Document 7Oado51xOdmxJydRn6E1k1gj6

FILE NAME: National Safety Council (NSC) DATE: 1941 & 1942 Oct DOC#: NSC202 DOCUMENT DESCRIPTION: Excerpts - Transactions of the NSC - 30th & 31st National Safety Congresses - Dusts, Gases & Vapors and Steam Railroad Section TRANSACTIONS 30th NATIONAL SAFETY CONGRESS GENERAL SUBJECT AND INDUSTRIAL SESSIONS CHICAGO OCTOBER 6-10, 1941 NATIONAL SAFETY COUNCIL, INC. 20 North Wacker Drive, Chicago Copyright, 1911* National Safety Council, Inc. Printed in the U. S. A. For^ffrord 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 Traf ic fie, 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 II 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, tpxtra 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 tlie 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, either in the matter presented or in the discussions based upon these papers. NATIONAL SAFETY COUNCIL, Inc. 20 North Wackcr Drive Chicago, Illinois u il C on ten ts Council O fficers............................... ................................. 4' Make Profitable Use of These Transactions.................. 9 Council Purposes and Program........................................ 11 Annual Meeting of M em b ers......................................... 13 .Congress B an q uet............................................................. 29 Subject Sessions-- Dusts, Fumes, Gases and Vapors............................ 35 Electric W eld in g ....................................................... 49 Elevators ..................................................................... '55 Fire Control and Prevention.................................... 65 Fundamental Causes of Accidents.......................... 77 Governmental Safety Service in Industry.......... .. 97 Human Engineering and Safety............................... 117 Industrial H ea lth ........................................................ 145 Industrial Nursing ............................. 159 Maintaining Safety Interest in Defense Industries 181 Sabotage Prevention............... 195 Safety Engineering Exchange................................... 207 Safety Organization and Program........................... 219 Safety T rainin g..........................................................235 Industrial Section Sessions-r- Aeronautical Section . .i.............................................. 253 ASSE--Engineering Section ............................. 263 Automotive and Machipe Shop Section...................269 Cement and Quarry Section...................................... 287 Chemical Section . . . . I.............................................. 301 Construction Section . | .............................................. 325 Food S ection ....................... i ..................................... 339 Marine S ectio n ............................................................369 Meat Packing, Tanning and Leather Industries S ectio n ..................... 425 Metals S ectio n ......................... 435 Mining S ection ................................................. 477 Paper and Pulp Section.............................................. 505 Petroleum S ectio n ...................................................... 563 Power Press Section................. 587 Public Utilities Section............................................. 599 Refrigeration S ectio n ..........' ................................. 625 Rubber Section .............................. 635 Steam Railroad Section.............................................. 655 Textile S ectio n ....................... 675 Wood Products Section.............................................. 691 Exposition Exhibitors ...................................................... 719 Index .................................................................................... 725 N ation al Safety C ou n cil,yn c. HONORARY MEMBERS A ssociation of I ron and S teel E ngineers Robert W. C ampbell I.i:w R. P almer OFFICERS (1941-1942) Col. J oh n S tihvell, President N f.d H. D earborn, Vice-President for Education I. W. Millard, Vice-President for Finance and Treasurer G. T. H ellmuth, Asst. Vice-President for Finance and Asst. Treasurer W alter S. P a in e. Vice-President for Industrial Safety L ew R. P almer, Vice-President for Transportation A. V. Rohweder, Vice-President for Home and Farm Safety R. T. Solexsten, Vice-President for Membership L eslie J. Sorenson, Vice-President for Public Safety Roy V. W right, Vice-President for Community Councils W. H. Cameron, Managing Director and Secretary EXECUTIVE COMMITTEE (1941-1942) Capt. F rank E. A mes, Marine Section J. I. B a n asii, Past President C. W. Bergquist, Past President II. R. Bixler, Union Carbide & Carbon Corporation II. W. Bogcess, Sinclair Prairie Oil Company K arl B rf.cht, Safely Div., South Bend Association of Commerce W. H. Cameron, National Safety Council, Inc. R obert W. Campbell, Past President D. B. C hant, Ontario Pulp & Paper Makers' Safely Association N f.d II. D earborn, New York University L ewis A. D eB lois, Past President C. W. D empesy, 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 ennell, Past President II. J. Griffith , ASSE-Engineering Section E. E. Grover, Columbus & Southern Ohio Electric Company H arry Guilbf.rt, The Pullman Company J ulien H . H arvey, Greater New York Safety Council . W. A. H azard, Construction Section D r. T. L yle H azlett, Westinghouse Electric & Mfg. Co. G. T. H ellmuth, Qiicago Rapid Transit Company * W alter G. K ing, Past President John E. Long, Past President C. H. Longman, Qiicago & North Western Railway Company J. W. Lord, Commercial Vehicle Section T hos. H. M acDonald, U. S. Public Roads Administration 4 OFFICERS (CONTO.) Roiiekt A. M cA rthur, Public Service Coordinated Transport B. i. McC(;u.ocir, Pureau of Safety, lue. I'. K. M cL ean, Petroleum Section I. W. Millard, Industrial Gloves Company H arold !.. M iner, E. I. du Pont de Nemours & Co. P h ilip M. Morc.an, Massachusetts Safety Council; Worcester'Safety Council H on. E liot N ess, Director of Public Safety, Cleveland E. J. O 'Brien, Jr., Louisville Safety Council W alter S. P aine, Aetna Life & Affiliated Companies Lew R. P almer, Past President C. E. P ettiiione, Past President G. H. P ff.if, General Electric Company R. J. R eiceluth, C. W . Blakeslec & Sons H. A. R enincer, Past President A. V. R ohweder, Duluth, Missabe & Iron Range Railway Company C. J. R utland, Street & Highway Traffic Section H enry G. S chafkner, Eric Safety Council Carl L. S m it h , Greater Cleveland Safety Council R. T. Solensten, Elliott Service Company L eslie J. Sorenson, City Traffic Engineer, Chicago IL J. Si'oerer, Metals Section Col. J ohn S tihvei.l, Consolidated Edison Company of New York, Inc. C. P. T oi.m a n , Past President G eorge G. T raver, Greater Chicago Safety Council Du. C. II. W atson, Past President A. W. W hitney, National Conservation Bureau Roy V. W right, Railway Age Magazine A rthur II. Young, Past President V. A. Zimmer, U. S. Department of Labor BOARD OF TRUSTEES (1941-1942) W inthrop W. A ldrich, Chairman Board o f Directors, The Chase National Bank, New York City Morgan B. Brainard, President, Aetna Life Insurance Company, Hartford, Conn. H oward Coonley, Chairman of the Board of Directors, Walworth Company, New York City. B en ja m in F. F airless, President, United States Steel Corporation, Pittsburgh, Pa. W. S. F arish, President, Standard Oil Company of New Jersey, New York City W alter Gifford, President, American Telephone & Telegraph Com pany, New York City E. R. H arriman, Director, Union Pacific Railroad Company, New York City T homas L P arknson, President, The Equitable Life Assurance S o ciety of the U. S., New York City A lfred P. S loan, J r., Chairman of the Board, General Motors Cor poration, New York City 5 OFFICERS (CONTI).) T homas J oh n W atson, President, International Business Machines Corporation, New York City C iiari.es E. W ilson, President, General Electric Company, New York City , DIRECTORS (1941-1942) H. J. A ldrich, Spencer Kellogg & Sons, Inc. Capt. F rank E. A mes, Marine Section T. O. A rmstrong, Springfield Safety Council; Hampden County Safety Council C. W. A very. Detroit Industrial Safety Council J. I. Banash, Past President E rnest W. Beck. United States Rubber Company C. W. Bergquist, Past President R. E. Bioofrs, Chattanooga Safety Council H. R. Bixler, Union Carbide & Carbon Corporation E. F. Bla nk, Jones & Laughlin Steel Corporation H. W. Bor,cess, Sinclair Prairie Oil Company . F. S. Brown, Standard Accident Insurance Company O. C. Botlea it. Wood Products Section E. G. Borserine, Kansas City Safety Council C. B. Boulet, Wisconsin Public Service Corporation Clayto.v O. B ea.um, Paper & Pulp Section K arl Brecht, Safety Div., South Bend Association of Commerce E dward H. B r in k , Grand Rapids Safety Council J oseph A. Brophy, Elizabeth Safety Council W. H. Cameron, National Safety Council, Inc. L. C. Campbell, The Koppers Coal Company Robert W. C ampbell, Past President R aymond A. Carey, Evanston Safety Council Robert I. Ca tlin, Aetna Casualty & Surety Company D. B. C ha nt, Paper & Pulp Section C harles A. C happell, Safety Div., Syracuse Chamber of Commerce Lam mot duP ont Copeland, Delaware Safety Council J. E. Cl'LLlNEY, Bethlehem Steel Company J ohn D 'A mbrosa, Sr., Rahway Safety Council N ed H. D earborn, New York University Louis A. D eB lois, P ast President C. W. D empesy, The Liquid Carbonic Corporation F. W. D en n is, Chemical Section Milton W. Doiirzensky, East Bay Safety Council C. R. Dooley, Socony-Vacuum Oil Company. Inc. J ames B. Douglas, The Philadelphia Gas Works Company Marcus A. Dow, Past President H arold F. E nblows, The American National Red Cross R. S. F aRn u m , Rubber Section D. D. F ennell, Past President Dr. H art 1!. F isher, Chicago Rapid Transit Company E dmund F itzgerald, Safety Div., Milwaukee Association of Com merce 6 OFFICERS (CONTO.) V ictor B. F itzpatrick, Richmond Safety Council H oward B. F onda, Burroughs Wellcome & Co. (U SA ) Inc. Arthur C F rey, Worcester Safely Council Lyle H. Gift, Peoria Association of Commerce Safety Council 0 . F. G nadinger, Steam Railroad Section H enry J. Gorman, Black-stone Valley Safety Council W. A. Gr iffin , American Telephone & Telegraph Company H. J. Griffith , ASSE-Engineering Section E. E. G rover, Columbus Safety Council H arry G uilbert, The Pullman Company D. T. H arrington, U. S. Bureau of Mines F rank H . H arrison, International Harvester Company J ulien H . H arvey, Greater New York Safety Council W. D. H asei.ton, Mining Section P. L. G. H asskarl, Public Utilities Section R. C. H aven, Food Section Louis H awes, Rochester Safety Council W. A. H azard, Construction Section D r. T. L yle H azi.ett, Wcstinghouse Electric & Mfg. Co. G. T. H ei.i.mutit, Chicago Rapid Transit Company H arold G. H offman, Unemployment Compensation Commission of New Jersey Dr. R alph H . H oughton, Kenosha Safety Council W.m. F. J am es, Philadelphia Safety Council J asper B. J ohnson, Madison County Safety Council T homas P. K earns, Industrial Commission of Ohio W alter C. K ing, Past President W m . C. K noei.k, Milwaukee Safety Commission C. L. I.aFountaine, Great Northern Railway Company Roy I.ef., Contra Costa County Safety Council J ohn E. L ong, Past President C. H. Longman, Chicago & North Western Railway Company J. W. Lord, Commercial Vehicle Section E isf.r S. L usk, Refrigeration Section Tnos. II. M acD onald, U. S. Public Roads Administration R. A. McA rthur, Public Service Coordinated Transport B. B. McC ulloch, Bureau of Safety, Inc. F. R. McLean, Petroleum Section Roy S. Marshall, Seattle Traffic & Safety Council C. M. M ense, Meat Packing, Tanning & Leather Industries Section D avid L. M illar, St. Louis Safety Council 1. W. M illard, Industrial Gloves Company H arold L. M iner, E. I. du Pont de Nemours & Company II. H. M ohler, St. Joseph Safety Council P hilip M. M organ, Massachusetts Safety Council; Worcester Safety Council R. B. Mori.f.y, Industrial Accident Prevention Associations C. L. M urray, Mason City-Ccrro Gordo County Safely Council H on. E liot N ess, Director of Public Safety of Cleveland F rank S. N ewell, Toledo Safety Council E. J. O 'Brien, J r., Louisville Safety Council 7 OFFICERS (CONTI).) George C. A. Opr, Tin; Detroit lidison Company J ohn M. Orts, Transit Section W alter S. P aine, Aetnat Life & Affiliated Companies L ew R. P almer, Past President D avid A. P atton, Newark Safety Council C. E. P f.ttibone, Past President C. II. P feif, General Electric Company D. W. P ontius, Greater Los Angeles Safety Council W. M. P owell, Cement & Quarry Section A lhert S. R egula, Industrail Relations Counselors, Inc. R. J. R f.ic.flu th, C. \V. BlakcsleeSr Sons LI. A. R f.ningf.r, Past President J. W. R eynolds, United Pacilic Insurance Company A. V. R ohwedf.r, Duluth, Missabe ft Iron Range Railway Company C. J. R utland. Street ft Highway Traffic Section H f.nry G. S chaffner, Erie Safety Council E. C. Schultes, 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 D r. L. A. S houdy, Bethlehem Steel Company L eslie R. S ilvernale, Giild Education Section Anoi.ru Skinner, Safety Dept., Nashville Chamher of Commerce Carl L. S m it h , Greater Cleveland Safety Council C. R. S m ith, American Air Lines, Inc. R. T. Soi.f.nsten, Elliott Service Company Leslie J. Sorenson, City Traffic Engineer of Chicago H. J. SroERER. Metals Section E. C. S pring, Philadelphia. Pa. T homas I. Starr, Employees' Publication Section Col. J ohn Stilwei.l, Consolitated Edison Company of New York, Inc. E dmund C. Stone, Western Pennsylvania Safety Council E mery E dward Stone. Berkeley Traffic Safety Commission P aul S. Strf.ckf.r. Automotive. & Machine. Shop Section George S. S troud. D cs Moines Safety Council H ugo S wanson, Superior & Douglas County Safety Council J. M. S vlvf.ster, Lehigh Valley Safety Council A rthur M. T ope, Consulting Engineer C. P. T oi.m an, Past President George G. T racer, Greater Chicago Safety Council W ilfred E. V olgf.k, Albany Safety Council Dr. C. H. W atson, Past President W. B. W eaver, Textile Section G. W ise W escott. Safety Dept., Automobile Club of Rhode Island T. A nglin W hite, Safety Div., Birmingham Cnamber of Commerce S. E. W hiting, Liberty Mutual Insurance Company A. W. W hitney, Natonal Conservation Bureau Roy V. W right, Railway Age Magazine Arthur H . Young, Past President E. J . Z a u ft , Safety Bureau. Duluth Chamber of Commerce V. A. Zimmer, U. S. Department of Labor 8 The Transa lished in two the prevention chiefly with ii public safety j cussions repro the experience tives, health d organized and programs that Do not be volume. Then what you nun organized, arr.. given subject, located easily. Pirn Note, first, I of Contents, in three group sions; then : (c) the Sessi of the Counci: The fourle. diately cliallc were selected est to all sae. many consuo.. However, Industrial Si sions on gene prove valuah Note that ranged in alpo that where . (as in the I. are arranged and calendar Now, nohi-d session, or t discussion, to outstanding sa; In the back prehensivc, be alphabetically, the material i '.-sidc.it's proe'imation was a plea ration. The National Safety Counptance of the task assigned to it, ill upon you to assist, also partook tine nature; it was a plea for as_tn the procedure that has been free cooperation that has been j mat will be forthcoming, we see /.i of democracy working at its best, exemplified the principles of unity idence and independence in unity .c this nation the greatest and the vilization that ever evolved on the .is earth--a civilization which, with P. will endure long after the blot :ism has been wiped forever from of Europe and even the threat' of re dictatorship of a few mad minds 'he earth rendered an absolute and d impossibility. Dusts, Fum es, Gases and Vapors ( THURSDAY MORNINC/SESSION October 9, 1941 Methods of Combating Industrial Health Hazards A Symposium Presiding:--W alter S. P aine, 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. HARROLD, Ph. D. Industrial Hygiene Laboratories, Medical Department, Chrysler Corporation, Detroit It is difficult to give details on the many f 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 specific cases. I Thus for gases, less pipe velocities are 1 needed than for fumes, mists or dusts. The i lower specific gravity of gases leads to various modifications for their handling. ' Carbon monoxide gas which is slightly light; cr than air could be taken upward. However, when mixed with automobile exhaust gas the . apparent specific gravity of the mixture is i raised so that it is much more feasible to | remove the gas by means of staggered floor i grills. Even more important than specific i gravity is the temperature of the gas mass | as increased temperature causes the heated { air to rise. 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. The 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 tire gas being gen erated above the breathing zone of the worker should canopy and other types of overhead hoods be used. A combination of back and 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 I 1 vent local spreading of the contaminant. The difficulty conies in devising simple and inex pensive systems which will not interfere with the worker. Recent tank studies have shown a number 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 by Brandt seetns to indicate that as 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 residts in increased power losses and inefficient operation. Silverman empha sizes the importance of flanges which in crease tank velocities from 20 to 33 percent. When the height of the flange is equal to the width of the tank the ventilation requirement is reduced 20 percent. While this is not al ways practical it is shown through bis cal culation that maximum efficiencies (arc 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 flanges.! 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. For this reason, the formulas are 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 he shows that 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 trichloretbylcnc degreasers. They showed that vertical slot ventilation caused the lowest solvent loss increase but was least efficient iu reducing solvent exposures. A round hole system caused the highest solvent loss increase and required approximately .twice as much power as the horizontal slot type to reduce solvent exposures to 100 p.p.m. The maximum solvent loss increase due to ventilation during continuous use of this degreaser was 2 gallons per 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 of the tank using the horizontal slot or round hole system reduced the average trichlorethylcne 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 are 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. f CUith or bag filters will collect these small particles but the maintenance costs are high. Electrical precipitation is also very efficient hut is often too expensive to install and maintain. The velocity of air in the pipes should be sufficient to prevent deposition. This velocity may be as high as 4500 linear feet in the case of lead dust. Since too great a velocity is wasteful and results in excessive pipe losses the system should he so designed as to elim inate the need for excessive velocity. Short distances to collectors, coupled with straight sections of pipe with no sharp bends, arc aids in this endeavor. When sections of branch pipe arc joined to a main pipe the joining angle should be 30 degrees or less. A corollary of Dalln Valles work is that the exhaust hood should be as close as pos sible to the source of dust formation. The idxal would lead to a total enclosure to re duce openings to a minimum and thus cause the resultant face velocities to be much higher. Often gases and fumes are collected to gether and usually the limit of air require ments is set by the velocity needed to keep the pipes from plugging up. In some cases as in foundry operation, back draft exhaust is resorted to in order to collect the airborne dust. Then a separate downdraft system keeps dust from getting into the air. Welding of various kinds produces iron fume, fumes from the flux and gases such as nitrogen dioxide and ozone. The iron fume apparently is only a nuisance dust but the manganese, fluorides, etc. resulting from the welding flux are harmful. The gasies noted arc harmful when in sufficient concentration. Work performed in the Chrysler Labora tories indicated that this situation would not be harmful in open spaces unless heavily coated rods were used. In tanks and closed .paces, dangerous concentrations of both gases and fumes could be predicted. Various types of exhaust systems have been devised. The most common one depends on a hood attached to flexibtc metal' pipe so that the face of the hood may be placed in near prox imity to the work. Other types range from floor grills to hood canopies, each type being adapted to the kind and size of the pieces to be welded. In closed tanks, the "Airbooster" as made by M.S.A. provides a means of readily ex hausting air from each tank or closed spare, or if desired, a large volume of air at rela tively low velocity may be introduced into the closed space. These units are portable and provide a good answer to jobs which change or move about frequently. Personal Protection Another means of providing safety when toxic substances are present is the use of individual air supplied hoods either open about the eyes or closed depending on the efficiency desired. In paint operations, the open type is satisfactory and vision is not obstructed while for more rigid control with more toxic substances the closed eyepiece type is more desirable. The numerous res pirator, canister, and self contained breath ing types, need no mention here except that the purpose they serve is well understood. Light Metals A new problem is now confronting safety and ventilation engineers in the growing use of magnesium and aluminum alloys. These metals are in themselves non-toxic--so much so that wounds inflicted by sharp articles will become infected much easier than those inflicted by heavy metals. They are haz ardous in finely divided form due to the fire and explosion hazard. The various hazards and precautionary measures are receiving attention in various periodicals but we wish to emphasize certain aspects relating to ex haust and ventilation systems. Ordinary type dust collectors should not be used for removing niagnesuin or aluminum dust. A special dust collecting system which utilizes a water spray nozzle to knock out the dust so that it may be carried away as a sludge is demanded. Good ventilation is necessary to remove the hydrogen which is formed. All piping should be in straight line with no sharp turns and should be smooth on the inside so that no dust remains in the piping system. The sludge should be col lected in drums and disposed of at frequent intervals either by mixing with 5 parts byweight of sand and burying in a dump, or covered with oil and burned. It should be noted that this is one of the few cases where magnesium, in particular, can be wetted with water but it should be noted that the sludge should not be allowed to become half wet but should be thoroughly flooded at all times. The parts of the system where work is done should be 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. We 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 g eatly 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. J J Always to be considered is whether the installation is to serve the purpose of remov ing toxic materials or those which may be classified as nuisance contaminants. Both are legitimate requirements but it should be clearly understood that one system is to pro tect health directly and 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. Conversely 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 M utual Insurance Company, Boston, Mass. Frankly, on this subject of industrial health hazards we do not know as much in a precise way as we do about guarding hells, gears, points of operation, and the like. That industrial health is an important subject is attested 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 the 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, cither immediate or delayed. A few technical schools have started courses in industrial hygiene and the number of chemists and medical school graduates who are going back 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 staffs; in fact it would be 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. Willi this as- lumption !n mind I have tried to plan this paper for the ordinary safety engineer and the safety committee man who doesn't re member his chemistry too well--but who docs feel that he should know more about the possible health hazards in his plant. He may also be somewhat worried about claims for alleged health damage that have been submitted and may wonder if there is any thing he can do about it himself. It certainly would be fine if every plant large enough to have even one man wholly interested in safety could arrange to have one trained as well as interested in the fundamental prob lems of industrial hygiene. However, this would take a long time to accomplish and for the present we shall have to get along with what we have. I should like this morning to try to tell plant safety men what they can do along this line without the benefit of specially trained industrial hygienists. I am assuming that you know the names of, and are familiar in some way with the materials used in connection with the operations in the plants where you are. This includes the dusts, fumes, vapors and gases, the solvents and other chemicals that are used, produced as necessary by products of, or enter at all into the manu facturing processes in any way. If you do' not you certainly should find them out--and perhaps this is the first thing you can do. We are safe in saying that wherever a toxic substance is used an exposure exists. For example, if you have in your plant a process using benzol you undoubtedly have a benzol exposure. If somewhere in your plant you are melting lead or a lead alloy for any purpose, an exposure to lead exists in that part of the process. This docs not mean necessarily that a health hazard to benzol or to lead exists, but we can say that we do have the exposure. Now over the years by means of animal experimentation, and by the results of human experience, it lias been shown that low dosages of these toxic materials which exist as air contaminants are pretty well taken care of by the healthy human organisms. High dosages in the time factor as well as the concentration arc not well handled and damage to various organs and tissues may result from continued exposure. Further, these same studies, both animal experimentation and industrial experiences have shown that the principal way the toxic material gets into the body is through the respiratory system. It is true that some in dustrial poisoning takes place through swal lowing and some through direct absorption through the skin. However, the important thing we have to remember is that most of the toxic materials used in industry get into the system where they can produce their damage through the common process of inhalation. For some time a number of important com mittees have been working on the problem of establishing what we might call a thresh old dosage of these industrial toxic materi als. A number of individual experts have defined threshold concentrations as those be low which health damage is very unlikely. State code committees have drawn up ten tative thresholds covering most of the wellknown industrial solvents and chemicals and suggested that these limits be used to meas ure tire dividing line between what on one hand constitutes a safe exposure and on the other one that may produce definite health damage. The American Standards Associa tion has appointed a sectional committee of well known experts to correlate all of these data and to establish threshold limits or max imum concentrations which we can use as guideposts or benchmarks in determining whether or not our own plant is a safe one to work in. However, these threshold dosages do not mean that if yon maintain a workroom air always below that concentration figure no one possibly can have any liarminl health effects at all nor does it mean that if the concentrations are always above that figure that everyone is going to show symptoms of poisoning. They simply mean that below such concentrations most workers will not be measurably affected and that above it some health damage may be expected, given sufficient time. Behind some of these sug gested exposure concentrations there is a wealth of experience and an impressive amount of factual data. Behind other figures there is very little in the way of experience ami such figures represent what we might call an intelligent guess on the part of people whose intelligent guesses we respect Thresholds need precise measurements. Because we need to know what degree of rs carbons such as carbon tetrachloride, tri- chlorcthylcne, 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 smiling 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 to point out that the very toxic carbon 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. 1 I know of several instances where the sense of smell has been iised 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 eatremcly toxic it can be detected by smell well below the sug gested threshold dosage of 20 ppm. Many of the solvents and mixtures such as the lacquer solvents in industry are 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 can recommend it to you if you are 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 or not a coating process or a mixing process or even such things as vapor degreasers shoutd not have something done about them. To 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 docs him self. I further ask him to tell me just how he feels at the end of this period. It is remarkable how often after going through this the safety engineer conies 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 band I wonder if we are 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 wc 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 been 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 band. Both operations had 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 are on record as having complained considerably. They had been nauseated sev eral times. They complained ot feeling tired and restless for quite some time before they finally became really seriously sick. An alert safety man nosing about the plant looking for trouble might well have picked every day. What used to be a short time job thij up and recognized it as a measure of of IS or 20 minutes now stretches out over excessive' exposure. Both cases terminated two or three hours. Complaints do not al fatally and in the medical picture at autopsy ways mean that a serious health hazard showed about what one would expect in an exists, hut they should be red flags to any cute case of carbon tetrachloride poisoning, safety man that since his original investiga ft is interesting to know that afterwards tion conditions may have changed to render olr samples were taken in a number of posi- ^ the exposure much more serious than it was. tions around the operation and concentra From years of experience in this business tions well over 100 ppm., the suggested I am of the opinion that the average worker threshold dosage, were found. does not complain about dust or fume or I think if we investigate our plants thor oughly we will find that there are a number of processes and operations involving toxic irritating vapors unless he 'had a good reason to do so and the wise safety engineer will recognize this and at least investigate. materials or at least materials with some There are a number of air contaminants degree of toxicity that have for years been that can only be measured by the accepted carried on safely without complaint or methods of sanitary air analysis and cer symptoms or any other evidence of health tainly precision measuring can be done only damage. The reason for this was the in by such means--but taken all together the frequency of the operation or the small ipiautily used or the short time of exposure. With increase in production a number of (line processes have speeded up so that gradually the weekly degree of exposure to the dust, fume, vapor or gas has been Increased. As a result of defense orders processes that used to take place every safety engineer himself, using reasonably bis sight, sense of smell, his own sense of feeling when exposed as the workers arc plus a knowledge of what the workers on some of these unpleasant jobs are saying and feeling has at his command several use ful measuring rods with which he can other Thursday are now being carried out evaluate the health hazard in his plant. Personal Respiratory Protective Equipment By DR. J. H. STERNER Director, Laboratory of Industrial Medicine, Eastman Kodak Co., Rochester, N. Y. The need for personal respiratory protec tion in many types of industrial operations I* now well recognized, but the problem of determining in a specific instance whether H respirator is required, and what type is best indicated, is sometimes not a simple one. Every type of respirator places some reRlrlction on the wearer, and although it may be only a slight inconvenience and insig nificant compared with the protection it pro vides, it must be recognized as a compro mise. Ideally, all operations would be con ducted so as not to contaminate the air which must be breathed, or the degree of contamination, would be kept at safe levels by ventilating devices. Only after the pri mary effort to achieve this ideal has proved to be impossible or impractical should the Use of personal respiratory protective cquip- ment be considered. Too frequently the apparent simplicity and the immediate eco nomic advantage in merely providing res pirators are the deciding factors in the choice of this type of protection. An understand ing of the purposes, operations, and limita tions of respirators is essential if respiratory protection is to be safely and intelligently applied to the varied types of hazards which exist. There are, however, many industrial situa tions where the use of a respirator is spe cifically indicated for the protection of work men ; situations where it is impossible or impractical to secure a safely respirable at mosphere by other means. The definition of an irrespirable or unsafe atmosphere is ad mittedly sometimes difficult. A discussion of the methods for determining if the air is safe for breathing is beyond the scope of this paper, but mention should be made of the recently increased impetus toward establish ing safe threshold values--the Maximum Allowable Concentrations which are being determined in increasing numbers for po tentially toxic materials which may he vola tilized in industrial processes. For this dis cussion, it is assumed that a respiratory hazard exists, that circumstances make it im practical to eliminate the hazard by other means, and that some form of personal respiratory protective device must be worn to permit the individual to safely carry on bis work. Many types of respirators have been found useful, and since many arc commercially available, it is logical to examine them before investigating the factors which should de termine the selection of a respirator for a specific hazard. Schrenk of the Bureau of Mines has classified personal respiratory protective equipment as follows: ! (1) Those that afford protection by re moving atmospheric contaminants ("Air purifying" ), and (2) those by which a 're s pirable atmosphere from an uncontamiiiated source is supplied to the wearer ("Airsupplying, or air-supplied"). The question as to the efficiency of res pirators is satisfied in part by the arrange ments for testing and approval setup by the Bureau of Mines of the U. S. Department of the Interior. For some years this organiza tion has given an official approval to certain types of respiratory protective devices which pass the rather rigid requirements specified. There are, however, useful respirators which are not included in the approved list and which give adequate protection for many types of exposures. In the opinion of the writer, it is better to choose a respirator with a Bureau of Mines Approval, if a respirator of the types eligible for approval is indicated in the specific exposure. This is particularly pertinent when the opportunity and facilities in the plant for checking the efficiency of respirators are limited. In lieu of official approval, the integrity and recognized qual ification of the manufacturer must rank high in the considerations for accepting the speci fications given with a particular respiratory protective device. What are the factors that should be con sidered in selecting a respirator for a specific hazard ? In many instances the actual selection will not require a step by step examination of each of these factors--the choice will be more or less obvious and made by simple "inspection," but if the selection is to he the best possible one, these principles must be examined, recognized, and applied. In most cases, a standard model of one of the com mercially available devices will be satisfac tory, but not infrequently the circumstances of exposure are such that sonic degree of modification gives a more adaptable and use ful protection. How these individual factors may influence the choice of a particular type of respirator, or require a modification due to the peculiarities of the exposure, will he considered in some detail. 1. The o.ryi/en content of the contaminated atmosphere. Normal air contains nearly 21 per cent oxygen, but this oxygen content may be greatly reduced in covered tanks, in vaults or cellars without ventilation, and in other confined areas, particularly where fires or explosions may have consumed the oxygen or where large quantities of gases or vapors may have been generated. Although an indi vidual may not be in serious danger as long as 12 per cent oxygen is present, a respirator giving an adequate supply of oxygen must be used in all situations where there is the danger of an oxygen deficiency. 2. The exact nature of the specific contam inants. It is extremely important to know the exact nature of the contaminating material-- not only the chemical properties, but all the physical forms in which the materials may he encountered in the particular exposure. In addition to the respiratory protection, it may be necessary to prevent contact with the eyes and skin, hence the nature of the con taminant also determines the type of face piece or covering which is to contain the respiratory device. Of the two general classes of respirators, it has greater import in the selection of the air-purifying type. A particular absorbent may have a relatively high restraining capaeity against one type or physical state of a contaminant and have little or no value against others. For ex ample, a filter which gives effective protection against lead fume may permit the passage of <1 l . 'U S i . y , / ' t U l i to, U i i S i ' S i l il u i ay//.. significant amounts of lead in a gaseous form. . Or a canister which will satisfactorily re strain the vapors of a chlorinated hydro carbon solvent may be much less effective against gases accidently generated by the combustion of this solvent, such as phosgene. increase gradually and thus may not giv an adequate warning. In such cases, the ab sorher type of respirator must be used wit caution, and the exhaustion of the absorbinj capacity controlled by limiting the time o use. There arc a variety of absorbing materials Concentration alone places a definite lim! which are used to "lifter out" the contami tation upon the use of air-purifying respira nants in air-purifying respirators. There is no tors. The Bureau of Mines has approvet one "universal absorbing material." Since canister masks for protection against 2 pci there is a direct relationship between the cent by volume of acid gases; organic vapors amount of the specific absorbent and the quan and carbon monoxide, and 3 per cent oi tity of material absorbed, it is desirable to ammonia, and such approval indicates th( have as great a quantity of this specific ab effective life of the absorber at this level i; sorber as possible. Occasionally, because of at least 30 minutes. No published data coult uncertainty as to which type of canister is be found which gave the absolute uppet indicated, the use of an "all-service" type limits of protection either as to concentration respirator is recommended. This respirator or capacity. affords protection against practically all types of gases, vapors, fumes, or smokes en countered industrially and would give pro tection by absorbing the contaminant in one or two of its layers, but its capacity for absorption would be much less than if the container were completely filled with the specific absorber. In contrast to the airpurifying respirator, the air-supplied type gives respiratory protection against all types of contaminants. If the respirator has a Bureau of Mines Approval, the efficiency for a given concen tration and a given time has been tested. For lower concentrations than the upper ap proval limit it is probably safe to assume a straight line relationship for the effective life. Thus, a canister effective against 2 per cent vapor for 30 minutes can be assumed to give protection against 1 per cent for 60 minutes, against 0.1 per cent for 600 minutes. 3. The concentration of the contaminants Since the efficiency of the air-purifying .and the duration of exposure. . (mechanical filter) respirator for dusts, fumes, and smokes increases with use, the These two factors are considered together, effective life is determined not by its failure for the concentration and duration are both to restrain the contaminant, but by its in important functions of the total capacity or creased resistance to inspiration. When this "life" of a given amount of absorbing ma resistance becomes uncomfortable, it is not terial. Theoretically, the air-supplied respi uncommon for the wearer to relax the fit of rators afford effective protection against any the mask, and while he then can breathe concentration of contaminant as long as the more easily, the protection is lost. air supply continues. The concentration and the duration of exposure impose very definite limitations upon the air-purifying types. Very 4. The character of the work to he done and of the work space. , little information is available concerning the Here must he considered, whether the work absolute capacities of the varied types of ab is of an etnergancy or non-emergency type, sorbing materials for the variety of con the amount and rate of physical exertion that taminants--even those against which they are must he done, the movements required in per most effective. In practice, the point of ex forming the work, the distance to be covered haustion of a given amount of absorbent is in the operation, the shape, size, and restric obvious if the odor of the contaminant is tions of the working space, and the time per noted (it is assumed that the face piece is mitted for putting on the device. It is essen well fitted). Unfortunately some very toxic tial that devices for emergency situations materials are odorless, for example, carbon give complete respiratory protection, ami that monoxide, and other substances vary greatly special provision be made against failure of as to their tendencies to fatigue the olfactory the device and the resultant exposure to an ?tnse as the concentration of the gases or immediately dangerous atmosphere. Em vapors passing thru the exhausted absorber phasis is on complete protection, with com J - LJ >-`" y / fort and convenience important, but secondary. In non-emergency situations it is assumed that the individual could escape from the harmful atmosphere without any protection. Devices for these situations usually give more consideration to the comfort and convenience of the wearer. To illustrate how ore or a combination of the above factors have re quired the modification of standard equip ment, the following examples arc given. In one manufacturing operation large quantities of a variety of solvents are evap orated in a completely inclosed apparatus, and the workman, on the outside of the ma chine, has not appreciable exposure. Occa sionally it is necessary for him to place his head inside the machine, with a consequent exposure to high concentrations of hot sol vent vapors. The work inside the machine is of such a nature that it must be started within a few seconds when the need arises, and the exposure may continue from a few seconds to many minutes. The workipan . must have protection for breathing and for the eyes. Because of the high concentrations, an absorber type respirator unless supplied with a prohibitively large amount of absorb ing material would be quickly exhausted. Standard air-line models equipped with a fullface piece were tried, but required too long a time for the operators to put them on. Finally one of this type ./as modified by attaching the face piece to a spring type head-band in such a manner that the respi rator could be put on in a few seconds. The short hoseline can be plugged in at any one of the numerous convenient terminals around the machine, and the simple insertion ini tiates an adequtee flow of air. The mask and hose attachment can be removed as quickly and easily as they were applied. This respi rator has proved to be a very satisfactory solution to a difficult problem. In this instance the high concentrations en countered favored the choice of the airsupplied mask over the absorber type, but the expense and difficulty in obtaining and maintaining a satisfactory air source seemed to outweigh this first indication. Other factors, the case and speed of applying and removing the mask determined the final se lection, since the positive pressure of the air-supplied respirator permitted this modi fication much more readily and safely. In another instance it was found that the use of a small cartridge absorber type res pirator was giving inadequate protection against the high concentrations of vapors encountered in spray painting the interiors of buildings. The alternatives in supplying additional protecion were to increase the quantity of absorbing material, or to use an air-supplied type. The relatively large vol ume of absorbent necessary to give complete protection for an eight-hour exposure to the high concentration of vapors, required cither an iuconvcntiently larger container or fre quent refilling of a small one. A valid ob jection to the standard air-line models was that when it was necessary to move scaffold ing or to perform other work in the room being sprayed, the painter must, to retain his air source, carry the supply line wherever he went, an inconvenient and even dangerous impediment to climbing on and off scaffold ing and ladders. If be cut loose from the airline ,he was exposed to the residual con centrations of five to ten thousand parts per million, an appreciable cumulative exposure during the course of a day. An airline respirator was modified to in clude a charcoal cartridge and automatic shutoff valves on both sides of the connection between the supply line and the respirator line. Thus when the airline connection is severed, the intake of air begins automatic ally thru the cartridge and continues until the reconnection with the airline again auto matically closes the small valve in the base of the cartridge. These modifications fre quently require considerable experimentation until a satisfactory result is obtained, but the protection and safety afforded is adequate compensation. 5. Other environmental factors, such as temperature and humidity. Temperature and humidity may influence the selection in at least two ways since (1) they have a definite effect on the capacity of certain types of absorbents, and (2) they affect the comfort of the wearer. The effect of moisture on the life of activated charcoal against gasoline vapors has heen shown in studies by the Bureau of Mines. The ca pacity of the dry charcoal (0.35% moisture) was six to twelve times as great as that containing 21 per cent moisture (in equili brium with air at 25 degrees C and 85 per cent relative humidity, and showing no sen sible moisture). The efficiency of hopcalite, o f ,'liSlS, J'IUH`'S, UtUS.S UUi! ilj > an absorbent (actually a catalytic agent for changing carbon monoxide to carbon diox ide) is readily destroyed by moisture. It is frequently difficult to control the temperature and humidity of the air for air-supplied res pirators. The lines carrying the compressed air for general plant purposes even though the latter may be pure for respirator use, frequently parallel steam lines or pass thru hot areas, resulting in uncomfortably high temperatures at the terminals. Otherwise satisfactory compressed air may have had the moisture removed because of certain opera ting requirements, and the relative humidity values below 10 or even 15 per cent may cause discomfort and dryness in the respi ratory tract. 6. Personal factors: comfort, sex, age, physical condition, intelligence, cooperation, etc. Most of the respirators now available, if ill proper working condition, can be worn, even for long periods of time, without appre ciable discomfort if the wearer has become psychologically adjusted to the situation. It Is probable that the chief cause of failure of protection in exposures where respirators are provided is the mental and physical discom fort due to faulty operation or maintenance-- the clogging of filters, the unclean condition of the face piece, the unsatisfactory fitting to the contour of the face. Unless the work men are exceptionally enlightened the un comfortable protection will seem worse than the hazard of the exposure. In general women adapt to the wearing of respirators less easily than men, and this relation in creases with the size of the face piece or covering and the amount of equipment in volved. Age and physical condition must be considered, especially when devices such as the self-contained oxygen breathing appara tus is to be worn in emergency operations. 1 he intelligence and cooperation of the work men are obvious factors. (7. Control of personnel exposed--educa tion, supervision. Too frequently the employee is merely handed the respirator with the order to "go head ami use it." Instruction as to the rca*on for the protection, the exact situations under which he shall wear the respirator, the signs of faulty operation and what he shall do to correct them, and the care and clean ing of the device, must depend upon the par ticular circumstances, but it is better to err on the side of too much rather than too little. The education must include the super vision, and the supervision of the supervision. Rarely, the enforcing of protection cannot be accomplished by securing the cooperation, and altho it should be the last resort, com pulsory' measures may be required. 8. Facilities for the care and cleaning. This very important condition to the proper functioning of respiratory protective equipment deserves more consideration than it usually receives. In plants where a num ber of respirators are used, provision should be made for the collection, cleaning, repair, and return of the respirators. In this con nection, it should be stressed that, if possible, each man should have his own respirator, suitably marked, so that it is returned to him after cleaning. If it is impractical to provide each individual with his own res pirator, provision must be made for thorough cleaning and repair if necessary before it is used by another workman. Where an indi vidual is responsible for the cleaning and maintenance of his own mask, there must be systematic supervision to insure its being done. Yant, in the article previously re ferred to, suggests several methods for clean ing and sterilizing different types of equip ment. It is unfortunate that a simple formula cannot be derived which might he applied in every instance to indicate the most effective type of personal respiratory protection. For the majority of hazardous industrial ex posures, the selection ef a satisfactory res pirator is a relatively simple one, but the factors discussed above must be recognized and applied if the choice is to he the best one. When the conditions of the hazard arc unusual, it may be necessary to examine in considerable detail each of the factors, to weigh the advantages and disadvantages, and to repeatedly modify the device until a practical, safe, and comfortable form of pro tection is obtained. ADJOURNM ENT moving tlii^ vaj)or. 'at 10 per cent of g all local ventila* r level. ~ \en ts requires a ^^foncentration in > probably familiar indicator for testing determine if an ex' and if it is safe for ink. The indication ament is a warning `.ity of acute poisoni or asphyxiation, iie vapor concentra te indicated on the i. A more sensitive is the M.S.A. Ben;;:!1 scale reading of dug 20 P.P.M. per is used, this instruv>e for determining ii workroom air. It pedal calibration for ;1 Cyclohexane and any combustible is very useful in . stems for incipient and pump gaskets. -mic poisoning, it is periodic tests be r especially during n and when any ventilating equip'tion of the solvent. Steam Railroad Section Officers 1940-1941 General Chairman--J. R. T enney, Western Maryland Railway Co., Hagerstown, Md. Vice-Chairman--O. F. Gnadinger, Elgin, Joliet & Eastern Railway, Co., Joliet, 111. Secretary and News Letter Editor--J. E. Long, The Delaware & Hudson Railroad Corp., Albany, N. Y. Program Committee--P. F. B uckle (Chairman), Chicago, Burlington & Quincy R. R. Co., Chicago, 111. F. A. Bogue, Chicago, Rock Island & Pacific Co., Chicago, 111. J. M. Guild, Union Pacific Railroad, Omaha, Nebr. Membership Committee--Robert Scott (Chairman), Atlantic Coast Line R. R. Co., Wil mington, N. C. A. V. R ohweder, Duluth, Missabe & Iron Range Railway Co., Duluth, Minn. Statistics Committee-- T. H. Carrow (Chairman), The Pennsylvania Railroad, Philadelphia. F. R. Bradford, Boston & Maine Railroad, Boston, Mass. D. G. P hillips, Wabash Railway Co., St. Louis, Mo. Contest Committee--C. L. L aF ountaine (Chairman), Great Northern Railway Co., St. Paul, Minn. L. G. Bentley, The Chesapeake & Ohio Railway Co., Richmond, Va. G. W. E lste, J r., Baltimore & Ohio R. R. Co., Baltimore, Md. L. R. P almer (Secretary), Equitable Life Assurance Society of U. S., New York City. J. J. Snavely, New York, New Haven & Hartford Railway Co., New Haven, Conn. Poster Committee--L. J. Benson (Chairman), Chicago, Milwaukee, St. Paul & Pacific R. R, Co., Chicago, 111. C. H. Blakemore. Norfolk & Western Railway Co., Roanoke, Va. W. R. Lofgren, Chicago, St. Paul, Minneapolis & Omaha Railway Co., St. Paul, Minn. Safe Practices Pamphlet Committee--T. K. Gage (Chairman), Chicago, Burlington & Quincy R. R. Co., Chicago, 111. W. J. F lannigan, Northern Pacific Railway Co., St. Paul, Minn. G. C. J efferis, Atchison, Topeka & Santa Fe Railway System, Chicago, 111. Nominations and Elections Committee--H. A. D aake (Chairman),Erie R. R. Co., Cleve land, Ohio. M. T . F ulton, Kansas City Southern Railway Co., Kansas City. Mo. E. L. H enry, 'Chicago & North Western Railway Co., Chicago, 111. Health Committee--D r. I. S. Cutter (Chairman), Chicago & North Western Railway Co., Chicago, 111. Dr. H arvey Bartle, The Pennsylvania Railroad, Philadelphia, Pa. Officers 1941-1942f General Chairman-- O. F. G nadinger, Elgin, Joliet & Eastern Railway Co., Joliet, III. Vice-Chairman-- F. A. Bogue, Chicago, Rock Island & Pacific Railway Co., Chicago, 111. .Secretary and News Letter Editor-- H. A. D aake, Erie Railroad Co., Cleveland, Ohio. Program Committee--F. A. Bogue, (Chairman), Chicago, Rock Island & Pacific Railway. Co., Oiicago, III. P. F. B uckle, Chicago, Burlington & Quincy Railroad Co., Chicago, 111. G. W. Elste, J r., Baltimore & Ohio Railroad Co., Baltimore, Md. fAs elected by delegates in Congress Session, 655 65o 3(ith National Safety Congress Membership Committee--R obert Scott (Chairman), Atlantic Coast Line Railroad Co., Wilmington, N. C. A. V. Rohweder, Duluth, Missabe & Iron Range Railway Co., Duluth, Minn. Statistics Committee--T. H. Carrow (Chairmen), The Pennsylvania Railroad, Philadelphia, Pa. F. R. Bradford, Boston & Maine Railroad, Boston. Mass. D. G. P hillips, Wabash Railway Co., St. Louis, Mo. Contest Committee--C. E. H ill (Chairman), New York Centra! System, New York, N. Y. L. G. Bentley, The Chesapeake & Ohio Railway Co., Richmond, Va. L. R. P almer (Secretary), Equitable Life Assurance Society of the U. S., New York, n . y. ;. J. J. S navely, New York, New Haven & Hartford Railroad Co,, New Haven, Conn. Poster Committee--W. R. Lofgren (Cltairman), Chicago, St. Paul, Minneapolis & Omaha Railway Co., St. Paul, Minn. G. M. D empsey, Chicago, Milwaukee, St. Paul & Pacific Railroad Co., Chicago, 111. O. A shworth, The Alton Railroad Co., Bloomington,.111. Safe Practices Pamphlet Committee--W. J. F la nnigan (Chairman), Northern Pacific Rail way Co., St. Paul, Minn. J. R. T enney, Western Maryland Railroad Co., Hagerstown, MdR. C. II elwig, The Delaware & Hudson Corp., Oneonta, N. Y. Nominations and Elections Committee--E. L. H enry (Chairman), Chicago & North Western Railway Co., Chicago, 111. M. T. F ulton, Kansas City Southern Railway Co., Kansas City, Mo. M. A. Leahy, Chicago, West Pullman & Southern Railroad Co., Chicago, 111. Health Committee--D r. I. S. Cutter (Chairman), Chicago & North Western Railway Co., Chicago, 111. D r. H arvey Bartle, The Pennsylvania Railroad, Philadelphia, Pa. TUESDAY AFTERNOON SESSION October 7, 1941 Presiding:--General C hairman J. R. T enney, Superintendent of Safety, Western Mary land Railway Company, Hagerstown, Md. Grade Crossing Accidents Presiding:--Ciias. E. H ill, General Safety Agent, New York Central System, New York City. The Highway Grade Crossing Accident Situation as Viewed by the Railroad Claim Department By WM. J. HOLDEN District Claim Agent, New York Central System, Cleveland, O. In 1940 over 1,800 people were killed and 4,500 injured in grade crossing accidents and for the first six months of 1941, 880 were killed and over 2,200 injured. There are approximately 230,000 highway grade crossings in the United States, each a potential accident hazard. The cure, if there is one, and we believe there is, lies primarily in education and law enforcement, and education must always begin with funda mentals. It is i ing alone will 'delude oursch't platitudes and torist to cross will avail us i understanding and face the . willing to adu dual obligation well as the hit part. The problem of the automob of the railroad the privilege a., crossing witho It is a basic pr railroad train highway each . same time, it is of the train to with the custom of the traveler not attempt t.. The violation < contest for pri underlying can dents. Motori realization of ti- bility and the not be a fiasi; must acquire its reiteration am: duties of the i road are rccipr the other. If every ques; crossing were ` safety and ti the right of oc. the railroad tr ciate the futil. grade crossing theory rather should carry ; of us living il; when \vc real:, the records Commission so states in auto dents arc Illim gan. The cha: enough not to Iv right of occup; 1 y/*: / k < r ^ l `, j , >* \ '.'A * >. * ' .*, ml , t yy-* y Y Y > , A >f 1 \ \k ` V ! 's A -.' '- A , - ' c y y / * VuY V L,}*" ' 1 l* t . S ' `s > s,:; , i v ( ^ 1?;i ' A , yy y shall lie brought hut'not less than ail at a railroad proceed until clue ascertain that the ^ ^ to r vehicles are rate that shall c before reaching ,g and to proceed ;ion has been taken is clear. The fact dents involve pasindicates that the it ions is quite union in safety bears ''e radio mav also ccidents, although ossing accidents it mission that the ! the time of the table exception to vhere a salesman crossing in broad that he had heard posed it was part which he was lis.c crossing. sing problem has opinion as to the > combat it. The requirement that ; to be brought to 1crossings or tor view may be ob is a panacea for irdly feasible to 'm.cs would enact ^tacted. whether comply. If the `e prevailed upon I to his reason to .idling a railroad legislation would wider realization of his responsiw.g traffic volume than any amount non. There has rove upon the old and Listen" at i.itcs have enacted ' marking certain rdous and have gns thereat, re Staun kailroad. Section 061 quiring the driver of all motor vehicles to come to a lull stop before proceeding over the crossing, yet these warnings are con stantly ignored and accidents occur. What, then, is the solution of the problem? Where do we go from here? Grade crossing elimination is glibly sug gested, but that is not entirely feasible. There are too many grade crossings in this country to hope for their complete elimination, al though the creation of additional crossings should be discouraged and, where possible, adjacent crossings should be consolidated. The thought is suggested that speed gover nors on all automobiles might tend to curb the speed maniac who insists upon going to his home in Heaven, "on high." But all cross ing accidents do not involve speed maniacs. so that alone will not solve the problem. lit the final analysis does not the solution lie largely with the motorist himself? We have discussed the necessity for education and law enforcement, vet we always have with us a certain proportion of automobile drivers who fail to drive in a safe or sane manner. Each year new models of automo biles become faster, both in their get-away and sustained traveling speed, and so long as we have automobiles that permit travel at a high' rate of speed and so long as we have motorists who make chance rather than safety their rule of conduct, just so long will there be grade crossing accidents. The problem . calls for a continued and co ordinated educational campaign sponsored by the railroads and the public authorities. WEDNESDAY AFTERNOON SESSION October 8, 1941 The Relationship of Off-Duty Injuries to a Sound Safety Performance By J. T. W ILLIAM SON Superintendent, Relief and Employment Departments, and Chairman, Board of Pensions, Chicago, Burlington & Quincy Railroad Company, Chicago Because of one particular phase of my work, the administration of our employees' insurance organization, known as the Bur lington Relief Fund, it has been brought forcibly home to me how much pain and suf fering and loss occur because of injuries. I also have had an unusual opportunity to ob serve the effect of personal injuries on the successful functioning of a large railroad organization. I have reviewed many thousands of re ports of injuries, and I can say, from my in vestigations. that nearly alt the injuries were avoidable : practically every one of them was caused by a direct disregard of the prime principles of safety. This direct disregard of the principles of safety is responsible for most of the off-duty injuries, as it is for the onduty injuries. A moment's inattention or a little careless act is responsible for so many accidents. A great many of the injuries which occur off du'y are the result of carelessness on the part of someone else. This is particularly true of highway accidents. Xot long ago. in one month, four of our employees were killed in automobile accidents: four valued employees, men of long training. As a man performs when off duty, so he will, as a rule. ierform when on duty. Man docs not-change from minute to minute, hour to hour, day to day, or month to month. He cannot he a careless individual at 7:30 in the morning and then when he goes to work at 8 be a careful individual. So I say it" a man makes a practice of ignoring the ordinary rules of safety when ofT duty, you may be sure that lie.will act in about the same man ner when he is on duty. Last year, out of the 20.0(10 members of our Relief Fund, 318 were injured while off duty. - i ' nr';-1. fV.; `S T T '- V l ' itvs.A*-h is'tt'.s,.A `--Ay Ufi, I'll*/i l'#-: ; L.'.z<\ `:` ' :~J. -.i'fktA.;-'teTvi -i-fe V 4- i,\ iV'1 u!_<*J '1A'.l; i': `!']t'V,'ii, t;,`b ltT A 'Y -i:,s l T il ^ T , o ; \-x~ * ... A `' * >-. r f ' fr- ; hTAi A jlw > ^ 4 hi ft 1 .t f-if Ot>6 30th National Safety Congress to tresspass. They must have legitimate op portunities to give their cver-ahuiulant energy and desire for action or they will turn to trespass and other destructive outlets. The Boy Scouts of America has a member ship of over 1.000.000. If we liad leaders and places to meet we would double our member ship. . We know from surveys which have been carefully made that four out of five boys want Scouting. If the railroads of America will hade- Scouting with volunteer personnel for Scoutmasters we can go a long way to ward helping you. This is not theory. It is a fact proved be yond question of doubt by the Delaware and Hudson Road among others. John Long, w ho' is here, can tell you of the results obtained by that road as a result of employing a Scout Executive, Mr. Macbride, who spent his time in developing Scouting along its right of way. Several other roads have done the same thing with excellent results. The Missouri Pacific was one of the first to adopt the plan. The purpose of Scouting is to train boys jor citizenship and to develop character. The program is one of education and activity is designed to achieve this. Safety is an important part of this pro gram, not the negative type of safety that would ro!) them of the chance to learn to de fend themselves, by surrounding them with fences, but rather the bold constructive type that teaches them skills. Skills that will pro vide an opportunity for more adventurous ac tivities with the maximum of safety. More swimming, canoeing, sailing, more mountain climbing and other activities that will fulfill the desire for action and at the same time provide education and build self-reliance. One of the safety skills that we attempt to teach is that of evaluation and judgment. How to distinguish between the things that can be done safely if done well and those that 'are foolhardy and destructive. To carry out such a program we need resourceful men of courage, character and leadership ability who will willingly give time to a fascinating game that will produce tangible results. There is no doubt in my mind that if the railroads of America will give backing to the Boy Scouts of America by providing volun teer personnel and providing professional workers when that is possible, that the Boy Scouts of America will in turn through its program help the railrods of America to solve its problem of trespass. `No Trespassing, Please" A technicolor motion picture film, made by the Erie Railroad, was shown at this point, the narrator being Lt. J. M. Collins, Police Department, Erie Railroad Co., Jer sey City, N. J. A general discussion of tres passing problems closed the session. THURSDAY AFTERNOON SESSION October 9, 1041 Presiding:--General C hairman J. R. T enney. What Part Should Safety Rules Play in the Safety Organization and Program of Steam Railroads By THOMAS H. CARROW Superintendent of Safety, The Pennsylvania Railroad, Philadelphia Nature's law provides that standing in front of a moving train will result in death. To circumvent the application of this law, man's law or, shall we say, rule, say : "Look in both directions for approaching trains be- fore stepping on or crossing railroad tracks." Experience shows that if there are no viola tions of the rule there will be no penalties exacted under the law. Nature's law says that if you stand on the u '\ f '. >' A, 4 end of a hold, eve off. To | man's law of car nc.i brakes, is complete i plcte imnv for violate Nature's tween two gether von "Going hi gines or c. no violatii' penalty au<: cause impli Nature's that the inbalance it s. is the most jury. Man of forms, s;. where you stepping or the law is munity fron Nature's of a train ;. not control are sure t "Getting on at high spi ` shows that be no accidi Nature's ed by a fan weight ane dains that : falling boo> Man's law. i law, provid freight or n. feet close i back erect, prevent ohji out of contr the legs. "When t\. heavy or bin 1--Desig lifting or 1< (a) Giv person is po WMMSCTMONS 31 st NATIONAL SAFETY CONGRESS General Subject and Industrial Sessions CHICAGO October 27-29, 1942 National Safety Council, Inc. 20 North Wacker Drive, Chicago Copyright, 1942. National Safety Council, Ir.c. Printed in U.S.A. National Safety Council, Inc. Honorary Members A ssociation- of Ikon and Steel E ngineers' VV. II. C ameron R obert \V. Campbell Lew R. P almer Officers (1942-1943) Cot.. J ohn S tiiavkll, President I. \V. Millard, Vice-President for Finance and Treasurer G. T. I I ki.lm utii, Asst. Vice-President for Finance and Asst. Treasurer B. B. McCci.i.ocii, Assistant Treasurer W alter S. P aine, Vice-President for Industrial Safety L ew R. P almer, Vice-President for Transportation A. V. Roiiwkdkr, Vice-President for Home and Farm Safety J udge L ef. E. S keei., Vice-President for Community Councils R. T. Solensten, Vice-President for Membership L eslie J. S orenson, Vice-President for Public Safety Du. Lewis A. W ilson, Vice-President for Education N ed II. Deardor.v, Executive Vice-President, Managing Director and Seeretary R. L. Forney, Assistant Secretary Executive Committee (1942-1943) J. I. Banas ii. Past President W allace N. B arker, Pullman-Standard Car Manufacturing Company C. W. Bergo cist, Past President R obert W. Campbell, Past President D. B. C iiant, Ontario Pulp & Paper Makers' Safety Association R. G. Creviston, Crane Company A. J. R. C urtis, Portland Cement Association N ed H. D earborn, National Safety Council, Inc. L ewis A. D eBlois, Past President R. E. D onovan, Standard Oil Company of California M arcus A. Dow, Past President G. W. E i.stk, J r., Baltimore & Ohio Railroad Company H arold F- E nlows, The American National Red Cross D. D. F ennell, Past President R. H. F erguson, Metals Section R obert F. Gilmour, Utica Safety Council E. E. Grover, Columbus & Southern Ohio Electrical Company J ulien H. H arvey, Greater "New York Safety Council W. A. H azard, Construction Section ' D r. T. Lyle H azlett, Westinghouse Electric & Manufacturing Com pany G. T. H ellmutii, Chicago Rapid Transit Company G. A. H euser, Louisville Safety Council Carl E. H olmes, Marine Section W. A. J arvis, Chase Brass & Copper Company, Inc. W. D ean K eeper, Lumbermen's Mutual Casualty Company W alter G. K ing, Past President J ohn E. Long, Past Piesident J. W illard Lord, Atlantic Refining Company I Twos. H. M acD onald, U. S. Public Roads Administration .t o I ^ Officers (contd.) W ills M aclachan, ASSE-Enginccring Section H on. Cakkoll E. M ealky, New York State Tax Commission I. W. M ii.lard, Industrial Gloves Company H arold L. M iner, E. I. du Pont dc Nemours & Company P h ilip M. M organ, Massachusetts Safety Council; Worcester Safety Council Clarence J. M u t ii, Safety Division, Milwaukee Ass'n of Commerce E liot N ess, U. S. Office of Defense Health & Welfare Services W alter S. P aine, Aetna f.ife and Affiliated Companies L kw R. P almer, Past President C. E. P kttiiione, P a st President R. J. R eigeluth, New Haven T ra p R; Company Col. H enry A. R eningi-r, U. S. Office of Civilian Defense, 3rd Region A. V. Roiiweuer, Duluth, Missablc & Iron Range Railway Company Caul J. R utland, Street & Highway Traffic Section H enry G. S chaffner, Erie Safety Council J udge L ee E. S kekl, Appellate Court, Cleveland Carl L. S m ith, Greater Cleveland Safety Council T heodore F. S m it h , Oliver Iron & Steel Corporation R. T . Solen sten, Elliott Service Company L eslie J. Sorenson, City Traffic Engineer, Chicago Col J ohn S tilwkll, Consolidated Edison Company of New York, Inc. Major R. C. Stratton, C.W.S., Chemical Section C. P. T oi.m an, Past President D r. C. H . W atson, Past President Dr. L ewis A. W ilson, The University of State of New York C. E. W ooliever, Automotive & Machine Shop Section A rthur H. Young, Past President V. A. Z immer, U. S. Department of Labor Board of Trustees (1942-1943) W inthrop W. A ldricii, Chairman Board of Directors, The Chase National Bank, New York City S ewell L. Avery, President, Montgomery W ard & Company, Inc., Chicago, 111. Morgan B. B rainakd, President, Aetna Life Insurance Company, Hartford, Conn. H oward Coonley, Chairman of the Board of Directors, Walworth Company, New York City B en ja m in F . F airlf.ss, President, United States Steel Corporation, Pittsburgh, Penn. * W. S. F arish, President, Standard Oil Company of New' Jersey, New York City W alter Gifford, President, American Telephone and Telegraph Com pany, New York City E. R. H arriman, Director, Union Pacific Railroad Company, New York City W illiam A. I rvin, Member Executive Committee, United States Steel Corporation, New York City T homas I. P arkinson, President, The Equitable Life Assurance So ciety of the U. S., New York City . * Deceased 5 V Officers (contd.) Robert C. S tanley. President, luteniational Nickel Company of Can ada, Ltd., New York City Cop. J ohn S tii.w h x , V ice-President, Consolidated Edison Company of New York, New York City T homas J ohn W atson, President, International Business Machines Corporation. New Y ork City OfAitf.Ks E. Wn.so n . President, General Electric Company, New York City Directors (1942-1943) H. J. A ldrich, Spencer Kellogg & Sons, Inc. T. O. A rmstrong, Springfield Safety C ouncil; i Lunpdin County Safety Council W . C. Baker, Pow er Press Section J. 1. Ban asii, P ast President W ai.i.ack N. B arker, P ullm an-S tandard C ar M anufacturing Company E rnest W . Beck, United States Rubber Company C ..W . Bkrgquist, Past President M iss F rancks Bkthunk, R.N., T ex tile Section W . F. Bices, Peoria Safety Council H . R. Bixlek, Mutual I.ifc Insurance Company of New York H. W. Bogokss. Sinclair P ra irie Oil Company F. A. Bogue, Steam Railroad Section K. G. Borshrink, Kansas City Safety Council C. B. Boulkt, W isconsin Public Service Corporation E merson A. Brandt, R efrigeration Section E dward H. Br in k , G rand Rapids Safety Council J oseph A. Bropiiv, Elizabeth Safety Council W . F. Brown, Commercial Vehicle Section S am W . Buruhiel, Automobile Club of Rhode [stand, Safety Depart ment W. H. C ameron, Evanston, III. Rohkrt W . C ampbell, P a st P resident Raymond A. Carey, Evanston Safety Council Ray Carr, Portland Traffic Safety Commission D. B. C hant. O ntario Pulp & P ap er M akers' Safety Association C harles A. C n . i m u , Safety Division, Syracuse Chamber of Cem- merce Lam mot iiuPont Copeland, D elaw are Safety Council C. S. Craigmii.e. G reater Chicago Safety Council R. G. C revtston, C rane Company W. H. Crisman. Seattle Traffic & Safety Council J. K. C ulm sky. Bethlehem Steel Company A. J. R. C urtis, Portland Cement Association J ohn D 'A mbkosa. S r., Railway Safety Council N ed H. Dearborn, National Safety Council, Inc. W. N. D eatiiekagk, Long Beach Traffic Safety Council Lewis A.- D kBlois, P a st P resident C. W. Dempsey, The Liquid Carbonic Corporation S. T. D iusdale, Wood Products Section Milton W . Dobrzensky, East Bay Safety Council R. E. Donovan, Standard Oil Company of California J ames li. Douglas, The Philadelphia Gas Works Company Marcus A. Dow, Past President D. C. D uncan, Public Utilities Section 6 Officers (contd.) G. VV. E i.ste, J r., Baltimore & Ohio Railroad Company H arold F. E nlovvs, The American National Red Cross i>. D. F ennell, Past President R. H. F erguson, Metals Section Dr. H art E. F isher, Chicago Rapid Transit Company V ictor B. F itzpatrick, Richmond Safety Council H oward R. Fonda, Burroughs Wellcome & Co. ( U. S. A.) Inc. R av Gim.ktt, Meat Packing, Tanning & Leather Industries Seetioii Robert F. G ilmocr, Utica Safety Council .John L. Grider, Ktihher Section VV. A. Griffin, American Telephone & Telegraph Company H. J. ( Irieeitii, Jones & I.aiighiiu Steel Corporation K. K. Grover, Columhus Safety Council H arrv Gvu.in.Hr, The Pullman Company A. J. H aoek, Lansing Safety Council D. T. H arrington, U. S. Bureau of Mines F rank H. H arrison, International Harvester Company J u lien H. H arvey, Greater New York Safety Council W. A. H azard, Construction Section D r. T. L yle: H azi.ett, Westinghouse Electric & Manufacturing Com pany G. T. H ellmuth, Chicago Rapid Transit Company G. A. H kusek, Louisville Safety Council H . W . H irsh rimer, Chattanooga Safety Council Carl E. Moi.mks, Marine Section D r. R alph H . H oughton, Kenosha Safety Council Stephen J. H urley, Rochester Safety Council W m F. J ame:s, Philadelphia! Safety Council E. A. J arvis, Chase Brass &f Copper Company, Inc. T homas P. K earns, Industrial Commission of Ohio \V. D ean K eefer, Lumbermen's Mutual Casualty Company W alter G. K ing, Past President C. L. L aFountains, Great Northern Railway Company George: L aMair, Des Moines Safety Council Roy Lee, Contra Costa County Safety Council W allace O. Lee, Safety Division, Indianapolis Chamber of Commerce J ohn E. Long, Past President C, H. Longman, Chicago & North Western Railway Company J. W iu .ard Lord, Atlantic Refining Company R. A. McA rthur, Public Service Coordinated Transport B. B. McC ulloch, Bureau of Safety, Inc. T hos. H. M acD onald, U. S. Public Roads Administration W ills M acL achlan, ASSE-Engineering Section Alfred E. M affi.y, Berkeley Traffic Safety Commission H. T. Makkke, Petroleum Section H on. Carroll E. M ealey, New York State Tax Commission L W . M illard, Industrial Gloves Company H arold L. M iner, E. I. du Pont de Nemours & Company H. H. M oiiler, St. Joseph Safety Council P h ilip M. Morgan, Massachusetts Safety Council R. B. M ori.ev, Industrial Accident Prevention Associations C. L. M urray, Mason City-Cerro Gordo County Safety Council Clarence J. M uth, Safety Division, Milwaukee Association of Com merce E liot N ess, U. S. Office of Defense Health & Welfare Services 7 (contd.) F rank S. N ewell, Toledo Safety Council F. E dward O 'N f.ii., The Safety Council of Greater St. Louis George C. A. The Detroit Edison Company W alter S. P aine, Aetna Life and Affiliated Companies L ew R. P almer, Past President D avid A. P atton, Newark Safety Council R. E. P krkey, South Bend Safety Council C. E. P ettihone, Past President G. H. P feif, General Electric Company D. W. P ontius, Greater Los Angeles Safety Council \V. M. P owell, Cement and Quarry Section A liiert S. R egula. General Time Instruments Corporation R. J. R kigklutii, New Haven Trap Rock Company Col. H enry A. R eninger, U. S. Office of Civilian Defense, 3rd Region J. W. R eynolds, United Pacific Insurance Company R oland W. R ichardson, Paper & Pulp Section Clifford T. R iplf.y, Superior & Douglas County Safety Council M iss Sadie R ogers, Employees' Publication Section A. V. Roiiweder, Duluth, Missabe & Iron Range Railway Company Carl J. R utland, Street & Highway Traffic Section H enry G. Sciiaffner, Eric Safety Council F rank T. S heets, Portland Cement Association J ohn R. S herwood, Baltimore Safety Council Du. L. A. S houdy, Bethlehem Steel Company J udge Lee E. S kef.l, Appellate Court, Cleveland Carl L. S m ith, Greater Cleveland Safety Council T heodore F. S m ith, Oliver Iron & Steel Corporation R. T. Solensten, Elliott Service Company L eslie J. Sorenson, City Traffic Engineer, Chicago J ohn L. Spencer, Blackstone Valiev Safety Council E. C. S pring, Philadelphia, Pa. E. B. Stahlman, Safety Dept., Nashville Chamber of Commerce Col. J ohn Stilwei.l, Consolidated Edison Company of New York, Inc. M ajor R. C. Stratton, C.W.S., Chemical Section II. B. T aylor, Food Section C. P. T olman, Past President J ohn T rewf.ek, Mining Section R. A. T ucker, Western Pennsylvania Safety Council J. A. V incent, Madison County Safety Council D r. C. H. W atson, Past President M. F. M. W ertii, Lehigh Valley Safety Council II. W . W hitcomb, Transit Section T. A nglin W hite, Safety Div,, Birmingham Chamber of Commerce A. W. W hitney, National Conservation Bureau C. E. W ilson, Detroit Industrial Saicty Council Dr. L ewis A. W ilson, The University of State of New York C. E. W ooliever, Automotive and Machine Siiop Section R oy V. W right, Simmons-Boardman Publishing Corporation Miss Mary May W yman, Child Education Section A rthur H. Young, Past President M. W . Y oung, Sacramento Safety Council W alter S. Y oung, Worcester Safety Council E. J. Zauft, Safety Bureau, Duluth Chamber of Commerce I rving R. Z erzan, Omaha Safety Council V. A. Z immer, U. S. Department of Labor c Each edition library of safet\ men and womenportation, insur. agencies--give tland background i vention at the An This knowledt ing year after y. gressive industri; Plan . Safety ideas, . as personalities i: ty, can be found Table of Conte" at the end of th The Table ri Sessions, (b) S problems comn. Industrial Sec^- Subjcct S e ^ . are arranged a:: the book the s', trial Section av the daily time gram. The detailed easy to find s | . hundreds of ii jects discussed. 1 shoti, third s'\ in the case of i are printed in tions, i. e., C Marine, etc. are listed the gram. Dust, Fumes, Gases and Vapors WEDNESDAY MORNING PESSIO N October 28, 1942 Presiding:--Stuart F. Meek, M.D., Asst. Medical Dir., Chrysler Corp., Detroit Maintenance of Exhaust Systems An Important Safety Measure By JOHN M. KANE Engineer, American Air Filter Company, Inc., Louisville, Kentucky In recent years the safety engineer's re sponsibilities have increased by leaps and bounds. Under his widening control logically comes the checking of exhaust systems for the control of hazardous dusts and fumes. This discussion will assume that such haz ards are evaluated by the industrial hygienist or safety engineer. Where exhaust ventila tion is required, the ventilation engineer makes recommendations for exhaust capaci ties, system and hood design to control the condition. It will be further assumed that this coordination results in an effective ex haust system removing the dust or fumes at the points of generation and preventing their dispersion to the workroom. Consequently, unless the process is changed, the hoods or enclosures altered, or the method of material handling revised, the hazard should remain controlled as long as the exhaust system func tions properly. The word "properly" can rightly be underscored because in many cases little attention is given to such an installation after the project has been completed. Yet mechanical exhaust equipment and dust col lectors require the same attention that ma chine tool and other plant equipment require and usually receive. If this precept is correct, a discussion of fundamentals may assist the safety engineer in quickly setting up a routine check on the performance of an exhaust system and catch ing any reduction in the system's effectiveness. The tools required under most cases are a manometer (U-Gage), and a short piece of rubber tubing. The engineer must also'have an understanding of static pressure losses and hood suction. While hood suction readings have rightfully fallen into a state oi ill repute as a means of measuring air flow, they do offer a quick and accurate method of measuring relative air flow. If the hood suction is known while an exhaust system is functioning properly, its continued effectiveness can be assured as long as the hood suction does not reduce from its original value. An expansion of this state ment, should indicate why this simple mea surement can be used as a ready check. The Exhaust System Exhaust ventilation is by far the most pre dominant means of controlling dust hazards. The fundamental elements and the design are not altered, whether the purpose oi the ex haust system is to remove toxic or explosive particles, or simply to prevent dispersion for reduction in workman fatigue, improvement of visibility or general betterment of work ing conditions. In most cases the system will of material exhausted, or leakage losses caused by loose cleanout doors, broken joints, holes worn in duct (most frequent in elbows), poor connection to exhauster inlet 1K1 Losses in suction can also be charged to additional exhaust points added to the sys tem (sometimes systems are designed for future connections and more air than re quired is handled by present branches until future connections are made), change of set ting of blast gates in branch lines (blast gates -,`ty - ' ,4 adjust the air distribution between the va- rious branches. Tampering with blast gates- f can seriously affect such distribution and ^ therefore gates should be locked in place im- -J medtely after system has been installed and f its effectiveness checked). Increased pres- `J sure loss through dust collector due to lack | of maintenance, improper operation, wear, etc. vary with the collector design. Refer to op- j | eration and maintenance instructions fur- nisbed with the collector or consult the % equipment manufacturer. * * Testing Toxic Atmospheres | By N. R. B E R N 2 Chief Industrial Hygienist, The Fidelity & Casualty Co. of N. Y., New York, New York In manufacturing, many operations and iirocesses of one industry are common to those of another, although the two indus tries may be engaged in the production of entirely different types of goods. For example, welding is used very extensively ijyoughout the aviation, shipbuilding, auto^ h ilc and steel industries; this applies also o- spray painting, electroplating, buffing, 'rinding, and many other operations. Simiarly with raw materials, various kinds of i ids, organic solvents, etc., art Wound in most any type of plant. For this reason ere are certain industrial poisons which ipear much more frequently than others kI .which may be found throughout the .tire defense industry. Some of these are: .usts nrbon Monoxide vdrogen Sulfide vdrogen Cyanide ilfur Dioxide rides of Nitrogen iimonia rosgen ad ' Imiutn nzene Toluene Xylene T richloroethylene Caibontctrachloride Carbon Disulfide Nitric Acid Chromic Acid Hydrofluoric Acid Hydrochloric Acid Sulfuric Acid Uhcrs which are more directly associated ' specific industries are: j Trinitrotoluene (dust and vapors) j Ammonium Picrate(dust) , 1 Mercury (vapors) ! Aniline j Radon I Thoron As will be seen by examination of the above list, some of these substances are pres ent as raw materials; others are final prod ucts, while a third group occurs as by-prod ucts generated in the various operations. Typical of the first group are the various acids, organic solvents, chlorinated hydro carbons, ammonia, and carbon disulfide. In the second class we have TNT and am monium picrate, while the remainder arc commonly occurring dusts, fumes, gases and vapors of a toxic nature generated in various industrial processes. While the theoretical possibilities for exposure to toxic substances in the above industries are far too numer ous for tabulation, this list represents those most commonly encountered. Dusts Silica-bearing inorganic dusts are prob ably found in all of the above industries. For example, mining of the iron ore in the steel industry presents exposures to free silica dust in considerable quantities. Buffing, polishing, and grinding operations done very o i-'.ist, ;iUu'*, Cn;.'W p/icf 1 a['on extensively in a great many industries, generate inorganic dusts, which for the most art consist of aluminum oxide and silicon carbide, but also include free silica in amor phous and crystalinc forms. For the purpose of quantitative determina tion, dusts may be divided roughly into three classes, as follows: 1. The inorganic type such as free silica and asbestos, which is collected and the num ber of particles per unit volume of air deter mined microscopically. 2. Organic dusts of natural origin, the amount of which is usually determined by weight. Typical of these are tobacco and flour dusts. 3. Synthetically manufactured organic compounds which may occur in the form of dusts, such as TNT and ammonium picrate. These substances when present as air con taminants in low concentrations are generally evaluated quantitatively by chemical means. Besides above types, there are also metallic dusts such as lead, zinc, cadmium, manganese, etc., some of which will be discussed under another heading. Inorganic Dusts The most common method for evaluation of this type of dust is to collect air samples in liquid solutions by means of an impinger (1) and to make the quantitative determina tion microscopically. When calculating the dust concentration, usually expressed in num ber of particles per cubic foot of air, the microscopic calibration factor, .the volume of the sampling liquid, and the size of the air sample arc taken into consideration. The sampling procedure, microscopic ar rangement, and calculations are extremely simple, hut the actual counting is a tedious job associated with severe eye strain and requires considerable experience before dust counts can be relied upon. In recent years the microprojection method (2) has been used for counting of impinger samples. With this method in which the microscopic field is pro jected on a translucent screen, the eye strain experienced in direct microscopic work, is eliminated. Other methods for evaluation of this type of dust are by means of electrostatic pre cipitators (3) and various types of "grab" samplers. With the electrostatic precipitator, the dust is collected iil a dry state and either weighed as is, or suspended in water and counted in a manner similar to that em ployed with the impinger method. Several of the grab samplers have microscopes in corporated with the sampling device and these are calibrated in such a manner that the number of particles per cubic foot of air can readily be obtained by almost instantan eous readings (4). Organic Dusts (Natural) This group as a rule is not classified by medical authorities as fibrosis producing dusts, and hardly warrants any discussion in this paper. While claims do exist to the effect that some dusts in this class have produced respiratory irritation, bronchitis, asthma, etc., these dusts are generally looked upon as nuisances rather than occupational disease producers. No official physiological threshold limits have been established and sampling of this type of dust for the purpose of evaluating an occupational disease hazard has little or no meaning. Most of these dusts, however, are ex plosive when dispersed in certain proportions in the air and require control from this point of view'. Considerable work to establish ex plosive limits for this type of dust lias been done by the United States Department of Agriculture. Synthetic Dusts In the manufacture of TN T and ammon ium picrate, both of which represent basic war industries, we are confronted with toxic raw materials as well as hvgienically injuri ous final products. In this industry great quantities of toluene, anhydrous ammonia, sulfuric and nitric acids arc used, all of which are classified as industrial poisons. TNT and ammonium picrate are themselves systemic poisons as well as skin irritants known to have produced fatalities and severe cases of dermatitis. A method for sampling and determination of T N T was described recently by Pinto and Fahy. (5) This procedure calls for the use of 10 c.c. of isopropyl alcohol in the midget rs . hu'iw m jcty L o n y tc ss impinger. The chemical determination is based on the reduction of TN T to triaminotoluene, and finally, a colorimetric compari son with known standards. Ammonium picrate is highly soluble in water which therefore can be used as the collection medium in an impinger when sampling for this material in industrial at mospheres. The deep color wlich results upon solution of ammonium picrate in water is also evident in extremely low concentrations and for this reason a direct colorimetric com parison of the sample with known standards can be made. With this method there is a possibility of interference from diuitrophcnol, the extent of which has not been determined ( 6). Carbon Monoxide This is a very toxic gas encountered in various industrial activities. The toxic limit for this gas is generally accepted as1100 p.p.m. for prolonged exposure. To the pub lic in general its presence is most commonly associated with automobile exhaust and gas burning appliances utilizing manufactured gas with a high percentage of carbon monoxide. As a result of incomplete combustion it may also he present when, burning natural gas or other fuels. In industrial operations in volving baking ovens, drying kilns, coke ovens, blast furnaces, etc. carbon monoxide is frequently encountered. In industrial proc esses in general, and particularly where chemical reactions are involved, carbon monoxide may be generated as a dangerous by-product. In prism grinding, which is closely allied with the defense industry, a high quality iron oxide rouge is required. Occasionally this material is manufactured on the premises as an adjunct to the prism grinding work. This involves the use of oxalic acid for production of iron oxalate which is later decomposed by heat to yield iron oxide rouge. In this process carbon monoxide as well as other gases are gen erated. Several methods have been developed for the quantitative determination of carbon monoxide, but only the two most expedient procedures employed in industrial hygiene work will be discussed here. One of these is the carbon monoxide indicator based oh the catalytic reaction of hopcalite which oxidizes carbon monoxide to carbon dioxide. The small electric current produced by the heat of the reaction through a thermo couple is calibrated in terms of carbon mon oxide concentration which is read directly on the dial of a milliammetcr. The source of suction in this instrument is a small centri fugal blower, the motor of which is operated either from a built-in 6 volt battery or from a 110 volt lighting circuit through a trans former. Another convenient method for estimation of carbon monoxide though less sensitive and not so accurate is the use of palladium chloride ampoules. In this reaction the palla dium chloride is reduced to metallic pal ladium thereby producing a stain, the in tensity of which is in direct proportion to the amount of carbon monoxide in the atmos phere under observation. The stain produced is compared to known color standards for evaluation of the carbon monoxide present. This method is not specific for carbon mon oxide, however; three are other reducing gases which also will produce a stain in the presence of palladium chloride. Incidentally, the standard method for carbon monoxide evaluation, adopted by the British Depart ment of Industrial Research (7) consists of a palladium chloride test paper through which the air to be sampled is drawn by means of a han'dpump. The stain thus produced is compared with a standard color chart. Hydrogen Sulfide Hydrogen sulfide is a very toxic gas with a disagreeable odor. It is found in many in dustrial operations where sulfur or sulfur compounds re used, but primarily it is en countered in the artificial silk, chemical and petroleum industries. Safe limits varying be tween 20 and 50 p.p.m. by volume have been suggested by various State authorities in this country. The most rapid method for determination of hydrogen sulfide is undoubtedly the use of a hand operated instrument consisting essentially of an aspirator bulb and a detector tube through which the air sample is drawn. The detector tube contains a chemical sub stance which when in contact with hydrogen sulfide produces a discoloration the length of which is in proportion to the amount of hydrogen sulfide present and can be meas ured on an attached scale. It can also be determined iodometrically, either by bubbling a t; Dust, /nines, Gases and Vapors 61 through a sodium hydroxide solution and pirating with iodine, or by bubbling through [< tassium iodide starch solution and a meas ured amount of standard iodine in which re action the disappearance of the color indi cates the end point (8). Hydrogen Cyanide This gas for which the industrial hygiene bureaus of California, Connecticut and MassaCnisctts have established a safe limit of 20 ppm. by volume, is found in electroplating operations, heat treating, etc. A portable instrument of the type dis cussed in connection with hydrogen sulfide, lias been developed for hydrogen cyanide also. I have been informed, however, that the hydrogen cyanide detector in its original form proved less satisfactory and that it has been withdrawn from the market temporarily pending further research. Chemical tests are available for detection of hydrogen cyanide, such as the Prussian blue and thiocyanate reactions, both of which are specific for this gas but allegedly not sensitive enough for concentrations encoun tered in industrial hygiene work. Other methods suitable for determination of this gas in small concentrations are the Congo red-silver nitrate and the benzidine--copper acetate test papers. These methods, which have been adopted as standard tests by the liritish Department of Industrial Research, are non-specific, however, so that the possible interference of other gases such as HCL, 1I.:X, SO; and H 2 S should be taken into consideration. In a method suggested by the Air Hygiene Foundation (A.H.F.) the air sample is bubbled through 0.5 per cent potassium hydroxide after which the determination is made hv titrating with silver nitrate (9). Sulfur Dioxide exposures to sulfur dioxide gas are com mon in the petroleum industry, rubber works, and sulfuric acid manufacturing. Sulfur dioxide is also encountered in bone and glue works, magnesium foundries, and other in dustries where sulfur compounds are used. 11 is an extremely irritating gas for which a threshold limit of 10 p.p.m. has been sugfe.'ted. For the testing of sulfur dioxide, the American Public Health Association (A.P. H.A.) (10) refers to an iodometric method (11) by means of which the air sample is passed through a gas wash bottle containing a measured amount of standard iodine in potassium iodide-starch solution. The disap pearance of .the color indicates the end of the test, after which the amount of sulfur dioxide present can be calculated. The British Department of Industrial Re search employs a starch-potassium iodate test paper through which the air sample is drawn by means of a handpump. The sulfur dioxide reduces the iodate to iodine with the production of a stain the degree of which is compared'to known color standards. Oxides of Nitrogen This is a group of gases, some of which are extremely' toxic. They are produced when nitric acid comes in contact with organic materials and certain metals; during chemical nitration processes and burning of nitrated materials; they are also present in small quantities during electrical discharges in the air. Above gases may, therefore, be found in such industries and operations as ammuni tion works, photographic film manufacturing, nitric acid plants, electroplating (bright dipping), detonation of explosives, electric welding, etc. During the chemical reactions that accom pany ahovc operations, a mixture of oxides are formed. The hazardous nature of this group, also called "nitrous fumes" is due primarily to the nitrogen dioxide, a reddish brown gas which reacts with water and upon respiration forms nitric acid in the lungs. The result is often pulmonary edema which frequently proves fatal. The fact that the respiration of these gases does not produce any immediate discomfort in spit of their toxicity, makes them doubly dangerous. A person may be exposed to these fumes and experience only a slight respiratory irrita tion immediately following the exposure, while the case may develop into a fatal con dition by next day. For example, I know of a case in a nitric acid plant where a man was engaged in filling nitric acid into carboys in a depart ment with a wooden floor. One of the car boys accidentally' broke causing the acid ,to J ,\ alio,lai ajciy Congress !. flow over the wooden floor producing the ical industry, It is a strong respiratory ir r i- | brown nitrogen dioxide gas in great volumes. tant for which safe limits ranging between The operator not being familiar with the SO and 85 p.p.m. have been recommended j toxicity of this gas and experiencing no im (Russian investigators 13-59 p.p.m.; State | mediate physiological warning, remained on of Massachusetts 50 p.p.m.; Flttry a n d ' the job attempting to clean the floor by mop Zernik 85 p.pan.). i ping up the acid, instead of leaving the work place for fresh air. As a result a consider able portion of this gas was probably inhaled. He became seriously ill a few hours later and died within 48 hours. Cases of men be coming sick while doing electric welding in side tanks or in other confined spaces are often referred to in the literature. Many of these cases are undoubtedly due Vo oxides of nitrogen generated in the electric arc. While there arc several methods known for the quantitative determination of oxides of nitrogen, testing for these air contaminants is not .so simple as that for some of the others discussed in this paper. Incidentally, in view of the cumbersome procedures in Ammonia vapors can be evaluated in the field by bubbling the air directly sample I# through a measured volume of 0.1 N hydro -Ii chloric acid in water solution using phcnol- fj phthalein as an indicator; the appearance of ;t a pink color indicates the end point. From the amount of acid used and the size of the 1 air sample, the concentration of ammonia t 5 vapors can be calculated (S). 'i Sulfuric acid can also be used with above method. In another method, recommended by the A.P.II.A., the air sample is collected in sulfuric acid, hut the final evaluation is made in. the laboratory by standard analytical means. volved in testing for these gases, the amount of ventilation required for their control after blasting in mining and tunnel work is some Lead times based on the amount of carbon jmon- Exposure to this metal occurs very' exten oxide present, which can readily be deter sively in nearly all types of manufacturing. mined. With explosives designed for i low The most frequently encountered forms of oxygen balance resulting in a relatively high lead are fumes, dust and dispersed pigments. carbon monoxide concentration and corre These occur around lead melting operations, spondingly low volumes of oxides of nitrogen, soldering, welding of metals covered with this is a safe and expedient procedure. lead-bearing paints, and in spray painting For' actual detection of nitrogen dioxide, work. the method employing starch-potassium Sampling of lead-contaminated atmos iodide test paper is probably the best known. pheres is usually done either by means of This paper when damp is colored blue in the the impinger or by the electrostatic precipita presence of nitrogen dioxide. The method is tor. When the impinger is used, as is fre non-specific, however, Other, specific meth quently the case when investigating spray ods for evaluation of nitrogen dioxide, and painting and many other types of work in sensitive at low concentrations are the Gricss- volving lead dispersion, the sampling liquid Ilosvay and the Bismarck B-ciwri tests. With may he either distilled water or dilute nitric both methods, the air sample is bubbled acid. through chemical solutions. after which the quantitative determinations are made in the laboratory by colorimetric analysis. Although physiological safe limits up to 40 p.p.m. have been proposed for these gases, atmos pheres which by odor or color indicate the presence of nitrous fumes should always be viewed with suspicion. Regardless of the collection method used, the final evaluation of the amount of lead present is done in the laboratory by various analytical methods, the description of which is beyond the scope oi this paper. It prob ably should be emphasized, however, that al though some of these methods are highly sensitive and the experienced analysts usual ly well-trained to handle minute quantities of Ammonia lead in their work, it is preferable to take large air samples wherever possible to facil As stated elsewhere, ammonia is an im itate the laboratory work. With the large portant raw material throughout the chem- impinger and the electro-static precipitator <1 Dust. Fumes, (uses u u . i l afurs with sampling rates of 1 and 3 cubic feet of air per minute respectively, this is not a problem. With the midget iinpinger, on the other hand, with a sampling rate of only.0.1 cubic foot per minute, this becomes a tiresome task, especially if the handcrankcd instru ment is used. Let us take, for example, a case in which the atmospheric lead dispersion is just about on the border line of the safe limit, i. e. 1.5 mg. per 10 cubic meters of air. For a 30 .minute sample with the midget iinpinger, only 3 cubic feet of air have been handled. This represents only 0.013 mg. of lead in the air sample, which evidently re quires a fairly sensitive analytical method and careful handling for a successful com pletion of the test. Cadmium The United Stales Public Health Service (U.S.P.ll.S.) (10) suggests as a safe limit with respect to toxicity of cadmium fumes a concentration of 1 mg. per 10 cubic meters of air. The metal is used extensively as a coat ing of iron and steel for rust prevention, as well as in structural steel to impart certain properties. Exposures to cadmium and cad mium fumes may, therefore, be encountered in such operations as electroplating, weld ing of cadmium-bearing iron and steel as well as many other processes where work in volves cadmium-plated articles. Some of you are probably familiar with the cases of cad mium intoxication in a plant in , Ontario, Canada, a few years ago, when 14 persons were poisoned--two fatally--during anneal ing of cadmium plated rivets (17). As in the case of lead, sampling for cad mium fumes or dust may be done either with the iinpinger (with water as collection medium--A.P.H.A.) or by the electrostatic precipitator and the samples evaluated in the laboratory by gravimetric or colorimetric analytical methods. At this point it probably should be brought out (fiat for sampling of metal fumes, the iinpinger lias a lower collecting efficiency ban the electrostatic precipitator, which should be taken into consideration when comparing results obtained on samples colIfeted with the two instruments (18). Mercury The present emergency lias greatly accel erated the use of mercury, not only in our ammunition works, but also in many other plants directly' or indirectly connected with the defense industry. In some cases entirely new uses have been introduced for this metal. For example, a recent development is an anti-fouling paint containing mercury, now used in our shipyards. Application of this mercury-bearing paint by means of spraying naturally introduces a serious exposure to mercury poisoning and calls for careful con trol ; this applies also to the manufacture of the paint. Due to the great demand for mercury and the shutting off of foreign sup plies, many old mercury mines arc now being reopened so that refining oi this metal with accompanying occupational disease hazards has expanded considerably during the past year. The toxic properties of mercury as a respiratory hazard when present in the form of vapors or in a finely divided metallic state are probably fairly well-known to most men concerned with industrial health. A safe limit, toxicologically, of about 2 mg. per 10 cubic meters of air appears to be generally accepted for inhalation exposures. Althouh the metal has a relatively low vapor pressure at or dinary temperatures, investigations have shown that sufficient vapors arc emitted to produce a mercury hazard in rooms where this material is used in metallic form. A number of methods are available for the evaluation of mercury vapors in air. One of the most expedient procedures is probably by means of the Nordlnder apparatus utilizing a selenium sulfide test paper, the color of which darkens in the presence of mercury. The amount of mercury present is estimated by comparing the degree of darkening with a standard color chart. Another more recently' developed method involves an optical instrument based on the opacity of mercury vapors to ultra violet light of a certain wave length. In this instrument, therefore, when ultra violet light of a specific wave-length is directed towards a phototube, interfering mercury vapor will reduce the light received by' the phototube and conse quently also its current flow, which in turn is calibrated in terms of mercury concentra tion. This instrument is not specific as It is . . . . u , u n ju jl t\ Congress subject to otlier light intercepting media such as smoke and fog. There are also other methods for determin ations of mercury, entailing condensation of the vapors and subsequent electrolytic deposi tion of the metal, chemical reaction methods, etc. The first two mentioned above, however, arc the most expedient and yield immediate results during the field investigations. Benzene (Benzol), Toluene and Xylene These three aromatic hydrocarbons are widely used as industrial solvents and ingredi ents in a number of chemical reactions. Tolu ene, for example, is an important raw mate rial in our ammunition manufacturing, espe cially in the production of trinitrotoluene. With the increased demand for toluene and the corresponding scarcity of this material, benzene is rapidly taking its place as a sol vent in many industries. Xylene, which besides being an important solvent, also does filter as a raw material in certain chemical processes, at present associated with the defense industry and therefore used in great quantities. For instance, in a plant I visited recently xylene is used in the production of a certain1type of resin, which in turn is employed in an article manufactured for the United States Army. All these three materials are classified as industrial poisons, although there appears to be some confusion as to the relative toxicity of each. Benzene is generally considered as the worst offender, although this may not be due to a greater toxicity of the material per sc hut to the fact that it has a higher vapor pressure than the other two so that for a given temperature more of it will be found in the air. However that may be,' the toxic effect of all of them, once dispersed in the air, is generally recognized and therefore in dicates the need for strict control wherever they are used. For the evaluation of these materials some chemical as well as physical methods are available. Most of these, however, arc com plicated and cumbersome, involving such operations as nitration by bubbling the air through nitric acid with subsequent colorimet ric determination, or condensation of the vapors followed up by laboratory analytical procedures for the final evaluation. While methods of this type may "be satisfactory for scientific purposes, for routine sampling in control work in industrial plants, a combus tible gas indicator is far more expedient. Most of these devices, used primarily for fire prevention work, are designed to read to within 1% of the lower explosive limit of the gas or vapor under test. For above sub stances with lower explosive limits around 1% by volume, this means that concentrations down to 100 p.p.m. can be detected, which is approximately the accepted toxic limit for these solvents. For benzene with a safe limit of 75 p.p.m. (19) a modified combustible gas indicator has been placed on the market, which measures concentrations ranging be tween 0 and 1000 p.p.m. A spectroscopic method for determination of benzene and .toluene in air has been described by Cole ( 20). Chlorinated Hydrocarbons Of these, trichloroethylene and carbon tetrachloride are probably most frequently found. They are used extensively as metal cleaning agents ; the former in regular de greasing machines on a production basis and the latter for work of a more occasional nature. These materials with their grease dissolving properties are regarded by medical authorities as very injurious to the fatty tis sues of the human body. As in the case of other substances referred to above, there are chemical methods for quantitative determination of vapors from these materials, but they are mostly too cum bersome for routine sampling. Optical instru ments are available, however, for rapid evalu ation of such vapors dispersed in the air. The best known of these is probably the portable interferometer in which the difference be tween the refraction of air (the comparison substance) and that of the gas mixture to be examined is measured. This difference is calibrated in terms of concentration of the gas or gases under observation. Naturally the same readings will he obtained for all gas mixtures resulting in the same refractive in dex, so the instrument is therefore not spe cific. With information, however, as to thetype of air contaminant concerned in a par ticular problem it is an exceedingly useful instrument applicable to the investigation of a great variety of gases and vapors. Carbon Disulfide This substance which at ordinary tempera tures occurs as a liquid with a high vapor pressure, generates toxic vapors for which o Dust, Fumes, Cases and Vapors 65 relatively low safe limits have been suggested t)v various authorities. Russian investigators have recommended a threshold limit of only .1 p.p.m. for prolonged exposures, while the British Department of Scientific and Industiiul Research has suggested a value of 10 p.p.m. and our own State of Massachusetts, 2(1 p.p.m. While there is a wide divergence between these values, they all tend to indicate the potential dangers connected with ex posures to vapors of carbon disulfide. Although this solvent may be encountered in a great many industrial operations, it is found primarily in the viscose--and rubber industries where it constitutes an important raw material. loir evaluation of these vapors, the Air Hygiene Foundation recommends drawing the air through an alcoholic potassium hy droxide solution to form potassium ethyl xanthate which is determined iodometrically. The British Department of Scientific and indus trial Research uses a colorimetric method consisting of bubbling the air through diclhylaminc and copper acetate forming a col ored compound the intensity of which is com pared with standards. In view of the inflam mability of these vapors, a rapid method of their evaluation in high concentrations would be hy means of a combustible gas indicator. Unfortunately, however, the sensitivities of these instruments as built at present, are not low enough to get within the physiological safety range of this material. Acids In this group probably nitric, chromic, hydrofluoric, hydrochloric and sulfuric acids are those most commonly encountered. Of these, nitric acid has been discussed under an other heading. Exposures to chromic acid resulting in chrome ulcers and the perforated nasal septum are frequently found around ilimmium plating tanks. A safe limit of 1 mg, per 10 cubic meters of air has been estab lished for chromic acid which in electroplating vunk occurs as a mist over the plating baths. Ilydiofluoric and hydrochloric acids also ex ist in gaseotis form as hydrogen fluoride and hydrogen chloride respectively. A safe limit of 3 p.p.m. has been suggested for the former, while it has been set at 10 p.p.m. for the latter. Sampling for nitric, chromic, and sulfuric acids is usually done by bubbling through a sodium hydroxide solution; hydrofluoric acid through potassium hydroxide; and hydro chloric acid through glycerol-potassium car bonate-water solution. For the final labora tory evaluation I refer to standard methods of the A.P.H.A. Bibliography 1. Greenburg, L. and Smith, G. \V. A New Instrument for Sampling Aerial Dust. R. I. 2392, U. S. Bureauo f Mines, 1922. 2. Brown, Carlton E .; Baum, Lester A. H .; Yant, William P., and Schrcnk, Helmuth H. Microprojection Method for Count ing Impinger Dust Samples. R.I. 3373, U. S. Bureau of Mines, January', 1938. 3. Barnes, E. C. and Penney, G. W. An Electrostatic Dust Weight Sampler. Jc. In dustrial Hvgicne & Toxicology, 20, 3, p. 259 March, 1938. -1. Bernz, N. R. Dust Counts and Their Significance. Heating, Piping and Air Con ditioning, March, June and October, 1942 5. Pinto, S. Sherman and Fahy, John P. A New Colorimetric Method for the Deter mination of T.N.T. (2, 4, 6 Trinitrotoluene) in Air. Jo. Industrial Hygiene & Toxicology. 24, 2, p. 24 February, 1942. 6. Sands, Frederick \V., 189 Claremont Avenue, New York, N. Y. Unpublished data obtained through persona! communication, August, 1942. 7. Department of Scientific and Industrial Research, London, England Methods for De tection of Toxic Gases in Industry. Leaflet No. 1--Hydrogen Sulfide Leaflet No. 2--Hydrogen Cyanide Leaflet No. 3--Sulfur Dioxide Leaflet No. 4--Benzene Leaflet No. 5--Nitrous Fumes Leaflet No. 6--Carbon Disulfide Leaflet No. 7--Carbon Monoxide Leaflet No. 8--Phosgcn Leaflet No. 9--Arsine Leaflet No. 10--Chlorine Leaflet No. 11--Aniline Leaflet No. 12--Organic Compounds 8. Method employed at the Harvard School of Public Health. 9. Air Hygiene Foundation of America, Inc. Preventive Engineering Series, Bulletin No. 2, Part 8. 10. Cook, Warren A. Report on Methods for Determination of Poisonous Atmospheric ou 31st National Safety Congress Contaminants, pp. 80-85, 1935-1936 Year Book, American Public Health -Association. 11. Fieldner et al. Jo. Industrial & Engi neering Chemistry 11:519, 1919. 12. Evans, R. D. Apparatus for the Deter mination of Minute Quantities of Radium, Radon and Thoron in Solids, Liquids and Gases. Review of Scientific Instruments, <5:99 -1 1 2 (1935). 13. Brown, S. C. ; Elliott, L. G. ; and Evans, R. D. Detection of Radon by Means of A Proportional Counter. Review of Scien tific Instruments 13: 147--151 (1942). 14. Evans, R. D. and Goodman, C. De termination of The Thoron Content of Air and Its Rearing on l.ung-Canccr Hazards in Industry. Jo. of Industrial Hygiene & Toxicology, 22, 3, pp. 89-99 March, 1940. 15. Evans, R. D. ; Nilson, S. J. ; Good man, C. ; and Bcrnz, N. R. Industrial Ap plication of a Method for Determining the Thoron Content of Air. Proceedings of the VIII International Congress on Occupational Diseases and Preventive Medicine, held at j Frankfurt a. M. Germany, September 26-30,, 1938. 16. United States Public Health Service, Division of Industrial Hygiene, National i Institute of Health, Washington, D. C. Cad- : mium Poisoning. Public Health Reports 57, ' 17 April 24, 1942. 17. Buhner, F. M. R .; Rothwcll, H. E.; ; and Frankish, E. R. Industrial Cadmium Poisoning. A report of fifteen cases, includ- : ing two deaths. Canadian Public Health Jo. 1938, V.29, 19-26. J 18. Littlefield, J. B .; Fcicht, Florence, L. j and Selirenk, II. H. Efficiency of Impingcrs for Collecting Lead Dusts and Fumes. R.I. 3401, U. S. Bureau of Mines, May, 1938. * 19. American Standard Association. Ben- 5 zene, allowable concentration. Z 37.4, 1941. 20. Cole, Peter A. Determination of the &g Concentration of Benzene and Toluene in * Air by a Spectroscopic Method. Jo. Optical-#! Soc. Am. 32, 304-306, May, 1942. $ Selection, Use an d Maintenance of.Respiratory Protective Devices* By H. H. SCHRENK Chief Chemist, Health Division, Bureau of Mines and S. J. PEARCE Associate Chemist, Gas and Dust Section, Central Experiment Station, Bureau of Mines, Pittsburgh, Pa. Published by permission of the Director, Bureau of Mines, U. S. Department of the Interior, Wash ington, D. C. ure or improper use of other control equip- ment. H. H. Schrenk, chief chemist, Health Di vision, Bureau of Mines and S. J. Pearce, associate chemist, Gas and Dust Section, Centra! -Experiment Station, Bureau of Mines, Pittsburgh, Pa. There are several well-recognized pro cedures for controlling exposure to hazard ous atmospheres in industry. They include (a) substitution of less toxic material, (b) enclosure of processes, (c) wet methods, (d) local exhaust, (e) general ventilation, and (f) use of respiratory protective de vices. In addition to their employment as a control measure in occupational exposures, respiratory protective devices also are essen tial in emergencies that may arise from fail Respiratory protective devices usually are ^ employed to supplement other methods of control, as a temporary expedient, or when ?. other methods are not readily applicable or 1 practicable. It seems reasonable to assume, :i| however, that where respirators are used, * consideration has been given to the factors 4' involved, and that the devices can provide satisfactory protection if used properly. Their '' use should not be arrived at simply by a \ process of elimination of other methods that i arc more difficult to apply. - Atmospheric contaminants include gases, ' vapors, dusts, fumes, mists, and fogs. Res- ? piratory protection against these contamin ants may be required for concentrations that ; are immediately dangerous to health or life Dust, 'times, Cases and Vapors 0. after comparatively short exposures, or that may produce injury only after prolonged or repeated exposures. Also, it may be necessary to use such devices against a single type of contaminant, against a combination of various types, or in atmospheres deficient in oxygen. To meet the conditions mentioned, various types of respirators have been developed. Two basic principles have been utilized in their development--purification of the inbaled air by removal of the contaminant (airpurifying respirators) and supplying a respir able atmosphere to the wearer from an uuenntaminated source (atmosphere--air or oxygen-supplying respirators). Air-Purifying Respirators Air-purifying respirators include canister gas masks and chemical cartridge respirators for removing gaseous contaminants and me chanical-filler respirators for removing par ticulate matter or dispersoids. Canister gas masks and chemical cartridge respirators may he equipped with filters for removing dis persoids, thereby giving protection against both gaseous and particulate contaminants. As these devices provide protection only by removing contaminants, it is obvious that sufficient oxygen must be present in the atmosphere to support life. A canister gas mask usually consists of a (til! facepiece connected by a flexible breath ing tube to a canister that may be carried in a harness on the chest, under the arm, ur on the back. The canister contains the materials for removing the contaminants and purifying the air. These materials remove the contaminants cither by chemical rcuctio. or by physical absorption, as on activate! charcoal. As no single substance has bcei discovered that will remove all types o gaseous contaminants, the canister fill de pends on the type of contaminant agains which it is designed to protect. Fortunately materials are available that will proter against groups of compounds; therefore, ; multiplicity of materials is not required. For example, activated charcoal will absorl organic vapors, and alkaline materials sud as soda lime and canstitc will remove ack gases. Ammonia may be removed by silica gel or by various materials impregnated will, such substances as copper or cobalt salts Carbon monoxide is removed by catalytic oxidation to carbon dioxide by Iiopcalite, a special preparation of manganese and cop per oxides. The protection that a canister affords depends on the material with which it is filled. For example, a canister may b< filled with activated charcoal alone and givt protection only against organic vapors, oi it may he filled with all types of the mate rials mentioned and give protection against all gaseous contaminants. For protection against a single contaminant the use of : single absorbent is desirable, as the life o the canister is longer, thus providing moi'economical protection. It is therefore extremely important t< know the contaminants against which ; canister will protect. To assist users in cas; identification, a classification of gas-mas! canisters has been developed in conjunctio with a color code. This code, which is a American standard used by all manufacture! of gas masks in the United States, is a follows ; Canister, type letter Contaminants proclccted against-- Colors A B C D A E, etc. AB ABC N Acid gases ......................................................... White.1 Organic vapors .................................................. Black.1 Ammonia ........................ ................................. Green. Carbon monoxide ........................................... Blue. Dusts, fumes, mists, fogs, and smokes in combi One-half inch contrasting bla nation with any of the above gases or vapors or white stripe around the ca ister near the top. Acid gases and organic vapors......................... Yellow. Acid gases, organic vapors, and ammonia...... Brown. All of the above atmospheric contaminants...... Red. Filters are included in tl canister, but stripes to indie . them are unnecessary. "Canisters for a single gas or vapor other than ammonia or carbon monoxide shall have a Z i-iv colored stripe around the canister near the bottom. The color of the stripe will be assigned. j j j / AiUional Sajcty Congress Canister gas masks have been developed primarily for protection against atmospheres immediately dangerous to life and are used mainly in emergencies. Therefore, first con sideration has been given to complete respira tory protection to prevent even momentary failure that might result fatally. These masks, however, are not designed for pro tection against extremely high concentra tions, and in Bureau of Mines Approval Schedule 14E concentrations are limited to two per cent by volume, with the exception of ammonia, for which the limit is three per cent. The service life of the canister depends on the individual characteristics and the amount of absorptive material used. Al though these masks are designed primarily for emergency use, they will, of course, give good protection for non-emergency situa tions, and filters may' be incorporated to remove' particulate matter. Chemical cartridge respirators usually con sist of a small cartridge or canister attached directly to a half-mask facepiece. The mate rials for removing the contaminants are the same or similar to those used in canister gas masks, and filters may be incorporated to remove particulate matter. These devices may be considered small gas masks and are designed for protection in atmospheres that could be breathed by workmen without pro tection, but that might be irritating or dis agreeable or produce injury to health after prolonged or repeated daily exposures; hence, primary consideration has been given to light ness, compactness, and comfort. Mechanical-filter respirators usually con sist of a filter arrangement of some fibrous material such as felt or paper, in a holder connected directly to a half-mask facepiece. The fdter consists of fine fibers criss-crossed to form a maze or intricate network of tortuous passages. The dust, fume, mist, and fog are removed by physical trapping when the air is drawn through this material. The filtering efficiency increases as the dust load on the filter increases. The service life of the filter, therefore, does not depend on recogniz able leakage, as does that of the gas masks, but on increase in resistance of the filter to a point where resistance to inhalation be comes excessive or uncomfortable. Although the filters will remove all types of particulate matter, the extent to which the material is removed depends on the characteristics of the particles, such as size and state. Also. the amount of permissible leakage depends on the toxicological significance ol the mate rial. Therefore, various types of filters are used; that is, a filter may be satisfactory for silica dust and not satisfactory for a toxic dust such as lead or cadmium, owing to the greater toxicity of the latter. A filter that is satisfactory for dust (mechanically generated, as by grinding) may not be satis factory for fume produced by heating or burning, as in lead burning, owing to par ticle-size differences. On the other hand, a filter satisfactory' for silica dust is considered satisfactory for all other fibrosis-producing dusts and nuisance dusts; and a filter con sidered satisfactory for lead dust is con sidered satisfactory for other toxic dusts, the toxicity of which does not exceed signif icantly that of lead. Mechanical-filter respirators have been de signed for protection against atmospheres that are not immediately harmful; there fore, primary consideration has been given to lightness, compactness, and comfort. Atmosphere-Supplying Respirators Respiratory protective equipment that sup plies a respirable atmosphere from a source independent of the wearer's immediate atmos pheric environment is of two basic types--a hose type, in which air from an uncontam inated source is conveyed to the wearer through a hose or tube, and a self-contained ty'pe, in which a supply of oxygen is carried by the wearer. The air-supplying respirators commercially available may he divided into three types: Hose masks, air-line respirators, and abra sive blasting helmets, hoods, or masks. Hose masks consist of a tight-fitting, full facepiece, breathing tube or tubes, a harness, a comparatively large-diameter, noncollapsible hose line, and a hand-operated blower. The. harness and hose arc strong enough for $ rtheetriehvoinseg tmheustwenaoret r cinollaanpseemuenrgdeenrcyh,eaavndy V* weight and must not kink. The maximum # length of hose approved by the Bureau of Mines is 150 feet. The use of a hand-oper ated blower assures that a second person will be present in the event of difficulty. Also, the attachment of the hose to the 1 blower and the large diameter of the hose permit breathing without undue resistance, even though the blower is not operated. The SCSI Dust, Fumes, (jases and Vapors oy intake to the blower must be in uncont.-mmiated air. Hose masks are sturdily constructed, as they arc designed to be worn in atmospheres immediately dangerous to life and to afford protection against all types of atmospheric contaminants and atmospheres deficient in oxygen. Special-type hose masks without blower and generally used with about 25 feet of huso also are available. Although the hose, breathing tubes, and facepieces are essentially the same as those for hose masks with a blower, the harness is much lighter and the device is designed for lightness, compactness, economy, and simplicity of operation. Such masks arc designed for non-emergency use or for use in atmospheres not immediately dangerous to life. Air-line respirators usually consist of a high-pressure air-supply system, a hose of relatively small internal diameter, a detach able coupling, and either a full or halfmask facepiece, or even a helmet or a hood. As the air for this type of respirator usually is sup]died from a high-pressure compressedair system, it must be checked to see that it does not contain objectionable or harm ful contaminants. Dust from dust, oil mists, odors, and even carbon monoxide may be present if the compressor becomes too h o t; therefore, critical attention should be given to the air supplied to these devices. Although this respirator will give respira tory protection against all types of contam inants, it is designed for routine protection against concentrations of contaminants that are not immediately dangerous to life or health. It is thus limited, owing to the pos sibility of leakage around the balf-.mask facepiece and also to the fact that no pro vision is made so that the wearer can breathe respirable air, should the air supply fail. Abrasive blasting respirators are essential ly air-supplying respirators that have been modified by the addition of a suitable cover ing to protect the head and shoulders against impact and abrasion by rebounding material. They arc designed primarily for use in abra sive blasting operations and not for use in atmospheres that arc immediately dangerous to life. Tlie most common devices for supplying "xygen to the wearer are self-contained oxygen breathing apparatus. These appafdtus consist of a cylinder of compressed oxygen, a reducing valve, an admission valve, a breathing hag, breathing tubes and mouth piece with valves for direction of inspired and exhaled air, a regenerator for removing carbon dioxide, and a cooler. They operate on a closed-circuit principle, and the entire device is worn by the user. When the cylin der valve is opened the oxygen flows through the reducing valve, thence through the ad mission valve, into the breathing bag, until the hag is expanded to a point at which the admission valve automatically cuts off the supply of oxygen. Oxygen is breathed from the bag, and the exhaled air passes through the regenerator to permit removal of carbon dioxide, thence through a cooler, and hack to the bag. As oxygen is consumed, the hag tends to collapse, and the admission valve automatically admits additional oxygen. Self-contained oxygen breathing apparatus give respiratory protection against all types of atmospheric contaminants in any concen tration that can be endured by the skin but require gas-tight goggles in atmospheres irri tating to the eyes. They also protect against atmospheres deficient in oxygen and are designed for protection against atmospheres that are immediately dangerous to life. Selection of Respirators The use of respiratory protective devices as a control procedure requires as much consideration as any other control method. In the selection of a respirator, thorough consideration should he given to various factors involved, such as: a. the chemical, physical, and toxicolog ical properties of the -substances against which protection is required b. the effect of the processes and condi tions of use of the substances as they relate to the |K>ssiblc formation of significant sec ondary products c. the processes and conditions of their use as they relate to the dissemination of contaminants d. an evaluation of actual and potential hazards to determine whether conditions im mediately dangerous to life or health might arise or whether injurious effects would be produced only after prolonged or repeated exposures ! 70 31st National Safety Congress e. the nature of the duties to be per with blowers and gas masks. Owing to formed by the wearer of protective devices their weight and maintenance and training s y.* - <: y v.yioV:#-* i-y as they relate particularly to restriction of requirements, oxygen breathing apparatus movements probably would not be used. The hose mask f. an understanding of the principles, de sign, scope of use, limitations, advantages, and disadvantages of the respiratory protec tive equipment available. would be satisfactory and might be chosen if the encumbrance of the hose line were not too great. The most probable choice would he a gas mask, because of its light weight, ease of maintenance, and the small amount of Virtually all applications of respiratory training required by the wearer. The appro protective devices are specific and require priate canister should, of course, be chosen. individual attention. Examples of typical conditions with indication of choice of appro priate respiratory protection are given. Low concentrations are atmospheres that can he breathed without protection but that will produce discomfort and possible chronic Atmospheres deficient in oxygen may be extremely hazardous and immediately dan gerous to life. Only oxygen breathing appar injury after repeated exposure to them. Hose masks and oxygen breathing apparatus would give satisfactory protection, hut they would atus or a hose mask with blower should be be given little consideration for such a situa chosen for protection under such conditions. tion for the reasons already outlined. Gas Final choice between these two devices will masks, chemical cartridge respirators, or air " i-y.LkiVvC- :- . <. depend on working conditions. , line respirators would he satisfactory. Final For example, for rescue work in mines, the men must proceed for considerable dis tances from a source of fresh air. Obvipusly, choice would depend on actual conditions and freedom of movement required by the worker. For pneumoconiosis-producing and nuisance hose masks would not be satisfactory, as dust, air-line respirators and pneumoconiosis? wearer? are limited to a distance of 15C| feet; producing- and nuisance-dust respirators or therefore, oxygen breathing apparatus must all-dust respirators could be chosen. If the be used. However, for use in entering con dust concentration is exceedingly high, air fined spaces, such as tanks and manholes, line respirators would be preferable. If the hose masks are generally preferred because conditions of work are such as to interfere they arc easier to maintain and relatively with the use of an air-line, mechanical-filter little training' is required to use them. Air- respirators will serve satisfactorily, even purifying devices should never be worn in though they are awkward to wear for many atmospheres deficient in oxygen. kinds of work. By very high concentrations is meant For toxic dust, air-line respirators, toxicthose exceeding two or three per cent. Either dust respirators, or all-dust respirators would oxygen breathing apparatus or hose masks be a logical choice. The final decision will de with blowers are the logical choice, and pend on local conditions of work and the ma- L;. again final selection will depend on working terials being used. Knowledge of the concenconditions. Although gas masks might afford trations likely to be encountered and of the some protection, they would not be a good safe or permissible concentration is necessary '$ choice, because very high concentrations in in evaluating the protection afforded. dicate a confined space with possibility of low oxygen ; moreover, the absorbents would Fume is particulate matter formed by > be used up rapidly. The marked discomfort volatilization and condensation, as in lead '! produced by such irritating gases as am burning. Fume is defined because it is a term monia ail'd sulfur dioxide ami the danger of used loosely to refer to gases, vapors, and poisoning through the skin by absorption of particulate matter. Such usage is confusing \ hydrogen cyanide limit the concentrations and may lead to serious injury if a median- that can he entered. ical-filtcr fume respirator is used for pro tection against some toxic gas or vapor Concentrations referred to here arc those against which it affords no protection. For not exceeding approximately two per cent fume as defined above, air-linc respirators but nevertheless immediately dangerous to or mechanical-filter fume respirators would lift. Oxygen breathing apparatus would, of be the logical choice, and final decision would course, be applicable, as would hose masks depend on local working conditions. ry Dust, F u m es, Gases and I 'apart 71 Frequently protection must be afforded against a combination of gases and particulate matter (dust, fume, mist, and fog). If the atmosphere is not immediately dangerous to life, air-line respirators are generally rec ommended. However, gas masks equipped with a suitable filter or cartridge-type respi rators equipped with a suitable filter may be used. Final decision not only would depend on the local conditions of work as they relate to freedom of movement but also on thorough consideration to ascertain whether gas masks or cartridge respirators would give the desired protection. Use of Respirators Although choice of a suitable respirator is important, other considerations are equally so. Obviously, if a respirator is to do the job for which it is chosen, it must be worn properly and he kept in good condition. Fre quently persons do not know how to wear a respirator, and if it is not clean it is un pleasant to wear. Better protection and fuller cooperation doubtless would be obtained if the respiratory protective devices were kept under the supervision of a responsible person who would see to it that the wearer is properly instructed in the use of the device, that the device is cleaned and disinfected regularly, and that it is maintained in firstclass condition. Xo instructions arc necessary when hard hats or hard-toed shoes arc given to work men, as they are used to wearing such ar ticles. Too frequently respirators are handed out in a similar manner. Even the simplest respirator is comparatively much more com plicated than protective hats or shoes and is a device that most workers are not accus tomed to wearing. The principles on which each device is based, its field of use, and its limitations, as well as the essential parts, should he explained to the wearer in terms be can understand. Detailed instructions with practice should he given to all persons who are expected to wear such devices. Further, an explanation of the importancc'of wearing the respirator should be helpful in obtaining more complete cooperation. For example, in the use of mechanicalfilter respirators attention should be called to the importance of a good facepiece fit and pi per but comfortable adjustment of the headband, and also to the fact that increased resistance to inhalation indicates that the filter should be cleaned or renewed. In the use of gas masks good facepiece fit is also necessary, and the proper canister must be chosen. As the wearer depends on odor or irritation to warn when the canistei is exhausted, he must be acquainted with the warning properties of contaminants for which protection is worn so that leakage will be delected readily. Persons using gas masks in toxic atmospheres should have had pre liminary training in the use and limitations of the equipment. All respirators approved by the Bureau ol Mines are furnished with an approval lahe' that gives concise information on use and limitations. Also, more detailed instructionthat have been reviewed by the Bureau ac company all approved devices. Both approva' label and instructions should be consulted by the user. Cleaning and Disinfecting Respirators Respirators, particularly the facepieces should be scrubbed daily after use with luke warm water and soap. This not only is good hygienic practice but also prolongs the life o: the rubber, as otherwise the dirt, oil, am perspiration from the face may cause rapii deterioration. Respirators should also be dis infected at regular intervals. If a respirato: is worn by the same person, disinfection onc< a neck probably should be satisfactory ir most instances, depending on conditions o use and thoroughness of cleansing with soa: and water. A respirator that has been won once should be disinfected before it is give: to another person to wear. There are several procedures for disin fecting respirators; however, as certain res pirator parts may be damaged by the dish: fecting agent, the manufacturer should ! consulted as to the best procedure for hdevice. This warning is particularly pcrtimi at present, when the use of substitute mat: rials is so common. Common disinfecting procedures includ scrubbing or immersing the respirator fu 1(1 minutes in 70 per cent alcohol, two pi cent crcsol, or a solution of formalin mac! by mixing one part of 40 per cent formaldi hyde in nine parts of water. W hen sm agents as cresols arc employed as disinter ants, the parts that come in contact with tl 72 31st National Safety Congress skill should lie rinsed thoroughly with water, made, it should be stored properly. as some persons are highly sensitive to such materials. A good procedure is to have a central place of storage, possibly with sub-stations Cleaning and disinfecting afford an oppor at strategic points if the plant is large. Stor tunity for cleaning or replacing filters, in age should be in essentially dustproof con specting valves, headbands, facepieces, and tainers away from sunlight and in a cool metal parts that might be distorted. place (not near radiators or steam pipes). Small devices, such as dust or chemical Maintenance and Storage cartridge respirators, can be kept in paper or cellophane bags. These devices may be A most important phase of any control numbered and assigned to some one person, procedure is maintenance. Choice of proper who returns them at the end of the shift equipment, and adequate instruction are com to the central station for cleaning and re pleted projects, but maintenance is a con placement of filter elements, and for repairs tinuous problem requiring constant atten if necessary. Thus, wearers are assured clean tion. As such it should be supervised by devices in good working order for each day's someone thoroughly familiar with the appar use. This program may be facilitated by as atus being used. signing two respirators to each person, one Washing and disinfecting the device af being used while the other is being serviced. fords an opportunity to inspect it for minor Larger devices, such as gas masks and repairs. In addition, it should be inspected hose masks, usually come equipped with a thoroughly at monthly or longer intervals, sturdy case or trunk that can serve as a depending on the apparatus, conditions of storage place. If they are stored at strategic use, and storage. Devices for emergency pur points for emergency use, they might be poses should be inspected after each use to placed in a case with a glass window that assure that they will be in good condition requires breaking of a seal to assure that t, and immediately available if an emergency they have not been used or tampered with. 1 arises. After the equipment has been cleaned The seal should bear the date of the last and inspected and any necessary repairs inspection. Fii Presiding. The pun. imum of d called "lawof certain .: reduce thr u-inch, acco tions, shoe.!' Since 19. going cons' of the ch.. greater hum When it and towns, forts and f<> open or u offer no re A non-C". gerent sta His person protected h is not a At the ' Hague tinthat hostil. commence equivocal i of a decla:. In this i" days of o broken. Tin can'ization represented . >tiy bigger today, five enty times bigger than ;co. The safety superjot that many problems ^ j n a n y problems again, ^ J fly in greater proporpersonnel involved. tanning Job "icrvisors in general take :is point: that the bigger ts to be, the less their e, which is perfectly all 'rganization, and vastly ning, training, coordinat o r people who in turn es to all levels of superloesn't it? And yet how illy changed our thinking not only saiety men but in a position of where ring miracles every day, h regular standards, and be balked by the little . has hit a point here-- miraculous operation yet t little key spot there, granted. . i take away the thought re, through all this dis' me, put it together, can :.lining, of thinking, of ittle things in principle i'-Of we cannot get away t so many personnel rather people concerned ispects of industry arc inuallv, and that is of to beg for the little . big things that must be that we become enough se little details, which have not thought to go plan a program such as - talked about here in is Miss Norton has gone ii links the problem once ding the idea to manage.es you a policy and a Steam Railroad Section Officers 1941-1942 General Chairman--O. F. Gnadinger, Elgin, Joliet & Eastern Railway Co., Joliet, 111. Vice-Chairman--F. A. Bogue, Chicago, Rock Island & Pacific Railway Co., Chicago, IU. Secretary and News Letter Editor--H . A. D aake, Erie Railroad Co., Cleveland, Ohio, Program Committee--F. A. Bogue, (Chairman), Chicago, Rock Island & Pacific Railway Co., Chicago, III. P. F. B uckle, Chicago, Burlington & Quincy Railroad Co., Chicago, 111. G. W. E lste, J r., Baltimore & Ohio Railroad Co., Baltimore, Md. Membership Committee--R obert Scott (Chairman), Atlantic Coast Line Railroad Co., Wilmington, N. C. _A. V. R oiiw eder, Duluth, Missabe & Iron Range Railway Co., Duluth, Minn. Statistics Committee--T. H. Carrow (Chairman), The Pennsylvania Railroad, Philadelphia, Pa. F. R. Bradford, Boston & Maine Railroad, Boston, Mass. D. G. P hillips, Wabash Railway Co., St. Louis, Mo. Contest Committee--C. E. H ill (Chairman), New York Central System, New York, N. Y. L. G. Bentley, The Chesapeake & Ohio Railway Co., Richmond, Va. L. R. P almer (Secretary), Equitable Life Assurance Society of the U. S., New York, N. Y. J. J. S navf.ly, New York, New Haven & Hartford Railroad Co., New Haven, Conn. Poster Committee--W. R. Lofgren (Chairman), Chicago, St. Paul, Minneapolis & Omaha Railway Co., St. Paul, Minn. G. M. D empsey, Chicago, Milwaukee, St. Paul & Pacific Railroad Co., Chicago, 111. O. A shworth, The Alton Railroad Co., Bloomington, 111. Safe Practices Pamphlet Committee--W. J. Flannigan (Chairman), Northern Pacific Rail way Co., St. Paul, Minn. J. R. T enney, Western Maryland Railroad Co., Hagerstown, Md. R. C. H f-lwig, The Delaware & Hudson Corp., Oneonta, N. Y. Nominations and Elections Committee--E. L. H enry (Chairman), Chicago & North Western Railway Co., Chicago, 111. M. T. F ulton, Kansas City Southern Railway Co., Kansas City, Mo. M. A. Lf.ahy, Chicago, West Pullman & Southern Railroad Co., Chicago, 111. Health Committee--D r. I. S. C utter (Chairman), Chicago & North Western Railway Co., Chicago, 111. D r. H arvey B artlf., The Pennsylvania Railroad, Philadelphia, Pa. 663 664 31st National Safely Congress Officers 1942-1943f General Chairman--F. A. Boc.uk, Chicago, Rock Island & Pacific Railway Co., Chicago, 111. I1'tee-Chairman--H. A. Daake, Erie Railroad Co., Cleveland, Ohio. Secretary-- M . T. F u l t o n , Kansas City Southern Railway Co., Kansas City, Mo. A'civs Letter Editors--M. T. F u l t o n , Kansas City Southern Railway Co., Kansas City, Mo. II. G. T o w n s e n d , Kansas City Southern Railway Co., Kansas City, Mo. Program Committee--J. R. T e n n e y (Chairman), Western Maryland Railway Co., Hagers town, Md. P. F. B u c k l e , Chicago, Burlington & Quincy Railroad Co., Chicago, 111. H. A. D a a k e , Erie Railroad Co., Cleveland, Ohio. Membership Committee--G. W. E l s t e , J r. (Chairman), Baltimore & Ohio Railroad Co., Baltimore, Md. J. E. L o n g , The Delaware & Hudson Railroad Corp., Albany, N. Y. Statistics Committee--T. H. C a r r o w (Chairman), The Pennsylvania Railroad, Philadelphia, Pa. F. R. B r a u f o r d , Boston & Maine Railroad, Boston, Mass. D. G. P h i l l i e s , Wabash Railway Co., St. Louis, Mo. Contest Committee--C. L. L a F o u n t a i n e (Chairman), Great Northern Paul, Minn. O. F. G n a d i n g e r , Elgin, Joliet & Eastern Railway Co., Joliet, III. L. R. P a l m e r (Secretary), Equitable Life Assurance Society of York, N. Y. Railway Co., St. the U. S., New Easter Committee--E. L. H e n r y (Chairman), Chicago & North Western Railway Co., Chicago, 111. G. M. D e m t s e v , Chicago, Milwaukee St. Paul & Pacific Railroad Co., Chicago, 111. J. J. Snayely, New York, New Haven & Hartford Railway Co., New Haven, Conn. Safe Practices Pamphlet Committee--W. J. F l a n n i g a n (Chairman), Northern Railway Co., St. Paul, Minn. S. C. F l a g l e r , Atchison, Topeka & Santa Fe Railway Co., Topeka, Kansas. H. C. H e l w i g , The Delaware & Hudson Railroad Corp., Oneonta, N. Y. Pacific Xominations and Elections Committee--W. R. L o f g r e n (Chairman), Chicago & North Western Railway Co., St. Paul, Minn. C. M. K i m b a l l , Southern Railway System, Washington, D. C. L. B. H a r p e r , Illinois Central System, Chicago, 111. Health Committee--Dr. I. S. C u t t e r (Chairman), Chicago & North Western Railway Co., Chicago, III. D r . H a r v e y B a r t l f ., The Pennsylvania Railroad, Philadelphia, Pa. a \ a Itclrtl lv delegates in Congress session. Steam Railroad Section 6S TUESDAY AFTERNOON SESSION October 27, 1942 Presiding:--O. F. G n a d i n g e r , Supvr. of Safety, F.lgin, Joliet and Eastern Railway Co., Joliet, 111. Greetings From Safety Section, A..R. By P. F. BUCKLE Supt. of Safety, Chicago, Burlington & Quincy Railroad Co., Chicago It is, of course, an honor and a privilege to be able to bring to this meeting greetings from the Safety Section of the Association of American Railroads. There never has been a time when it was so important that those of us who are en gaged in accident prevention endeavor to consolidate our positions, to do everything within our power to promote harmonious relations between all safety agencies in the interest of producing the maximum of coop erative effort in this most worthwhile of activities. Whatever may have taken place in the past that brought about disunity or lack of har mony between these two important agencies should now be forgotten, and it should be the duty of each and everyone of us to make these two organizations as effective as pos sible, above everything else, in the interest of winning this war, never forgetting the humanitarian aspect of our responsibilities. We can only bring these things to pass by subordinating our personal prejudices or de sires for the common good. I hope I shall always be able to do this and I need the help of every one of my associates in bring ing this to pass. Whatever accomplishment has come to the Safety Section during the time that I have been privileged to serve the Section as chairman has resulted because of the cooperative effort of all active members of the organization; for that I am deeply grateful. We cannot continue these two organiza tions and have them function as we desire them to function unless able men are willing to serve as officers, as chairmen of commit tees and as members of these committees, giving freely of their time and best efforts for the benefit of the sections and their re spective endeavors. Both of these organiza tions are necessary, especially during these times which "try the souls of men." The Steam Railroad Section needs to be a strong, going concern to take its place in carrying out the War Production Fund program. Tin Safety- Section should back this endeavor te the full. Personally I pledge that support. It is again a privilege and an honor t< bring to the Steam Railroad Section greet ings from the Safety Section of the A. A. R and I think all of us ought to keep in mim' the need for strengthening friendships. Tin gift of friends, to my mind, the most potoiv ami pleasant thing in life, becomes increas ingly important with the passing of the days lu- attempted to govern solely 60 days every one of his em- '.vorking at cross purposes-- but because no matter what ~ y satisfied. It was neces^ n n of the headship of his 1er to accomplish-the assigned delaying the work of other Desirous of saving him for imi-e was made an-assistant to a :'y old chief. His shortcomings -d to him and he was smart fit by his mistakes. Today he is 'dly. He has learned to know !c of production. v are justified in taking on :s, if arrangements can be made re-examinations. In addition, uy corrective procedures that -ted that will render one thor>cd to take a job for which would be rejected. Infections i cavity may be eliminated, and uarded with proper spectacles. ">t is no indication for non\ertheless the adjustment of ir to a badly depressed long- utarsal arch may be followed v.provemcnt in general health, in for work instead of the ise abscessed tonsils may be ; pre-employment hernia may ive have what is known as iiie soldier. It would be a not- industry if we could revive in te re st in the school of the * supervisor could be in.-^ortant physical deficiencies . a position to help preserve men. There are a few simple i ll his employees would take than any one else. Further->tild heed. He can emphasize tv of excess weight, the im- feet, of proper clothing, of s food, of prompt attention `ie carefully controlled use of t.nnot gainsay the fact that nent predisposes to accidents, used to excess. >.ary organizations grade from .? to the highest ranking gen\ there are a number of com-.-e at the same time teachers Steam Railroad Section 673 and leaders. In fact, it is a well recognized concept that the sergeants, from buck to mas ter, run the army. In like fashion, the fore men run the industry. They know their men. But they can become mentors not only in technical procedures but in all the factors which make for well being. They can learn and pass on simple first aid regulations which are safe as well as numerous precautions which will reduce hazards. A few hours of in struction to the members of this group (foremen) will be fertile seed sown upon rich soil. The output of many a plant can be gauged by the active integration of the organization coupled with the good health of the em ployees. But every task does not require a Hercules. In fact, there are many jobs that can be performed with dispatch by a man with one leg, one eye, etc. It becomes then the task of fitting the qualities, attributes, and skills of the applicant to the duties to be accomplished. It is well known that handi capped men and women are among our most loyal, faithful, and conscientious workers. WEDNESDAY AFTERNOON SESSION October 28, 1942 Presiding:--O. F. G n a d i n g e r , Supvr. of Safety, Elgin, Joliet and Eastern Railway Co., Joliet, 111. Safety and Labor Relations By H. J. HOGLUND Chicago, Burlington & Quincy Railroad, Chicago Labor relationship has much to do with the attitude of mind of the worker, and upon this attitude of mind hinges the thinking before acting which is so fundamental to safety. Because of lack of control of action, be cause of thoughtlessness or because of mental laziness, needless accidents occur, and pre vention constitutes a real problem to perfect the attitude of mind. Good housekeeping, keeping tools and ma chinery in order eliminates much exposure to hazard, and its importance cannot be over emphasized, but despite these precautions ac cidents occur unless there is good labor re lationship. For years safety officers have been preach ing safety, and the results speak for them selves; they arc reflected in the record of the American railroads. You started way back in the early 20's talking about the three E's of safety--cardinal principles of great im- portance--yet consciously or otherwise, you added a fourth E which stands for the en thusiasm you have steadfastly maintained. Safety is the work of morale builders and morale cannot be built without the Nth de gree of enthusiasm. Our supervisors should keep this in mind. Primarily the supervisor is responsible for the safety of his workers, and he should devote a great deal of effort to the art of handling or leading men. Generally speaking, this skill can be acquired only through lead ership training. The worker's attitude toward his job, his company, his fellow workers and toward his supervisor is, to a greater extent than some realize, the essence of good labor relations. Everything possible should be done to avoid irritating workers. Irrespective of all other conditions surrounding a man's job, if he has an irritating type of supervisor, he will not perform his work cheerfully, and lie is not, under such conditions, likely to be as I production schedules in ued delivery. Existing listed at 9:25 A. M. . . . : parts will begin to be ^bt so they will arrive A. M. No loss of "no lapse of time that the bullets out of Allied 11 laid plans, but, then a anders aimlessly through The fast freight loaded rials bears down on him, Vrhaps that train is debecause of that accident. - to be arranged to give in light that will once n the rails at full speed. : its destination at 11:08 two hours late, and the cded parts arrive at the 1:25 A. M., which is alhours of war production re 8,000 persons in that r material to start down . That's a total of more man-hours lost because wandered into the path Sounds a little fantastic, "right agent or someone rent of a railroad com- | he surprised to learn this j ill too often. But, then j >f this nature would be | -%e officers of the rail* because they come rthe trespass problem. 1 1,781,398 trespassers ad property, some of cords. Railroad officers en of great assistance . persons who have no e railroad and will convely. ' Steam Railroad Section 677 THURSDAY AFTERNOON SESSION October 29, 1942 Presiding:--0 . F. Gxapixgkr, Supervisor of Safety, Elgin, Joliet & Eastern Railway Co., Joliet, 111. Notes By W. R. LO FG REN Ass't. Supt. of Safety, Chicago & North W estern System, St. Paul, Minn. A highlight of the entire program was ~Mime, and meets. Messrs, Helhveg (D&H), that portion conducted by the inquisitive Mr. Phillips (Wabash) and Lofgren (CStPM \V. J. Flar.nigan, Superintendent of Safety, &0) responded to questions. Northern Pacific Railway, who desired to know so many things. This type of program is outstanding and reminds us very much of Train Accidents the lively "rump" sessions of 1939 at At The inquisitor called attention to the in lantic City and last year at Chicago. The crease in train accidents per million locomo delegates also requested a great deal of in tive miles run in 1941 over 1940, and in formation and the response was energetic. connection with checking speed restrictions, Mr. Flannigan's first interrogation dealt with the involvement of hand signals in a large number of train accidents and the fact that failure in this respect could probably be charged to the new employee--the rules providing that utmost care must be exer cised by train, engine and yardmen in order to prevent taking signals that may be in tended for other trains. The question in con observance of block signals, not permitting second or other sections of regular trains to proceed on yellow block, strict compliance with Rule 99 instead of merely "decorating" and other means oi preventing collisions, Mr. Allison of the Baltimore and Ohio was called upon and gave a very good description of plans employed to train and supervise em ployees to comply with the rules. nection with supervision of older employees Mr. Washburn of the Milwaukee Road and likewise the training of new employees made an excellent response to the question to see that proper signals arc always given of manner of preventing hand brake accidents was answered by Mr. Cates of the Seaboard by describing the CMStP&P hand brake in Air Line, who stated the practices in effect struction car which has been on the road on the SAL. since last February. (See News-Bulletin A number m' delegates participated in an swering the next item which covered the causes accounting for the largest group of train accidents, i. c.. overrunning meeting point, disregard of stvp and caution signals, which would mostly he chargeable to the older employees, and how they were being prevented by ta) physical examination, (1>) rules examination, (c) surprise test and (d) checking dispatchers and operators for ac curacy and compliance with the rules pro viding for issuance of train orders. Other sub jects covered were higher speed, advance yard limit boards, proper respacing of auto Number 3 c: March, 31st). Mr. Lowe like wise described the plan of the Southern Pacific Company of having the different types of hand brakes mounted on a platform at two locations--Klamath Fails and Duusmuir-- where train and yardmen arc hired and given complete instruction in operating hand brakes safely. In this connection, Mr. Collett of the Santa Fe suggested that a 16 mm. sound film be prepared on the proper operation of hand brakes, etc., Chairman Gnadinger ad vising that preparations for a sound slide film were being made by the Committee on Educa tion, Safety Section, AofAR. matic block signals and checking of brake- Question if constant checks were made men on assistance given to conductors and to make certain that proper elevation of engineers in watching train order signals, curves and other track maintenance stand-