norton Company A1undrum wheel, operating at 1800 RHL *A rather erode dust oolleotor has been Installed, but the average dust (8,760,320 partioles per oubio foot) produced by this grinder In operation indicates that it is inadequate. About 90# of the dust partioles in samples taken during the grinding of a Gang Saw Blade wore semiopaquo in appearance and about two miorons or less In size). 10# were black round, opaque, one micron, or less in size. There were numerous minute black spooks too small to oount accurately, - . . H. - EDGER. SAW. QRUJDp* .fipjain .60,.firadft.J, -Norton .Company -Alundm wheei, operating at 1650 REM. Ho hood or any other dust oolleotor for this grinder. The low dost oount, an average of only 463,120 partioles, ten mlorbns .or less per oubio foot, indleates that there Is very little real need tor suoh equip ment The dust particles produced vhlle grinding an Edger Saw Blade are awpil-- - erystalline, about two miorons or less in size. . - * 0 - CIRCULAR SLAB CUT-OFF SAW' GRINDERt 230 Uses a 3/4" x 10* Grain N, Norton ' 001474 18-OOOOOJ J------- -48- Joapauy Alundum wheel operating at 1650 HIM, A rather ineffective duet oolleotor has jflen installed, hut the average-'high dust concentration (10,951,521 particles per jwhlo foot) shows that It la inadequate. About 80# of the duet partiolea in samples :en during the sharpening of a Circular Slab Cut-off Saw were opaque in appearance, two mierons or lesa in size} 20# were slightly angular crystalline, fire microns or less in aise. There were also a large number of minute blaclc opaque particles* ? -- "gpo IHIFS" GRINDERs Uses a ll/2" x 24" Carborundum wheel operating at 500 RRt Thi* grinder Is completely enclosed hy a metal hood, but the dust |s 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 1,669,120 particles per cubic foot. About 75# of these dust particles were angular cryatalllna in appearance trader the Konlaseter microscope and four microns or leas in sitej 25# were round, black opaque, two microns or less in size. Q - COTTER GRINDER*- Uses a 5-1/2* x 2-l/2" x l/2" Horton Alundum wheel (3645 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 particles per eu, ft. " " " reamer.................... i...1,019,620 " " * The dust particles are about 96# opaque metallic in appearance and about one mioron or less in site,. ` . What' Precautions Should Be Adopted For Safeguarding Those Who Use Grinding Wheels! Authorities generally agree (Jour. Induet,Hy-g.Vel,711 Ho.8 August 1925 p. 351)" that workers who habitually use grinding wheels will run but slight risk of developing pneumoconiosis if they use certified abrasive rather than s andstope wheels /or all grinding operations and if the machines upon whioh the artlflolal abrasive . wheals axe mounted are properly hooded and exoessivo dust removed by suction. * Control of Dust Fkcm 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 aot to-'proteet the worker in ease the. wheel bursts. The chief difficulty to be overcome in grinding wheels, .aeoordlng to V. S. Public Health Bulletin So.' 217, "The Determination and Control of Industrial Bust" (1935), is the outward sweep of air, a fan action? due~tc the-revolving wheel.__Thie effect is very marked with high speed and rough wheels and Is so strong that in many Instances it is suTH.<fiefit toecuxrter-- . aot the normal inward flow of air. The same effect exists with polishing and bufflag vdieels but to a less marked degree. - -" Practically all industrial States have codes regulating the eonstruotioa dust connections for grinding, polishing and buffing wheels. They also regulate the air required for wheels of various sizes in terms of static auction In the connect ing duets. 'These oodes possess no uniformity. However, the requirements designat ed by State codes 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 iat least two lnohes of water between the two sides of a D-shaped tube, " - * >* . ** -A member-ef the-wheels hears been provided with suction exhaust produced by a motor driven fun or a hood, with a two-inch pipe one end of whloE is immersed in1 a - buekit of water. The dust Is drawn in by the rapid revolution of the wheels (1750 . BHi). This simple arrangement is particularly effective. Three samples taken near the discharge of a motor driven suction Am connected with the hood of 1-1/%* x 10* - 231 001475 IB-0000056 i- Alundum (Grit 46, Grade P) wheel while a tool was 'being sharpened bad an average < 2 076,989 partlolea per cubicrfoot whioh would have' otherwise been thrown Into th machine shop atmosphere* ' - As pointed out by Dr. W. Irrlng Clark In his paper "Dust Hazards and the' Pre vention of Injury from the Same" read at a meeting of Government Officials in Indus try at Boston, Haas, on Hay 21, 1931, the most effeotive method of removing' fIns particles ~bf 'tTy 'ewetloa-appllred^ua close -assessIbistoAha^point ahare, they . are -Generated 1111(1 <Lmoun't this suction is great enough to overcome the dis persing aotfcon upon the dust of the work being done.' . The velocity at the air duets of an efficient dust removing tuba should be 1500 linear feet per minute. Quoting Dr. Clark ` "Ko matter how well a workman is protected ho should be kept under medical supervision and have a perlodio examination of hla heart 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 experionoo with workers exposed to inorganio dust, non-silioous in charaoter, a yearly physical examination with an X-ray every second year after ten years exposure Is sufficient but lt must be romeabered^that this is the result of work in a factory where the eharaoter of the dust is relatively harmless and where excellent dust remor- lng devices are installed on every machine where it is possible. Where free silica is present in large quantities the examinations should begin after two or threo years exposure and an X-ray should ` be taken every year. . Dr, Clark also states that men who are asthmatic, who suffer from ohronio bronohitis, or- who have had pulmonary tuberculosis should not work at a dusty job. VH - HANDLING POWDERED OR PULVERIZED MATERIAL A largo amount of powdered or pulverized materials are used in the treatment of petrolema products and boiler water and in the manufacture of greases lnseo- tioidesr "In most* oases approved respiratory protection is provided and its use re quired when handling the materials. Exposure to dust is usually intermittent of ' short duration. Among -the powdered or pulverized materials used in the refining of petroleu;^products and associated activities are* .A -- LdEt Lime is extensively used in the hydrated form and.to a much lesser de gree as lump quiokllme. - .' _ - ~ . 1* Hydrated Limet Used in the preparation of lime soap grease and the manu facture of pressure gun and oup greaaoj also In the treatment of boiler feed water to "soften it". It ernes in fifty pound paper bags by railroad, usual ' ly about 1,000 bags to a car. According to a chemical analysis of a typioal * sample, hydrated lime contains! . FeoOjA^Oj........... 0.30 per oent. CaO................................73.64 HgO........................... 0.93 " " ....... "lh5tfltrtttt`*Wliwa flealdUB... . 1. 01 " " _ (Remainder mostly Hoistur.o and Volatile Hatter) Fom 150 to 350 pounds of lime are used per batch In the manufacture of greases. 00147 b' is-0000-057 232 -50- sacks of lima are usually opened and dumped into the mixing kettle. Con siderable dust (as high as 34,890,240 particles less ^han ten microns per cu- hio foot in one sample) is produoed by this operation. The averago dust pro duced is 4,733,306 particles per oubic foot and the average exposure per batoh is about five minutes. The number of batches made per reek varies from one to treaty-five. No respirators are worn by men dumping hydrated lime at any of . the poimtayrhei>e-t4s-a>ad-aMith<.th*-xaeptioa nfHatonJlauge jsh.are. tho ,,aar-- <Tig of the HSJ_',Ccmfo" respirator is required. About 855? of the dust partioles In aaaplesbtaken while dumping lime in mixing kettles are slightly angular, slightly opaque, crystalline. In appearance under the Konlmeter microscope,and five microns or less in sizoj 15# are rounded, soni-opaque, with.a metallic 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 batoh and about six batohos - 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 partiales.~tonHierbns or luss, per xmbio Poet. This low dust concentration is the result of a spray of water from a two inoh pipe across 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 partioles in samples taken while the .lime was being dumped into the mixing tank were semi-angular crystalline in appear ance, and from five'microns or less in size, and 5# were round opaque, two mi- orons or less In size. ' - 2. Lump QulcVlict Used to "soften" boiler feedwater. The lime used for this purpose is Oyster Shell Lump Quicklime (97% CaO). It comes in fifty pound paper-lined burlap bags, and eight bags are usually used per batoh. One batoh la made per shift. The dumping and mixing requires* about ten minutes per batoh* and the man doing this work is proteoted by rubber type goggles, but no respi- rator. The average dust produoed by handling the bags of limp Oyster Shell Quicklime is 2,605,440 particles per oubio foot. The average dust produoed while-dumping, the bags -of lump Oyster Shell Quicklime into the mixing tank is 294,528 particles, less than ten microns', per oubio foot. The handling and dumping of this Oyster Shell Quiokllmo produces leea dust than is produoed by the hydrated lime usually used. About 95# of the dust partioles. in samples taken wring the dumping of Oyster Shell Quicklime into the mining kettle ap- ^. . pear slightly angular, crystalline under the Konlmeter miorosoopo/iuilare five' microns or less In size) 2% are round, ami-opaque, over ten microns in alzej and 3% are black opaque scale-like, five microns or leas In size. What Phyalloglcal Effect la Produoed Vy Lime DustT According to the Inter national Labor Office (Occupation and Health, Yol. II, 1934) partiolea of lime mix with the sweat of workmen handling it and irritate the unoovered pores of the akinj lesions of the muoous membranes are also set up. We 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 alkallpe oxides or --`aHfalAttc "wrttet- -QuAefclA---eweyfae-<ee seatlally -a .1coal nation (on the skin and muoous membranes) irritating and eaustlo, which \ * __ is naturally less marked in the ease of slaked lime. TLLlk of lime is a feeble eaustlo acting only on the muoous membranes. . The dilute lyes are only eaustio to the skin after prolonged ao- ' tlon and especially when they are warn. * ,BVoooooe 233 00147V i_ "la practice it ie the duet of quloklime and alaked lime, given off la the course of manufacture and manipulation, wbdoh gives rise to the well known lesions. This very fine dust Is deposit ed reedlly on the mucous membranes and skin.' When Inhaled It may penetrate as far as- the respiratory tract." * . . Although limo has a tendency to irritate the mucous membranes of the respira tory tract, it. Is not considered particulaxly hai'ardous"'lfdi#hr'WWthfct-in snail, quantities at Intermittent Intervale. However, complications may result when a large amovfot of-the dust Is breathed more or less' regularly, therefore, it 1# desirable to wear an approved respirator suoh as the MSA "Ccefo" or the Willson "Duet-tite". .* " a 3L - METALLIC ZINC DUSTt Metallic line dust (9Qj( through 300 mesh) is an iapo, iant constituent in Pipe Thread Coating Compound, About 1500 pounds of this material Is used per batch, and about fifty batches are made per month. Tho eino dust ooaes in 400 pound wooden kegs or 500 pound steel drums. According to a chemical analysis, this slno dust is SS. 20JJmetallio lino and 0. 80 sino oxide (ZhO), the partlole sise distribution of a typical sample as determined by a standard screen analysis is* All through 120 mesh soreen 3. 76jC retained on 200 mesh 2,04j " " 250 " 22.2A% " " 325 " - The sine dust is dumped from the keg or drum onto a metal sheet in front of the ket-- tie and shoveled into the kottle by two or three men (with an average aervioe of about three months) from the General Labor Department.* This ie a very dusty opera tion, One sample taken during the shoveling of xlno dust had as high as 68,760,960 particles per cubic foot of air the average concentration being 28,331,326 par- tioles, less than ten microns, per cubio foot. The worlmen are exposed to this dust about thirty minutes per batch or approximately 2-l/2 hours per month. They wear- dust respirators. About 9S% of those dust particles are dark grey, opaque, angular ` In appearance under the Korimeter microscope, and about five mlorons or less In sizej 6% appear slightly angular, crystalline, ten microns or less in alee. The . crystalline material is probably line oxide. ,, ._ \QlS* Physiological Effect is Produced by jlno ftugtf Although lino oxide (ZnO) produoo^definito physiological effects, metallic lino* dust does mot seem to affect the person breaUTlhg^It'oth*r'tluia`tflt*icsras*ed-ty-the -tidialatlon-uf-t^-inert-dust, Nevertheless seme investigators are of the opinion that slno is sot entirely Inert and harmless. Certainly it is not as harmful as lead or arsenic, but the-tfaited States Public Health Serrioe has certain limitations on the amount of lias that is' . ' permitted in drinking water* According to tfuok, E, Rasy, and F, Foltnann (Jour, ' Indust. Hyg* . Vol. 12, 1930, page 171 Ah.) Zlno-dust can cause lung trouble after being Inhaled in large quantities. Zinc dust is also very definitely explosive. UL r ASIlSSfOS "FLOAT*'t Float asbestos is used in the manufacture of tractor lubri cants. It comes in 150 pound cloth bags by railroad, about 2000 bags to a oar. Trim 200 to 3000 pounds are used per batch and from two to fifteen batches are made per month. The bags of asbestos float are dumped into the mixing kettle by three men with eg-areivge-rerviee^c.f^-fcwtlxe -yanca. - Jhrse ,1 ahorars japes ed to dust . about forty minutes per batch. Dust concentration as high ** 8,269,440 partiolea, * ten microns >r less in site, per cubic foot are produeed during the dumping of'as- besfejs float, the average being 3,058,560 particles per oubio foot. About 9Bf& of these partioles are slightly angular, round, transparent in appearance under the * * Jtonlaeter.microscope. and two miorona or less in sizej 2# are round, semi-opaque, , 234 001478 10-0000059 -52- plate like, fiTO miorons or orer in size. - ' e* ' Rooent inrestigations have indicated that the inhalation of asbestos particlea ten microns or leas in else ia eren. taore hazardous than was originally hollered, and that in order to prerent harmful offoots concentrations should he kept bolorr fire aillion_partioles (10 microns or less)jpor cubio foot. The physiologioal offopts haTe already "been discussed under"*ASBfcSTbSIS" so need not he giron any further con sideration. Iflen handling asbestos float should be required to wear approved reepi- rators. y .. ' D - GROUND ftlCAi Ground mica (60 nesh) is used in the manufacture of axlo grease. It comes in 100 pound burlap bags. About fifty pounds, of ground mica is used per batch and an arerage of fire batches are made per month, The period of exposure will not exooed ten minutes a batch. Handling ground mica produces an arerage of ?,577,120 particles ten microns or loss in site, per cubic foot. About 60# of these particles are transparent irregularly shaped scale like in appearance under the Xonlmeter mioroseope, and fire microns or loss in site) about 4Q# are crer ten ml- orons in site. The transparent plates hare small lines or fissures and appear to oontain small air-bubbles. - Although ground mica has nerer been considered a hatardous dust, acme reoesb studies made among the workers in North Carolina Indicate that continued-exposure to large quantities of ground mioa orer a period of years will produoa a fibrosis. Eon- oror, there is rery little probability of any trouble where concentrations are kept below 10,000,000 particles per cubio foot of air and where the exposure to ptioa dust is such a small percentage of the employee's working time. _ JE - SULEHURt Sulphur flour is used for sulphurising outtisg oils and in the preparation of special lubricants for hypoid gears. Crude sulphur is used In.the manufaoturo of sulphuric aoid and in the treatment of gasoline and naphtha for re moral of impurities such as the mercaptans, -' Sulphur FIour Sulphur flour comes in paper-lined wooden barrels, 100-pound . doth bags, or 150-pound burlap bags. About 25CO pounds of this sulphur is ' dumped into the melting kettle by two men with an arerage serrloe of twelre years,, onos a day. Their exposure to the dust which results from and dumping the bags, an arerage of 1,540,606, partiolos, ten microns or jV&a, per cubio foot, la about fifteen minutes per man per shift on an aro- rdge. Vo goggles or respirators- are worn. About 90# of the dust partioles lamranplea taken rfurlng thtr-duaplng "Of~tho'sulphur ~flour wera Tilghtly angu lar crystalline in appearance under the Konlmeter mioroaoope, and fire ml-" ' crons or less Is else) 10# were semi-opaque, rounded, and orer fire mlerons In size. The larger particles appear to oontain small air bubbles^ There ' were also a number of rery small spooks. - About 370 pounds of flour sulphur Is used per bateh in the preparation of hypoid gear lubricant. Two batehes are made per week on an arerage. The exposure to the sulphur dust is only about two hours per week os an arerage. Slnoe the sulphur is dumped into drums of oil being agitated by a rapidly rerolring propeller type mixer more dust la produced than where the bags are simply dumped into a kettle. Samples taken during this opera tion hagj^Jktyh.a^ .Jtan,mloxjoaaumr,,le*.ln,,Alzfu .,pnr oublo foot. The arerage was 3,783,552 particles per oubio foot. Thodust "*partlelea had the same characteristic* as those giron in the preceding , paragraph. .~ -. Crude Suluhurt Crude sulphur comes in box ears holding about 90,000 pounds, * usually from Jl-eeport, Texas. Towers are filled with this sulphur by four ~ '- 00147:1 ie-00060 235 A -53- nea wj,th an average service of eight years. It require* about two hours to fill a tower with about 19,000 pound* of orude sulphur. Two towers are charg ed every week. Consequently, the non are exposed- about four hours a week to the sulphur dust caused by breaking up the lumps (4,504,640 particles, ten mi- erons-orJUan, oer cubic foot) and shoveling the orude sulphur into the tower eleTstor (an average ofS,357;640 pifr^Jlefc'per'Wd^ amount.-of dust produced by this operation is somewhat reduced by the steam turned qji da- side the elevator shaft to. prevent dust explosions. About 60# of the dust partielvs in samples taken while the tower was being filled were slightly angu lar crystalline in appearance'under the Konimeter mlorosoope and five miorona or leas in oitej 35# were rounded semi-opaque, ten microns or over in sizo) and. .5# were opaque soale like, between five and twelve microns in size. Sulphur dust particles are explosive but otherwise are not oonsldorod hazard ous any more than any of the other "nuisance" dusts, although thoy will irritato the muoous membranes and the eyes after- slight exposure. Consequently, it is adrie- . able to wear rubber type goggles and approved resplratora, suoh as the USA Caafo type. Tn an artiole by Aldo Ceatari (Aroh. Intern. Pharmaoodynamle, .1933, vol. 46, pp, SOO-314) it is stated* "Xntratraehoal injection of sulfur suspensions brings about ex- orotlon of hydrogen sulfide in a period of 60 hours. There aro slight exudative and infiltrative reactions in the lungs. It la supposed that a substance similar to glutathione reduoes the sulfur to hydrogen sulfide." F -- LITHARGE* Litharge is added to the Flumblte or "Doctor" Solution to assist in the removal of more aptana, other sulphur compounds and unsaturated hydrocarbons from gasoline and naphtha. From, ono to five 600-pound drums of litharge are used in a batch, depending upon the stcok to be treated and the condition of the "Dootor So-- " lution". 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 onbe a week on an average. The average servioe of the men lmrolved in this operation is seven years. They wear MSA Cmafo respirators with an ^approved lead filter and rubber type goggles. 11^ of the work of adding litharge is done in the open air on a platform at the tops of the solution tanks. ' ^he Average.dust produoed during the dumping or shoveling of litharge into the solution tank is 3,077,460 particles, ten miorona or less in size, per-oubio foot, although there were as high as 9,280,960 partiolss per oublo foot adoring the operation. A rough estimation of this litharge o ono entration Indioate* -the presenoe of from five to fifteen milligrams of lead per ten oubio meters - the amount that an average person doing moderate work would breathe in one day. This is in exnesa of 1*6 milligrams in'ten oubio meters which is the maxima allowable limit set by the Halted States Publlo Health Servioe. About 80# of these dust partloles were .rounded, transparent, crystalline in appearance under tho Konimeter miorosoope, and five ml-- orona or leaa in size} about 15# were over ten microns and appeared to contain small air bubbles) 6# were dark opaque scale-like, from five to ten microns in size, . ' Hooessanr Precautionary Measures When Handling Litharge^ "'TLlthSjfjfe is -m xncia- pound of lead, and consequently there is the possibility of lead poisoning unless a. _ few simple precautions arp observed to prevent the entrance of lead into the body * ' by swallowing minute partloles cf the litharge dust, by inhaling the dust, or by absorption from the skin when handling the litharge. An effort should be made to - ' cause as little dust-as possible. Instructions issued by the Medical Department re quire that* .* - 236 001480 ie-000006 -54- "1, Ho employee shall handle litharge until lie has been examined and certified as physically qualified by the Company Dootor. "2. ftnployees must he seat to the Company Doctor for physical sx jthe ilrft .||gn of ill health. ' , "3. Respirators - An approved type of lead dust respirator, proper- . jJLy adjusted; shall he worn when handling litharge. All respi rators shall he thoroughly cleaned with soap and warm water, "4. Clothing - Onlonalls, cape or some head covering and gauntlet gloves shall he worn when handling' litharge. Upon the comple tion of this operation the outer olothlng must be removed and placed in a locker used for' this purpose only. Unionalls should he washed at least onoe a week. "5. Bathing "and looker "fcgilirtiPB -Arconreni-exrtly located -looker and was h room shall be designated for use of employees hand- ling litharge. Separate lookers should he provided for street clothes, work olothes, and one for Qhionalla worn fdioa hand- . ling litharge. In plants where men are handling litharge - throughout the shift, only two lookers need he provided, the floors of the looker rooms where the men change their dust covered Union&lls and the henohes shall he thoroughly moisten ed before being cleaned. . "6. . Personal cleanliness - General personal cleanliness is of first importance, '' (a) Hands must ho thorou^ily washed on the completion of the litharge handling operation. Hands must also he thoroughly wished before eating or plaolng anything in the mouth. X special effort should he made to elearn the finger nails so .. as to remove any litharge. ' ' , . Ch) Hover eat" until 'litharge covered clothing has been removed and the hands washed. ^ Teeth should be brushed at least twice a. day and the teeth and gins kept in good condition. ' ' - * (d) The mouth should be rinsed thoroughly before eating. ' ~ (e) Hover use tobaoeo in any fona *hlle working in and around litharge. " * The.responsibility for tlie careful ohservasoe of ALL of these imstruotions should he placed upon the foreman. JL - SOBfcrKSSr-Tgd<"VVh--f9a3rttigOl-T*~eBodto>ifctw-^^ -ell, -Thirty -20D*poiad doth.hags of' soda ash are dumped .into a tank of water par hatch by six men, with an average service of five years, froa the General Labor De partmentj three hatches a week. Hen exposed to dust resulting from opening and \ dumping the bags of soda ash about five hours a week. Eight nexrspend about half a" day-.month unloading bags from railroad box oars. The men *he do the unloading - wear USA Comfo 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 diaping, and 237 00148JI l8_Q000062 w4-rW operation is 1,003,337 partioles, leas than ten miorons, per oubio foot of air. -These partiolos are all slightly angular, crystalline in appearance under the lonimeter nloroeoope and about fire microns in else. Many aro transparent, glass ^Vil There-ajpe ^.number. of small black specks. H ,, T^Tf! or *S0XPST0H,,t Poirerlead talc or "soapstone" is used as a filler in the manufacture of-"hot neck" greases used in the steel mills. According to R. B. Ladoo (O.S. Bureaulof Mines Bui. Mo. 213, 1919) ordinary talo or soapstone is Steatito ' (hydrous Magnesium silicate - S2Mg3(Si03)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* S102.................. CaO..................... MgO.................... Combined Oxides 46.04 per o cut 4.39 " " 26.20 * " 16.64 " " Grease makers usually consider the composition of "soapstone" r&ioh'they use as approxim&tely 90# magnesivm silicate and 10# oaloirn carbonate. It oames in 90-pound paper hags, 700 hags to a box ear. About 7200 pounds are used per batoh and one batoh is made a day on an average. The "soapstone" la dumped into the mixing kettle by two men with an average service of ten years. This dumping *diich requires about . an hour per b&toh Is a rather dusty operation. One sample taken at faoe level Just after a bag had been dumped had as high as 22,995,840 partiolos, ten nlerons orless in site, per cublo.foot of air. The average dust produoed was 13,064,960 dust par ticles per cubio foot. About 98# of these dust partiolos wore transparent, crystal line, irregularly shaped plates and rods, in appearanoe under the Konimeter micro* * soope. Most_ of these particles (about 90#) were live microns or less in size, the - remainder being ten microns or over; about 2# were scale-like, semi-opaque, five ail erons or less in size. Physiological- Effects Produoed By Talo Dusts. About two years ago Dr. V. C. Dreesaen, Passed Assistant Surgeon, and J. M. Dalia Valle, Assistant Sanitary Engi neer, United States Publlo-Health Serrlae, made a study to ascertain, whethor there la a connection between talo dust exposure and the relatively high tuberouloais - death"rate in'Hurray County,'Georgia, where two. talo mills and nines are located. They found (Reprint Ho. 1669 from the Publio Health Reporta VoL 60, Ho. 6, Feb. 1, 1935, pages 131-143)* "Physical and roentgenologic 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 hare Pnsuaoooniosls I and 8 to have Pnemooonlosls XX or III. Six of~tho thirteen examined were diagnosed, as having Pneurnooonloils I. Ho advanced stages of the disease were found in this group. In the group exposed to low concentrations of dust, no Fneumoooniosis _. was found." - - -. ' The final conolusion of this study was that although Georgia tale appears to be "more inJuA<nhf**than,"tx,euiolie-'alc"-<-tha,Jiigh -tuberculosis mortality rate in the County loould not -he attributed to the talo industry". _ ................... .. Investigators have suggested, however, that for more' or less acntinuous expo-, sures concentrations of tale or "soapstone" dust should net .exceed 15,000,000 par-- tioles, ten mloross or less in site, per oubie foot of air. ' '1 1 -- GRAPHITE* Powdered graphite (80# to 85# graphitio carbon and 15# probably magnesium ailloate) is used in the manufacture of spring, and pressure lubricants. It 238 001482 10-ooooo63 i -56- . o ernes in metal drums or 100-pound paper lined bag#.' About 5700 pound# of powdered graphite is used per batch and tone batch 1# made per day on an average. The -raphlte i* dumped into the mixing kettle by sen with an average service of seven ars. vM-f operation requires about forty minutes per batch per man on an average. Three men are usually engag1ffl"lir'thi'dwpjgg. .Jhey waar respirators while hand ling and duiping -graphite, which ia not a particularly dusty operation. The average dust produced is 1,803,080 particles, ten alorons or less, per enblo foot of air. All of these dust-particles are rounded or slightly.angular, black opaque, amorphous, sooty or darifr grey, in appearance under the Konimeter miorosoope, and three microns or lees in size. .' J SLATE FLOURi Slate flour (300 mesh) glees rigidity to asphalt on "fast surft.ces" such as steep roofs and pipe lines, and prevents its running off. It also produees desirable weathering properties. Mixtures as low 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. Sinoe the slato flour is Introduced by .the use of closed pipe lines and centrifugal pmps, the only* dust produced is that which results during We unloading -of -the eaoks-and. damping them into the hopper. The slate flour comes in SO-pound paper bags, 760 bags to a railroad box ear. Four mon with an average servioe of about a year, open the bags and dunp the slate Hour directly into a hopper from which it is siphoned by earn- pressed air to a storage tank holding about 15 tons. About four carloads a.month are received and an average of about 5-1/2 hours is required to unload each oar. About one and three-quarter million pounds were dumped during the last quarter period. The men wear /ISA Comfo respirators. A screen analysis of this slate Hour showed that 99.7# passed through a ZOO mesh screen and 96,8# through a 325 mesh soreen. Sue to the fineness of slate flour and its low bulk density (1.04) oeniderable dust, an average of 12,007,680'partioles, ten microns or less in size, per cubio foot of air, and counts as high as 16,538,880 partioles per oubio foot, ars 'produced during dimping the sacks and filling the storage tank. About 98# of these dust particles are slightly angular, transparent, crystalline in appearanoe under the Konimeter' miorosoope, and five microns or less in size; 2# are seal-opaque,. sli ghtly angular. There were a few plate like partioles which appeared to oontain small air bubbles, and a large nuaber of small black partioles. . A "petrographic examination made of .a slate flour sample at .the United States Bureau cf Hines Experiment Station in Pittsburgh, Pennsylvania showed that it oon- tained more than l#-<hntrt-45i0a->. -3Q#,,Serioita JKv,0-3A2203-6 Si02-g%0), 4C# .opaque a^g 3Q# five different unidentified constituents. A chemical' afiKlysls ""'of slate granules and flour (Jour.Indust.Byg.Vol.X7. ,Ko.2,Mar.l933,p. 67) .reports these . oonstltuentsY - Silloon Dioxide ....59.27# .. . #Magnesias Oxide... 2 21 Titanium Dioxide......... . 0.99# Potassium Oxide... ..3.76# Alwlnum Oxide........... 18. 81# Ferric Oxide............ 1,12# Sodium Oxide...... ..1.88# WSter below 110oC, .. 0.32# Ferroas Oxide .......... 5.58# Managanous Oxide.............0.13# Caleim Oxide........... 0.42# * above * . .. . #Phosphorie Oxide.. .. . #Carbon Dioxide.... ..3.98# 0 11 0 21 ^--Sanium.fbdda..................... 0.05# Ferrio Sulphide... ..0.15# Spec ific Gravity - 2.795 "The silloon found, though expressed in the ehemieal analysis as silloon dioxide. Is not differentiated chcaieaUy as to the * forms present in the original mineral#, whether free silioa or sllloate." . .? ' 00148-J 239 *18-0000064 4 Effect of Slato Flour on Tho Lmgs * in his paper "Bffeots of Certain Silioate Dusts In the Lungs" road before the Industrial Hygiene Section of the American Public* Health Association at Washington, D. C. on October 27, 1932, Dr, Waldwnar C. Droesaeu Of the United States Public Health Servico, reporting the results of his studies of workers exposed to slate dust, wrotet - "Of the 4B oases of pneumoconiosis observed, all were in tho first stage except 5 cases.' In general, the pneumoconiosis observed in ihe e"arly or first stage cases resemblod that induced by cement ust.The bronchial striationa, however, were somewhat more promi nent. There was always a moderate bilateral increase in the alee and density of the hilar shadows with accentuations of bronchial striationa which-extended well out into each lung field. Tho linear striationa seemed "softer" in appearance and lacked some of the sharpness of detail which is usually observed in the X-rays of individuals who have inhaled silica dust. This diffuse, fine generalized fibrosis was chiefly confined to tho lower two-thirds of the -lung, -fields, "In the seoond stage an increased prominence of the above .mentlozved characteristics was present with the appearanoo 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. Dreess-en 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 pneumoonmio-- sis until after more than ten years* exposure. He did not find any evidenoe that the resultant pneumoconiosis had led to disability. . . - GRX1ID1HG PERRIS ROOTt Derrls root is used in the manufacture of inseotloldes. It comes in 500-pound bales from the Dutch East Isdiss. In order to reduce dust, the bales are thoroughly wetted with white oil. The root is ground at the rats of 500 pounds an hour to pass through 3/8"-screen. One man with three years* service is exposed to an average dust oono entrati on of 1,604,800 particles, ten aiorona or leas, per eublo foot of 'air. About 80# of these dust partloles are rather round, crystalline in appearanoo under the Konimeter microsoope, and about five microns in size) 20# aro^sharplyTLngularv -fi-ve-miorons--or-lasa-in -ai-ze.. -Iha.-parialas- ap pear t<^e more inorganio than organic in character. Evidently the lighter root dust partloles are either larger than 30 microns and ware, therefore, filtered out by the Konimeter filter or were carried out by the exhaust ventilation, thus leaving the dirt or soil which had adhered to the roots. The grinder is looated in a room well ventilated by means of a 30-lnoh motor-driven fan. This explains the Ion * dust concentration in the samples taken during the grinding operation. Tho operator wears rubber gloves, eover-alle, and is provided with a fresh air hose typo-of mask: * while grinding. Xp V<hat Extent Jg Derrls ToxicT According to recent studies by the United States Department of Agriculture (Indust. & Eng. Cheat. Vol. 28, Ho. 7, July 1936, pps. 815^821).--Derrls -is-a.possible health hazard tp thpse .engaged in milling, grind ing, and diluting it (Derrls) without the use of suitable protective measures. Tharnacologlcal studies show that Derrls and its water extracts affeet the respire^ tory center which is initially stimulated and then, .after fatal doses, completely . depressed, with death resulting. Derrls dust when applied to-the armpits was elsor found to provoke a "mild evanesoent irritation." -. J*_ -- GEHIDING PYRETflROK HAMERSt Fyrethrum flowers are an important sourco of one ~ . 2-10 001484 18-0000065 i -58- of the essential ingredients of insecticides. Thdy oome from Japan in mat oerrored bales weighing about 450 pounds. On an average, about ten bales are ground per ihift. Opening the bales of compressed flowers is the dustiest, part of the operas ;ion, produoing on an average 2,039,040 partiolet, ten niorons or leas, per oubio foot* of aiK'"^'hdW^88^^iMhea-^articl**Mare1 agigulftr., eryetallino in ' appearance -under the lConimeior mloroscopo, and three microns or less ih 'sliej lCbdtrt``15^ are flat round particles and discs and shreds, ten mioTons or lees. The crystalline -- appearing dust ^probably originates from the soil which has blown on the flowers or plants. One man.is exposed per shift for about four hours a day during a nine month period. Ha wears a Willson dust respirator. The grinder is enclosed in a metal housing connected by a fourteen-inch duet to a sixteen-inch motor driven exhaust" fan. jyrethrura dust seems to irritate the skin of some individuals and not. af^e^t others in the least; as a matter of fact it causes an allergic type of reaotion in some individuals to such an extent that it is inadvisable for suoh persons to work in pyrethrum dust. ft - MIXING AND PACKING " FLtf" "POWDER?^ndt^Towdor -ia-a-mijctura nf .nulvflr.lt od derris root, pyrethrum flowers and other ingredients. It Is mixed in a speolal room provided with exhaust ventilation by a man wearing a respirator. The dustiest part of this operation is sifting the pulverized derris and pyrethrum rdilch- produoes an average of 8,722,560 particles, ten microns or less, per ouble foot of air. About 95# of these dust partioles are angular, orystalline in appearanoe under the Koniaeter microscope, and about three microns in size; about 5# are less orystalline and more opaque, five microns or less in size. F*1! Cana? Three-quarter and two and one-quarter ounee tin cans are fill ed by automatic machines, the filler ends of whloh are enclosed in a metal housing with a four-inch exhaust duct to a fourteea-inoh motor-driven fan. That this ex haust arrangement is fairly effective le shown by an average dust concentration in samples taken at fade level of the operator during the filling operation of 1,755,840 partioles, ten microns or less, per eubio foot of air. The girl at the . Sealer wears a bag-type dust respirator. . _ VIII - CLEANING TUBES AND DRUMS CONTENTS Cleaning tubes and drums of boilers and process equipment la a routine opera tion which produces considerable dust belonging Bore to the "nuiaanoe" class than to the flbmesls causation group, .->.,.1 *J VfawyeWem..vng suoh dust down to a 'minimum of not more than 10,000,000 partioles per oubio foot due to the number of men engaged- in this- work and their more or less continuous ex* . posure '. ._ - I. - CRACXTT.G COIL SOAKING DRUMS? Cracking coll soaking drum "coke-up" about onee a month, so that in many eases they are almost completely filled with the ex ception of an opening down through the center no greater than twelve inches in diam eter. At.most plants, this eoke is remoTed by a special machine; at .the othera, men with an average service of ten years are regularly engaged in cleaning these druss by means of a concrete buster type of pneumatic chisel, starting at the top of the drvre. One mr. rvht Iasi** frd the top manhole. The temperature inside the drum is .about 90 degrees Fahrenheit. 2ach' man 'dfks "halr'ah -hemr AmsJ da and ..is ^fcben relieved for about an hour. On an average, eaeh man works about two and a half hours per shift, two shifts a week. A "bqatswaln" qhair is used to get in and out of -the '' drum. They wear "hardboiled" hats and' life-belts. Excellent ventilation is provided bjr~ 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 pneumatic chisel had an average of only 311,520 dust particles, ten microns or less, per ouble foot* of-, .eir. About 60# of these particles were sharply angular, crystalline in appe&ranoe 001485 ie.ooooo 241 i -59- tn)der the Konimeter microscope, end about fivo microns or less in else; 36# nor# round, semi-opaque, crystalline, about ton microns or crverj and about 6% wore small tlaok particlas. Tbaro wore 'also a few blaok scale-like partioles orar ton miorons i size. The major portion of this dust is probably colco or carbon and the aoale^.iko particles are, no doubt, metal from tho sides of the drum or raa. the ohisol, . U, _ .CRACKING COIL TUBESt There aro 183 tubos in'aTiT^'^reBrttra-'cra'oking coil unit, After running from twenty to twenty-fire days, depending upon lie char acter of the stock boing run, tho temperature and pressure, tho petroleum ooko whioh is doposlteo on*tho tubes must bo removed. Liberty air-driron tube oleaners with cone and star cutters operated by men with an average servioe 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 gogglea nor respl- r&tors although e dust sample taken immediately after reversing the oleanlng machine while in a tube contained as high as 9,062,400 particles, ten microns or less in sice, per cubic foot. About 305% of these dust particles are blaok, opaque in appearanoe under the Konimeter microscope, and two microns or less, in size} 4QJ{ are angular, transparent, ..plate-like, ten nlorons or larger; and 30# are angular, transparent crystalline, five microns or less in aixe. ' Samples taken on the Cleaning Platform while cleaning Cracking Coll Furnace tubes at a Northern refinery had an average of 113,280 partioles per cubic foot. Ninety-eight per cent* of these dust particles were rounded crystalline in appearance under the microscope and five microtis or less in size. Samples taken in the passage way back of the furnace while tubes were being cleaned had as high as 1,076,160 partioles, ten microns or less in size, per cubic foot of air. This indicates that the men in the passageway, back, of the furnaoe are exposed to more dust than those on the cleaning platform. * HZ, -- WATER HEADERS AND BOILER TUBESt Tubes and headers are cleaned -twioe a year by means of air-driven turbines. It has boea found that oleanlng can be done more effectively if done dry rather than wet because the dust , can be blown out. If - . water were used, the loosened material would soon fora a paste whioh-would be smear ed back on the tubes by the action of the cleaning turbine. Regardless of the dust which is produced in concentrations-as high as 30,359,040 partioles, ten microns or less in .size per. cubic foot of air, workmen prefer working in dry drums rather than In wet ones. Eight men two oh each turbine; are* engaged in this oleanlng operation whioh requires about twelve days a year. Hen with an average servioe of fifteen years .are assigned "to *thjs*--job from,the.IsJbar,Department, The temperature Inside of the drums o^hoaders Is about 70 degrees Fahrenheit. In accdrdano'o *with-the-usual -prac tice, men operating the turbines, inside the drum or header, work about ten minutes and are relieved for ten minutes by their co-workers who assist In handling, the air . hose in and out of the drum manhole. Respirators have been provided in most oases - but are not always worn. The average.dust produced while cleaning water-headers boiler tubes in samples taken fromt Lower Platform, Front Water Heador......................... In #2 Drum While Cleaning Water Wall and Tubes. e OfODtfWV Inside H&nhole Drum 3 While Being Cleaned..... ...28,320,000 " " About 4Q&4kf-th ^dnsli particles in the samples taken on the lower front water-header platform, while-'header was .betng clcVhidV'ewreToaadcd. -Aark. jsd.in jppearanoe under the Konimeter miorosoope, and about two microns in siz*t 6Q2 were opaque, more or * less angular, and about five microns in size; 10jj wore oryatalllne, slightly angular,* * and over ten microns in size. About 65/C of the partioles in the sample taken'inside - 2'rdrua during oleaning were black, opaque, angular, less than two microns la size; and about 15X were round, more or less opaque, over ten miorons. The oonoentratlon * of dust MSIDE the dnsa during oleanlng appears to decrease with the distance from 242 001480 1s-000006 i -60- tho ramhole as ia demonstrated by these oounts in samples from Drum #2 (Riloy Boil er)* . ;* Loo ation Particles par cu. ft. Inside Manhole...................................................................................................... .. 19,257,900 About B ft, Inaido Drum,..^'dyOW^OflC * ll-- r" " ................ ............................................................... .. 2,265,600 " 16 * " B .................................................. ................................. 1,585,920 ' " 24 V " ............. ...................................................................... 1,132,800 The dust particles from inside the drua appear black, angular and were less than two microns in size. The dust frcm these cleaning operations are supposed to be largely the results of metal corrosion and sediment (largely Calcium 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 reportedi . ~ Quartz^iOg)....-. --- ...................... .. Opaque or Coated with Opaque Material.. Unidentified Clay-like................ ;............ 1 per oent. 90 * " 9" " According to a chemical analysis of this same material made by a regular re finery chemist using the method of Adolph Knopf, U.S.Publlo Health Service, the dust oontainedt Free Silica............... .................................... 0.70 per cent. Combined Silica........................... .....................41.01 " " Although the analyele of the dust shows a low free silica content, the high 'ust'concentrations found and the poasibility that at times such concentrations may higher than those found, demonstrate the desirability of wearing respirators re gardless of the kind of-dust encountered. ' DC FOUNDRY OPERATIONS Poring recent years considerable attention Ms been focused' upon the health of foundry workers by the operation of the so-eallod "Silioosia Racket" whioh has ex tracted large sums of money from the Foundry Industry. It is difficult to isolate this type`sf work wWeh 'givt>8"ri3`e-to-a-very-gno*al -axpo*ure..to .dnst Hhloh w^ in- . valve all workers employed In the foundry. In many eases the worker Is in such elose oontaot with the duty atmosphere as to cause serious exposure. Much progress has . been made in reduoing the dustiness of our foundry 'operations end plans erenow being considered whioh will further safeguard our foundry workers. The following is a - brief outline of foundxy dust producing operations! A, - POURING HCUEN METAL INTO SAND MOULDS - About 19-1/2 tons of metal are poured per. ."heat". Thirty-five men with an avenge aerrloe of twelve years spend about one and a half hours pouring and six and a half hours moulding per day, fire days a week. Goggles, asbestos leggings and congress-type shoes are worn by the men handling the molten metal. About 60% of the moulding sand, which is the prlnoipal souroe ofsjdust, JLs-f1(,J9"During the pouring operation the foundry air appears to be full of dust and smoke, however, "Vsaaples ~t&1&'Hitftih|;v>th!s '-Work"a'i ei-- -- ... aged only 395,430 particles ten microns -or less in sice par cubic foot of air. Prao- tleally all of these dust particles appeared angular, crystalline under the Korineter microscope and were about two microns or less in site. . * A sample of dust from the top of the crane rail over the moulding floor was - 243 ' ia_000006B 001487 - I -61- ciTen 4 petrographic examination by the U.S. Bureau of Minos Experiment Station in Pittsburgh, Pennsylvania who ^reported SOjC quart! (SiQ2)f lSji Clay Mineral not ocom pletely Identified. Kaolinito is A1203.2 SiO 2- 2H20j 6% Caloite (CaC03 ) and 30jC Opaque. ' B# - 3O*JS!(C?-OOT5>u^?^fiSs--Xftex4>0^S^, the castings are allowed to cool, then the moulds are liberally sprinkled with water from a hoseV 'ThV'bahds or clamps are removed and the flask is thrown ovor and broken open. The rough eastings are pulled but, -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 foundories but duo 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 loss por cublo foot of air. The lmplnger method would no doubt reveal much higher counts. About 98% of the dust partioloa were slightly angular crystalline in appearance under the Xanlooter microscope md were one micros 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. TwelTe men with an average service of eight years work on this Job, eight hours per shift, five shifts per rieek. . After the castings have been removed the moulding sand is again wotted and thoroughly worked 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 electric motor, mounted on a rubber-tired four-wheeled carriage which moves back and forth over the moulding floor.-;,- Moisture`tests are me.de end Then these tests indicate 4,6 to 5.6 moisture the sand is considered ready for the moulders. During the operation of this sand eUbter, the operator is exposed to an average dust concentration of 1,529,260 particles ten microns or less per oubic foot. These particles were less than two microns and were slightly angular crystalline in appearance under the Xonlmetor microsoope. C. - CLEAHIHG CASTINGS - Various methods are used to clean castings depend ing on their size and shape. All of these methods produoe more or loss dust acme of which can be taken care of by exhaust ventilations, others cannot. The methods most connonly employed arer (a]H Preliminary Cleaning'- Castings are brought from the moulding floor during* the night and deposited in the Cleaning Room. The following morning tho cores aro knocked out, the sprues and gates are broken off and seme scratch cleaning Is dono. This wok produce3-ronaidcratle dust espeoially when the sand and old. cores are shovelled through the ,-rating into the ear or bucket'belbw"t3,455,t>40 `pax tioleften microns or less per oubio foot of air). Under the Xonlmeter microsoope about 70j of the dust partioles appear angular, crystalline, three microns or less ln^sizei.ZOjC were rounded crystalline, five microns In site and about $ were scale-like semi- . * opaque with a reddish-brown tinge and over ton microns in'size. Pulmosan Respirator! have been provided but are not always worn by men doing this work. NO attempt has . been made to control dust from preliminary cleaning although seme study has been given to the provision of a special sir-tight room with a grating floor and a hopper underneath with a sorew oonveyor at the bottom to convey the debris to the disposal car or bucket and thus eliminate the dust-produoing shovelling and handling. Tinder this plan exhaust duets with a series of outlets around the top of the hopper oarry off the dust. : Air is also introduced into the room about slman's breathing level mnA the amount'of air' tSiuJceh *th*n^^o-Jthat.jl-negative, pres sure is maintained and a complete air change is made about every three minutes. *' _ (b) Tumblast -- The Tuablast is a m&ahlne which combines tunbling with air blast ing. From 400 to 1500 pounds of eastings are put into a drum which revolves about ` 10 REM. They run from about 20 ninutes to four hours, depending upon the type of _ c astinge end cleanliness required. While the eastings are-being tumbled they receive ` 244 001488 18-200006 * it 'blast of #20 Steel shot through three S/lS inch nozzles \mder an air proosuro of 85 pounds per square inch. This machine is operated bjr three non, with an. averago servloe of eight years. for a period of two and a half hours per nan per day, firs ys a week. Pulmosan Oust respirators are provided but are not always worm A ,,en-inch exhaust pipe has been installed at the top of the machine and a six-innh exhaust pipe*orer-dde scr^en. . .Jhe^suction .on.-these exhAustjpipea is said to be . about -2-l/2 Inches- water. Samples taken during the operation of this machine aret>> aged 1,200,760 dust particles, ten microns or less in size, per euble foot whloh lax- dicates that fche 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 Konimeter microscope; about 60# are five microns or less in size and are angular crystalline in appearance; 40# are ten ailerons or over in size, rather rounded in appearance. There are also a large number of minute blaok metallic specks entirely too small and numerous to count accurately. (o) Sly Tumbling Mill - Cleans brass castings by a combination of tumbling and air-blasting with =3 Sand Blast Sand and 65 pounds per square inoh air pressure. The Mill holds from 100 to 150C pounds of castings and deans five loads a day. Two men , with an average service of l5 years, operate-thls udii-which runsabout-five-hours day. They wear Pulnosan Dust respirators and roggles tdien opening the machine. This Hill is hooded with an 8-inch exhaust pipe having a 2-inch water suction, also a IO-Idoh exhaust pipe over the sand screen at the rear of the machine. Samples of dust taken during the operation of the Sly Tumbling Mill had as high as 2,492,160 particles ten microns or less in size per cubic foot of air and an average of 1,393,344 particles per cubio foot. About 90# of these dust partloles were rounded crystalline in appearance under the Konimeter microscope and two microns or leas in Size; 5# were black, opaque scale-like and 5# were rounded crystalline about five ' microns in size.-- -(d) Tumbling Barrels - 36" x 42" Whiting Tumbling Barrels remove sand frcmoast- ngs. They hold from 1200 to 1500 pounds of castings per load and revolve at 10 RFH. ~ The castings are -tumbled .about two hours with about 700 pounds of one-inch unanneal- * ed east malleable iron stars and jacks. An exhaust system with a 6-inoh pipe through the trunnion having a suction of l-l/4 inches water. This suction has been found in adequate to give the desired results consequently the suotlon is to be inoreasod to -4--inches -water; Samples taken during the operation of the Tumbling Barrels had an average of 1,348,032 dust particles ten microns or less in size per oubio foot of air. About 90# of these particles were angular crystalline in appearanoe under the Konimeter ttiornscopc and three mlorons or less in size; about 10# were rounded semi-- crystalling, ten microns in size. There were also a few trlangSLar-dhipera opaque ' metallio particles. Three men, with an average service of twelve years, operate these tumbling barrels eifht hours a shift, five shifts a week. - Pulmosan Dust Proof ' respirators and goggles hare been provided bat are not always worn. . The type of Tumbling Barrels being used has been condemned by a major ocom pany because it is impossible to ventilate it properly. The holes in the end liners elog up when the barrel starts * revolving, thus preventing circulation of air through the barrel. This condition bus been remedied, in a new design non on the market, by the use of two shells - an inner perforated and an outer solid shell. Both trun nions are hollow, and are eonneoted with the air chamber between the two shells. Air under pressure is introduced through one trunnion and exhausted through the othorc a (*) AixvBlaatlng - Castings which cannot be tuabled due to their size and fra-- *' girjLty are cleaned by air-blasting (65 pounds per square inoh1) with mixture of ep- . proximately half and half sand and #40 Steel Grit. Syracuse Core sand is used vdien a special finish is desired. There are three men, with an average servloe of three ` years, on this job who work 45 admites 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;) 18-0080070 4 -63- while Hearing a Sly Sand-blast Helmet supplied with outside fresh' air provided by . ^ epooial blower used for that .purpose only. Semples taken inside the room while a * easting was being air-blasted had an average of 3,736,240 dust particles ton micron* or lesa per oubio foot of air. About 80# of these dust particles were sharply angu lar erystalllne in appearanoe under the Xonimeter miorosoope and three inieroaa or less in aliT'2tf#"wwr'B vouaidod^uarta-lJJco^orystala about ten microns in size. There were -also a few rust-like scales and a large number of black metallicpartibios too minute and too numerous to be counted accurately. The silicosis hazard of this opera tion eoul<^ be g'reatly reduced by the use of steel abrasives exclusively. ` (f) Rough Snagging Wheels - These snchines are used for removing projections suoh as sprues, parts and gates from castings. There are two types of these wheels* the DOUBLE END using either lS-l/2" x 3" Carborundum and Vitrified or 24" X 2-1/2," Redmanol (Bakelite bound) Wheelsj and the HORIZONTAL DISC Orindor having a .SO* ' * ` diameter vitrified wheel. These wheels are used by seven men having an average jerrlee of nine hours per shift, five shifts per week. Eaoh wheel is hooded and has a four-inoh suotion pipe. There is an eight-inoh suotien pipe on the Horizontal. " Crlnder. Goggles and.respirators are provided but the latter are not always worn with the exception of the men on the'Wrizi^tl""GrmIere. ''VitTifiedHahela -ara-iuc at a slower speed (1800 RBI) than the Bekelite Bound Wheels which operate at 3400 RFH. Samples taken during the operation of the Rough Shagging Wheels had the fol lowing dust concentrations. Double End Snagging Wheelsi Average Dust from Vitrified Wheels,.................... 3,653,260 particles per cubic foot ** " * Carborundum " ........... 3,322,620 *" " "' " " " " Bakelite Bound Wheels............ 2,662,080 * " * Horizontal Dlso Grind en . Average Dust from 50" Vitrified Wheel.......... .. 2*124,000 particles per oubio foot The average dust produced by all the Sough Snagging Wheels was 2',322,820 particles, tea microns or less in size, per oubio foot of air. - * About 60# of the dust particles-from the vitrified wheels appeared blaok angu lar opaque under the Eo'nimeter miorosoope and two microns or less in sitej 20# azvgular nrystaliine-vtbeut -Mie-mioraa nr-.liuA. There.,were, alM a large maker of black misut#^particles too small sad msnerwsto count. The dust partiblesTram^d^Orlzontal (Vitrified) wheel were approximately 90# angular, orystalllne and 10# blaok opaque. All of these particles were about two microns or. leas in size. ^About 60#. of the dust partiales from the Bakelite bound wheel were black angular two microns. or leas in sitej 25# were angular crystalline, less than one mlerat in size and about IS# were 'rounded crystalline about five mlorons in size. (g) fine Snagging and Polishing Wheels - These wheels grind off snail projec tions and remove rust from stook whioh has been in storage. There are three types* DOUBLE 4" x 14" PQLISBIHO BfERT WHEELS - Wheels after being made up are dipped in glue and then rolled in Alundum Grinding Grain, sizes 60, 80 and IS? mesh. DOUBU2 DISC owragsd.jdthJafi-iSaat Iren Opsin or Silleon Carbide (sn eloetrio furaaoe produet) sud WIRE SCRATCH BRUSHES - nde" w^'^our'lT" sefftlons. Eahaust hoods with a suotion of from three to flvo indies water, have been installed . . on the Polishing Wheels and Disc Grinders. There is TO hood on the Wire Sorateh. * Those wheels are used by four men with an average serflse of two years. They ***" goggles and gloves but no respirators. Samples taken at face level during thb operation of this equipment had the following average dust e anoeatrationst _ * 18_0000071 001490 - i -64- * Dust Produoed by 38" Mao Girder.................... 1,418,000 partioles per oublo foot h * 12* Wire Scratch Brush............ 736,320 " " " * " 4* x 14" Polishing Wheels.. 481,440 " ** fhoso comparatively low dust count3r'lhdlca'tcJ^tha*t~tfa,JdustMoontrol moasuras-Twfalnfc . hare been provided are either effective or the dust partlolos produoed are over 30 microns in size and were thus filtered out by the Konimator filter, tftider the mi croscope du^ particles from the Polishing Wheels appeared all round crystalline and, about one micron*in size. About 40# of the dust particles produoed by the Double Disc Grinder were sharply angular, opaque about three microns or less in slzej 60# were less angular crystalline about one micron in size. The dust particles produoed by the Wire Scratch Brush were all rounded, crystalline and about on# micron in size. There were no metallic particles in any of the samples examined. Pew exhaust hoods have been Installed on Wire Scratch Brushes because it has been generally assumed that these brushes did not produce any dust. This assuaption, however, is untrue an one sample from a wire brush at a Southern Refinery had as high as 8,683,820 pass, tides ten microns or-les* -peg-eubio -foot nf air. (h) Cone Grinding Wheels - These wheels are operated with ecmpreased air and * are used to do miscellaneous grinding on castings by four men, with an average ser- viee of twelve years, about two hours a day on an average. The eones are 5-i/i* x 3~l/4* vitrified and produce an average dust of 1,869,120 particles ten miorons- or leas per cubic foot of air. About 80# of these particles are sharp angular crystal line. In appearance under the JConiaeter microscope they are five miorons or less in size; 20# are round opaque but non-aetallio In appearance and five miorons or error in size. There are no hoods error these wheels and the operators~wear no respirators. Average Dustiness of Cleaning Room Air - A series of fire samples we're taken between 9*30 and 9t40 A. J- to determine the average amount of dust in the air of the eleaning room while the various cleaning operations were in full blast, Aaother series of five samples were taken, about .3*30 F.M. in the afternoon after the room bad been given its regular clean-ujw There was quite a difference in the amount of dust in the air during the morning (2,166,480 particles ten miorms or less per cable foot of air) and during*the afternoon toward the elose of the shift (338,272 particles per cubic foot). About 95# of the dust partiales in the evening samples were angular ciystalline in appearano e and about two microns in size. There were a few large s enti-epaque_or scale-like partides about 20 miorons in size. About 98# of the dust partioles iq'themOfgiqfr^Slmptea wcrw-*gni^w~awyi-s'1'11pa .two mlnrrn. .pr less in 9lze and about'2# were round, crystalline ever five miorons In size. A sample of dust from top of one of the larger Exhaust Duets in ..the center- of the oleaning room was given a petrographic examination by the D.S. Bureau of Hines Experiment Station at Pittsburg*, Pennsylvania and found to eontain 4Q# Quarts ' (SlOj), 2Q# Clay Mineral not completely identified] 40# opaque. . Mi -- CORE KAEZEQ - A large number of oores are made by the Doamler Air Ope 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* . ,0i6~(1) Shovelling. Sand to fill the Machine Hopper. 71,019 partleiei p^^dOBleTcdt 12) Blowing out Core-boxes........... ............ ................... 786,329 * * `* (3) Blowing sand into the Core-Moulds..................... 758,200 * About 98# of the dust particles from blowing out the eore boxes are dark, opaque in appearanee and about one micron in size. The dust partioles from-blowing sand into the core moulds are angular -crystalline less thsa one micron in size. 247 18-0000072 00149.i. 4 Cores are "smoothed up" after being baked In the core oven by soratohlng . off the rough .edges with an. ol-d hacksaw blade. This operation produces an average of 906 240 dust partioles ten microns or less in site per oubio foot of air. About 98# of ttese't>*mtl*s^*e.nngular.1.....ystalline in appearance under the Xonimoter mi croscope and leas than one micron in"tfito. . E. - SEPARATION OF BRASS FOUNDRY SKB1MINCS - A Stelnlein Separator, revolv ing about 5 RPG) separates brass from about 100 pounds of skimmings an'hour. The separator has a _4-Inoh exhaust duct to a 12-inoh fan which produces a auotion 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 ohute appeared opaque angular black in color under the Konimetor microscope end were less than one mloron in size. About BO# of the dust particles In samples from the trunnion were more erystalllne and rounded in appearance end less than one micron in slzo. This was also true of the semples taken in front of the machine where the slag drops down into a buoket* The dust partrdls~in~samples -X5nom..the.metal being discharged from the caohlne were about 50# metallic in appearance about 50# angular crystalline, -Both crystalline and opaque particle? were about two mlerons 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. X - MASON'S OPERATIONS " - - -- ' X, -- 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-oovored bottoms of orank ing ooil furnace fire boxes. Temperature inside fire box is about 85F, The bot toms which are oomposed 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 partioles were glassy sharply erystalllne In appearance under the Kent- - meter miorosoope. About 90# were five microns or less in size and IQ# ware over ten microns. The larger particles were aemi-opaque. There were also a large number of round blaok opaque partioles about one micron or less in size. After the bottoms 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 natural ly produces-more-.dust than the breaking up inside the fire box. Although no wind was blowing samples taken at had dust con centrations as high as 2,435.520 partioles ten microns or less per oublo foot of"xir and an average of 1,345,200. Goggles but no respirators were worn by the workmen. XI, -- CHIPPING OR CUTTING CONCRETE -- A large number of employees with an average service of three years, spend at least ten per oont. of their time dismant ling or outting oonorete structures with pneumatio chisels in the removal of bid ' - foundations, oonorete supports and blocks and in cutting holes in walls tw< floors, Saaples taken during tba cutting or chipping of oonorete had as high as 6,910,080 partioles ten microns or less in size per oubio foot and a general average of . 1,591,051 partioles per oubio foot. All of these dust partioles are slightly angolar orystaliine in appearance under the Konimeter miorOsoope. About 86# of the dust par tioles -ere fivVmi'c?jiS! 'or 'twss Hka-'Ziz.e? .10# .between five and ten aiorens and about "5# over ten microns in size. In many eases neither goggles Or~Tasplrafrcrs~wor*e,wora by the workmen. Regardless of the rather low dost counts found, men engaged in ohip- ping .or outting ooncrete should wear oonorete due-to the high silica content in the usual aggregate used in oonorete. . \ `III. III. - CHIPPING MORTAR FROM BETWEBI BRICK - Chipping Mortar with pneumatio chisels from between bricks inwalls of structures preparatory, to weather-proofing is a particularly dusty operation. 'Samples taken during this work had dust oanooxxtratlau 248 ` 001492 IB-0000073 i -66- * M hich as 20,956.800 particles ten microns or less por oubio foot of air and a general average of 13,848,480 particles per cubic foot. All of these partiolea were ' anruler orystalllne In appearanoe under the Konlmetor microscope and about eix mi crons oFleSJ' itt Ylrc.'"-Tftwc-wcrc ^leo^-oountlflsa.jnuiabcr-,nfja.lnut e reddish-gray -particles. Shis work was done by an outside contractor whose employees wore goggles but no dust respirators. IV. - CRUSHING FIRE BRICK - Firo brioks are crushed in a bolt-driven Williams or a Motor-driven Sturtevant Brick Crusher so that 80# will pass through a 3/8" or a 150-roeeh screen - much of it ie powdered during the crushing. This material is -then mixed with fire clay, crushed asbestos end cement to make "Ganieter" 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 ae high as * 11,554,560 particles ten microns or less in sire per oubio foot and a general average of 2,562,960 particles per cubic foot. Crushing new fire briok produces about six -times as many dust partiples (4,375,733 per cubio foot) as is produced when crushing old, used fire briok"(736,320 particles por cubic "foot). ' "Wder"tho hcuimeter -mi-- oroscope about 94# of the dust -particles produoed by crushing new fire briok appear angular crystalline, one mioron or less in sire; about 6# are opaque over ten mi crons and about 1# are dark opaque, soale-like about five microns in also. The dust particles front crushing old used fire brick are more rounded crystalline in appearanoe and are about five microns or less in size. 'An analysis of Alamo Flre-olay Brick, which is ootmonly used and was the new unused fire briok being crushed at the time our samples were taken, supplied by the manufacturers (Harblsan-Walker Refractorlei Company) reports* * Silica. .................................... Alumina and Titania..... Ferric. .O..x.id..e................. ...... Hagnosla............ ................ Alkalies................................. per cent. ft II ft It VI ft ft ft ft ft Fire, brick is crushed by two men assigned from the Labor Department, the aver age servioe of these men is about 14 years. Two to three tons are orushed per day. The total length of exposure per month depends upon the demand for crushed fire briok and will-vary-from-a-gemeral-average._<if,,flftflflnhow?._porman_por month to as much as twelve hours a week. Goggles and H.S.A*Comfo dust respirators are worn. ' Y. - SHAPING TIRE BRICK OR EHEHT WHEEL - Fire briok are ground to a speoifiod shape and size on a 2" x 24" Carborundum (Grit 16, Grade 1, Bond 6C) Whcbl whioh re volves 900 RPK. This wheel* is almost completely enoloaed by a hood whioh has a 4- . lnoh duct to a 24-lnoh motor-driven fan operating at 1750 RRL , but this exhaust Is evidently inadequate as samples taken while rounding off the edges of a firs elay fur nace blook had a dust concentration as high as 4,078,080 partloles ten mlorons or less in size per oubio foot of air. The general average was 2,001,658 partinles per oubio fooiu.. All of these dust particles were slightly angular and slightly opaque in appearanoe under the microscope and five mlorons or less in size. One man wearing goggles.and_a K. S. A. Confp respirator, with about 15 years servioe, spends an average of about two days a month shaping fJure Tbr loSc ahd 'bl8ckS"tSff'thlK'-vdieel, * VX. - DISMANTLING HASCURT - 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. . i, 249 *. 001493 ' ia-ooo0O74 - i -67- _ XI - WOODWORKING OPERATIONS * * ' Woodworking operations, as performed In oonneetion with tho refining of pe- trolruBtf^rtdnot7*-*dvJLas^latod -actlTitiea, are need In tho production of pattern*, -boxjhook*. ooatainere, and o onetruetion or miliiTtaTb~work.- - -"These-woodworking . operations produce nore or lens duet which is largely organlo and although It nay- hare some spores and hare an allergic off eot on some Ind It 1duals, it is not o one idor- ed harmful. Miy' D* Harrington of the U. S. Bureau of Mines adrlses that the IkS. De partmentof Labpr in a recent bulletin indicate that workers breathing wood dust are far more definitely afflicted with tuberculosis than tho general run of industrial workers. In large quantities, howerer, wood dust belongs in the "nuisance" claas and may also be an explosion hazard ' * A. - 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. * (a) Resawing - Band saws, twenty-fire feet four inches in olrcumferenoo, re saw four-quarter end fire-quaf-ter lumber into 3/8-inoh and l/2-lnoh shooks respeo- - tirely. Samples taken during this resawing had an average dust concentration of 165,760 particles ten microns or less per eublo foot of air when sawing pine'and 996,864 partloles per oubio foot when sawing gum. These low-eousts indicate that - the exhaust and dust oolleoting system whieh has been prorided is functioning. This N exhaust system includes hoods orer each saw with 8-inch ducts to a belt drlren fan with fire-foot blades rerolring 3500 RHi. About 60f{ of the dust particles in samples taken while resawing pine were crystalline, rather glass-like-ln appearanoo - prob ably resin - under the Xoaiaeter microscope and orer ten microns in slxej 40JC yrore round wltlv rough edges gray and opaque, fire microns or less In sice. About 80^ of -the dust partloles from cutting gum lumber were round crystalline semi-opaque in. ap- pearanoe, fire microns or less in size; Z0$? were orer'fire microns in size. Gum lum ber is resawed only about four days a month. -. (b) Ripsawing - Rip saws. 14 lnohes in diameter out ends from four-quarter gum lumber. An exhaust system has been prorided with a hood orer each saw and four lnoh metal duots to a belt-driren fan with six-foot blades rerolring 3600 RRi. Samples taken during this operation had an arerage dust concentration of 169,920 partloles ten microns or leaser cubio foot of air. All of these partloles were angular crys talline semi-opaque in appearance under ~the~X0la2iSetvr~miero3e-ope'ai)d~abaut these-mi cron^in size. - (o) Cut-Off Sawing -- Saw four-quarter lumber to make box ends,. --About 85jC. of the tins gum lumber la sawed, and 15X pine lumber is sawed* Samples-taken while saw ing gum lumber bad an arerage dust concentration of 877,920 partloles ten miorons or less per oubio foot of sir. About SOjC'of these partloles were round crystalline semi opaque, gray in oolor and freo fire to ten miorons In size) 50jC were slightly angu lar crystalline in appearanoo -under the Xonimeter miorosoope and three nlorcns or less in size. There were also sereral rery small black specks. The low dust count indi cates that either the partloles were mostly orer 30 miorons in size and were thus filtered out by the porcelain filter or that the exhaust system was effootire. - {d) Planing - Planers or double surfaoers resurface the four^quartor fire quarter lumber to giro it the proper finish. There is an exhaust hood orer eaoh ma chine with an eight-lnoh metal duct to a bolt-driren fan with six-foot blades rerolr-- ing *5500 RFM, Samples taken during the operation of planers or double aurfabers baud . general arerage dust concentration of 509,760 partloles ten nioroas or less per oubio foot of air when planing pine lumber and 415,360 partloles per eubio foot when plkning gum lumber, Partloles of-dust produced while planing pine Timber were - crystalline rather round in appearance under the KonimetOr microsoope, about 76j were - . 001494 lB-0000 250 i ._ * -68 * fire miorona or loss in aizoj 25fC were larger than two microns and rather opaque* Du*t particles from planing guA lumber were retold opaquo in appearance and ono m- *ron or lees in size. Dustiness 6^ShdgkrTB3ton-y^T .jCiT^.gafflplea were taken at fire strategic points to determine the average dust oonoentration of the faotory air. These samples gave an avorage concentration of only 141,600 dust particles ten mi crons or legs per" cubic foot of air which indicates that either the major portion, of the dust is over SO microns in site or that the ventilation system ie proving offoo- tive. The latter is probably the more logical explanation although the exoollent housekeeping is undoubtedly an important factor. About 98jC of the dust particles in the faotory air samples wore slightly angular crystalline in appearance under the Konimeter microscope and about five microns or leas in size; 2% were round, opaque dark gray in color and two microns or less in size. 2. - BELT SANDERS, SAND DISCS AND SPINDLES OR CYLINDERS - This equipment Is Used, for "squaring-4ip."_and saoothing surfhees of wooden patterns, -oleanlng and finishing barrel-heading and staves and general"mill wdpk'ln "the -Carpenter -Slope. Sanders are a notorious souroe of fine wood dusts. They are also oontamlnated 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 -dlffloult to. properly hood a sander to prevent the fine dust being carried around by the abrasive member, particularly dlao senders. Our attention has been called to a case where a eiv-, gaged in the use of senders suffered recurring respiratory illness and ultimately * death from pneumonia. Hie "attacks of illness socmod to oorrelate with extended use of the senders. - (a) Belt Sandora - An 8" x 28-1/2 ft. Bolt Sander (Lightning Adalox Cloth . 1-1/2 - 40 X Grit Norton Abrasives) runs on an average of two hours per day and is used by eight different men with an average sorrioo of fifteen years* Samples taken while finishing #1 Pine lumber had a dust oonoentration as high as 15,619,360 paro tides ten alorons or less per cubio foot of air and a general average of 3,443,712 particles per. eublo foot. About 9Q of these pcrtloles wero angular crystalline In appearance under the Konimeter microscope and five microns or less in slsej 5j were over five "microns in sizej 6% were opaquo eoale-llke. ten miorona or less in size* There was no hood over this sander and the dust produoed was thrown into the shop . air. ........... . A 6 in. x 18 ft. Belt Sanding machine (#3 Production .Cloth fllnnesota Mining Company) runs on average from four to six hours a week and is used by four different men, with an average servioe of feur years* This work was fomerly dose'by bawd on a lathe with sand paper. Samples taken while finishing the outside of; a barrel had as average dust oonoentration of 481,440 partloles ten miorona or less per oublo foot. These partloles were largely angular crystalline in appearance under the Koai- meter microscope. About 50$ were five microns or less, and 50^ were over five mi crons in size. * " (b) Sand Discs or Hhcels - These discs run from 40jC to 6Cof the time and are uewaldyeed.-by. evwylyjsJy.in ^the shop in which they are located. Semples taken during-the operation of sand A< --*' ......... nTr^Vms:. 251 18-0000076 001495 4 Ho. Slse Abrasive (Itta.) Used Work Being Done ....1 1........... .-- ..... .............. . ..| Particles Per Cubie Foot Charaoteristios of Dust Fartloles (Sixes and Per centages Estimated) t 1 .&w% 4?| Smrt. :.Clesning_ Paper Minn. heads. Mining Co. . Finished b Barrela II 24" #i-l/Z Gar Squaring net Paper. Wood Mian. Min Pattern ing Co. 604,160 623,040 Angular crystalline -~*feeb*G'f4flr >adoon* or less and 60% larger than five microns. * About 8Sjf angular crys talline two miorons or lessi 5% quarts-like rounded about 10 mi crons in sice. III 30" #40 Grit Smoothing on Bristol off Pat- Board. - "tern --- Gardner Ma chine Co. 1,925,760 About 9QjC angular crys talline three miorons or leasj 10% opaque angular one micron in site. IT 30" #2 Garnet Hat Back. Gardner M&ohiae Co. Squaring Wood Pat tern 3-, 624,560 - About 98|! semi-opaque, sand-like, one mioron or less, 2% opaque 6 miorons or over in size. . Ths sand diao is No. I was used is & well ventilated cabinet eonneoted to a 48" motor driven fan by a 7-inch duot. The men wore goggles and "Ccmfo* respire* tors. The sand wheels in Vo. IZ am) Ho. Ill had hoods with about 3-1/2 inohes water suction eonneoted to a 24" motor driven fan hy 4-inch dusts. fits men wore neither goggles nor respirators. The wheel la Ho. IT had an exhaust hood with a 6* inoh duot oozmeoted to a 24-inch duot which in turn was eonneoted with a 36-lnoh mo* tor driven fan. (o) SmM SpIMlgji fiT gyilndgj - Sand spindles or oylinders are used on an average of about two hours per man per day. No hood or suetion exhaust has hem pro* vidodnfor this equipment. 'Hen uslag^VdoTigt wear-gegg4es,ar^sapimtoga altfrgwgh the dust particle's produced are more angular in appearance than those produo ad by sand discs or wheels. *. Samples taken during the operation of Sand Spindles or Cylinders had the fol lowing dust eonoentrationsi Sice (Dia. ) Abrasive Used `.Work Being Done Fartioles Per Cubie Foot Charaoteristios of Dust Particles (Sices and percentage Estimated) #U|JtiieC ftiper -- 'OutMrng -lasldm. .,Jg,?g2,2*0. Gardner Machine Core Boxes Co. ^ About 60% quartr-like eroos or ever in a'isei 40% semi-opaque five mlaraoM or less in sice. ?I nr T5..r 2 001496 -10-0000077 i -70- DUST PRODUCED BY SAMP SPINDLES OR CYUNICRS (Concluded) Si** ... (Die- ) Abraslv# Ui#8 3-1/& #l*l/2 Carnet paper Mian. Mining Co. * Nork Being Partioles Per >*-Ooae-*"*5"-^ ..--Cubic Fqpt Putting Taper on Pattern- 877,920 Characteristica of Dust Partioles (Sizes Pero ehtap'H5ft iMffjT) About 90# angular crys talline two microns ia aizoi 10# opaque fire microns or less in size. C. - liAKIHG t-TOQDBN CRATES - Two types of sows aro used in preparing lumber for malting crates for gasoline pumps and tankst (*) Band Saw - Samples taken d'urldg "the operation"Of -Baad -Saif liad a dust conoentratlon of* 453,120 particles tea aiorons or less per eubio foot of air, ill of these dust particles ware round, opaque in appearanoe under the Xenimeter miorosoope and three.microns or less in site, . (b) Railroad Saws - Samples taken during the operation of an 18" Railroad Saw had a dust concentration of 3,964,800 particles ten adorons or less per eubio foot of air. All of thesa particle# were round, grayish opaque in appearanoe under . the Komiaeter microscope and about fire microns or lass in site, Thore were also nu merous minute gray specks too small to count accurately, ' XII - ROCK EXCAVATION Rook excavation is. usually a dust producing operation which is limited to con struction activities in the petroleum industry. The hasardoupness of rook excavation depends entirely upon the nature of the rook being excavated, the length of exposure and the methods being followed. The prinelpal souroea of dust are rook drilling, blasting, mucking and handling of the rook. Of these, drilling probably produces the . greatest amount of dust.- . X, -"DRlIi^III3 Tl foeumatie^Qok dri.ll .op.oratos essentially as a oruahing device which shatters the rook to a ponder at the point"of' lmp5ti ~Auoordlng to . Theodore Eatoh of the Harvard Sohool of Public Health (N.T, 2nd,lhill.7ol,16, Ho* 9 Sept. 1936} tiie particles of dust thus generated vary In size from. one-quarter -inch or larger down to sub-mioroso oplo diameters. The dust is removed from the drill, hole by a stream of air or water or a combination of the two Introduoed through the hollorr drill steel. In the case of Jack-hammer drilling a considerable amount of rook dust ejected free the hole falls back to be orushed further before it is removed again. Quoting Mr. Batohi ^ ' ' .-- ' "The amount of dust produced by a rook drill is surprisingly large - a Jack-hammer., operating at the over-all rate of 100 .^^aat.af-drilling per day, aotually orushes more than 2Q0 pounds of rock in eight hows^ uf'tKl8 ;'<t*'Tast `dd*e-fttn.m*a...ia in tii form of*'partialcs smaller than ten aiorons} hence, more than * fifty grams of dust small enough to be air floated ia gmekated * per foot drilled. In terns o' mashers -of partioles the figures ' are enormous - it has been found that a Jaok hammer prp&&0** as - muoh as one billion partioles. of hygienic interest during one minute of operation*. * .* .. " . ' ia-000007 001497 - 253 i -71- B. - BLASTING - It ie ofttm said that blasting produces the greatest amount of dust `n rook-excavation. This statement Is eontradioted by some authorities who refer to tho faot that the blast dislodges, a great deal of dust from the rook sur faces depoiitod there from earlier drilling operation in addition to that aotuallygenerated by it. Under this condition blasting is undoubtedly followed by a higher dust ooribtntratten^than..the.-case when all the dust produoed by drilling ie oaptured and oonreyed to a remote oolleotor so that only'"tbit `iSttbOTy-generated hy-the explosion^escapee into the air. While it is undoubtedly true that if drilling la dono 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, because the slushed out particles tend to fora agglomerates, which are not to readi ly raised by the blasting operation. Also, when good practioe is followed, the fnoo nd sides are wet down with water before blasting, and in mining work, there ia a continuous wator 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 minimtan. C. - MUCKING - The amount of dust produced by mucking and other r00k-handling operations Tiriea greatly with the nature of the operation. On open excavation it is probably of little importance, but in confined sources as-in tunnels and mipsa the dust concentration associated with rook handling may reach dangerous levels. D. - DUST CONTROL - Methods for the control of dust in rock excavation as suggested by Mr. Hatch include 1 - (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-free material such as lime-stone. The usefulness of water is limited when freezing temperatures are encountered and it produces objectionable working conditions. especially for overhead drill operators and is certainly to be avoided if a pneu monia hazard exists. A fundamental objeotlon to the wet method'is that the dust is not removed from the soene of operation but simply suppressed near its source where it remains to be thrown into the air by a subsequent disturbance suoh as blasting. (b) -- General Ventilation - The purpose of general ventilation ia to dilute the dusty air with suffloient olean air to bring the oonoeutretden down to a satis factory level. --Two.-precautions are required! . 1st. - the fresh air Itself muet be free roa dust and_ 2nd. - it must be properly distributed through the work ings to Insure maximum mixing with the dust laden -* air. - (o) -- Dust Exhaust Hoods on Drills and Other Mucking Operations and Local Sources of Dust - Effeotivo dust control can be secured by means of a dust trap whioh surrounds tho drill steel at the rook surfaee. The dust-laden air is captured as it emerges from the drill-hole by the Inflow of olean air into the trap. To be effoo-- tlve, the inlet velocities must be great enough to prevent the outward movement of the dust ami suffloient yeloolty must be maintained at all points within the trap to prat oht settling Vhd Bld^ging.' "The-eei'lavbed^Mai da.joenveyod 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 olean air. .Traps 'of dif ferent designs are required with various drilling operations and speoial supporting devices are necessary to hold the trap in proper alignment with the*several operat- lng positions. (NOTE* The dust trap is satisfactory under many conditions, but again under many other conditions has not proved satis factory. RSB) -- 254 001498 l-?oo i -72- . rh dust dispersed during mucking, as well as that arising pram rook drill** lag, can bo oontrollod by looal exhaust ventilation and requires no elaborate ap- leratus. , fd> .-..Jcrsonal Frcrteetlon jy Keans of Respiratory Hi Fp*tllg - Fressuro Masks - An. effectlre respirator or * pn`itn^*icrpriaswa ^ " quantity or tust-fjrw air provides the wearer with protection when it fits the face properly anil Is worn continuously in dusty atmospheres. Respirators and masks hare . a legitimate place.in the field of silicosis control, especially to preside pro- teotion against infrequent unexpeoted dust eonoentrations but cannot be recommended as a substitute for dust control In continuous operations. .i 255 - 001499 16-oooooeo r dusts of the following size characterlstiesr 99 per ceht smaller than 2. 80 microns 95 n it IT " .1.80 If . it --1. 40 11 80 n it " 1.00 n - 70 n ' n it 0.85 a 60 it n ti * 0.72 n 50 n it it " 0.60 * k It will ha noted that 80 per cent of the dust used in these approval tests is below one si oron (l/25,000th of an inch) and SO per cent is below 0.6 microns. Canisters will not remove dusts of these characteristics and should not be used as dust respi rators. In order to obtain the desired proteotion, it is essential that the faoepieces of the. aeohanicalefUter respirators fit the face of the workman snugly but with minimum of head-band tension. ""X slmpl~praotloal test. -snggeated by Carlton E. Drown Qf the V. S. Bureau of Mines Experiment Station in Pittsburgh, Pennsylvania (dour. Indust.BEyg. Feb.1937 Vol. 19, Ko. 2, p.98). that anyone can run to determine whether a respirator facepiece is making a tight seal, is to wear it in a high con centration. of eoal dust. The time of the test can ba shortened by blowing a stream of air,containing a high concentration of ooal dust around the edges of the faoepiece. ' The location and approximate magnitude of the'leaks are shown by-streak* of ooal dust on the part of the face covered by the facepiooe. Another test, according to Mr. Brown, ^.consists of plugging the intakes of the respirator and then attempting to inhale. This type of teat could wall be supplemented by tl\e Coal dust test. (b) Supplied Air Respirators - Industrial processes suoh. as pneumatic drilling, ab rasive blasting and spray coating havo introduced atmospheric conditions for nhloh the 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 mist be protected not only against the inhalation of air containing high, concentra tions of dust, but also against impact and abrasion of the head and shoulder by the rebounding abrasive and loosened abraded material. Spray coating is responsible fre quently for pollution of the surrounding atmosphere by a combination of partioulate matter (mists' that are^Urquid -particles nr a combination of solid and liquid par ticles) and harmful vapors resulting from the eraporatioh oTthe "Ti-quid'vahiole-of the aQfcting used' in the spray gun. . Since these operations are oarrled out frequently in isolated plaoea and at different locations at various times, they do not lead themselves always'to general oontrol measures. Therefore, supplied air respirators perform a definite aerri.ee.' The types in general use are those ecesaonly known as hose masks, air-line respirators, and abrasive blasting respirators suoh ea sand blast masks, helmets, and hoods. Supplled-alr respirators have the following advantages for routine non-emer gency use over those, of the air-purl lying respirators suoh as gas masks, mechanicalfilter rresplratoiw and the combination of gas mask with a mechanical filter* - 3, V0 resistance to inhalation. .. 2. freedom from Inward leakage of contaminated air. , ~ 5. Protection against all kinds of contaminants and even against at- * nospheres deficient in oxygen which will not poison or IrritEto the skis. la-0000085 ? rlO POISON fi still remain enough Tory 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 -risible dust it is certain that mueh of the smaller invisible, and probably moat harmful dust has also been removed, '' . "Manifestly, if dust is kept cub"br'tbd Air'brathed'byv*orkers, the latter cannot woeewab to dust disease of a respiratory character.N k ** -' " In closing, we acknowledge with gratitudo the support and cooperation of Dr. W. J. Denno, General Medica Director, Standard Oil Company (Hew Jersey) whose.i:,: vision and active interest in Hedloo-Safety problems mad# this Dust Study, jxierible,* : He also appreciate the advice and assistance rendered by* '* ' I! Mr. H. P. Tant, Director of Research & Development, Mine Safety Appliances Company, Pittsburgh, Pennsylvania, Dr. ^eoimrd-Greehburg,-xeoutiraJ}ireotor, Division of Industrial Hygiene, Department of Debar, State of Hew York, Hew York, H.Y. Dr. R. R. Sayors, Senior Surgeon, -- TJ. s. Public Heath Servloe . Chief, Division of Industrial Hygiene, Nationa Institute of Heath, Washington, D. C, Mr, Daniel Harrington, Chief, Heath and Safely Dlvioion ~ Dhited States Bureau of Mines, Washington, D. C. Dr. A. h Lansa, Assistant Medina Director, ' Metropolitan life Insurance Company, Hew York, B.Y. Mr. E. E. Barlow, Chief Engineer, ' Standard Oil Development Company, Elisabeth, Hew Jersey, Mr. H. K. Blakeslee, Department of Aooident Prevention, American Petroleum Institute, Hot* York, H.Y, Hew Tork. H.Y. July Fifteenth 1 9 *' 8 T i 265 R. S. Bonslb Chief Safety Inspector Standard Oil Co. (H. J. ) * -vf 18r009b oofjoa i for dusty jobs men who are past the age of 40 end not young *" 4*"* taking up a trad*. i HI worker* iDpc,d in harmful dusty operations should ho periodically thorsuchly re-examined. lnoludtng X-ray tosts. Pertiouler emphasis should ho planed on say ladlostlos of shortnoss of breath snd chost pains Seguletfuns should ho enforced concerning the tine limitation of work of say eaployeoe Igt'dirra -lfrlfaayv^fWBetagf~upere.tin.-~-9noh Qya)r-w|Ulti ons-emoem- ing sandblasting' calling for a fixed slx-nonth aejdnua period os suoh work, after idileh a minimum six-month period away from dust producing work should be followed ore olosely. k For protection from a legal angle, the worker ahould he given a final thor ough examination Including X-ray before being permanently transferred to ease other type of work, laid off or dlsohargadL, ' CONCLUSION There is still a treaendous amount to be learned, about (neuaoooniosis and dust-produolng operations. One thing, however. Is oertain -there is a vary definite tendency to require compensation for industrial or occupational diseases. If these compens ation costs are to be kept to a minimum and the health and safety of workman are to be promoted itM.ir'bsseoairxTytO-aaks-fttrther-stadloe-andtopvonp'tly adopt adequate precautionary measures. Many of theso are now la effect, the others , should be put in foroe as soon as possible. After years of study and direct oootaot with the Dust Problem, Hr. Dan Harrington, Chief, Health sad Safety Sranoh, United States Bureau of Mines, has ease to this conclusion (Eng. A Hin. Joar. March 1937' . ppe. 117-21) with which we are heartily in accord , _' ' . . ! "In the Base, of uncertainties eonneoted with almost all phases of ' 'the psueatIon and diagnosis of dust disease, about the only really well-determined fact available is that breathing large quantities of duet (or possibly of oertain dust) over extended periods is ilkely under some conditions to be hejcnful to health end that subsequent al-- . lerletlon or owe Is difficult or impossible. Therefore, It would seem to be logical to try to prevent dust formation thus preventing it from harming workers through respiration or otherwise. Here Is a reel job for the engineer, and little or no help can bo.expeoted in these vital Amotions from any agency oxeopt the engineers andoperat- ing officials. . "The most harmful of the ordinary dusts to breath is probably silioa dust, but, on the other hand, not even Are# alllea, supposed ly the most detrimental of the silica dusts, is harmful unless it Is breathed, in considerable quantities and orvr extended periods. Ho human being ever lived any considerable time on this earth of ours without breathing silica dust (free silica dust), yet by no means nil of the people of the world have or have had slZioosis. In other words, --the auawtbtv-of-dust.-taken.-lata,the rsani retory orrana is a contrail- _ ing footer In dust respiratory harmfulaess. *. One eonon-senae answer is that any atmosphere in nhleh dost is visible to the naked eye is certainly too dusty to be bPeathed with safety by buses beings, and the miss, farsighted, kunam employer will' . Isnedlatsly start to decrease the dust sontent In say atmosphere where dust is visible. After he has eliminated visible dust, there msy - " OOl'SOn M-0006089 264 t -