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1935 TRANSACTIONS National Safety Council . Incorporated TWENTY-FOURTH ANNUAL SAFETY CONGRESS Louisville, Kentucky October 14 to October 18, 1935 The Brown, Kentucky and^Scelbach Hotels Copyright, 1936, National Safety Council, Inc. Twenly-foiftth Annual Safety Congress--National Safely Council Carney, Chicago Safety Council. n:r I. Cati.in, Aetna Casually & Surely Company. ' . Ciiue, Evanston Safety Council. II. Coleman, Cement Section. IkiniriiT Corson, Safety Dept., Nashville Chamber of Commerce. nk Kmiry Con, Berkeley Traflie Safety Commission. Ctij. nky, Bethlehem Steel Company. W. Da'.h, Metals Section. ii.iam G. Dkani.ii. Rochester Safety Council. us A. DrllLOis, Consulting Engineer. E. Dec \Kti, Mason City Safely Council. W. Demfesv, EooiI Section. M. Diet/, Rubber Section. Mrs II. Douglas, The Philadelphia Gas Works Co. . Lons I. Duuu.v. Metropolitan Life Insurance Co. ' 1). Pennell, Consulting Engineer. \'Ai.it A. Fixkbeinkr. Toledo Safety Council. . ll.\uT E. Pi sun:, Chicago Rapid Transit Co. W. P kk, Jn., Marine Section. . ins. Pr ^glr.vi.d, Western Pennsylvania Safety Council. vyaiiu I... Fonua, nurroughs, Wellcome & Co. (U. S. A.), Inc. !!. Foul.jin, Lehigh Valley Safety Council. Foster, Jr., Quarry Section, itn n. Giiison, Western Electric Company. A" M. Godwin, Public Utilities Section. I". Grant, Paper & Pulp Section. `' . MiHV Gu'tt.nr.RT, The Pullman Company'. viaii II.nr, The Atchison, Topcko & Santa Fe Ry. Co. ajor Roi.i.inc II. Handy, Richmond Safety Council. . T. Harrington, U. S. Rureau of Mines. J C. Haven, Vehicle Fleet Section. :. W. IIimss, Textile Section. .' I . T. ifu.f.Mcm, Chicago, North Shore A- Miluaul.ee R. R. Co. " harms 1C. Ilii.i., New York Central .Lines. . on. IIariu.d G. I Inn .max, GuviTimr nf New Jersey. i. ii/tit: J. Holding, A litany Safety Cmimil. mviN A. K.\vsi r, St. Louis Safety Council. iiomss 1*. Kearns, Industrial GmmuViuii nf Ohio. . I`. KiLI.tr,. Detroit Imln.trial Safety Council. A V. Kki'.vlh, Pennsylvania Salt Mfg. Co. iii.hm C. Knoki.k, Street & Highway Trail!c Section. . 1.. LaFountaine, Great Northern Railway Co. . F. Larson, Missouri Pacific Railroad Company. MO.v Lazarus, Safely Council of Columbus (O.) Chamber of Commerce. It. Long, The Delaware Sc Hudson Railroad Corp. '. R. I.oyd, Safety Div. Birmingham Chamber of Commerce, nos. II. MacDonald, U. S. Department of Agriculture. . T. McArthur, Peoria Safely Council. J. McCann, Meal Packing, Tanning & Leather Industries Section. Officers and Directors Miller MuCuntock, Harvard University. ' T. H. McKenney, Carncgic-Illinois Steel Corp. A. D. McWhorter, Safety Div., Memphis Chamber of Commerce. II. T. Martin, Fisk Rubber Company F. W. Matson, Minnesota Safety Council. James R. Mays, Elizabeth Safety Council. E. J. Mkiiukn, Portland Cement Association. I. W. Mii.i.ard, Industrial Gloves Corporation. James K. Miller, Grand Rapids Safety Council. Leslie W. Miller, Superior Safety Council. Harold L. Miner, E. I. du Pout de Nemours & Co. Lawrence M. Moore, Eastbay Safety Council. . R. B. Morley, Industrial Accident Prevention Assus. George C. A. OPi*. The Detroit Edison Company. George Oppen^eimer, Kansas City Safety Council. Lew R. Palmer/Equitable Life Assurance Society. David A. Patton, Newark Safety Council. Charles W. PtVuoCK, Safety Div., Milwaukee Assn, of Commerce. C. E. Pettiuone, American Mutual Liability Insurance Co. Gen. George B. Pillsdury, United Slates Engineer Office. Arthur Potterton, Hudson County Safety Council. W. D. Price, Employees' Publication Section, j. A. Purdy, Wood Products Section. Aluert S. Recula, Industrial Relations Counselors, Inc. Lt. Col. Henry A. Renincer, Lehigh Portland Cement Co. Marin us Riter, Paterson Safety Council. R. B. Roaper, Petroleum Section. A. V. Roiiweder, Duluth, Missabc & Northern Uy. Co. George E. Sanford, General Electric Company. Henry G. Schaifner, Eric Safety Council. ' Rouert L. Schmitt, Louisville Safety Council. Karl G. Schokffler, Railway Safety Council. Harry A. Schultz, United States Steel Corp. Karl S. Siiartzkk, Utica Safety Council. Rav H. Sheets, Madison Comity Safety Council. Gen. John II. Shkkiiurne, Massachusetts Safely Council. Dr. L. A. SltuutiY, llclldeliem Steel Company. Ernest L. Si.monds, New Havrn Safely Couueil. Juih;e Lee E, Skkel, Cleveland Safety Couueil. C. W. Smith, Standard Oil Company (Iml.). Edwin C. Smith, Blackstone Valley Safely Council. Walter Dent Smith, Delaware Safety Couueil. W. A. Snow, Construction Section R. T. Solknsten, Elliott Service Company. E. C. Spring, I.ansdale, Penna. George R. Stephens, Safety Bureau, BufTalo Chamber ol Commerce. James M. Strike, St. Joseph Safety Council. Arthur M. Tode, Consulting Marine Engineer. Harold M. Toomds, Refrigeration Section. 8 T~vcvly-fourlh Aiuiunl Safety Congress--National Safely Council W. W. Trench, Schenectady Safety Council. W. D. Tukueville, San Antonio Safety Council. E. J. \Vali-mak. Power Press Section. Dr. C. H. Watson', American Telephone & Telegraph Co. Harry M. Webber, Illinois Bell Telephone Co. Albert C. White, Jr., Springfield Safety Council. S. F.. Whiting, Liberty Mutual Insurance Company. A. W. Whitney, National Bureau of "Casualty & Surety Underwriters. T. A. Willson, Accident Prevention Equipment Manufacturers' Section. W. II. Wina ns, Union Carbide & Carbon Corp. C. T. Winegar, Automotive K: Machine Shop Section. Harry Wise, Sr., Qiattanooga Safety Council. J. M. Woltr, The Youngstown Sheet & Tube Co. W. E. Worth. International Harvester Company. E. J. Zauft, Safety Bureau, Duluth Chamber of Commerce. Earl W. Zimmerman, Safety Div., Syracuse Chamber of Commerce. . Occupational Diseases Occupational Diseases . FRIDAY MORNING SESSION October 18, 1935 The session *vas coiled to order by Mr. W. Dean Keefer, director. Industrial Division. Xation.il Safety Council. Dr. C. H. Watson, newly-elected President m The Matronal Safety Council and Medical Director, American Telephone and Tele graph Company, N'cw York City, presided. Present and Prospective Occupational Disease Legislation By F. ROBERTSON JONES General Manager, Association of Casualty and Surety Executives ... New York, N. Y. ' Shtce me prevention of diseases is. to -some degree, a community problem, the state ought to dn its part toward the prevention of occupational diseases, along with all others. The. public health authorities should study the causes nt such dis eases, their prevalence, virulence and the means for their prevention. They should advise as to such means of control, and. as a last resort, appeal to legislatures for power to order compliance with their rules. Statutory regulations for prevention, emanating from other sources^ such as are common in "labor" or "factory" laws, have too serious drawbacks to he efficient. They are apt to he indexible and (piicklv become "out of date": and they arc too apt to lie perverted tor the establishment of fictitious liases for wasteful and demoralizing damage-suit litigation. Scientific bureaus of occupational hygiene, under direction of public health authorities, are the best public instrumentality. Efficient bureaus of that character are now to be found in several states: lint, generally, such public health organizations are inadequately manned and equipped. Therefore the primary need in occupational disease legislation is for measures to improve our mihlii- health services. Emphasis should lie placed on prevention, not merely because "an ounce of pre vention is worth a pound of cure." but because public measures for the assurance of relief to victims arc perilously susceptible of being so perverted that those affected will tend to rely upon and abuse the protection afforded as a substitute for, instead of as a supplement to , means for self-protection. Expert opinion now calls strongly for the entire elimination of employers' liahility for "damages" for occupational injuries--by disease as well as by accident--based upon negligence. That remedy is too uncertain in operation, litigious, demoralizing and wasteful: it furnishes relief to too few of the victims unless it he so liberalized as to he grosslv unjust and financially perilous to emplovcrs--and thereby harmful to industry and all dependent upon industry. I-osses from ill-health among workmen arc primarily subjects for scif-providcncc or for "social insurance"--fur "sickness insurance" to heln out during brief illnesses, and for "invalidity." "old age" and "widows' and orphans' '' insurance where illnesses or infirmities result in long or permanent disability or untimely dealth. The cost of these insurances against the common misfortunes of life cannot rightly or expediently be imposed wholly upon industry, hut needs to be distributed somewhat in proportion 117 .'0 Twcnly-faurlh .tniinalSafcly Conyrcss--National Safely Council Tlic iilioic tirograni is sound and would l>c highly conducive to occupational aw prevention. Hut I am nut so confident that it would lie safe. The pressure is ng for "liberality" in compensation laws. Merely a few among a large manlier i lohahlc slight diversions from what 1 suggest would convert compensation for palional diseases into indefinite health, old-age and life insurance'fur workmen in .) industries. The cost might ruin the industries, and, at least, would he so deniable as to make the risks `uninsuralde," except on the unlimited assessment at. ttiih all its financial perils and uncertainties. In regard to prevention, there are still some practices to he decided upon in '.cling a regime of compensation for occupational diseases about which there >ins much ilouhl. l-'or example: Such a regime will practically compel employers, riving employment, to discriminate against all the ailing or aging--against all pt the most healthy and rolnist. That seems to lie desirable in occupations when occupational disease hazards are great. Hut is it desirable otherwise? Again, an ideal'common In those of us who emphasize prevention is to require prompt 'removal from exposure of workmen manifesting the first symptoms of an ip.iliniinl disease. Hut for the cldcily or skilled workman the loss of lii.s trade-job . lie worse, in every respect, than the danger of continuing his exposure. How . should such rases he defined and trcalcd and how should the law he framed to .1 or iiultirc si eh treatment ? I'olitieal impatience is the chief obstacle to a just and equitable settlement of the ip.ilioital disease problem. If those thoroughly informed as to this complex suh- u bo have sincerely at heart the welfare of workers could he delegated the auity to devise a solution, some progress might he made. Hut when political igantla is injected into the situation there is little chance for an adjustment i.ielory to all concerned. The greatest need today is the divorcement of occnpad disease legislation from politics or political considerations. Some Practical Considerations in Dust Control By J. J. BLOOMFIELD . vjitary Engineer, United States Public Health Service, Washington, D. C. The pi .vcutioii of ocrui>atioiial diseases due In the inhalation.of industrial dust i imarily an engineering problem. Until recently, however, little attention had di-volei.'* to the control of dust, accounting for the paucity of fundamental data Mibji-t. The ennwquenres of the neglect to furnish adequate protection from hazards ire now being fell, and the cost is becoming a serious drain on industry, mm- wi I established that exposure to certain kinds of dust, snclt as those con ig considerable amounts of quartz, has increased the morbidity anil mortality from respiratory diseases; while metallic dusts, snclt as lead and its compounds, In-ell associated with general systemic poisoning of workers. It is obvious, lore, that any serious allnnpl to control the dust hazard should, in time, result iilv tii the improvement of the health of workers, hut also he of definite economic 'I In industry. I lie benefits of a preventive program. in the field of accidents arc well known, try is fast realizing the need of a similar picvcntivc program with respect to atinnal diseases. Evaluation of the Dust Hazard t lie first step in the evaluation of the dust hazard is the determination of the -itional exposure to the dust in question. A typical example of snclt a study serve to clarify the methodology involved. I aide 1 show s the various occupations in a granite quarry and the number of .rs enqiloveil in each occupation. Drillers arc the only persons using pneu- lools, known to. produce cmi'idcraldc quantities of dust. In other words, 38 ` "* " the quarry personnel arc shown to he cxposctl to a potentially dangerous i/aid. fhi. occupational analysis at once indicates that the dust investigation Occupational Diseases 121 Table 1--Occupational Classification of Granite Quarricr* Occupation Drillers: I.eyner ...................... Plug and jack hammer Ulhcr quarry employees Superintendent .......... Foremen ..................... Compressor engineer . Hoisting engineers ... Locomotive engineer . I.ocojiiolivc fireman .. Slcpm-shovel man ... CAlttF operator .......... Derrick men .............. Muckers ..................... Hlacksmiths ................ Tool hoys ................... Water boys ................ Machinists ................. Air-line repairers .... Pipe fillers................. Number in Each . Occupation . 17 . 37 1 7 1 12 1 1 1 1 24 24 6 2 1 3 1 2 Total 142 Table 2--Occupational Dust Exposure of Granite Quarriers ` Occupation Number in each' uccupal ion 1 finer drillers..................................................................... Plug ami jack-hammer drillers (quarry-bole).............. I'hig drillers (yard)............................................................ All other workers.......................................................f......... 17 37 88 Dust counts in millions of panicles per cubic font of air. Weighted Average 144 4 112.1 3f>9 5.8 should especially concern itself with these workers. The next step involves the determination of the occupational dust exposure. Table 2 shows the results of such a study. ' ft is apparent in this table that the drillers arc exposed to high dust concentra tions, especially the I.eyner and jackhammer drillers working in the quarry hole. From a further analysis of the occupational dust exposure ol drillers it is possible to determine which activities are responsible for the dust. For example, experience has taught us that the various activities comprising the processes of most dusty occupations are usually associated with dissimilar dust vxposnrcs. For this re.,'.on it is essential to estimate the amount of lime spent in each activity in any one occu pation and to determine the dust exposure for cad). Table 3 shows the results of such a study in the ease of a I.eyner driller. It will he seen that a Leyncr driller has five different dust exposures. A differ ential analysis, as presented in Table 3. yields several valuable findings. First, it rnahlcs otic to obtain a true average (lust exposure for workers cngaecd in the occu pation of I.eyner drilling. (In this ease the weighted average is 144.4 as contracted with 213.4 million particles per cubic font found during drilling operations only.) Second, it enables one to determine which activity, or activities, contribute most to the * .\ 1 Twenty-fourth Annual Safely Congress--National Safety Council Me 6--Showing Reduction in Concentration and Quartz Content of Dust In Sandblast Rooms With the Substitution of Steel for Sand Abrasive c of rasiir .1 ... I ... Average dust concentration . in millions of particles Percentage per cubic foot of Quartz 969 -12-98 IS5 3 [I he second method of dust control, isolating the ilnslv process, possesses many ibilities, but unforttmalely is not widely used. The theory underlying isolation * concentrate the dust sources to one locality or to a single closed space. In this , a loioiuuun miiubcr of employees are exposed At present, many foundries, durshnl.c-ont expose workers who normally are engaged in occupations with low ! concentrations. 1 Inis, molders in a foundry may he ex-posed to a dust coiicen- ion of 3 million particles per cubic foot under normal occupational conditions, but u slial.e-out operations are carried on close bv. their exposure may be increased .lore than 50 million. The same eondition cxi-ds when annealing flasks containing md slag arc emptied in malleable iron foundries, exposing grinders and tumbling cl alliudants at work dose by. lYibups the - vst example of isolation of a dusty process is the abrasive cleaning o. I bis completely encloses a hazardous process ami exposes only the blaster who rocrally cipiipprd with a protective helmet. The room is also exhausted, which her reduces the dust concentration. Processes which arc isolated rctpiirc good 'ilalion. Other examples of isolation are the automatic turntable for abrasive ling, lipubliiig barrels, and batch-mixing rooms found in some pottery cstahlish- 1s. 1 ' ' riic- third method, perhaps the oldest known, is the practice of wetting the dust x source. In Table 7 an example is depicted in connection with the drilling and mg of rock in anthracite coal mine operations.' It is apparent that a tremendous a. lion in dust lias been effected by ibis method. However, as already pointed out, " a particular method is attendant with a reduction of the dust to a safe limit, unoi be Vouxiilereil successful. In the present instance, the workers engaged in mg are still exposed to unsafe concentrations of a highly dangerous dusUaud more positive method of controlling the dust in drilling operations by dust traps 'I lie indicated. For drilling and loading operations involving an exposure to dusts toxic an those containing high amounts of free silica, as in the case of coal or iji lab . the reduction shown by the use of wet methods may be considered live. ' lc 7--Ci ntrasting "Wet" and "Dry" Methods of Rock Drilling and Loading "'cs No. of Samples Average dust count in millions of particles per cubic foot "Dry" "Wet" - mg ............................................... mg ............................................... 23 10 568 6.16 33 32 The fourth method---exhaust vent ilalion--is perhaps the most effective, and one the widest application. We cannot discuss here the details of the theory and ii of local exhaust systems, except to point out there is a real need for more -inrnlnl studies of the Ivor conducted by DallaVallc with reference to the design e.d exhaust hoods, which he has presented in Public Health RuUcthi 217. Th~ of Hatch and his colleagues" op the control of the silicosis hazard in the hard industries is another example of a scientific approach to the dust elimination :m. t Occupational Diseases 125 Table 8--Summary of Results Contrasting the Dust Exposure of Mine Workers Under Controlled and Uncontrolled Working Conditions . Operation Dust Concentration in millions of particles per cubic foot of air Controlled Uncontrolled Remarks Firing charge ..............40 l.uading coal or ruck.. 32 Loading coal ........ 3-26 Drilling........ vJf-j...........33 Hauling coal in'-luiucs. 1.2 I'rcparaliim of coal... 24 834 636 291-1133* 568 17 ' 380 Unless at least 15 minutes elapsed after firing a charge, miners found to be exposed tu high dust concentrations. llv wetting the loaded material the dust count is reduced as shown. Mechanical loading decreases the dust ex posure as indicated. Wet drilling is effective in reducing the dust concentration. Further reduction would necessitate exhaust ventilation. Welting coal and empty cars reduces dust in haulagcways. ' Wet breakers retluce dust counts as shown. 'Hit timer icsutl U asMK.-i.ilcl w-iili (lie li.uul Inailiws <d ct coal ivlulc ilic higher avciayc i> l>:i>ctl mi (lie liaml lo.atliii|? ot ilr> rowl. It is apparent that there are no set rules for the mechanical protection of workers from the industrial dust hazard. Specific conditions in an industry, or a plant, will determine the type of protection to be employed. The present discussion has empha sized the importance of approaching the problem from the standpoint of the occupa tional exposure. Studies in representative plants of an industry often rc\t-al the various methods which may he employed in controlling the dust hazard. The follow ing two examples indicate the value of such investigations. . Table 8 indicates the various control measures which were found tn use in the anthracite coal mines investigated ill the study referred tn earlier. Although no single 'mine practiced all of the control measures shown in this table, by an necupatioual study in several representative mines it was possible to show that methods are nut known and practiced for the elimination of the dust hazard in this industry. Another example is indicated in the results of a study now in progress in connec tion with incrcurialism among workers in the hatters" fur cutting industry. Table 9 shows the exposure to mercury dust and vapor oi some of the workers in this industry Table 9--Exposure of Hatters" Fur Workers to Mercury Dust and Vapor Under Controlled and Uncontrolled Conditions Occupation Total Mercury Exposure in Milligrams per 10 cubic meters UncuiiirolUit Controlled .. .. .. ** Drummers ' .. .. ................................. ... .. 4.6 7.2 4.(1 3.8 31 2.5 1.5 . 18 1.7 12 06 07 Method of Control Nunc practical Local exhaust venti*lation " Segregllation J 126 Twenty-fourth Annual Safety Congress--National Safety Council under controlled and uncontrolled working conditions. It is apparent that where some measure of control is practiced by such methods as segregation or local exhaust ventilation, a material reduction in the exposure to mercury has been effected. It ts onr belie! that in the ease of the blowers' exposure, a reduction may be effected by mechanical enclosure and local exhaust ventilation, and that the shippers' exposure to mercury vapor may be lessened by a general system of ventilation sufficient to change the air in the sture room freiptoully enough to bring the mercury concentra- iratiun to a lower level. Unfortunately, in the present investigation it has been im. iuismMc to null a plant in which an attempt lias been made to reduce the exposure for these two occupations. In some dusty occupations the methods of controlling dust have not been devel oped. In fact, operations such as removing the core? from very large foundry castings, sand l^isliiiR, handling of used storage battery plates, paint chipping, and cadmium oxide lamif ietnre appear to offer no practical means of adequately controlling the dipt geucr.Vcd. In such cases, it is therefore necessary to furnish the worker with persona respiratory protection devices to prevent his exposure to the harmful effects of the i lists present. These devices consist of various types of respirators, masks, and hell vets. It is important to hold in mind the limited use of personal protection devices. Because a worker cannot with comfort wear a mask or helmet continuously, such devices must be employed intermittently. Their use is generally extended to those operations where all other methods have failed or supplementary to them, as in storage battery repair where the exposure to small amounts of lead breathed is known to be detrimental to health. . It should be pointed out that the L*. S. Iiurcau of Mines is equipped to conduct approval tests oi respirators vised for protection against various dusts and fumes (Schedule 21). These tests arc conducted against the dust for which the device is to he used anil arc rated, not on an efficiency basis, but on the quantity of dust which actually passes live respirator. The results of a study of masks or helmets of the positive pressure type, made .during the sandblast investigation conducted several years -go by the Public Health Service in cooperation with (he National Safety Ccniii.il.' showed that die only practical safeguard to the worker inside the sand blast room was to provide him with a mask or helmet of the positive pressure type. In studying the efficiency of such devices it eyas found that a relationship existed between the amount of air supplied to the helmet and the concentration of dust iti-ide the helmet during blasting. To determine the optimum air volume to be sup plied to such protective devices, it was necessary to obtain dust samples from inside the helmet while varying the air volume, at the same time maintaining the dust con- nliniioii in the sandblast room (outside the helmet) constant. The positive supply of 6 eu. ft. of dust-free air per minute will protect a worker under the operating conditions now in practice in sand-blast rooms. The ultimate criterion of protection, however, is the result of dust determinations of the air within the helmet, that is, the, air actually breathed by the worker and not the volume of air supplied. Too much emphasis cannot he stressed on the necessity of maintaining in good order the personal respiratory devices for the protection of the worker against various toxic dusts. Maintenance of exhaust ventilation systems, and other types of protec tive equipment, should be a rule in industry rather than an exception. Too often the erm "good housekeeping" has been interpreted as signifying only the periodic removal f dtisl collected on floors, rafters, etc. Although such practice contributes to the general stale of cleanliness of a workroom ami should always he in force, the time ias study come'when serious attention should he given to tiic installation and rigid iiaintenniicc of all types of dust control devices. In every plant there should be _uuvc iciponsildc individual charged with die periodic inspection of all workrooms ' to sanitation, ventilation, and maiiiiruaiiec of all dust removal and odicr protective c'iccs I'trh.ips the best criterion of die effectiveness of these devices is the ii'..-l,r J, i. r ,1,m it,,.,i of die .hot .niiirnt oi the air at the vvorhet s' bicathing rone. l) I) (an .oi wciljmc amt in 11 | .i oa> It lo die problem as outlined in lliiv paper . I. is- i.. n.jkc i-iogrcit in the (onliol of die dust hazard in industry. ' 1,1 ' d- l - if ( 11 if even < i.i..t (Minsnr program of dust control arc not 1 n*1'1' ic-duol i Ini is c v j is s i dly line in dealing null fibrosis-producing dusts i pi mil "lure some ol the workmen have already inhaled sufficient quantities to Occiifalional Diseases 127 cause disability. However, in dealing with stvch dusts as lead, cadmium, and mercury compounds, control measures may produce salubrious results in a relatively brief period. It is difficult, because of lack of sufficient reliable data, to indicate here the economic benefits resulting Iron) a preventive program of dust control. It has been estimated by Dean K. rtrmiilage. statistician of ibis office, that the minimum expectancy in savings to employer and employee from an indicated reduction of the accident rale and of the time lost on account of illness (or an equivalent reduction in mortality), demonstrated as attainable, is 520,0(10 per year per l.tiOO employees. And this estimate is lor plants whose accident rate is considerably below the average, in which there arc no occupational health hazards. In plants where hazards arc known lo exist live savings should be far in excess of this conservative estimate. When one realizes that in this country there arc approximately 15 millions oi workers engaged in manu facturing, mechanical, and mineral industries, then it is evident that the magnitude of the problem lias not been overemphasized. , Reference* .. . 1. IMooitificbF,' T. J. ami Prccsscu, \V. C.: Silicv*K anmm; i;r unite quanic*. Public HeJib Reports, Vol. fA No. 23, June I, 1**31, _ ... 2.. AmhracVfjtiilicoMS among hard coal miners. Public Health Uulleim No. 221, 1933. 3. IHuotnfield, J. J., and Greenbure, Lcon.ud: Sand and metallic abrasive blaMmi; as an industrial health hazard. Jour. lml. Hyp., vol. 1\ no. 4, July, 1933. ... . 4. Hatch, \IJhxndnie, Diiither, l'hdip, and Ornate. Sarah I'.r Control`ol the mIicoms hazard in the hard*rock iifllustiics. I. A. laboratory study id, the dc-i^n ol <lu<t control systems lor u*-e with {ncumattc granite cutting lords. Jour. I ml. Ihtf,, vol. 12. no. 3'. March, PUO. Hatch, Theodore, Kelley, Gcoi^e S., and h'cl.nct. J. W.; Control of the Mlun-is hazatd in the hard*rock industries. Jl. An investigation d the Kell> dust trap lor u<c \tiih pneumatic rock diill* of the "Jack-hammer'* type*. Jour, lml, Hy#., vd. 14, no. 2, l'ehruary, 1932. Hatch, Theodore, Warren, Hcnrjv and Kelley, IIc.-ikc S.: Control of the silicons hazard in the hard-rock industries. 111. Dcmk ami operation of a diet-control system for use with pneumatic r*ck drills in open excavation. Jmjr. lml. Hvp., vol. U, no. 1, September, 1932. ^ r- Silicosis and Silico-Tuberculosis Medical Problems of an Important Industrial Disease By EDGAR MAYER, M.D. New York City A bidden element of the cost of prniliii-tiuii is industrial disease.- Industry lias reached a stage lnyoml the concern only .if wages and lu-tirs. Far more iinportant is conservation of man power by preventive medicine and improved engineering. Disease preventive measures are nut a rust, Imt, in the long run, a great economic saving. ' Incidence. In the United States it has been computed that tin re are from 5(10,000 lo a 1.000,0(10 people employed in occupation, where a silicosis hazard exists. In New York City there arc about (if.OliO such employees. In a representative group of granite workers in Massachusetts silicosis alone was present in about 15 per Cent ami silicosis complicated with tuberculosis in almost S per lent. Tuberculosis was the cause of death in over one-third of the granite is other, which is lour times the incidence fur males of 20 years and over in ibis country. In foundry nun studied in Massachusetts, silicosis was less frequent lalioui o per cent l and lc<s advanced in degree than in granite workers. The dotation oi exposure in foundry workers vvilli pnciumnmcuiiinsis lias averaged many more sears than that required to pioducc silicosis in an industry such as gold mining. The tuberculosis hazard in foundries is nearly as great as that reported for some of the other dusty tiades. but the figures are much lower than those of miners oi gold, silver, copper and lead, among whom the mortality from tuberculosis is S to IS times the general expectancy. Death rales for all nun-tuberculous infections have been repoited higher among workers in siliceous dusts than in the general population. It is suggested that the worker in silica succumbs more often to acute pnlmnuary infections rather than surviving the chronic fibrosis. i J