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'f " " <V / Safety ffitsrsress NATIONAL SAFETY COUNCIL, l,,c. KANSAS CITY, MISSOURI OCTOBER 11 to OCTOBER 15, 1937 Municipal Auditorium Copyriffrl, 1937, Nalitail S/*lr J. THE Transactions of the Twenty-sixth National Safely Congress, 1937, are published by the National Safety Council in two volumes. This, the first, contains the general, the special subject, and the Industrial Section sessions. The second volume contains the sessions of the Child Education, Home Safety, Street anti Highway Traffic, Commercial Ve hicle and Transit Sections. All-industrial members of the Council automatically receive Volume I. Volume II is sent to members believed to be interestc,l chiefly in the sessions it covers. Other Council mem bers, however, may obtain it upon request. Many members have found it worth while to distribute copies of the Transactions to supervisors, foremen, and olhers in an administrative or supervisory position who may make practical use of them for reference purposes. The fol lowing quantity prices are quoted on extra copies: I to II) copies of the large volume (Volume I), $2 each; 11 copies or more, $1.75 each; copies of the smaller volume (Volume 11.I, 75 cents each. THE Transactions arc published as a condensed record of the proceedings at the National Congress. The papers ol: each session or division of the Congress have been edited1 carefully to eliminate extraneous matter and to abbreviate the less essential portions because oi space limitations. Thus the material herein presented is not a verbatim report of all the speeches presented at the Congress, but rather an abridged version made as compact as possible, yet without injury to the technical aspects of any address. The original manuscripts arc on file in the Council's llurenu of Informa tion, where they are available for additional reference. Where illustrations were sent by the speakers to the Council, these also arc on file. The National Safety' Council at its Congresses seeks to eliminate from discussion matters which are not pertinent to the aim of the Congress or which are contrary to Council policies. It cannot accept responsibility for the views ex pressed either in the papers presented or in the discussion;, based upon the papers. NATIONAL SAFETY COUNCIL, Inc. 20 North Wacker Drive Chicago Council Officers and Directors...................................................... * Council Purposes and Policies.................................................... 9 Annual Meeting of Members......................... .............................. ft Annual Banquet................................................................................ Subject Sessions- After Work Accidents............................................................ 33 Agricultural Safety....... ............ 41 Community Safety Organization.......................................... SI Fire Prevention .................................................... *............... 59 Healllj,Service'in Industry............................ 71 Industrial Dusts............................................ 85 Indusj^jat Fumes, Cases and Vapors................................... 99 Industrial Safety Lectures.................................. .................109 Maintaining Interest in Safety...........................................HI Pressure Vessels .............................................. 157 * Safety Fundamentals ..............................................................173 Safety Inspectors ...................................................................183 Safety Training ........................................................................193 Safe Use of Acids...............................................T................... 201 Aeronautical Section....................................................................... 211 , A.S.S.E.--Engineering Section...................................... ............. 221; Automotive and Machine Shop--Power Press Sections......... 225 Cement and Quarry Sections...........................................................249 Chemical Section .................................,......................................... 271 ' Construction Section.......................................................................28S Food Section.............................;......................................................307 Industrial Nursing ...........................................................................323 Marine Section .................................................................................. 341 Meat Packing, Tanning and Leather Industries Section....... 371 Metals Section............................................ 381 Mining Section........................................................................... .401 Paper and Puip Section....................................................................429 Petroleum Section ...........................................................................489 Power Press Section.............................. 535 Public Utilities Section.......................... 537 Quarry Section...........................................>....................................... 5S7 Refrigeration Section......................................................................559 Rubber Section ..........................................;.................................... 577 Safety Equipment Section.................................................................... 581-- Steam Railroad Meeting.............................'................................... 587 Textile Section ................................................................................ 601 Wood Products Section..................................................................611 Index .........................................................I................................... 621 afiiowal ifelhy Esae. I HONORARY MEMBERS Assort \tion of Ikon' anh S\u:i. Engineers \ Rom kt \V. Cvmi iii 11 Lew K*. Pai.mer > OFFICERS (1937-1938) I). .). Fenneie, President .j C. W. Demi-ksv, Vice-President lor Finance ami Treasurer Harry Ouii.ni RT, Vicc-Prcddcnt for Membership Frank II. Harrison, Vice-President for Industrial Safety I Ion. ll ARrii.ii C. Hoitsian, Vice-President for Public Safety W.\l.n.R S. Paine, Vice-President for Engineering A. V. Roiivveiiek, Vice-President for I.ocal Safely Council* A. W. Whitney, Vice-President for Education U'. H. Cameron, Secretary and Managing Director EXECUTIVE COMMITTEE (1937-1938) ( H. W. Anukrson, General Motors Corporation J. I. Hanasii, Past President C. W. IJercouist, Past President Henry \V. Uoockss, Petroleum Secliuu C. ft. Holt.kt, ASSE-Etigincering Section H. W. Boulton, Automotive and Machine Shop Section Haroi.d S. IlunENHttM, The American City Magazine W. H. Cameron, National Safety Council, Inc. Kouent W. Cami'mi:i.i., Pa-i President Korn ht I. C.YTI.IS, Aetna Casualty Sr Surety Company If. A. ClIAFFlN, Metals Seelimi I.eivis A. DeBi.ois, Past President C. \V. Pemfesy, The Liquid CarlMmic Corporation Mmia A. Pmv, I'a-l President I). I*. FeNXEI.i.. (oiisullinw Engineer John ll. Cinso.N, Western Electric Company Harry Giui.iiner, The Pullman Company Frank 11. Harrison, International Harvester Company P. L. G. Hasskari., Lehigh Valley Safety Council Hon. Haloid G. Huffman, Governor, Slate of New Jersey S. It. Morrell, F'ood Section Waitir G. Kino, Past'President -I OFFICERS AND DIRECTORS, Continued Wm. C. Knuf.i.k, Milwaukee Safety Commission John E. Lone, Past President Tims. H. MacDonald, U. S. Department of Agriculture Walter 11. Martin, Peoria Association of Commerce Safely Council L W. Millard, Industrial Gloves Company Harui.ii L. Miner, E. I. Utt Pont de Nemours K: Co. Prof. Roger L. Morrison, Street Jfc Highway Traffic Section E. J. 0`Hrien, Jr., Louisville Safety Council Wai.\E(( S. Paine, Aetna Life & Affiliated Cos. Lew E': Palmer, Past President C. Evij;ettihonk, Last President Ai.uekt S. Rev.ui.a, Industrial Relations Counselors, Inc. Lt. G/^l. Henry A. Kfkincer, Past President A. V. Roiiwedkr, Duluth, Missahe & Iron Range Railway Co. Geoki'.f. E. Sanford, General Electric Co. Charles II. Scott, Past President Gen. John H. Siierhuknf, Massacliuselts Safety Council ,, Judge Lee: E. Skeei, Cleveland Safety Council C. W. Smith, Standard Oil Company (lud.) Walter Dent Smith, Delaware Safely Council K. T. Soi.ensten, Elliott Service Company C. P. Toi.man, Past President George G. Traver, Greater Chicago Safety Council, Inc. Dr. C. H. Watson, Past President A. W, Whitney, National Conservation Itureau T. A, Wii.son, Textile Section W. E. Worth, International Harvester Co. Arthur H. Young, Past President DIRECTORS (1937-1938) George J. Adams, Paper and Pulp Section II. W. Anderson, General Motors Corp. A. L. Armstrong, Eastman Kodak Company II. II. IIah.ev, Chattanooga Safety Council J. I. Hanasii, Consulting Engineer Carl Barker, St. Louis Safety Council G. I. Harrf.it, Mining Section Ernlst W. Deck, United Slates Rubber Products, Inc. C. W. llLRGCjiasT, Western Eteclrie Co. F. Blank. Jones & Laughlin Steel Corp. Henry W. ItOGGESs, Pctroicum Section 11^ E. llol.T, South lltnd Civic Safely Council 5 Il FICERS AND DIRECTORS, Continued C. IJ. nout.LT, ASSE-Engiiiecring Section , II. W. UntiuoN, Automotive & Machine Shop Section 1'. S. IltamN, Standard Accident Insurance Co. W. A. IIiuhvn, Safely Department, Nashville Chamher of Commerce . W. T. I!i;cki.iiu>i'.i:, Employees' 1'uldication Section S. W. Ih'uctmi, Safetj Department, Automohilc Club of Rhode Island Hauoi ii S. lit; rKNitrui, The American City Magazine II. J. Cat t-M.iiAN. Contra Costa County Safety Council W. If. Cami:ruX. National Safety Council, luc. Uav Carney, Kenosha Safety Council Komar I. Catiin. Aetna Casualty & Surely Co.- R. A. Chaffin, Metals Section Ivennktii It. Oilman, Seattle Tral'lic & Safety Council J. E. Cut i.ixi.y, lielhlehcm Steel Co. Lewis A. Dt.litois, Consulting Engineer ( Jay E. Decker, Mason City Safety Council C. W. Demi-esv, The Liquid Carbonic Corp. James 11. Dolt.i.as. The Philadelphia Gas Works Co. Or. I.olis I. Dum.ix, Metropolitan Life Insurance Co. O. M. Edwards, Jr..,Safety Div, Syracuse Chamber of Commerce W. i\ Ei-stun, Public Utilities Section 1). I). Fenni.i.i, Consulting Engineer IT L. Fennell, Katt-as City Safety Council Donald A. l'i.\Kut:iM:ii, Toledo Safely Council I )r. Hart E. Fisher, Chicago Rapid Transit Co. Chester C. Fisk, llerkeley Traffic Safety Commission IhnvAKU li. Fonda, Burroughs Wellcome X; Co. (U.S.A.) Inc. Alexander I-usti k, Ju, Quarry Section John 11. Gitisnx, Western Electric Co. Howard E. Gilbert, Elizabeth Safety Council Onto M. Gravi s, The General Crushed Stone Co. W. A. Griffin, American Telephone &: Telegraph Co. . I Iariiv Guiliiekt, The Pullman Co. Isaiah Hale, The Atchison, Topeka & Santa Fc Ry. Co. C. If. Hvritr, Refrigeration Section D. T. II xkKlxt.lfiX, U. S. Bureau of Mines Frank II. Harrison. International Harvester ('>. P. L. G. IIasskxRI, Lehigh Valley Safety Council R. C. Hwln. Commercial Vehicle Section G T lint unit, Clin ago. Ninth Shore & Milwaukee RR. (Jo. (' n \s I llui. N\ \u.h (\ntial I mi, II..> llik.iint. Ihuiuw Gmciiu.r. State of New Jcrsiy I t 11 ..i i.i In , VI ii pic Sit I mu 6 1 II OFFICERS AND DIRECTORS, Continued Evkkctt Horii, Madison County Safety Council S. II. Horkli.i, Food Section II. C. Howsam, Power Press Section 1). Hunt, Cement Section Major Norman A. I Mint:, Columbus Safely Council R. I). Jtsvkit, Springfield Safety Council Tiiomas P. Kearns, Industrial Commission of Ohio Titos. L. Kei.i.kv, Paterson Safety Council J. M. Kerriuan, Rubber Section VVm.' C. Knoi.i.k, Milwaukee Safely Commission WmMS. Knudskn, Detroit Industrial Safety Council C. LT1al-'ountatNE, Great Northern Railway Co. Millard C. Lefi.f.r, Child Education Section UaknA' Levy, Jk., Rochester Safety Council A. Aucustus Low, Brooklyn Safety Council Titos. H. MacDonai.u, U. S. Department of Agriculture Walter B. Martin, Peoria`Association of Commerce Safety Council F. W. Matson, Minnesota Safely Council R. A. McArthur, Transit Section Miller McClintock, Harvard University' ~ I. W. Millard, Industrial Gloves Co. James K. Mili.kr, Grand Rapids Safety Council Harold L. Miner, E. 1. du Pont dc Nemours & Co. R. II. Muut.EV, Industrial Accident Prevention Assns. Prof. Roukr L. Morrison, Street & Highway Tralftc Section Ernest Mukviiv. Albany Safety Council E. J. O'Uhien, Jr, Louisville Safety Council Georoe C. A. Off, The Detroit Edison Co. Walter S. Paine, Aetna Life Sc Aflilipted Cos. Lew R. Palmer, The Equitable Life Assurance Society of the U. S. David A. Patton, Newark Safety Council Mrs. G. if. Pki.ton, Evanston Safely Council Charles W. Pendock, Safety Div. Milwaukee Association of Com merce C. E. Pettioone:, American Mutual Liability Insurance Co. Gin. Glohoi: II. PillstiL'KV, United Slates Engineer Office AkTitL'R Potiehion, Hudson County Safely Council Albert S. Rkcula, Industrial Relations Counselors, Inc. Lt. Col. Henry A. Rfxini.ek, Lehigh Portland Cement Co. Bestor Robinson, Easlbav Safely Council viA. V. Roihyeder, Duluth, Missahc & Iron Range Ry. Co. Walter Roseniiaum, Western Peimsylvaitia Safety Council G,.E. Sanford, General Electric Co. 7 OFFICERS AND DIRECTORS, Continued Henry C>. Schaffnkr. Eric Safely Council Karl G. Schof.fh.er. Rahway Safety Council Harry A. Schultz, United States Steel Corp. H. E. Seely, Wood Products Section Earl S. Shartzek, Utica Safety Council Gen. John H. Sherrurne. Massachusetts Safety Council Dr. L. A. Shouoy, Bethlehem Steel Co. ' Ernest L. Simondr, New Haven Safety Council A. E. Sinclair, Meat Packing, Tannine & Leather fndu-tries Section Judge Lee E. Skeei, Cleveland Safety Council C. W. Smith. Standard Oil Company (Iml.) Edwin C Smith, Blackstonc Valley Safety Council Walter Dent Smith, Delaware Safety Council W. A. Snow, Construction Section R. T. Soi.ensten. Elliott Service Co. E. C. Spring, Lansdalc. I'a. George R. Stephens, Safety Bureau, Buffalo Chamher of Commerce -^'joiisf^TH.WEM, Greater New York Safety Council Arthur M. Tour, Consulting Marine Engineer George G. Traver. Greater Chicago Safely Council. Inc. ,, Major R. D. Tkimiilk, Richmond Safety Council Prank E. Vitz, Superior Safety Council Dr. C. H. Watson, American Telephone & Telegraph Co. Harry M. Wkbuer, Wilmette, III. I >k. David E. Weglein, Baltimore Safety Council S. E. Whiting, Liberty Mutual Insurance Co. A. W. Whitney, National Conservation Bureau Howard R. Whitney, Worcester Safety Council T. A. Wilson, Textile Section W. H. Winans, Union Carbide & Carbon Corp. I'. H. Winslow, Safety Div, Birmingham Chamher of Commerce W. E. Worth, International Harvester Co. 1C J. Zauft, Safety Bureau, Duluth Chamber of Commerce G. L. Zwick, St Joseph Safety Council Industrial Dusts / WEDNESDAY MORNING SESSION October 13, 1937 The meeting was called to order by Chair- York City, and Vice-President for Engineerman A. S, Regula, Executive Secretary, In- ing, National Safety Council, who. introdtistrial Relation* Counselors, Inc, New dttced the speakers. What Industrial Dusts Are Harmful? Why? By SENIOR SURGEON R. R. SAYERS Chief, Division of Industrial Hygiene, U. S. Public Health Service . While dusts exist everywhere in the at mosphere, it has been recognized for cen turies that workers in certain dusty occupations are less healthy than those not so, .exposed. ^Jhe number of persons ex posed-^ dusty occupations comprises one of the largest industrial groups. The occu pational diseases of workers in dusty at mospheres have been found to be due to entrance of dust into the system by inhala tion, by ingestion, by direct absorption through the skin, by irritation of the skin, or by a combination of the foregoing. The suspensions of particulate matter in air have been broadly termed dusts, fumes, and smokes. Such a classification is neces sarily arbitrary, since'the line of demarca tion between them is not very sharp, and the chief differentiation is based on the size of the particles. Investigations by the Pub lic Health Scrviec in dusty industries' re vealed that about 70 per cent of the dust particles examined were between 1 and 3 microns in size, only about 20 per cent were less than 1 micron, and the median size was 1-3 microns. Industrial dusts arc mainly loss than 10 microns in size. However, fibrous dusts in the air, such as asbestos, have been found to contain particles as large as 200400 mircons in the greatest diameter. While, generally speaking, according to ColHs. dusts arc more injurious as their chemical composition differs from that of the human body, or from the elements of which the body is normally composed,' it is difficult to establish a comprehensive, definition for toxic dusts. Sollmann,' after analysis of various definitions for poison, felt that it is very difficult to give a definition which will not be ambiguous in some cases, but believed that the following covers most of the points which must be considered in classing a substance as such: "A poison is any substance which, act ing directly through its inherent chemic properties, and by its ordinary action, is capable of destroying life, or of seriously endangering health, when it is applied to the hody. externally, or in moderate doses (to SO Gin.) internally." Some dusts arc known to be poisonous, while others, in the concentrations usually encountered, are comparatively harmless. I fowever, it may be stated that breathing dust in high concentration is not desirable. According to Fairhall, the damage arising from the inhalation of toxic dust may be either local or remote, and depends upon whether the material is a protoplasmic poi son. whether it is caustic in reaction, or whether it is absorbed into the blood stream and carried to other centers which arc in turn alTected.* It is now well established that expo>urc to certain kinds'of dusts, sucii as those con taining considerable quantities of free silica, has increased the morbidity and mortality rate from respiratory diseases: while me tallic dusts, such as lead and its compounds. Ii.nc been associated with general systemic poisoning.' Dusts may be swallowed with faliia. water, or food, and direct poisoning ha< been traced to absorption Id' this method; other dusts may act as irritants and produce adections of the skin, irritate mu cous membranes of nose, eves and throat,. often causing inflammatory diseases of these organs.* Some inorganic dusts arc able to pene trate the deep lung (issues and arc sufficiently insoluble lo be retained there. Some of these may be active in the human tissues, causing definite and permanent in jury. while others arc inert and may he retained for jears, apparently without seri ous damage: some are gradually absorbed without causing pathological changes.' All inhaled particles are soluble, at least to a small extent. If harmless, cell activity is stimulated so that phagocytes remove the dust. If the solute is toxic, the viability of the phagocyte is affected and an ineffective accumulation results. At the same time, further solute may diffuse into neighboring tissues, setting up an irritation and subse quent fibrosis. The nature as well as the solubility of the solute is an important fac tor, hut of two substances of approximately equal toxicity, the more soluble form causes the greater damage. However, sub stances of such low solubility as silica may ultimately produce extensive injury.* Kellie has stated that harmful dusts, if inhaled into the lungs, may activate a latent tuberculous infection; they may exaggerate an active tuberculous lesion or a coincident infection. If sufficient quantities of a harm less dust arc inhaled, some of it remains in the lungs and causes a inild degree of fibro sis merely through mechanical irritation, but such fibrosis is never sufficient to inter fere with the function of the lung* Some writers state that while the influ ence of nonpoisonous dusts on health is a debatable subject, abnormally high death rales from bronchitis and pneumonia arc sometimes attributed lo chronic exposure to uontoxie. dusts. Large amounts of dust arc occasionally found in supposedly normal lungs, at autopsy* Acrordittg to Drinker, there arc four dif ferent types of reaction produced in man by the inhalation of dust. The first ami rno-t important arc the pneumoconioses, sttcli as silicosis and asbestosis, which cause specific lung pathology and often are followed by pulmonary tuberculosis. .The second type of reaction is caused by toxic dusts like lead, cadmium, and radium. A third type of mal ady follows the inhalatioiVof finely divided metallic fume particles such its zinc oxitle, and is known as metal fume fever. The fourth reaction, allergic hi character, is caused by breathing organic dusts such as pollen and certain types of pulverized wood and flour. In all four cases the sole cause of the disability may be dust inhalation, but the reactions from toxic dust- result from swallowing as well as from inhalation." I;or various reasons it is difficult to set up an absolute classification for dusts. Opinion is rapidly changing regarding socalled inert or harmless dusts and further investigation may prove some of them to be injurious. Some dusts may have both a toxic and an irritant action: while on the oilier hand, the poisoning resulting from ex posure to a dust may be the combined effect of more Ilian one mode of entrance into the body. However, the following classification of dusts, according lo physical character istics and physiological effect, is used for convenience. I. Organic Dusts Organic dusts are those which contain carbon, and were originally supposed to come from organized substances derived from animal or plant life. Living dust; romc under this classification, and arc thought to be of the same order of size as industrial dusts, with which they arc fre quently associated, lfactcria arc usually be tween 0.5 and 3 microns, except in a few rases, such as the anthrax bacillus, which ranges from 1 lo r.2i micron in breadth and 4.5 to 10 microns in length ami 10 or 12 .microns in diamctriuJInwcvcr, it is possi ble that the larger mid heavier satieties, like the larger and z|ipavicr dust particles, settle due lo gravity,' and do not remain suspended in the air. Many Ihousimts of organic substances, earlinu-roiitniiiing, are made synthetically by chemical processes, surli as dyestuff-, explosives, rle. l. .vo.v/./1/iVg' oRc.txic nr.sts. ,\< the name implies, lliese are comprised of nouviahic particles, vvliirh may m may not he inherently toxic or irritant, hut which nevertheless produce untoward effects in the liimiau organism. `'Allergic" du.ts, or those to which only certain person arc oi may become hypersensitive, with resulting dust, or powder form of the prcparatioi asthma, rhinitis, or other disturbances, are erting a direct irritating effei I on the s included ill this classification. Dermatitis due to other vegetable t a. Toxic nnii/or Irritant. Toxic or irritant such as vanilla, powdered arnica, ; dints arc all organic dusts which produce thrum, etc., have been reported." untoward symptoms, either systemic or Dental lesions, of occupational oi local. Those producing local symptoms are have been reported among workers in si usually described as irritant; those produc The gingivitis caused by sugar dust is . ing general or systemic symptoms are sifted as purely mechanical, with I termed toxic. A dust may be both toxic and developing caries. Digestive dison irritant. respiratory conditions, and cutaneous In reported eases of injury or death fol ditions (especially of the face) were lowing inhalation of dust from organic com found." pounds, among the chief offenders are Dock svorkers, transporters of g paranitranilinc, the dinitrohcnzcncs, cliloro- workers in grain and flour mills, etc. dittitrohcnzcncs, trinitrophcnol, and nitro- exposed to dusts during their work. I) , naphthalene. Eye damage due to inflamma from cereals may contain many impuri tion of the cornea has occurred among which may cause an irritating action on workers exposed to methyl violet dust. The respiratory passages, as well as inflarr. dust from paraphcnylcnc diamine derivatives tion of the skin. Digestive dislurhar is particularly irritating and dangerous, dental defects, diminution in hearing, causing not only a severe form of derma conjunctivitis have been observed an titis where the dust comes in contact with millers, and have been attributed to the <1 the skin, but also producing acute inflamma to which such workers arc exposed." tion of the mucous membrane of'the respiratory passages.* Toxic (lusts may be generated during tile handling of powdered dyes and in preliminary dyeing operations, b. Allergic. Many apparently iunoci: substances may produce reactions in t sons of peculiar personal susceptibility, term "allergy" is used to describe this r particularly the hydro-extractor process, dition of liypcrscnsilivcncss or susccpti'd' where particles arc disseminated in all di and allergic phenomena most frcquei rections." Coal tar and indigo dyes are manifest themselves in skin reactions. Ik substances most frequently used. ever, they may cause arutc reactions r' Cases of amblyopia have been reported where in the body. When the respirno from exposure to inhalation of tobacco tract is involved we have such well kno ` dust." It lias been found that inhaled to diseases as hay fever or asthma. Tl- bacco dust exerts a nicotine action on the diseases may develop as a rcsi.lt of h\| organism fifteen times greater than that sensitiveness to such substance. as poll produced by the same quanfity of smoked from plants, horsehair, rahfiitT, fur, fi tobacco with an equal nicotine content." feathers, ctr. > Severe dermatitis is experienced by many workers handling powder containing T.M.T., wliieli is used in making high explosives. Picric acid, which is also used for this pur pose, requires drying, and ill this latter slate has been found to produce a dermatitis. Picric acid is also the oldest synthetic or ganic dyestuff." Dermatitis occurs among handlers of silk with varying frequency. Sails determined that a rash occurring among workers in a silk factory was due lo I'or instance, furriers, workers "n cloth industries who arc expo-cd to wool ih etc., may suffer from hay fever nr a-llitr It is unnecessary for the oliciding ilu-l reach the depths of the lungs--''giant pnlh for example arc reported to produce Ih effect after being cajight in tin upper r piratory passages. Should such : a offend substance be finely ground it i vuld re: the alveoli and as a result probably physiologic reactions would he aerelcrato dustfrom silk cocoons imported from In a survey of a plant where re-in Africa." mixed, ground, and molded, it wa< Inn Persons engaged in the manufacture of that 80 per cent of the occupational dern quinine and quinine preparations suffer from litis there wa- due lo lujiersmsilh ily skin phenomena, which occur for the most hexamethylenetetramine a.id forinahlchj part on exposed parts of the body, and contained in the dust lo which the wnrki may be caused by ingestion or by quinine were exposed." During the first prnec-- Pulton sp>. .11:, cotton-strippers arc ex- ij 10 dust arising from col Ion husks and iris, which produces a typical form of inn.i.' ' irdinary wood dust has been of interest e lo ils purely mechanical action, but II greater care is required in handling tain kinds, especially woods coming from road, because of the essential oils impregtin).' then), which when freed in the dust .V affect the health of the workers con ned Some of the woods capable of isimr 'kin lesions arc IJrazi! wood, satin>d. leak-wood, cuniaru or tonka wood, ck eliony wood. West Indian mahogany. .ant-'C tagasasan, roccoloba, chestnut wood, vcwood, California sequoia, etc. All per ns who handle these woods are not inred, only those particularly susceptible to e substances they contain becoming reeled. 2. Llt'IXG ORG.-ISTC DUSTS. These main particles capable of exhibiting the enomena of life1 (especially the property reproduction or multiplication), such as teteria and fungi. They are usually found low concentrations and are associated :lh nonliving dusts in the air. a. Bacteria. One of the most important nong these is the anthrax bacillus, which contained in the dust from skins, furs, no), and animal hair, horns, hoofs, bones, c. This disease may occur in two forms: djii.-.yii.t (in which the organism affects e skin), and pulmonary (when it is inhaled, - in the fnrm of anthrax known as woolricrs" dicac)," Cases of tetanus, reported in connection ith jute manufacture, were traced to the iw- material, the bacillus having been found the factory dust.,> Diphtheria, tubereu-sis, smallpox, typhoid, or other bacillusoduced diseases, may result from exposure infected dusts. Qactcrial sensitization can be the cause of -iy of the allergic diseases, namely, asthma, vrcimial. hay fever, urticaria, angioneurotic Icma, rczvina, or migraine headaches." b. Fungi. Dusts containing the niycclia id spores of parasitic fungi give rise to nnoyancc and discomfort. "Maltster's" itch 'nm the dust alone has been reported. In rovcncc. reeds used for ceilings arc stacked bile still wet and undergo fermentation; ty become covered with a white powder ;t dry fungus of the Mucor family : Sporo- tiicluuu dermatodcs), which is scattered nhrnuhe hark is stripped off. This powder is irritating to the skin and mucous mem branes. Mjcelia and spores of uimiildi arc commonly found to cause ra>hs: for in stance, the black powder coming from macerated sugarcane stalks. Among basketmakers, the mycelium and spores, in the form of a while mould (hyphoinycete) from the rhattau canes used, gel shaken out when the canes arc split, hammered, and cm, causing painful fissures to devcinpt on the skin where they alight." A form of asthma or spasmodic cough, suffered by cotton weavers'and known as aspergillosis, has been considered due to in halation of spores of a mildew which some times occurs on the threads." In a study of silicosis among miners, made by the Public Health Service, a number of eases of typical miliary calcification were en countered. Unstained smears of those eases examined were positive for fungus, two types of Aspergillus fungi being identified. All of the subjects blit one were farmers, teamsters, feedmiil workers, or residents of small agricultural towns where grain is marketed. Farmers are exposed to fungi in threshing wheat, baling hay,' nr handling various small grains." Some other fungus diseases such as actino mycosis and blastomycosis are associated with occupational exposure to dust. The former occurs among workers handling straw-, hay, grass, vegetable debris contami nated with mould, etc. Actinomycosis is likely to affect people engaged in commercial handling, storing, and cleansing of grain (grain distilleries, Hour mills, grain crush ing, breweries,'and malting houses, etc.)." II. Inorganic Dusts Inorganic compounds arc ol mineral origin, not requiring a living organism to produce them." A number of dusts not usually classed as toxic may, under some conditions, produce untoward effects on the human organism. Classified under inorganic arc toxic and/or irritant, fihrnsis-pioducing, and nonlibrosis-prodiicing dusts. a. Tn iit and/or Irritant. Toxic dusts arc lliosr which are inherently toxie when in haled. ingested, or olliti wie absorbed. Among those which produce systemic poi soning, some of which arc also irritant, arc the dust'- freon heavy metals and their salts, such as lead, inercuiy", arscnii, radmiun.. zinc, etc. Irritant dusts arc injurious by reason of their strong irritative or corro sive properties. As a rule, inhaled irritant substances im mediately cause a reaction in the upper respiratory tract of such severity that they are prevented from reaching the lungs, al though they may cause lung damage by extension of inflammation if the niiieous membrane is corroded.' Lime, calcium oxide, and the di-chroniatrs are examples of irri tant dusts. An inorganic dust may possess both toxic and irritant properties, and the poisoning produced may be the combined effect of more than one mode of entrance into the body. Of the directly poisonous dusts, the most widely prevalent are those of certain lead compounds, particularly the oxide, carbon ate and (lie chromate. The dust is readily absorbed hv the mucous membrane; some dust passes into the stomach and is dissolved by the gastric juice.* According lo Fairhall, perforated nasal septum is a common occurrence among workers with bi-chromate dusts.' In a study made by the U. S. Public Health Service it was foi|nd that continuous daily exposure to concentrations of chromic acid mist greater than I milligram in 10 cubic meters is likely to cause definite injury to the nasal tissues." It is believed that a similar concentration of the dust would be equally toxic. . In the ease of poisoning from some heavy metals, exposure may be to both dust and vapor. For instance, investigations have shown the safe limit of total exposure to tead oxide dust and fumes to be less than 1.5 mg. per 10 cubic meters of air, except for prolonged exposure." In exposure to mercury dust and vapor, it was shown that the incidence of chronic mcrcurialism in creases rapidly with increasing mercury concentration, after such concentration ex ceeds 2.0 mg. per 10 cubic meters." Alkalis and metallic oxides arc common causes of dermatoses. Lye, potash and lime arc known lo cause irritation to plas terers, rement-makers, bricklayers, masons, stonecutters, modellers, and metal platers." Ulceration and perforation of the naal sep tum occur among workers exposed to the dust of soda ash; systemic poisoning also occurs from inhalation of calcium cy.mimidc dust." Cases of dermatitis, scleroderma and can I cer are reported -.ve been c; td b> exposure to dust of arsenic con (.omuls Certain aluminum salts are skin i ritals and aluminum dints may cuutrihni, to the infection of skin and mucous men. .uc', through mechanical action." I>. Fibrosis-Producing Dusts. The ntci-i important of these are the inorganic, sli'-duls soluble dusts which cause fibrous changes in the lung tissues, some of which arc seri ous, and some of which cause little or no disability.' So far as is known, no inorganii substances other than silicon derivativecame more than a very moderate degree ol fibrosis of the lung. Morcovct, there seemto be no evidence tiiat any oti.er con-nitticn` of ordinary dusts can influence so unlavnr,^ bl.v a pulmonary infection.* Although other dusts, when inhaled ii sufficient concentrations over a long prriot of time, have been shown capable of pro ducing a pulmonary fibrosis, nevertheless the pneumoconiosis characterized by noJu lar fibrosis lias to date been shown cl ini cally and experimentally to be associate* only with the inhalation of dusts coutaium: free silica. Since this dust, to exert its harmful action must enter the finer divisions of the limp the partirlc size of (he atmospheric du`i may hear a definite relationship to the in jurious effect produced. The silica must In present in tire air in particles smnlf i-notig!, lo enter the finer air spaces and of sin1* dimensions that the phagocytic cells ir.v. engulf them. The greater majority <>f par tides found upon microscopic examiuarlo ot the lung fall within the limits of from 1 to 3 microns." Examples of siliceous dust are granite, quartz, sand, puinice, slate, etc In a recent study among anthracite miners, the correlations between exposure lo du<i (which contained silica) and the cvidcncof constitutional changes left little iloulc as to the etiological significance of the dll" in the air breathed. Like correlations wert found between the silica exposure and tin extent of pulmonary changes." When tin inhaled dust consists of silica combine with bases, silicates, some degree of chnng, in the pulmonary tissue may result. In thi respect asbestos dust seems to he iiniqiu among silicates in the prevalence anil sc Verity of the disease it causes." The chief distinction between si!i..-is :m conditions due In simple reactions r.ui-, by other dusts is the actin' prolifer.-rtf'  faction i. .ie tissues which results in .-ingtc.'MVC itoihllatioit. Silicosis, when once .-et.iblislict), strongly predisposes Hie lungs 0 infection, especially with the tubercle 'ucillus. Chronic interstitial pneumonia, -hrouic bronchitis, and emphysema arc frepicnt complications of advanced degrees of ilicosis. The relation of the acute respiratory in- 'ccliows to the reaction due to dusts other ban free silica has never been established, `hough a heightened incidence has often mi shown statistically in workers in dusty miles. It is fairly certain that a dust d.nn- igcd lung, whatever the cause, fares much nrsc if an acute infection dues supervene iii'im it.' , In a study conducted by the U. S. Public Health Service among marble finishers in Vermont, it was found that marble dust then inhaled in the concentrations found in :hc examined plants produced a mild, lii'jleral, linear fibrosis in some cases, but no -erious lung changes were noted mid there was no disability due to the dust, even after years of exposure." c. Xonfibrosis-Producing Dusts. These are inert, that is, they do not cause fibrous tissue to he produced, hut may become encapsulated or lie free in the tissues; or they arc absorbed without production of fibrous tissue. Included among them are alundum, coal, corundum, emery, limestone, magnesite, marble, plaslcr of paris (gypiiiii). and polisher's rouge. Dust Control Kngimering and medical control are the two most important factors in combating the industrial dust hazard, and are to a large extent complementary. /iiiyinerriiiij Control. As l.;inz:i" has -taled in a recent paper, "It is a Im-ic principle in dealing with a dust hazard that the dust should he attacked at its point of origin and thus prevented from being dis seminated into the atmosphere." After, the du-t has been spread throughout the air it is difficult to deal with it. and reliance must he placed on individual protection, which is avver wholly salisfactory. I.nnra (wither cites various methods used 1 ('Mutolhng dull. These will he reviewed -ui biml). s.nee a pai-er dealing with the l net <! Jn-t control in detail, will follow i I Ini piogrjni Dust may be entrapped at its source by Siicfinu devices and thus removed and ad jected. Familiar examples are exhaust hoods in grinding operations, and the devices used in rock drilling. * Generally speaking, (lie exhaust ventila tion method, where applicable, is In be pre ferred in controlling a dust hazard. Water may be used to entrap dust and prevent its dispersal, and undvr certain circumstances it may lie of advantage to combine the u-e of water and the use of suction. Sometimes a dusty process can lie completely enclosed in a scaled room or compartment. It iiin-.t be remembered, however, that any mechani cal device of this kind offers adequate pro tection only if it is properly designed, installed, and maintained. A great deal of attention has been given (lie subject of individual protection liom dust, ami there arc many types of respira tory protective devices now available. These arc generally of two types; those which provide fresh air from an 'uncontamiiialed source and those which rely upon a filtering medium for removing dust from the air breathed. Where the use of such a device is indicated, only one of the .types approved by the U. S. Uurcaii of Mines should he used. As a rule, it may he said that masks, respirators, or other such protective device should lie used only where exposure to the dust is intermittent and brief, or where some unusual condition makes a more ade quate dust control impracticable." Where bacteria or other living dusts in the air are associated with a process, steri lization methods such as increased tempera ture, ultraviolet radiation, and chemicals like chlorine or other bactericidal substances, may he of use. Pasteurization temperature (about 140* F.) will kill most organisms except those bearing spores. Steam disin fection is used for horsehair, mid proves to be practicable if the temperature does not exceed 2.10* F. Wool fibres, however, lose their elasticity hj steam disinfection, and the "1 bickering'' process now used in F.ngland includes soaking of the wool in a form aldehyde solution, and drying in a current of air at a temperature of 160* F.,! There arc few occupations in which there would he a sulTicicnt concentration of tlcad bac teria to cause untoward effects in man. In the ease of dusts producing external iriitjtinn. auxiliary prolctlivc measures may include the use of1 protective clothing, gloves, goggles and aprons; as well as pro tective salves, ointments, or other com pounds to delay nr diminish the irritant action. General rules for hygiene and good housekeeping should also be observed. bltdical Control. Equally important, and chi-civ interrelated with the engineering phase, is medical cottlrol of occupational hazards. In addition to directing the proper placement of new workers, and guarding the health of all employees, medical control is a check on the efficacy of llic engineering control methods already instituted, or a iiie.i-ure of the need for new protective de- Vices. It has been slated that "Industry lias found llmt the best way to treat industrial injuries and illness is to prevent them."" and medical control, through prccmplnymriit and periodic physical examinations, is one of the most important factors in such prevention. The preemployment examination is made to determine the employee's physical and mental fitness for work. It serves to discln-c the presence of any contagious dis ease. reveals any minor physical defects which might later become serious, or whetherthe examinee's condition precludes his.em ployment in certain or in all types of work. It should be remembered that such preemploimcnt examinations arc not to he made for the purpose of eliminating an employee, hut rather for allocating him to the type of work for which lie is physically suited. A `worker should be given employment unless totally unfit, or unless his disability,' even though slight, would cause him to he a haz ard to himself or his associates. Further more, the practice of preemployment examinations^should be extended to include executives and officials of industrial organi zations. "The purpose of periodic physical examinations is to secure and maintain physical fitness and thereby lengthen work spans."" Reexamination of employees some times results in the discovery of defects and disabilities which were not observed at the time of employment. In such cases, an oc cupational adjustment should lie made to provide continued employment, but remove the risk of permanent injury. Reexamination of employees is required by law in certain occupations in which the handling of poisonous or otherwise deleteri ous substances may result in the contraction of disease.1' Si. some occupalion.d d eases tend to clear up and recur, records previous occupations should he included' the pin deal examinations. The firiuci of examinations should he dctcriiiiiw'd (tic medical director, unless ollicrw isc sp< fled by law. Those exposed to known oo pation.il disease hazards may have w eel or monthly examinations." "It should always lie kept in mind that t basic principle of physical examinations industry is to keep men on the job and i allow the physical examination to be trier a weeding out process."'' References ) ' ........... J. /.. anil ll.ill.iV.illv. J. M. Determination and (Vmtrnl I Industrial lht. S. Public I(rnltlk Bulletin No. 217, April, 193' * Collis, Fdear la. "Industrial Pnnnimconul with special reference to Dut I'lulmiv** >M Lecture*. IHS. 11. M.S.O-. London. J Soltmann. Torald. "A Manual of PJui} colncy.*' W. II. Saunders A* Co., Philadelphia. It * FairhaU, Lawrence T. "Toxic Dn-s ! Fume*." journal of Industrial Hygiene and T coincv, November, 1936. 1 * Rloomtarld. J. J. "The Samidinrj and An of Industrial Dust*.'* American I'uhlic Health ci.ihon, S'enrbnnk*. |9J5 .16. 4 CiiMn, \\\ K. "Hum llarard in Industry.** V.r.< Hentt, Ltd. London, 1925. | I Air Ifyeicnc Foundation of America. Inc co*is anil Allied Disorders." Medical Series, flj tin No. I. Pittxburcli, Pa. April |a.PM6. * Kettle. E. H. "The Action of if.vmfitf Du*.' Inst. of Mining and Mct-allurcy, Lou ,*mi. lum1 19JL , i *"Duts. Fumes, and Smokes.'* Oc upation f Health Series, International Labour O *ace. I M 1919. # ' Drinker. Philip. "Causation of harumnr* osis." Journal of Industrial Hygiem ami T colocy, October, 1936. II "Dyeing.** Occupation and Health Sc International Labour Office, Ocneva, t'MO Lecce, Sic Thomas. "Industrial. Matadi> Oxford Citiversily Prc*. Loudon. 19JL '* Rurstein. A. "Nicotine Action from luhv Tobacco I)u*t." Journal of Industrial Hjuiene. 1 ceinher. 1927. White, R. Prosper. "The Dermaii-rcns*-. Occupational Affection* of the Skin.'* II. K. L. St Co. Ltd., l-otvlon, 19.14. "Schwartr. Louis. "Sim llarard* in Atinri, Industry.'* L\ S. Public Health bulletin No. ? October, 1911. 'Donning, J. O. "Industrial Dermatan**: Tr. incut and Local Aspects; Review of Recent l.iii lure.*' Journal of Industrial H>k<cmo Toxicology, July, 1915. M "Occupational l.c'iori* in Workers in Sue Rclcinm Letter. Journal of American Medical A ciaiintt, Sept. 10. 1927. Ahst. Journal <f iedti.f Hvciine. Ichruatv. 192*. '"Flour Mills." Occupation and ll< tlih Nrc International Labour Office, lieneva, pip). 'Masers. Mav R. "Snserptthihlv to Di'rinatit The Industrial HuMctiu, Albany, N. V. |'cli, I'J vol. 16, no. 2. Drinker. Philip, and Hatch, Theodore VIhm trial Dust.'* McOraw.ffill Rook Compau**. I New York. 1936 Schwattr. Louis. "Skin llar.ardx in Ainm Industry. Part II.*' 1J. S. I'nhlic ILalilt Hull No. 22'!, Sept. 19.16. 15 "Poisonous^ Woods.'* Ocrupalinn and Ur Series, International Labour Office. *<ctirva I9H a Uoi* * Hanna. U*., and Stallj-braM, C. . "InJu svlill and mticinc and Hygiene.** Haitlierc. . London. 1923. H Drown, ft. T. ."The UngnoMs of Bacterial !ler*y." Southern Medical Journal. Vol. 27, No. . Oct. 1931. *l Snrrs, R. R. and Mcrcwetlicr, F. V. `'Miliary nog |ii>ca<e Hue to Unknown Caute. U. S. 1`ullic Inlth Repot n. lire. 5, 1930. n "Aciinmnyeo'is.'* Oernpation and Health Series, ntcrnational Labour Office* Geneva, 1930. n Ifotiand, J. W. **Te\thook of Medical Clicmiury td Toxicology.** W. B. Saunders Company, Phila* clphia, 1920. * Bloomfield, J. J. and Blum. W'm. "Health Hat* *d in Chromium rinting." U. S. Public Health -rvicc Reprint No. 1215, Washington, 1930. 9 Rmscll, Jnnc5, Bloomfield, Britten and Thomp. m. "Lead Poisouinq in a Storage Battery riant." \ S. Public Health Iluflciiii No. 205, June, 1933. "Neal. Jones. Bloomfield, P.MIaVaUc and F.d* 'rd. "A Study of Chronic Mercuriali.Mii in the (.liters* Fur Cutting Industry.'* U. S. Public !<*alth Bulletin No. 234, May, 1937. 11 Sayer*, R. R. and Jnue, R.*K. "Silico'N and Similar J)mt DUca^e*." National Siliro'is Con* fereucc. Washington, l>. C., April H, 1936. "S.yer, Bloomfield. DallaVatle, Jones l>rerrn, Brumhgc and Britten. "Anthra<o*Sihrni* among Hard Coal MinerIL S. I'tihhc Health fliilUiin No. 221. Uecemher, 1935. 7. M Middleton, F.. I- "InduMml I'ulmnnaty IBs* eae line to the Inhalation of ])ut." *1 he Lancet, July 4 and II, I0J6. u Dree*seif, Waldcniar C. "Lflcet of Inhaled Marble Dust as Observed in Vermont Marble Finishers.** U. S. Public Health Service Keirint No. 1630. - " Lanta, A. J. "Control and Prevention of Sili* com*." SynigOMunt on Silicons. California Tider* culosis Association, San Francisco, 1937. M Newquist, M. N. "Medical Service*in Industry and Workmen's Compensation Laws." American College of Surgeons, Chicago, 1934. # w "Medical Care of Industrial Worli-rs" Na* tional Industrial Conference Boird, Inc. New Vork. 1921 The Engineer's Part in Eliminating Dust Hazards By ARTHUR S. JOHNSON Assistant to Manager, Engineering Department,1 American Mutual Liability Insurance Co., Boston, Mass. U lieu om realizes that control of the dust -..iznrtt depends upon the combined contribuons of tire physician and the engineer, lie apTccialcs that the solution requires scientific rcatincut. By scientific treatment I mean the cclitiic.il analysis o( the hazard io discover he causes which contribute to injury or ill icalth, and the development o control mctli'ds which obey physical law and physiology, nd which will be directed at causes that '..linit of most immediate ami economical reatment. That goes for handling the dust hazard in '. given plant. It goes double fur acquiring uinwlcdgc to the end that the whole problem lay reach ultimate solution. Right now onr .nowlcdge of the problem is in big chunks, sely put together and largely empirical. There arc estimates only to judge the mag. litudc of the dust health problem, and it is so losclv associated with other health problem* 'hat a clean-cut estimate of it alone is imHissiblc. Wc do know that it is great in the ggregate, and for the individual plant it may c very bothersome and expensive. What actually makes quartz dust cause ilicosis is not known. It docs, so the air 'readied by workmen must not contain harm 'll quantities of respirable quartz dust. Inex pensive methods for making die air clean are still in the realm of dreams. Much work must be done to know more about silicosis and more bow to make atmospheres safe iiir.rpntjiie/v. As an accident prevention job. dust control lies almost entirely within the admin istrative responsibility. The control measures are capital expenditures of considerable size. A plant with a dust hazard is sick, it needs an expert diagnosis and scientific treatment, which may include expensive major opera tions. Home remedies are seldom much good, and supervision and employee safely con sciousness alone cannot accomplish anything. There may be observed iifcyouiitless shops installations for exhausting' dust which are derisively called "tin knoc^qr" jobs in which the horsepower dissipated is'out of all pro portion to the air-borne dust moved. Tonnage efficiency of material moved may be the proper yardstick for pneumatic conveyors hut il the material to be moved is air, contaminated witli nearly weightless particles of dust, the entire health hazard can lie in the halt of one per cent of material not moved. I do not mean that unless a dust supressiun job was engineered it can be no good. There arc many good installations that were never figured at all but grew liter Topsy. The re sulting freedom from dustiness was so satis factory that efficiency held little interest to the owner. This is exceptional, however, and I olTer the opinion that dust suppression jobs should lie engineered. A diol-supprcssiou installation is a safety device, designed anil operated to provide pro tection against possible disease ami provide a sense of security which must he absolute. Its saicty is not rushing air and rattling chips but a minimal'residual dustiness. There is no more pathetic defeat for a dust control job than to find faith in its effectiveness so low lliat workers must wear respirators to find the reasonable safety that was expected from the bonds, duets and fans. Diagnosis and Control l.et us examine some of (he features by uliich wc recognize this dust hazard problem, leaving out the soeio-lcgal aspects. In order to develop more fully the engi neer's place in ibis dust control program, il scents desirable lo separate as sharply as w c can the diagnostic considerations from tlm-e which deal, with control. Ill the first com partment wc can place all the analytical com ponents which describe the hazard and its exposure,Mic probability of its producing ill health ami all the rest of the medical and industrial hygiene facts which make out a case against the existing dust. In the second compartment place the knowledge of physics and engineering necessary lo plan the dust control program and so design' it that when .installed its performance follows prediction that the probability of industrial disease is reduced to insignificance. The Industrial Hygienist Our first fca|ure of interest would naturally be the specific and relative toxicity ol silica, silica-bearing and other dusts which make up the dust health hazard. Much might be said to advantage about the quality and quantity of hazard in many dusts. The acquiring of this knowledge has been, and must remain a medical problem. It involves gross and micro. scopic pathology and x-rays, and experimental animals. Engineers do not talk that language. 'Industrial hygienists do; they arc a happy combination, half doctor and half engineer. Many of them are quite capable of handling the dust health hazard in all its phases of investigation and control. For the purpose of this discussion I throw their interest in with die doctors. I want to f ar in n:y opiniu'l a state dial the i .ccr sluuilr. not attorn' define die quality of health hazard in a | plant or industry, nor should be est.v threshold limits of safe or permissible tl ness. Tliis may be debatable, but I shall tend that the engineer who writes the si lications of hazard and dust tolerance is r ail industrial hygienist, and is using a much broader knowledge than cngincc alone. In the fir.*! case the quality ol the I" hazard is an opinion arrived at af.cr stuil all the environmental conditions vi vlmliw) general sanitation, occupational a. alysis a scientific analysis of the dust exposi In the exploration of dust exposures; nature ui dusty operations must he vit Iriiin physical, chemical and inerlia aspects, the dctcruiiualious of dustiness j lie not only counted and classified by par late siz.es, tint chemically and mincralngu analyzed. The plant layout must be stu witli respect to dust production ami disti tion, ami (lie housekeeping and existing control equipment evaluated. The proem specific hazards, such as toxic gases, all mal temperature and humidity conditions, must lie explored for their c inplicatiug el upon (lie whole pirlurc. This is ilisiiuclh industrial hygiene joh, and some of llic n critical data requires only medical vievvp This is absolute in the case of tiilx-rcol1 study and the qualifying nf men for cmpl nicnt. So far. not one atom of engineering suppress dust is involved. It is entirely ai ysis of hazard. The diagnosis must be i the dustiness is hazardous to health nr tin is safe. If it is hazardous, it must be broil down to a specified residue. If it isn't. It it alone. On the second point, if live liygien can not specify threshold limits grndiia upward for relatively less Itazardous do let llic engineer not worry about it. I diagnosis is dust which is harmful and much <d il. The remedy is control ol ihc d The engineer designs controls which produce the lowest prarliral residual tin ness, lie should not attempt to write In's < specifications of threshold limits or peri sildc (lustiness. This may lie an im|K)ri goal in the study of dust health hazards. Safe Limits At the present time the medical nicn . hygienists believe that quartz dost is - Iii'lmv . lillion particles. They seem will ing to graduate upward to 20 million lor medium silica and 50 million lor low silica percentages. Tivc million particles is virtually dust (rev, and is very difficult ami expensive achieve and maintain. The declaration of 'aicty of the installations must remain in the hands of the medical and hygiene groups in whose hands now lies the responsibility for determining the hazard. U'e now enur the chapter of onr discussion intended to demonstrate that dust control is an engineering job, that it must be given weulilic treatment, not guess work, applying engineering methods which arc based upon a knowledge of physical law, the behavior of Inst, the performance of air-moving machin ery, etc. Prerequisite Knowledge I.et me recite hriclly, a few of the tilings which, in my opinion, the engineer should know to do tin's job correctly. He must know how to make a survey. Surveys depend upon sampling, and sampling is. not a catch-ascaich-can proposition. It involves the place, the lime, the frequency, the amount in a sam ple. and the immhcr of samples so that maxi mum. minimum and average data mean some thing. su that credibility can be given them. I-or the type ol sample involved hr must know how to weigh or count respirable dust, as distinguished front large masses of uonre.qiirablc dust which rmnpliratc the picture. I Ic must know how to observe the sources of dust floods as distinguished frum conditions of normal dustiness. He must know the sources of dust anil the principles involved in the (lis|iersioii of dust. lie must determine how much dust enters the problem because it is part of the material, and what dust is created in the- process by the fracturing of the material. Any less survey cannot tell the engineer w bat bis task of dust control is. To visualize that task intelligently lie should know the physics of Ilrmviiiau motion, laws of resist ance to the mution of purlirlrs moving in air. hmh when the air is in turbulence and for stream-line- motion. He should know terminal velocities, movements due to centrifugal mntiun; flocculation and the effects of air motion and the effects of humidification bn it. He must know all about tile- difficulties of wetting and ubat is known almut overcoming these difliiuliics. lie should know the several elec trical phenomena which bear upon dust h vhavior. Those arc all principles of physics which explain the behavior of ilusppiid upon which engineering practice must be based. Tiny must be understood ami be taken into account. Dust control is not a matter only of general ventilation; the engineer must study the pruductinn as well as the dispersion. The problem shuulil he analyzed to determine the applica bility of segregation, enclosure, wetting, lural exhaust ami general ventilation, lit some instances, substitution of nun-haz ardous material, or non-ijust-prodiicing oper ations may have specific application, and they should be explored first. This implies plant engineering. 1 am convinced that many bail installations arc bad because plant engineering was not used, lit the designing of exhaust systems installed lo capture live dust at the (mints of generation, the physical behavior of air moving toward hoods and in duels must lie known, ami that knowledge used, Each system must consist of collection hoods, pip ing. air-cleaning plant and a source of suction. Hefore selecting a hood for a job the engineer most know dust dispersion by dynamic pro jection as well as dust dispersion by air cur rents, and design the Itooil accordingly. Knowledge Needed The aero-dynamic characteristics of suction hoods appear to be little known because little thought was given to them In ilrsigning thousands of hoods which can he found every where in industry. All the possibility for entrapping dust and much of the eflicii-my oi the system lies in this factor. Air velocity, static suction, and rate of air flow arc all related, anil they must he known. It is essen tial to use high velocity of air in certain types id exhaust systems to entrap dust projected at high velocities as in the case of a granite surfacing machine, and low velocities must he used in others, as in the ease of cleaning asbestos fibre of dust to prevent waiting material. Quantity of air and its velocity iniiM he determined, then the piping should be de signed to lake into account the behavior oi air-flow through pipes at low- and high veloc ities. Where the problem is complicated by the large sized particles which go along with the fine dost, how these behave must be taken into account. Pressure losses are very impor tant elements in Ibe design of an exhaust system. l.osS at tin- hoods, loss at the bends, and loss in the ducts must not be guessed at. Pipe design must take into account the gage of the metal and reinforcing to withstand pressures ami erosion. The selection of a fail and its motive power is a matter of calculation, not guess work. Power consumption in the system is calcula ble. fans follow certain laws, so the engineer must know the behavior of axial flow, pro peller type, radial flow, paddle wheel anil other fan performance. More physics and engineering calculation goes into the air-cleaning apparatus. The selection of gravitation, inertial or filtration method depends upon what the dust is, the calculation for any methods requires knowl edge of discharge through stacks, the deter mination of sizes of settling chambers; the behavior of cyclones. The use or non-use of a filter, and if so. what type, how it should perfurm, how- big it should be. what kind of resistance anil how much each kind offers, to say nothing of their proper location witli relation to cleaning, accessibility, etc., are all items fur accurate engineering determination. Apparatus to check the behavior of installa- V lions must be . . anil used. IVn">,`" cannot be left to guess work. Suppbi"g - Client air to be exhausted is part of the p lent. The same may be said of heating Do f give the problem too severe a In up? I think not. Remember .hesc two lliii 1. Von are dealing with nazardous m rial so small in size and so little of il weight that it is as invisible as the air i hears it. 2. Physical laws involved in the bclia of ilu-t and air do not permit incxpi n methods of control, l am acquainted \ budgets set up for this purpose which a in' to more than a quarter of a un'li-ni doll and l know of many where 60 Ic 80 ilium dollars is involved. The need (or this much engines- 'lug i< cgnizi'il by men who know*. Ah ady m has been done toward getting the kuovili into handbook shape, l'crhaps the heM of this sort to dale is "Funilameii'als Ki-I.d to the Design and Operation of I- xli. Systems" developed under Amer.can Sl.i ards Association procedure. * The Doctor's Part in Controlling Dust Hazards By A. D. LAZENBY, M.D.. F.A.C.S. Chief Surgeon, Maryland Casualty Co., Baltimore, Maryland Considerable confusion has existed in the past as to just vvliat is the physician's func tion in the prevention of dust diseases, and just what is \hc engineer's. It is very ob vious upon even casual thought that the tuo sciences must work hand in hand in their efforts to solve the problem. The physician through Ids special training must be able lo tell the engineer what dusts are dangerous and what are not. He must know bow those dusts enter the body and the manner in which they do their harm. He must be trained in the examination of per sons who are to be employed to work in dost, and to discover those who arc already diseased, or arc peculiarly susceptible to dust disease. He must be able to detect the first signs of disease in workers who arc exposed to dust, and must be prepared lo recognize the disease when it is lully i vclopcd. It is not necessarily the physician's fm tion to analyze dust. That is a task for t chemist and the petrographer. It is not I physician's function to conic the particles dust in a given industrial atmosphere. Th in reality, is the function of the engineer, is not the physician's function lo dev ventilating equipment for the removal dust, nor even to he more than an .ulvi as to the means that must he adopted render the atmosphere safe. The physician nevertheless must corn), with his medical knowledge and with I studies of the industrial worker the finiliiof the engineer. A diagnosis of silico-is. I example, requires not merely charartcrii occupational history and characteristic plq ta. :i, but the knowledge as ucll that We have no real know ledge as to the p.v..uit has been exposed tu hazardous figures, but as a simple ride, we can adopt du-ts in dangerous concentration*. v for practical purposes the thought that the All dusts when inhaled in excessive human body can withstand successfully a quantities may be considered as harmful, lull concentration of dust cimlrvining 100 per cent only a I'civ can be regarded as dangerous. From the standpoint of their dangerous properties, they may he dii ideal into three general groups. 1. Tlmsc which arc dangerous because of their poisonous action, such as lead, arsenic, uicrcuiy, and similar substances. silica dioxide in a particulate size less than 10 microns, in a concentration not in excess of 5.000,000 paitides per cubic foot. If we decrease the percentage of silica dioxide present in the dust, we can correspondingly increase the concent ration with comparative safety. We must, of emu sc, take into ac count the portion of the worker's time spent 2. Those which cause only irritation in the in the dusty atmosphere. respiratory tract, resulting in such condi tions as bronchitis or local inflammation; such substances as vegetable fibre, cork dust, Hour, starch, and other relatively innocuous organic or inorganic materials. To arrive at a rough conception of a safe atmosphere, we multiply the percentage of free silica in a given dust by the total num ber of particles per cubic foot. If the result is under 5,000.000 the condition may he con J. Those which tend to produce fibrosis sidered relatively safe. If the result is over of the lungs, thereby predisposing to respira 5,000,000 the condition must he regarded as tory infections, especially tuberculosis, such unsafe. dusts as asbestos, silica dioxide or mag nesium silicate. Dear in mind too that silicosis is essentially a disease of great chrrmicity. Except in a I shall confine my remarks chiefly to few' exceptional instances it will require dusts occurring in the latter category. from seven to thirty years ior a worker to It has been generally believed that the harmful effects of dusts inhaled into the lungs depended more upon their physical structure than upon their chemical, ft was believed, for example, that silica dioxide, or quartz, was particularly harmful because of its crystalline structure, and the hardness and sharpness of its particles. This concep tion is now known to be faulty. The dusts develop advanced silicosis. It is evident loo that coincident dusts may either retard the development of silicosis or hasten it. Recent research seems to indicate that the admix ture of aluminum dust to a silicious dust will greatly inhibit tire reaction of the latter; whereas a silicious dust combined with some alkaline coincident dusts may hasten the de velopment of silicosis. which cause their damage hv mechanical in Much research is now under wav in prob terference with function arc the dusts which arc relatively innocuous, whose symptoms are transitory, and which subside upon re moval from exposure to the dust. Chemical Effect Is Harmful lems such as this. We have never learned how to cure silicosis, but we are learning rapidly how to prevent it. Our knowledge in this respect seems to he limited to (lie removal of dust from the breathing zone of the worker. Later discoveries may show us how to The disease of particular interest to us :modify existing dusts with contaminant today, silicosis, owes its harmful effects very dusts that will render silica dioxide innocu largely to a harmful chemical reaction oc ous. curring between silica dioxide and the body tissucs. It so happens that silica dioxide is decidedly a tissue irritant to the body, re gardless of the part of the body it invades, it causes local irritation, local destruction of tissue, and the replacement of that tissue bv scars. Owing to its very great chronicity, it is only the rare ease who actually develops disabling silicosis during Ids industrial life time. It is realized, of com sc, that excep tional instances Ukc place, hut the coincident ravages of age usually keep pace with the effects of dust, so that much n` the dis Tluis, given a dust containing silica diox ability usually attributed to silicosis is often, ide in sufficient concentration, in sizes small in fact, actually attributable to other dis enough to permit its entrance to the ultimate eases or incapacities which advancing years air spaces in the lungs, we have a situation bring in tbeir wake. To me the great peril of which offers danger to the worker. silicosis, the peril not only to the industrial worker himself, hut his family, ro-uorkers and the public generally, is tire accompany ing .susceptibility to tuberculosis. Complicated by Tuberculosis Silicosis per sc does not kill. Tuberculosis as a complicating factor of silicosis rarely recovers despite treatment, and the indi vidual so afflicted is not only totally dis abled himself, but a definite ntcunec to all with whom he comes in contact, patliriilnrly the fellow worker who may have siliensis. So pci haps the most important places in which the services of the physician in a dusty trade are necessary arc--first, along lines of discovering and barring from exposure to a silicious dust those persons who may al ready have arrested tuberculosis; and sec ondly. discovering those persons already ex posed to dust, possibly already silicotic, in whom tuberculous infectious may have de veloped. It is well recognized that no individual should be exposed to dust containing silica dioxide until lie has undergone a thorough physical. examination, including carefully made and interpreted x-ray films of his chest. It is likewise obvious to anyone fa miliar \ith silicosis that no person who is exposed to silicious dust should be denied the privilege of frequent physical examina tions and x-rays of the chest, not entirely to discover the existence of possible silicosis, but to discover a coincident tuberculosis if such exists. A man so diseased should, in protection to himself and to all with whom he conics in contact, he removed from industry. Let me emphasize the uselessness of a physical examination, unless it be accompanied by properly taken x-ray films, except in cases of gross tuberculosis. It is the function of the physician, there fore, to conduct in a thorough and an intelli gent maimer the prc-cmployineiit examina tion of all persons who are to be engaged in a dusty trade. The purpose of this ex amination should he threefold. First, to discover and bar from employment in dust, any person who is suffering from tuber culous in nil active, a quiescent or an ar rested state. A possible exception might be made in individuals suffering from a so called healed primary complex, or a healed childhood in fection. It is well known that exposure to silica dioxii cry libily to . '.rii activity a tur....colons le-ion wlmh m (pile-cent or arrested, ami i" c snrh a is ruiclivatcd, the iliance- of rtvn'o remote. _' The second problem which coiilrnn plivsiriait at the pre-employ meiil ph> animation is whether a given indivi.h by reason of secondary physical di more susceptible to the development o crisis than a normal. Is lie suffering diseases of the nose or upper rr*pi tract, such as chronic sinusitis, disease, lungs or air pas-ages. or obstructions produce mouth breathing? We must remember that siliia dim not dangerous until it reaches the him that the normal individual retains nose and the upper air passages a quantity oi the dust inhaled from the ; pliere. In instances where this nasal tion is disturbed, exposure to silica d dust may be dangerous to that indc where it would not he to another. It is believed that certain di-ca-is heart and circulation, of the kidneys,' lily syphilis, chronic coincident disea the lungs, all may render a man mol ceptible to silicosis than normal. Tliv cian at his pre-employ incut cxaminaiioi follow certain established crileria it respect, and liar from exposure Indani dusts tlipsc persons who through c.v disease may be more ready prey to si or tuberculosis. Re-Examination Needed After the applicant for employmci successfully passed his physical vs.unp and is engaged in a dusty trade. I hi of the physician is not yet ended. Tlri' man must be periodically re-examined to discover the early appearances ui monary fibrosis, but what is even moi portant, to detect the early evidem complicating tuberculous infection. A man should not be dismissed frni ploymcut in a dusty trade merely Leva lias evidences oi non-disal ting si! Workers in dusty trade*, especially cutters, moulders, pottery vnrhcrv similar craftsmen, aie usually . iglilv ; and it seems unfortunate fnmi a *<>cij' economic point of view to ilvi.y lIt* i ploymcut so long as they are phy-icall to carry on, especially since the nelu. ailing qualities of silicosis arc in iloul vs /'Wnlysixth Xaliniwl Safely C'anyress They sliouItt lie denied employment in a dusty trade if that condition is found at l>re-ctnploymcnt examination, but they should not be barred from continuing an employment in which they arc already en gaged. Of course, in such instances yon, as engineer*, must realize that you have failed, because if you had kept the breathing zone of the worker free from dangerous dusts, silicosis would not be present on physical examination. intervals, conferring with the physician in an effort to discover whether, in the light of their joint knowledge, working conditions arc dangerous. He must develop and install carefully designed ventilating equipment. He must arrange for modification of chemical and other industrial processes, where such modification is possible, and must bend his efforts toward removing from the danger zone of the worker the offending substance, whatever it may be. In this work of preventing dust diseases in industry, it should be evident that the closest and most intelligent cooperation between the physician and the engineer is necessary. The Too many engineers construe this function loosely. They pass on to the physician as his responsibility certain functions which es sentially arc theirs: such functions as dust physician must, through his knowledge and research, tell the engineer what dusts, or. for that matter, what other substances used in industry are harmful. He must tell the engineer how such dusts or other materials enter the l>ody, how they leave the body and what they do in their passages through or their residence in the body. analyses, dust counts, and similar technical duties. All too often it is considered ade quate merely to install a fan. Ventilating devices in dusty work rooms must lie constructed only after careful en gineering study has given a knowledge of the physical properties of the air and of substances polluting it. It is possible to Must Make Analyses calculate to a very fine point the volume of air that must be removed from a given spot The engineer must in turn tell the physi cian of the harmful''dusts and other sub stances surrounding his .workers. He must make chemical and petrographic analyses of to-remove the dust originating at that place, and the engineer must approach his task "from just as scientific an angle as the physi cian approaches his. j the dusts, and other indicated analyses of the There is no room in industry inf hap atmosphere in the workshop. He must make hazard methods on the part of either tlie lust counts and check his counts at regular physician or the engineer. ,in.rOURNMl:.\'T Centum tint! Quarry Seri inns course. some similarity of procedure in di recting tlie work of any man on any jtili: hut different industries employ such different types of iniiple, tinder such a wide variety of eirrimistanees. and place such a diver* senee of requirements upon them that the problem of stii>ervisory training in its mure comprehensive aspects is peculiar to each type of industry. The ccucrat treatises on leadership give the "roundwork, but the subject matter for any supervisory training rniire for any par ticular industry lies within that iiuhi-try. U'c must go out and -ep bow nur job is being superviseit now; analyze the procedure of every foreman and supervisor: compare them and select the best: link ii|sm supervision as a process in itself, and sec bow best to direct the work of the people. It is a tong. tedious, and costly process, but one which, carried through to completion, will pay dividends in the end. WEDNESDAY LUNCHEON SESSION October 13, 1937 The Wednesday Luncheon session of the Cement and Quarry Sections was addressed by Isaiah Hale. Superintendent of Safety. Atchison. Topeka and Santa Fe Railroad, .who spoke on "The Common Sense of Safety." The address was substantially the i same as another address by Mr. Hale before the Steam Railroad Meeting. The complete paper will be found in the Steam Railroad section of ibis volume. WEDNESDAY AFTERNOON SESSION October 13, 1937 Work of the National Silicosis Conference By R. CAMPBELL STARR Assistant Safety Engineer, U. S. Department of Labor, Division of Labor Standards, Washington, D. C. Silicosis is strictly an occupational disease. Medical science has not reported silica dust as affecting any individuals except those who, over relatively long periods of . time, have worked in an atmosphere where the air which they breathe contained excessive con centrations of free silica. The interest of the U. S. Department of Labor in a broad social anil economic prob lem such as this lias its origin in the Organic Act, effective March 4, 191.1, which created the Department. This act, among other things, gives the Department of Labor the duty "to foster, promote, anil develop the welfare of the wage earners of the United States, to improve their working conditions, and to advance llicir opportunities for profit able employment." With this in mind, and believing that through joint effort of all concerned, much could he done to eliminate the hazard, the Secretary of Lalior called together in Wash- mg Ecbruary 2ti, I'JJh a group l' visors, one ml labor problems and on. about .ncii representing leaders in indus v mining matters. tries having a silica problem, labor leaders and miManding representatives of the medi These committee members served without cal. legal, and engineering professions as compensation .uni gave freely of Ihcir lime well as insurance carriers and Stale adminis trators. and effort in studying the problem from their respective viewpoints. After nine months of careful and searching stud);' these commit After considering various phases of the tees advised the Secretary of l.abnr that silicosis problem, this group generally agreed they were ready In rcpml. Consequently, but through a pooling of knowledge and a on hchriiary .1, I'D/ iln- Second National Irani, discussion through the eoiilereuei: Silicosis (. onfcicnee was vailed in Washing method important advances could he made ton. At this time summary .committee re toward, first, overcoming the hysterical al ports were presented in the Secretary ami titude on the part of employers, labor, and considerable discussion was given them. others; second, after careful investigation, to consolidate in one place all known data with regard to the preventive engineering methods; third, analysis ami recommenda tions in connection with adequate standards of compensation for those workers disabled as a result of the disease. Shortly after this second national confer ence the Department published, as Ihillctin No.' IJ of the Division of Labor Standards, the summary reports of the four cnnunillccs referred to above, together with an abstract version containing the principal findings and recommendations written in nmi-lcchnicnl As an outgrowth of this initial meeting, language. another group, similar in composition to the first conference, hut expanded to include some AMI individuals, was itivilcd to come lo Wa-hingimi mi April Id, I'ljii to outline ways ami means of attacking the problem. After hearing silicosis discussed from the stand point of .the employer, lalmr, and the medical The full reports of the committees, com prising several llunisainl typewritten pages, arc nlm* being edited and will go to the printer very shortly. It is expected that they w ill lie issued in fouf separate volumes sometime during the fall or early winter. profession, bv outstanding experts in the field, this large group endorsed the confer Nature and Extent of Silicosis ence method as proposed, and as a residt four main working committees were ap Physicians generally agree that silicosis, pointed by the Secretary of Labor with the in the layman's language, is a disease of the advice anil consent of the group to investi - lungs, caused by breathing air containing gate and report upon the outstanding phases silica dust, in which the normal lung tissue of tile silicosis problem. These committees is replaced liv fibrous or sear tissue. were: Silica dust is found in many industrial operations, hut the hazard is acute only in (1) Committee on the Prevention of such industries as inelal mining; anlliracile Silicosis through Medical Control, mining; quarrying, drilling, and tunneling in (2) Committee on the Prevention of granite, gauistcr, and sandstone; smelling Silicosis through engineering Control, and refining; foundries; potteries; glass (J) Committee on the economic. Legal works; stone-products industries; grinding; and Insurance Phases of the Silicosis huffing; ami sandblasting. Problem, (-4) Committee on the Ncgulalmy and Administrative Phases of the Silicosis Problem. Of the -10,flOt),(101) workers in the I'nitcd Stales, only 1 .OtVfi.fKH). or 2 per cent, il is es timated, arc in any way exposed to the haz ard of silicosis. About half of this number, or I per cent of the total number of workers A fifth committee, known as the Correlat in the country, are expired lo a serious haz ing Committee, was named. It was under the ard, and approximate!) 110,000 of these have chairmanship of \V. H. Cameron, Managing silicosis in some degree. Medical examina Director of the National Safety Council, anil tion 'of men actually at work indicates that consisted of the chairman of the four tech between -4.000 and 5.000 workers arc seri nical committees just mentioned and two ad ously affected by the disease, in addition lo those already permanently detached from their employment by reason of disabling sili cosis. The stains of ihc f.000,000 workers ex posed to the hazard of silicosis was analyzed thus by (lie committees making the snney: A percentage of the 4,000 to 5,000 workers having silicosis arc completely or pailinlly disabled became of this disease and have their difficulties further com plicated with tulieieulosis. The remainder of the 4,000 to 5,000 have silicosis ami disability in some degree, but mi tuberculosis. Approximately 105.000 have silicosis, hut no disability and no tuberculosis. Approximately 900,000 arc exposed to silica dust, but have not contracted the dis ease. Contrary to popular belief, silicosis is slow In develop. Usually it lakes seven years or more of exposure to siliea dust for a worker lo cowtraet the disease. A few cases that have been known In develop ill as short a period as one ami one-half years occurred under extreme and unusual conditions:* On the other hand, many workers have labored under ordinary exposures l silica lor more than JO years without demonstrating any trouble whatever that could be diagnosed as silicosis. Silicosis Prevention ' Silicosis can lie prevented in three general ways; I-'irst, by preventing Ihc creation of silica dust; second, by preventing the dis persion of dust into the atmosphere of a working area; and third, if it is impossible to apply the first two methods, by the use of personal protective equipment such as respirators, to prevent the inhalation of the dust. In carrying out a prevention program, many agencies must cooperate. In the view of the committees studying the problem, the employer is called on to do most of the woik ami to spend most of the money, lint his work and money will never accomplish the maximum results unless the worker is will ing to cooperate and carry his share of the responsibility for helping lo conlrol dust and for using the personal protective equip ment. In addition, physicians can play a definite part in prevenling*silicosis, as can also cn- I ginccrs, insura. ^inpanies, legislator s, minixtrators, and others. The reports of the conference commit on engineering control anti medical Cut recommend specific procedures fur nit iug tlie problem through those two avi. of prcecution. A partial list of tltc'C ret meudnlimis follows: Survey Ihc working conditions to ch mine the severity of the hazard ami i cate what needs to lie done lo lu'rea Secure information on best p pee*tnt lb sign plant for dust control..'' I'rovidc building ventilation. * Store dusty materials in dnsttit 'it Wit Enclose material-handling equipment Isolate dusty processus, i'rovidc wet methods of opera lio Water, oil, and other liquids may 1>c t effectively-- 1. To suppress tltisl at the point of ot in such operations as rock-drilling ; I dliug, pulverizing, and milling rock ore; grinding ntclal on grind-tutaltrasive-w heel culling of granite ami sn stone. .2. To prevent the rcdi-pcrsimi o| d that has settled oil ihc Ilnurs, wails, a oilier surfaces such as in the granite tltlslry aiql in foundries. Design equipment to control du>t. Establish good maintenance ami lion keeping procedure. I'rnvidc- respirators. Instruct the workers. Responsibility of Workers The cooperation of the workers is licit sary if the hazard of silicosis is to lie t dured to the minimum. The worker shot realize that the safe practices recommend and the equipment provided arc (cxigncd prevent injury to himself and to Ids fell cmplojccs. The equipment should ,>e used directed and every effort should It; made maintain it in good working ordir.'i'urtli more, the worker is frequently in a pi. lion lo observe faulty equipment ami inis, practices, and he should make it a point report all Mich conditions lo his supervis. Statutory Regulation While the primary approach to the pn lem imi't he the prevention and dimiiniln I 2C>0 N'tiliniial Sitfclv Ctiiit/rc.<.t of the hazard, the tact must be recncnizcd that until silicosis has been wiped out. workers who now have the disease, as ncll as those who may contract it. must receive workmen's compensation just as do those workers who al-c injured in accidents. Accordingly, the Committees of the silico sis conference were unanimous in presenting the following recommendations : Coverage for silicosis in the compensa tion acts of all States. This coverage should be compulsory. Because of competition between the same or similar industries in various Status, the laws, rules, and regulations of the several States should be as uniform as practicable. Should Be Insured The employer should insure his obliga tion for compensation either through selfinsurance subject to the posting of adc quale funds, or with an authorized in surance institution. Insurance should not he denied any em ployer, provided the State authorities certi fy that he complies with the State require ments ns' to proper safe working condi tions. and pays the premiums involved. Workers having active pulmonary tuber culosis and silicosis should lie removed from employment. Such workers should . he granted suitable compensation payments and medical care. Workers disabled from silicosis (hut with no tuberculosis) should ultimately he granted the same amount of compensa tion as those disabled by accidental in jury. Two years is- a reasonable minimum limitation period for tiling claims subse quent to the date of the last exposure. Further Activities of the Department of Labor In carrying out ils duty as stated in the basic law, the Id. S. Department of Labor has conceived that there is immediate need for the conversion of known facts in the medical and engineering fields working toward prevention, and in the legal, insurance and regulatory phases looking toward ade quate workmen'* compensation, into a prac tical, readily understood program which will adequately take care of the silicosis prob lem. In its program of cooperation with the IS States, the Department of Labor lias in cluded a section covering silicosis and simi lar dust diseases. This breaks down into three main sub-headings: (1) Assistance in the preparation of reasonable and adequate codes, rules. an<I regulations prescribing methods of prevention: (2) assistance in the establishment of equitable standards of workmen's compensation for those em ployees disabled as a result of the disease; (o) a general educational program among State official*. factory inspectors, etc. so that they will be equipped with adequate knowledge concerning the disease, its mctliud of prevention, and its proper treat ment under the workmen's compensation law. Follows Two Lines This application program, which is just now getting tinder wav lias been commenced along two principal lines: (1) The compiling of practical information concerning actual du*l control installations in typical silica hazardous plants, together with approxima tions as to cost, not only of installation, but also of maiiitenaiirc of dust control equip ment in such plants; (2) a program of visual education supplementing the summary and full committee reports of the National Sili cosis Conference. It is contemplated ilmr in tins held such media a* film strips, lantern slides. |Hi*tcrs, illustrated bulletins, cte. will lie utilized. Further, in connection with the various exhibits of the department, show n at various large expositions, trade association meetings, labor and technical organization meetings, etc., it is contemplated that much factual information will he used, pointing toward ways and means of correcting the hazard ami of establishing adequate stand ards of workmen's compensation. Following the address bv Mr. Starr a hazards in quarry operation took place. This round table discussion of outstanding concluded the Wednesday program. Steam Railroad Meeting WEDNESDAY AFTERNOON SESSION October 13, 1937 Tlie Nc.ssion was called to order fy \\\ \V\ more, Md,, who presided, inlrodticim; the Wood, Bnllimorc and Ohio Railroad, Balti .speakers and directing the discussion. The Past, Present and Future of Railroad Safety By J. M. SYMES Vice President, Operations and Maintenance Department, Association of American Railroads, Washington, D. C. No industry in the world requires more diversified study and more exacting applica tion of safety principles than the steam rail road industry. Picture a quarter of a million miles of railroad line covering in a virtual network the vast expanse of the United Stales. Over this network arc operated a billion train miles annually. Vast yard and terminal operations arc necessary to make up the beginning of the journey of passengers and goods, amt to break up at the end of that journey the 12 million trains that accumulate that billion miles. These trains carry 500 million passengers and one billion tons of freight annually. It requires more than one million railroad employees to run the trains, make them ready for road movement, su pervise and safeguard their movement and maintain the equipment and roadbed, as well as perform the many other ditties incidental to (lie production of railroad transportation. Safety has in the past, is today, and always will lie the first principle in railroad opera tions. But it is within the past fifteen years that greatest advances have been made in railroad safety. During that period we have seen a complete remodeling and moderniza tion of railroad physical properties. Road beds have been strengthened; bridges, trestles and culverts rebuilt; tracks have been laid with heavier rail and with treated tics of greater service life and de pendability; grades and curves have been eliminated or reduced; signal systems have liccn modernized and extended; other safety devices have been installed; new and more powerful locomotives, embracing all modern safety devices, have been purchased; new ears, both freight and passenger, have been installed. This capital improvement program has cost the railroads alxiut eight billion dol lars since IV2J, and a large part, if not all, of that huge sum had a hciierteial effect, di rectly or indirectly, on the safety of opera tions. But the engineer's job is never done. As soon as new equipment, new rail, or other devices in e instaiieti the engineers go to work to develop more efficient and safer units. The railroads spent! millions of dollars annually in research and laboratory work experimenting with engineering improve ments. In all this work safely is of primary importance. An invention which might mean great economics to the railroads would not find its way to a single loeumotive or car if its use in any way lessened the opportunity for safe operation. Conversely, any improve ment. mechanical or otherwise, promoting safety of operation immediately commends itself to railroad officers anti employees. The search for greater safety will continue so long as railroatl transportation is used. About a quarter of a century ago, the 5S7 S/t'ani luiilnniil illrrliinj ' THURSDAY AFTERNOON SESSION October 14, 1937 Safety, An Executive Operating Problem By R. C. WHITE Assistant General Manager, Missouri Pacific R. R., St. Louis, Mo. Safety i; an obligation of management. Without the constructive leadership and dayto-day urge from the executive and_ operat ing heads, the movement would lapse into a perfuntory activity. The safety movement is recognized by executive and operating officers as a medium tor building up and maintaining that rela tionship, that fellowship, which broadens our views, enriches character, and brings the Gulden Rule into practical application. Management recognizes that our economic system must.enaule mgy, to live on an. in creasingly high 'gfhnc. -{t must enable them to fulfill their desires and satisfy their rea sonable wants, attentive them that feeling of security which is essential to happiness and efficiency. Having made the decision that safety is an executive problem and responsibility--that accidents must stop--it is then essential that management promulgate, and follow through, a plan that will definitely fix this decision in the minds of all the individuals who collectively comprise the industry. The follow through must be such that department heads, superintendents, and every member of the supervisory force will appreciate the need tor a constant, active interest in safety; will understand that passive interest will iio more produce results than would the same interest in production. Supervisors must be made to feci that the prevention of accidents demands the same type of heads-up super vision that is given to tltc other problems affecting cost and service. The executive must find a way to indicate directly that it is the responsibility of the department heads to carry out management's program, that authority is placed in each superintendent's bands to put accident pre vention on the same basis as production. A complctc.faettt.il ami descriptive report of each accident must be made. This must be followed by a thorough analysis to find the direct and underlying causes and the pro cedure necessary to prevent a recurrence. Proof of its sincerity will depend pri marily on whether management will make the first essential move in the program-- that is, authorize the expenditure of money necessary to make the maintenance and op erating plant a safe place to work. Safety and Efficiency Analysis of the underlying causes of in dustrial accidents and preventive measures to be applied has made it increasingly appar ent that those factors which arc producing accidents are very largely the same factors which tend to lower the quantity and quality of production. Expressed in another way, safety and efficiency arc as inseparable as though one worth In coupling safety with efficiency I have not minimized it as an executive problem, but have endeavored to indicate that its solu tion is an executive responsibility, both to his individual industry ami to the employees that make it a going concern. Rail transportation is a scientific business in which laboratory research, expert tnginecring, trained builders, and skilled works r< share a part. One of the mailt factors is a group of employees who are loyal--who appreciate that their railroad must give the kind of service that will .stimulate and accelerate the development of the territory traversed. The successful solution of our problem de mands tbe type of aggressive individualism in executive leadership that will attract anti command loyal, collective, cooperative effort tin the part of all who produce rail transpor tation. Our major concern is leadership--leader-