Document 0gnmwQ9vVXVr9wwgwom8mRk2n

FILE NAME: General Electric (GE) DATE: 1941 DOC#: GE026 DOCUMENT DESCRIPTION: Transactions of the National Safety Council -- x rn m rp m w iim iT iim m B i:" !riK n w im w p in w n w m n r -- ' ' 1 /i A ! f v ,.,i TRANSACTIONS c '1-3 30th NATIONAL SAFETY CONGRESS L N- " L ri* Y& GENERAL SUBJECT AND INDUSTRIAL SESSIONS CHICAGO OCTOBER 6-10, 1941 iS K" NATIONAL SAFETY COUNCIL, INC. 20 North Wackcr Drive, Chicago Copyright, I9-U, National Safety Council, Inc. Printed in the U, S. A. ft; 1i S eword T HE Transactions of the 30th National Safety Con gress and Exposition of the National Safety Coun cil are published in two volumes. Volume I contains the General Subject Sessions and the Industrial Section Ses sions. Volume II contains the Street and Highway Trafp fic, Commercial Vehicle, Transit, Child Education, Home Safety and Farm Safety Sessions. Volume I is distributed automatically to the industrial members of the Council. Volume II is sent to those mem bers who are believed to be interested chiefly in the ses sions it contains. However, other members of the Council may obtain Volume H upon request. All types of Council members have found it advantageous to distribute these Transactions volumes to foremen, supervisors, executives and other officers of their organ izations, who make use of the information they contain in organized accident prevention programs. On page 9 of this volume some practical suggestions are made for the profitable use of these Transactions. Extra copies of Volume I may be obtained by Council Members at the following rates: 1 to 10 copies at $2.00 each; 11 or more copies at $1.75 each. Extra copies of Volume II may be had at 75 cents each. The Transactions are a condensed record of the proceed ings of the Congress, reproduced here for reference pur poses. The papers, addresses and many' of the discussions have been edited to delete extraneous matter and empha size those parts which outline ideas of particular useful ness in safety organization and all other accident preven tion procedures. The volumes are, therefore, a somewhat abridged version; the original manuscripts, however, are available in the files of the National Safety- Council. The National Safety Council, at its Congresses, seeks to eliminate from discussion matters which are not pertinent to the aims of the Congress, or which may be contrary to the Council's policies. However, it cannot accept respon sibility for all the views expressed, cither in the matter presented or in the discussions based upon these papers. NATIONAL SAFETY COUNCIL, Inc. 20 North Wackcr Drive Chicago, Illinois Il Contents Council O fficers........ Make Profitable Use ol Council Purposes and 1 Annual Meeting of M .Congress Banquet . .. Subject Sessions-- Dusts, Fumes, Gas Electric Welding Elevators ............ Fire Control and 1 Fundamental Cam Governmental Safe Human Engineer Industrial Health . Industrial Nursing Maintaining Safety Sabotage Preventie Safety Engineering Safety Organizatic Safety Training . . Induslrial Section Sess Aeronautical Sectic ASSE--Engineerir Automotive and M Cement and Quarr; Chemical Section . Construction Sectic Food S ection ........ Marine Section .. . Meat Packing, Tai Industries Sec1 Metals Section . .. Mining Section . . . Paper and Pulp Sec Petroleum Section Power Press Sectic Public Utilities Sec Refrigeration Sectic Rubber Section .. Steam Railroad Sec Textile Section . .. Wood Products Sec Exposition Exhibitors Index ............................. National Safety Council,^Inc. HONORARY MEMBERS A ssociation of I ron and S teel E ngineers R obert W. C ampbe ll Ijnv R. P almer OFFICERS (1941-1942) Col. J ohn Stilwell, President N e d H . D earborn, Vice-President for Education I. W. M illard, Vice-President for Finance and Treasurer G. T. H el l m h t h , Asst. Vice-President for Finance and Asst. Treasurer W alter S. P a in e , Vice-President for Industrial Safely L ew R. P almer, Vice-President for Transportation A. V. R ohweder, Vice-President for Home and Farm Safety R. T. Soi.en sten , Vice-President for Membership L eslie J. S orenson, Vice-President for Public Safety Roy V. W kiciit, V ice-President for Community Councils W. II. Cameron, Managin'; Direclor and Secretary EXECUTIVE COMMITTEE (1941-1942) Capt. F ra n k E. A m es, M arine Section J. 1. B a n a s ii, Past President C. \V. B ercquist, P ast President II. IL B ixler, Union Carbide & Carbon Corporation II. \V. Bogcess, Sinclair Prairie Oil Company K arl B recht, Safety Div., South Bend Association of Commerce W. II. Camlkon, National Safety Council, Inc. R obert W. C ampbell, P ast President D. B. C h a n t , Ontario Pulp & Paper Makers' Safety Association N ed II. D earborn, New York University L ewis A. D e B eois, P ast President C. \V. D kmpesy, Liquid Carbonic Corporation M arcus A. Dow, Past President H arold F. E n id w s , The American National Red Cross D. D. F en n ell, Past President II. J. G r if fit h , ASSE-Euginecring Section E. E. Grover, Columbus & Southern Ohio Electric Company H arry G uiliiert, The Pullman Company J ulien II. H arvey, Greater New York Safety Council , W. A. H azard, Construction Section D r. T. L yi.e H azlett, Wesliiighouse Electric & Mfg. Co. G. X H f.l l m u t h , Qiicago Rapid Transit Company W alter G. K in g , P ast President J ohn E. Long, Past President C. II. L ongm an, Qiicago & N orth W estern Railway Company J. W. Lord, Commercial Vehicle Section T hos. H. M acD onald, U. S. Public Roads Administration 4 OFFICERS (CONTI).) Robert A. M cA r t h u r , Pul. B. II. M cC ulloch, Bureau F. R. M cL ean, Petroleum . I. W. M illard, Industrial (. H arold L. M in e r , E. I. du P iiii.ii* M. M organ, Massa Council H on. F.i.iot N e s s , Director E. J. O 'B rien, J r., Louisvil W alter S. P a i n e , Aetna I. Lew R. P almer, Past Pros C. E. P eitibone, Past Pres G. IL P feif, General Klecli f R. J. Rkicki.uth, C. W. Bk II. A. R eninger, Past Pres A. V. Rohwkdf.r , Duluth, A C. J. R utland, Street & H H enry G. S c h a f f n e r , Eric Carl L. S m it h , Greater CU K. T . Soi.e n s t e n , Elliott Si L eslie J. Sorenson, City 1 If. J. S i'oekeu, Metals Scctii Coi.. J ohn S til w ei.i., Conso C. 1'. Toi.man, Past Prcsid' G eorgi-. G. T raviai, Gu-aU r Uit. C. 11. W atson, Past Pi A. W. W h itn ey , National RuV V. W right, Railway / A rthur II. Young, Past P V. A. /. immer, U. S. Depar BOARI) OF TRU W tnthroi* W. A ldrich, C National Bank, New York Morgan B. Brainahd, I 'p H artford, Conn. H oward O jonley, Qiairmr Company, New York City B e n j a m i n F. F aihless, P r Pittsburgh, Pa. W. S. F arish, President, St York City W alter Glfforu, President, pauy, New York City E. R. H a rrima n , Director, York City T homas I. P a r k i n s o n , P rt ciety of the U. S., New Y< A lfred P. S loan, J r., ( liai poration, New Yurk City O F F I C E R S ( C O N T I ).) T homas J ohn W at- on, President, International Business Machines Corporation. Neu" York City Charles E. Wit,son. President, General Electric Company, New York City DIRECTORS (1941-1942) H. J. A ldrich, Spencer Kellogg 8: Sons, Inc. Capt. F rank F,, Ames. Marine Section T. O. A rmstrong, Springfield Safety Council; Hampden County Safety Council C. W. Averv. Detroit Industrial Safety Council J. I. B a n a s h , Past President E rnest W. B eck. United States Rubber Company C. \V. Bekgqimst. Past President R. F.. Riggers, Chattanooga Safety Council II. R. Bixi.er, Uniun Carbide ic Carbon Corporation E. F. B la n k , Jones 8; Laugldin Steel Corporation Id. W. Buggers, Sinclair I'rairic Oil Company F. S. B rown, Standard Accident Insurance Company O. C. B oileac, Wood Products Section E. G. B orseri.ne, Kansas City Safety Council C. B. Eot i.i.r. Wisconsin Public Service Corporation Clayton O. B raat/, Paper S: Pulp Section K arl B recht, Safety Div., South Bend Association of Commerce E dward H. B r in k , Grand Rapids Safety Councir J oseph A. B ropiiy, Elizabeth Safety Council W. II. C ameron. National Safely Council, Inc. L. C. C ampbell, The Koppcrs Coal Company R orkrt W. C ampbell, Past President R aymond A. Carey, Evanston Safety Council R obert I. C a t m n . Aetna Casualty S; Surety Company D. B. C iia n t, Paper & Pulp Section C harles A. C happell, Safety Div., Syracuse Chamber of Commerce Lam mot du P ont Cor n. and, Delaware Safety Council J. E. CiH.LiNKV, Bethlehem Steel Company J o h n D 'A mbrosa, S r., Rahway Safety Council N f.d H. Dearborn, New York University Louts A. D eBi.ois. Past President C. W . D emfesy, The Liquid Carbonic Corporation F. W. D e n n is , Chemical Section M ilton- W. D ohrzf.n sk y , East Bay Safely Council C. R. D ooley, Soconv-Vacuum Oil Company. Inc. J ames B. D ouglas, The Philadelphia Gas W orks Company M arcus A. Dow, Past President H arold F. E nhi.ows, The American National Red Cross R. S. K a&n u m , Rubber Section D. D. F enn ell, Past President D r. H art E. F isher , Chicago Rapid Transit Company E dmund F itzgerald, Safety Div., Milwaukee Association of Com merce 6 OFFICERS (CONTO.) V ictor B. F itzpatr H oward B. F onda, Arthur C. F rey, V Lyi.e II. Gift, Poor O. F. C nadfngf.r, S H enry J. Gorman, W. A. G r i f f i n , Am H. J. G r if f it h , AS. E. E. G rover, Colon H arry G hilbert, Tl D. T. H arrington, ' F r a n k I I . H arrison J ulien I I . H arvey, W. D. H aselton, M P. L. G. H asskarl, R. C. H aven, Food i I. o u is H awes, Roch. W. A. H azard, Cons D r. T. L yi.e H azlei G. T. H ellmuth, G H arold G. H offma New Jersey Dr. R a lph II. Houc W.M. F. J a m e s , Pliiln J asper B . J ohn son , ! T h o m a s P. K f.arns, W alter C. K in g , Pa W m. C. K noei. k, Mi C. L. L a F o u n t a i n e , Roy L ee, Contra Cost J ohn E. L ong, Past C. H. L o ng m an , Gii J. W. I-ord, Commerc E her S. L u s k , Refri; Titos. II. M acDonai. R. A. M cA r t h u r , P i B. B. M c Culloch, B F. R. McLean, Petrr R oy S. M a r s h a l l , S. C. M. M e n s e , Meat I D avid L. M ii.lar, St. I. W . M illard, Indus H arold L . M i n e r , E. II. II. M ouler, St. Jc P hilip M. M organ, 1 Council R. H. M ori.ey, Industi C. L. M urray, Mason H on. E liot N f.ss, Di F rank S. N ewell, T E. J. O 'B rien, J r., L c OFFICERS (CONTO.) G eorge C. A. Opr, The Detroit Edison Company J ohn M. O rts, Transit Section W alter S. P aine. Aetnat Life & Affiliated Companies L ew R. P ai.mf.ii, Past President D.-win A. P atton, Newark Safety Council C. E. P ettiboxe, Past President C. II. P it.if, General Electric Cotn|)any D. W. P ontius, Greater Los Angeles Safety Council W. M. P owell. Cement S: Quarry Section A lbert S . R egui.a, Indus! rail Relations Counselors, Inc. R. J. R ktgeluth, C. W. Blakeslee & Sons IT. A. Rf.nixgf.r, Past President J. W. R eynolds, United Pacilic Insurance Company A. V. R oiiweder, Duluth, Missabe & Iron Range Railway Company C. J. R utland, Street & Highway Traffic Section H enry G. S c h affne r . E r ie Safety Council E. C. S chultes, J r.. Power Press Section E arl S. S hartzer, Utica Safety Council F rank T. S heets, Portland Cement Association J ohn R. S herwood, Baltimore Safety Council Dr. L. A. SnoL'DY.JJcthlehem Steel Company L eslie R. S ilvernai.e. Giild Education Section A dolph S kinner, Safety Dept., Nashville Chamber of Commerce Carl L. S m it h , Greater Cleveland Safety Conned C. R. S mith. American Air Lines. Inc. R. T. Soi.F.xsTEN, Elliott Service Company L eslie J. Sorenson, City Traffic Engineer of Chicago H. J. S poerer, NTctals Section E. C. S print.. Philadelphia. Pa. T homas I. Starr, Employees' Publication Section Col. J ohn S tilwei.i., Consolitated Edison Company of New York. Lie. E dmond C. Stone. Western Pennsylvania Safety Council E mery E dward Stone. Berkeley Traffic Safety Commission P aul S. Streekeu. Automotive & Machine Shop Section C.i oiii-.r S. Stroi'd. Dcs Moines Safety Council H ugo S wanson, Superior & Douglas County Safety Council J. M. S ylvester, Lehigh Valley Safety Council A rthur M. T ope, Consulting Engineer C. P. T olman, Past President George. G. T hayer. Greater Chicago Safety Council W ilfred E. Y olgee, Albany Safely Council Dr. C. II. W atson. Past President W. B. W eaver, Textile Section G. W ise W f.'TOtt. Safety Dept., Automobile Club of Rhode Island T. A nt.ltn W hite, Safety Div., Birmingham Cnamher of Commerce S. E. W hiting, Liberty Mutual Insurance Company A. W. W mitnf.y, Natoual Conservation Bureau Roy V. W right, Railway Age Magazine Arthur H. Young. Past President E. J. Z.umt, Safety Bureau. Duluth Chamber of Commerce Y. A. Z immer, U. S. Department of Labor Tin lishet! the p clued publx cuss the c: tives, orgai progr Do volllll what orgai given locat. Nc of C in til s ions (c) of ti- Tli diate were est t, man} Hi I mlu sioin prov X, ran,. that (as are and X scssi disci outs In preli alph the Ujress :vsidc.it's proc'amation was a plea i ation. The National Safety Coun- i ;Uance of the1task assigned to it, -.11 upon you to assist, also partook i one nature; it was a plea for as- fn the procedure that has been i i the free cooperation that has been j "! that will be forthcoming, we see ; . of democracy working at its best. * exemplified the principles of unity ; i lence and independence in unity ; .e this nation the greatest and the j .-lization that ever evolved on the 1 iis earth--a civilization which, with i l>, will endure long after the blot | hm has been wiped forever from i if Europe and even the threat of | re dictatorship of a few mad minds | 'he earth rendered an absolute and i d impossibility. ! Dusts, Fumes, Gases and Vapors THURSDAY MORNING SESSION October 9, 1941 Methods of Combating Industrial Health Hazards A Symposium Presiding:--W alter S. P a in e , Manager, Engineering & Inspection Department, Aetna Casualty & Surety Company, Hartford, Conn., and Vice-President for Industrial Safety, National Safety Council. Ventilation and Exhaust Equipment By GORDON C. HA R R O LD , Ph. D. \ Industrial Hygiene LaboratoriesfMedical Department, Chrysler Corporation, Detroit It is difficult to give details on the many phases of ventilation and exhaust equipment which are applicable to the problems of pro tecting the workers' health. Some general principles of every day usage can be covered however, as well as specilic cases. Thus for gases, less pipe velocities are t reeded than for fumes, mists or dusts. The i bwer specific gravity of gases leads to various modifications for their handling. Carbon monoxide gas which is slightly light er than air could be taken upward. However, when mixed with automobile exhaust gas the I apparent specific gravity of the mixture is raised so that it is much more feasible to Il I remove the gas by means of staggered floor grills. Even more important than specific l gravity is the temperature of the gas mass \ as increased temperature causes the healed i air to rise. i For this reason numerous exhaust systems are built without forced draft and are suit able particularly in smoke removal where high toxicity is not encountered. Gases such as hydrogen chloride or hydrogen cyanide are of such toxicity that a totally enclosed hood with up-draft exhaust is preferable. The factors of concentration and relative toxicity play an important part in the choice of exhaust systems. Of further interest is the question of whether any cumulative poisons or those leading to chronic illness may be present. Tbc older up-draft exhaust systems have in many cases been replaced with back or side draft ventilation even for gases lighter than air because of the danger of carrying the hazardous material through the breathing zone of the worker. Only in such cases as result from tlie gas being gen erated above tbc breathing zone of the worker should canopy and other types of overhead hoods be used. A combination of back anti up-draft will take care of all such situations and should a canopy be open on all sides a solid partition can usually be built in the center of the operation to pro vide a back wall for both sides of the ex hausted operation. Liquids which give off vapors or mists are both simpler and more difficult to treat. Since the liquid is usually confined in a tank, the focal source only need be considered to pre- 35 f i vent local spreading of the contaminant. The difficulty conics in devising simple and inex pensive systems which will not interfere with the worker. Recent tank studies have shown a Tunnher of facts which either have not been generally understood or have not had experi mental proof offered to substantiate the be lief of individual experimenters. It seems necessary to caution against care less use of formulae. Thus the formula de veloped hy Brandt seems to indicate that ns the tank becomes wider the amount of venti lation required per unit becomes less. The author points out that the work of Battista. Hatch and Greenberg proves that increased width results in increased power losses and inefficient operation. Silverman empha sises the importance of Manges which in crease tank velocities from 20 to 2.2 percent. When the height of the Mange is equal to the width of the tank the ventilation requirement is reduced 20 percent. While 111is is lint al ways practical it is shown through his cal culation that maximum efficiencies are ob tained as the flange angles are increased and that the ideal situation is found when a com pletely closed hood may be used. The width of slot openings is not very important where we have Manges. This is not true of unflanged hoods where the reduc tion of slot width will give lower velocities at the remote corners. As shown by Dalla Valle and Brandt, the slot velocity exerts rapidly decreasing influence as the distance from the face of the exhaust hood increases, and that two slotted openings, one on each side of the tank, are more efficient than the one slot due to the higher velocity obtainable at the most remote part of the tank from the exhaust slots. It is pointed out in nearly all these papers that disturbances of work opera tions, extraneous air currents, and vapor turbulence must be overcome by a sufficiently high velocity at the most remote portion of the tank. F or this reason, the formulas arc not a true criterion unless all outside condi tions are evaluated. It was pointed out that with flanged slots, decreasing the depth of the liquid below the slot reduced the air required by about IS to 20 percent. This is probably due to decreased turbulence as an unflanged hood is not affeettd by the depth of liquid. It is also point ed out that a single long tank suitably par titioned is more efficient than several small tanks. Also of interest is an efficient mani fold system to deliver equal quantities of air to all parts of the slot. Silverman has shown that ventilation requirements vary with the physical characteristics of the liquid sub stance in the tank. Thus in one instance lie shows tiiat flange slots increase efficiency with decreasing depth of liquid but that high ly volatile liquids will be lost through en trainment and evaporation so that the depth would have to be increased for efficient op eration with such substances. A case of this kind is thoroughly discussed by Witheridge et al in regard to the ven tilation of trichlorthylne degreasers. They showed that vertical slot ventilation caused the lowest solvent loss increase but was least efficient in reducing solvent exposures. A round bole system caused the highest solvent loss increase and required approximately .twice as much power as the horizontal slot type to reduce solvent exposures to 1(H) p.p.m. The maximum solvent loss increase due In ventilation during continuous use of this de greaser was 2 gallons tier 9-hour day or 1.2 gallons per square foot of tank area per 100 hours' operation. No significant relation be tween ventilation rate and solvent loss was shown. A ventilation rate of 615 c.f.m. around the 20' perimeter ^f the tank using the horizontal slot or round hole system reduced the average trichlorethylene concentrations in the oper ator's breathing zone from a maximum of 400 p.p.m. without ventilation to below 100 p.p.m. The vertical slot system required a ventilation rate of 1400 c.f.m. to accomplish the same result. Dust When solids in the form of dust must be removed, considerable attention must be giv en to the collector system, the velocities in the pipes, and the design of the piping sys tem. In addition, the face of the exhaust hood should be so designed as to be close to the source of dust generated. 1. While great emphasis is now being laid on wet collector systems it should be under stood that such systems will not remove large amounts of the dust sizes which arc signifi cant from the health standpoint. Cyclones, unless of the micro variety, which will not handle the larger volumes of air often en countered, suffer from the same handicap. Cloth or bag filters will collect these particles but the maintenance costs are Klrclrical precipitation is also very ef bid is often too expensive to instal maintain. The velocity of air in the pipes shot sufficient to prevent deposition. This vt may be as high as 4500 linear feet in th of lead dust. Since too great a vclot wasteful and results in excessive pipe the system should be so designed as to inatc the need for excessive velocity, distances to collectors, coupled with st sections of pipe with no sharp bends, ar in this endeavor. When sections of I: pipe arc joined to a main pipe the j< angle should be 30 degrees or less. A corollary of Dalla Valles work i: tbs exhaust hood should be as close at sible to the source of dust formation, itl.-al would lead to a total enclosure I tluee openings to a minimum and thus the resultant face velocities to be higher. Often gases and fumes are collccte getber and usually the limit of air rei nients is set by the velocity needed to the pipes from plugging up. In some an in foundry operation, back draft exha resorted to in order to collect the air dust. Then a separate downdraft s; keeps dust from getting into the air. Welding of various kinds produces fume, fumes from the flux and gases si nitrogen dioxide and ozone. The iron apparently is only a nuisance dust bi manganese, fluorides, etc. resulting fro: welding flux arc harmful. The gases arc harmful when in sufficient concentr Work performed in the Chrysler Lf tories indicated that this situation wou! be harmful in open spaces unless h coated rods were used. In tanks and i spaces, dangerous concentrations of gases and fumes could be predicted. V: lypes of exhaust systems have been de The most common one depends on a attached to flexible metal' pipe so the face of the hood may be placed in near imity to the work. Other types range lloor grills to hood canopies, each type adapted to the kind and size of the to be welded. In dosed tanks, the "Airbooster" as should not be allowed to become hall wet but should be thoroughly flooded at all times. The parts of the system where work is done should he of non-sparking material. It is not safe to collect this material in filter screen or cyclone collectors, nor should sparking type metals be allowed to get into the ven tilation system. Wc have pointed out some of the specific items involved in ventilation in connection with health and safety hazards. Some of the limiting factors in a large scale ventilation program should also be dealt with. Indis criminate installation of exhaust ventilation without a careful evaluation of the extent of the need will lead to extremely high first costs of installation. The engineer who in stalls a system three or four times as elabor ate as needed to control a given complaint may "control" a situation but at an excess cost of thousands of dollars. The next step after this excess air has been exhausted from the plant, must be to supply fresh air which in the industrial north must be heated for eight months of the year. Even with closely controlled systems, this factor of heated air is a real limitation. In many instances, power houses have had to be greatly enlarged be cause of such programs. The power needed to ruti motors and auxiliary equipment is also a limiting factor. A system which is too small will not be criticized on the above score but if its purpose is not fulfilled, the entire layout may have to be scrapped. Always to he considered is whether tbc installation is to serve the purpose of remov ing toxic materials or those which may be classified as nuisance contaminants. Both arc legitimate requirements but it should be clearly understood that one system is to pro tect health directly ami the other to provide, comfort. Proper consideration can then be given to the question of "how much" and "what kind" of ventilation is to be installed. A common sense program will include ex haust ventilation as one very important aid but only as related to other possible methods of solving the problem involved. When sub stitution is feasible and economical, or re vision of process if possible, these may pro vide a cheaper, more satisfactory answer. At times, personal protection will best serve the purpose and in some instances a few simple rules of operation and maintenance may be all that is needed. Ventilation often proves the only answer, but indiscriminate ventilation is the poorest and most costly answer that can be devised. A system should be completely designed at one time with no additions with out a complete revision of all parts of the system. It is, of course, permissible to com pletely design a system in such a way that units may be added from time to time but this should be a part of the original consid eration. Converti}' systems well designed and installed to meet the condition encoun tered in the degree necessary are major aids in any health program. Measuring Concentrations of Toxic Substances By S. W. G U R N EY Laboratory Director, Liberty Mutual Insurance Company, Boston, Mass. Frankly, on this subject of industrial hcrdlli hazards we do not know as much in a precise way as we do ahoiit guarding belts, gears, points of operation, and the like. T hat industrial health is an important subject is attcstcrl by the fact that we now have a relatively new profession called Industrial Hygiene, which might be defined as a study of working environments including all of tbc air contaminants as well as abnormal condi tions of temperature, humidity and even now of atmospheric pressure. The criterion is the effect upon the health of workers, either immediate or delayed. A few technical schools have slarlcd courses in iiidustrial hygiene and the number of chemists and medical school graduates who are going hark and taking these courses is a further measure of the increasing importance of this general subject of industrial health. Not many plants have experienced indus trial hygienists on their siaffs; in fact it would he impossible for them to do so as there are not enough of them to go around. I believe that there arc very few in this meeting this morning who would call them selves industrial hygienists. With this as- mmption in mind I have tried to ph paper for the ordinary safety enginei the safety committee man who does! member his chemistry too well--bu does feel that he should know more the possible licaltb hazards in his piar may also be somewhat worried about for alleged health damage that have submitted and may wonder if there i: thing he can do about it himself. It cei would be fine if every plant large e to have even one man wholly inters safety could arrange to have one trail well as interested in the fundamental lems of industrial hygiene. However would take a long time to accomplish ai the present we shall have to get along what wc have. I should like this morning to try t plant safety men what they can do alon; line without the benefit of specially tr industrial hygienists. I am assuming the know the names of, and are familiar in way with the materials used in count with the operations in the plants when are. This includes the dusts, fumes, v; nrd gases, the solvents and other chcn lhat are used, produced as necessary products of, or enter at all into the n facturing processes in any way. If yc not you certainly should find them outperhaps this is the first thing you can Wc arc safe in saying that wherev toxic substance is used an exposure c: I'or example, if you have in your pin pmcess using benzol you undoubtedly a benzol exposure. If somewhere in plant you are melting lead or a lead for any purpose, an exposure to lead c in that part of the process. This docs mean necessarily that a health bazar benzol or In lead exists, hut wc can soy wc do have the exposure. Now over the years by means of an cvpci'imeiilalion, and by the results of hi experience, it lias been shown that dosages of these toxic materials which i as air contaminants are pretty well t care of by the healthy human organi High dosages in the time factor as wc the conccii Iration arc not well handled damage to various organs and tissues result from continued exposure. Further, these same studies, both an exposure exists in our plant some reliable way of actual measurement becomes a neces sity. Otherwise how arc we to know whether these exposures constitute health hazards or do not. Of course, if we have an industrial hygienist in our plant, the answer is easily obtainable. H e will proceed to use known techniques of sanitary air analysis, a spe cialized chemical job usually involving quite a bit of time and fussy analysis. In any event, the job is not impossible no matter what the particular air contaminant may be. Before this section in past congresses ex cellent papers have been delivered on sam pling methods and analytical procedures for the various air contaminants, I believe by Mr. Warren Cook and again by Ur. E. C. Meitcr. There is no particular point in going over that ground again. From ninny sources anyone interested can secure detailed infofniation on procedures for the measuring of any of the common air contaminants. Many plants which have not felt that they bad enough of a problem to warrant the hiring of an industrial hygienist have pro vided their safety engineers with some of the newly developed measuring instruments which, with a little experience, can be operated by almost anyone. I refer to such devices as the Carbon Monoxide Indicator, the Flammable Gas Indicator, the Mercury Vapor Detector, and certain dust counters. There are a number of such devices on the market which do a perfectly swell job of distinguishing between exposures which may be dangerous and those which are not, for specific contaminants; and you don't have to be a chemist to operate one and inter pret the results. A number of instrument manufacturers are working on the problem of extending the application of such instru ments to different contaminants. I have no doubt that the next few years will see on the market simple instruments for many more of the air contaminants you are likely to see in industry. Some of these arc made automatic in their operation and give contin uous readings--or sound a gong, flash a light or turn on additional ventilation when a dangerous concentration is reached. Where we can get such instruments we find them a great help to the safety engineer in pro viding him an answer to his problem. However, there arc a large number of air contaminants that we cannot yet measure by these simply operated instruments. Most of the safety engineers have to depend upon their own ingenuity to provide the answers. By far the majority of our plant safety men have no industrial hygienist to lean upon, neither have they been able to procure simply operated Instruments which will give them the answer they want for the particular air contaminant or exposure that exists in their plant. Such safety engineers are not entirely without recourse and there is quite a lot they can do to get some measure or estimation of sonic of their plant exposures without outside help. For example, take visual inspection, which is simply the intelligent use of the sense of sight. Dusts, which have given us more cases, probably than all of the other air contaminants combined, are usually perfectly visible tilings. Considerable stress lias been laid upon the point that it is necessary to know the size distribution of such dust sus pended in the air before we can truly measure the hazard that exists. In this it has been my experience that wherever there have been big particles which can easily be seen there arc always plenty of small ones which are deeply respirable which cannot be seen. I have never yet made any dust studies in plants where if was obviously dusty by sight that there were not many times more fine particles well down in the so-called respirable range than there were big ones. Conversely you seldom find fine dust without large ones along with it which can be seen particularly near the source of the dust in question. If your plant is a dusty one some evidence of dustiness is visible, even if you have to climb up on the rafter to look for it as settled dust. I can recall one safety engineer hauling me half way across the continent to take dust counts at a brushing machine in a radiator foundry. So much dust was thrown of! into the air by this operation that it was difficult to see from 25 feet away the two men who were operating it. It was obvious to anyone that so much dust could not possibly be beneficial regardless of the silica content and common sense should have told him that here was a situation about which something should be done and promptly. As a matter of interest the dust counts ran up into several billions per cubic foot and the free silica content as quartz wai somewhere between 10 and 15 per Siich information may be helpful in g( improvements but it seems to me that one taking the trouble to view this oper would have immediately recognized health hazard. I have often been asked to define oi scribe by appearance what constitutes much dust. I'm afraid I have no pr Answer to that question. I have often rc; to sin'll questions that if you actually see clouds of any dust produced or diss Hated into the air of a working area 1 city process it is a good idea to enclose ventilate it, or at least to try to control dust source in some way. / It has been my experience that most / dintrial commissions and accident bo; tire not particularly impressed with i (.cunts and analyses and discussions threshold dosages as such. If testim shows that a plant is dusty, and anyone see that it is so, the plant is pretty lil'v to have to accept any claims for respirat \sy stem damage as an industrial case. The acid vapor which arises from hot a pickle tanks may not be visible hut steam that accompanies it usually is. ^ call see where it is coming from and get Idea where it is going. The etched or rus Appearance of metal work in the room w these pickle tanks is also visible evidci that acid vapors have escaped into the roc J he fumes from arc welding are perfee visible--and the 25 mgs. per cubic me suggested as a limiting dosage in Massac! setts is a very dense cloud. One investigat describes it as so thick you could cut out lunik with a knife and wrap it up and ta It home. I'B.uu, Dy watemng the rebound of spr hi n spray painting operation you can ti pretty accurately if the operator is well pr lected and if the booth has sufficient air tiike care of the fumes. The human nose is probably not a pa tlcularly precise measuring device and i doubt different people's noses differ wide hi their ability to detect and estimate a contaminants by this means. However, mai of our industrial vapors and gases do hai distinct and characteristic odors and nine can be done by a safety engineer by tf intelligent use of the good old nose. carbons such as carbon tetrachloride, trichlorcthylcnc, and the like, most people have no trouble in recognizing the contaminant as a chlorinated hydrocarbon as a general class down to around 10 to 25 ppm., although it is difficult to distinguish them apart. I be lieve that the safety engineer who is willing to do a little sniffing around the plant is going to find out a lot about some of the air contaminants as to their source location and where they go to. There is one thing . about the chlorinated hydrocarbons that I should like to mention and that is the fact that nasal fatigue enters into the picture very shortly' and after a few minutes in the exposure your nose loses much of its ability to distinguish these solvents. The sense of smell is recovered by a few minutes in the fresh air. The same thing is very true of concentrations of hydrogen sulfide. There is no need tc> point out that the very toxic carhon monoxide and the very common 'carbon dioxide gas in the pure state have no odor. However, carbon dioxide in a brewery around the fermenting vats has a peculiar tickling sensation to the nose which is quite characteristic and after a few minutes around 500 or 600 ppm. in that process you begin to have a feeling that all is not quite as it should be. I know of several instances where the sense of smell has been used as a practical measuring rod. The foreman of a large plating shop doing much cyanide plating uses and has demonstrated the fact that a hydrogen cyanide smell is a sure sign that the electrical system or the plating bath concentration needs attention. Although hydrogen cyanide is ejtrem cly toxic it can be detected by smell well below the sug gested threshold dosage of 21) ppm. Many of the solvents and mixtures such as the lacquer solvents in industry arc not particularly toxic and exposures constitute more of a nuisance than they do a real health hazard. Nuisances, however, can he real and we do not want to remain com placent just because no real health hazard can be proved. There is also the very real danger of getting into the explosive range with some of these lacquer solvent mixtures of low toxicity. There is another way of estimating con centrations and I etui recommend it to you if you arc in doubt as to whether or not some process should be further enclosed or ventilated or otherwise protected to keep down the concentration. It should be used with caution and understanding. Safety en gineers often ask me whether nr not a coating process or a mixing process or even such things as vapor degreasers should not have something done about them. T o such inquiries I frequently ask the safety en gineer to go out and stand alongside of the operator of the process in question for as much of the day as the operator does him self. I further ask him to tell me just how lie feels at the end of tins period. It is remarkable how often after going through this the safety engineer comes to the con clusion that further protection is necessary, at least very desirable. Now you know that there are lots of smells, irritating gases and the like that workers finally get used to-- and they will probably affect you much more violently than they do the experienced operator. On the other hand I wonder-ii we arc right in asking people to work in disagreeable atmosphere where they have to "get used to it" before they become rea sonably reconciled to their job. There is one other way we have of esti mating exposure that is probably not as good as the three I have mentioned but nevertheless it has its uses. I refer to com plaints on the part of the workers them selves. Safety engineers should be close enough to workers in the departments where toxic materials are used so they will get verbal reports of any complaints or ob jective symptoms that arise. I recall two fatalities this year allegedly caused by high exposure to carbon tetra chloride vapor. There may have hccn other cases but these two were such that I had access to the. reports of the investigations. They were both rather simple jobs of clean ing metal objects with carbon tetrachloride and the whole operation was by hand. Doth operations bad been performed occasionally for a number of years, but as a result of large defense orders the time spent at these operations had increased considerably. Both men arc on record as having complained considerably. They had been nauseated sev eral times. They complained of feeling tired and restless for quite some time before they finally became really seriously sick. An alert safely man nosing about the plant looking for trouble might well have this up and recognized it as a measexcessive exposure. Both cases tern: fatally and in the medical picture at aallowed about wliat one would expect ftcutc case of carbon tetrachloride pois It is interesting to know that after nir samples were taken in a number ol tions around the operation and cone lions well over 100 ppm., the sug: threshold dosage, were found. I think if we investigate our plants (Highly we will find that there arc a n of processes and operations involving materials or at least materials with degree of toxicity that have for year carried on safely without complaii symptoms or any other evidence of damage. The reason for this was tl frequency of the operation or the qiianlity used or the short time of exp With increase in production a numb three processes have speeded up so gradually the weekly degree of exj to the dust, fume, vapor or gas has Increased. As a result of defense < processes that used to take place other Thursday arc now being carrie Personal Respira By DI Director, Laboratory of Industrial 1 The need for personal respiratory p lion in many types of industrial open Is now well recognized, but the probh determining in a specific instance wh B respirator is required, and what ty lirst indicated, is sometimes not a simph livery type of respirator places son: Mrlethm on the wearer, and although it he only a slight inconvenience and llilicaiit compared with the protection il vlilcs, it must be recognized as a cor llilse. Ideally, all operations would be ducted so as not to contaminate th W'lncli must be breathed, or the degr contamination, would be kept at safe hy ventilating devices. Only after the inary effort to achieve this ideal has p to be impossible or impractical shouk mo of personal respiratory protective c