Document 2RGMMwDLzx7BGJDG06o90w0Er

A f 1932 TRANSACTIONS TWENTY-FIRST ANNUAL SAFETY CONGRESS Washington. D. C. October 3 to October 7, 1932 The Wardmaii Park ami Shorcham Hotels Copyright, 1933, Natio-iol Softly Cewnii. Inc. e u G 3. O. O Xlc cc CO u o O' o o C G o o cud CD v, 5 /. IS U CO J u 05 a WS >o 5 j u Q 'S ,V? k-Sj g -4 < 2 u >* co t.* : w CO < V* * 9 05 < ~ Oo* 2it<: u O* O s* ** 3 2 o CM VVX>I < PWn o* oo 05 0} 3M _ fe;=2fc.-: fe fcw o fe te. O :feu*{^Eaici, li^lsssS r**n> o. a <N C"T>\ E E 6 teo. c W H (5 -- y ox 5 ** = ^ i>^ S2 u.jSsHJ jsJ.Ss U. ?-*J*5*" , o M . w c~e " *-->* L+ -- w M < . c. c3 VV >s Jc5. nx |. c Jc U s 6 CS o tt " CO es<x ss <-S< 3 *o* tej --o w oiio'-siio I40 oc U u U -o K o e P0 5-n =nC c g ^5c jjj O -Sr 0*.oNI<.MNNN(itNpaNm<blNsnONoNnNInSNvfAlnx>cno TTfT CO .z. w. E- ' s o o e >2S *(2| rw 2- Uu eu 2X x CO II = s| 3 ^5^ o< xo .so, 0-0 g 5 , * uS o %? _ o v J3 6 X*- _c w * 2^ " 3 ^ *o rwr c r w CWO 5o a c Z$ o -- " wU w Uu CO 0. -- 3O' CO J? rcMS w c 3 '5 I J -o f 3 g O c v'-.^^ZU. O. 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S -- "2 S2< g-gs JSS *5 c ^.5^- C 2 v-^y 7. U c 3 w & l = o J2 s. \c < < J* St O-* t o* vw *i " O jj 10 < w * a 5 g>- 2 fc J --a 3u o " r w to x - *a <W T^.e-JH!. <s u" B J. -< V. / . S c = . v' f , v * c: z 7X ua :!!=<"; ^c .ir. 2 < -- * J O ,^ - u5 g~ = vi U< c<a a ^ v < to ^ = - v< ^ Sz-g . o " " ^ o< t 6~ | UCliU^hcic^^- :y ? < ^ Tivcuty-first Congress--National Safety Council C. L. Rice, Chicago Safety Council.' Da. A. D. Risteen, The Travelers Insurance Company. John Roach, Chemical Section. Cuas. J. Ron, Newark Safety Council. Tobias Roth, Rochester Safety Council. John Russell. Jjl, Construction Section. G. E. Sahforb, General Electric Company. Henry G. ScHAjTNt*. Erie Safety Council. Otto Schenk. Wheeling Safety Council. Robert L. ScnutTT. Metals Section. Cuakles.B. Scott. Bureau of Safety. '' Gen. Joun H. Sherburne. Massachusetts Safety Council. Da. L. A. Suouor, Bethlehem Steel Company. Ernest L. Suxonos. Netr Hasan Safety Council. Geoacc P. Since*. Reading-Berks County Safety Council. Outer T. Shout. Safety Division, St. Paul Association. Charles F. Smith, Rubber Section. C. W. Ssixth, Standard Oil Company (Indiana). E. J. Smith, Power Press Section. H. $. Smith, ASSE--Engineering Section. *- R. T. SotXNSTEN, Accident Prevention Equipment Manufacturers' Section. E. C SrxtNC. Lamdale. Montgomery Co, Pa. Geoacc R. Stetuens, Tlie Safety Bureau. Buffalo Gtamber of Commerce. ETitcLSGJtT Stewart. Washington. D. C. Carl Stoxck. Automotive & Machine Shop Section. Lucius S. Stoars. United Railways & Electric Co. Alfreb H. Swayne, General Motors Corporation. John H. Taylor, Birmingham Safety Council. Henry D. Terft. Meat Packing, Tanning & Leather Industries Section. Norman F. Titus, Hudson County Safety Council. Arthur M. Tope. Consulting Marine Engineer. W. D. Turbeytux. San Antonio Safety Council. William F. Veech, Rahway Safety Council. Vincent Wakefield, Kansas City Safety Council. George H. Warfel. Union Pacific Railroad Company. Dr. Cassius H. Watson, American Telephone & Telegraph Company. Harry M. Webber. Illinois Bell Telephone Company. Carroll V. Wells, Delivery, Taxicab & Bus Section. Albert C. White, Jr-. Springfield Safety Council. W. L. White. Jr.. Cement Section. S. E. Whiting. Liberty Mutual insurance Company. A. H. Whitney, National Bureau of Casualty & Surety Underwriters. W. H. WtNANS, Union Carbide S: Carbon Corporation. C. T. Winecar. Detroit Industrial Safety Council. Dr. C.-E. -A Winslow, Yale Medical School. J. M. Woltz. Youngstown Sheet & Tube Company. fir ne de ..fiT Un tvs Y< nif wc rer ant pre aec exa ten: 5 deal mot of j deer year elfei safe to p The: accit Si best mad< 74 p. 2 t t *? Txvcntv-first Congress--Notional Safety Council a proper staff, and not by some enthusiastic person who has not been trained for the work. Why not use more registered nurses in the smaller plants? The registered nurse is much better qualified to interpret a physician's plan ot medical sendee than any lay attendant. - Much depends upon the physical condition of the employees. I am of the opinion that the physician, by reason of his.professional attainments, is best qualified to handle some of the problem cases among employees. Mental symptoms, brought about by worry over home affairs, quite often produce accidents. In many cases the fear and worry of sickness in the family ean be greatly allayed by a talk with the doctor or the nurse. Many of these cases hare come under my personal observation. It should also be absolutely the part of the physician to say when a man shall return to his regular employment after injury, and this decision should not be in fluenced in the slightest by its possible affect on any "no-lost time accident" contest or record. Theses contests are proper and have brought about outstanding results in the reduction of lost-time frequency figures. However, there have been cases of injured employees being urged unduly to return to some form of work merely to prevent the marking up of a lost-time accident. Nothing should be allowed to inter fere with the employee's welfare. The physician has every motive to return the employee to his regular work as promptly as possible, but his higher duty is to conserve both the physical and economic welfare of the employee as well as the employer. The safety director has need of the medical service, and the two should earnestly co-operate and seek to bring about a mutual feeling among the employees. Both departments are striving by all possible means to prevent economic waste chargeable to the disabilities and Ita2ards of industry. TUESDAY AFTERNOON SESSION October 4, 1932 The delegates first attended an informal luncheon, and then gathered for the after noon meeting iti a Joint Session with the Metals Section. This session was devoted to a symposium on the dust problem in Industry. Chairman Greenburg immediately introduced the first speaker. ` - a. . The Effects of Inhaled Mineral Dusts By LEROY U. GARDNER Director, Saranac Laboratory for the Study of Tuberculosis, Saranac Lake, .N. V. As long as men iiavc worked in stone it has been appreciated that an unusually large proportion of them suiter from disease of the lungs. It was natural to assume that such disease would be caused by the dust generated, and this .belies was strength ened by the discovery of black, grey or red pigments in- the lungs, sometimes accom panied by the formation of scar tissue. The term, pneumonokoniosis was introduced to describe the lung pigmented in this manner. With further observation pathologists attempted to classiiy various forms of pneumonokoniosis on a basis of the type of dust inhaled and such names as anthracosis, siderosis, chacicosis and even byssinosis and tobaccosis made their appear ance. It was recognized that some forms ot the disease were -attended by severe symptoms and result in death but there was no correlation between the clinical and pathological pictures and the causative dust. Finally, statistical study demonstrated that of all kinds of industrial dusts silica generally produced a definite type of disease with a characteristic pathological lesion and complex of symptoms. _i .sT * <3 n r< w <h in *ii tu pr cu du de: prr tul rat is.; \ far: amt nat: coir V tin* tic*: and can.. asbr part tissiport: spec: Fi has nodu dram remo fram. Of tl: synip exces n trained tor 'lie registered * service than , the opinion lifted to handle cght about by : the fear and i the doctor or ntioa. r. a mao shall nld not be in cident" contest nag results in been cases of itk merely to `.towed to inter- to return the "u-r duff is to well as the Sxsld earnestly `.r-loyees. Both sue chargeable . foe the afterAt was devoted irg immediately T^v .uc lake, N. Y. -at an unusually v.urai to assume was strengthtsetimes accom* lamented in this various forms it names as an* Je their appearmded by severe . the clinical and Ty demonstrated ; type of disease Industrial Health Section 51 Today the clinical entity known as silicosis is one form oi pneumonokoniosis which is quite dearly defined. Moreover, within the last three or' four years asbestos dust ha* also been siiown to produce another specific tyjw of reaction attended by symp toms differing in some respects from silicosis. The other forms of pneumonokaniosi* still lack complete definition. The wide spread use of radiography has brought together a mass of descriptive data from indi viduals exposed to many kinds of occupational dusts hut these findings have not yet been correlated with pathological anatomy, chemical studies of the tissues and de tailed analyses of Industrial atmospheres. There is a tendency to assume tliat many of. these pulmonary changes are due to the action of silica perhaps modified by the chemical components of the dust. We shall only be in a position to speak with assur ance about them when the pure types of dust and their various combinations have been studied in human beings or in experimental animals.' * For the sake of clarity no mention lias been made of Use infections which so fre quently complicate some forms of pneumonokoniosis. In the prebacteriological era of medicine the use of such terms as "grinders' consumption" and "miners' phthisis" reflects the popular association of pneumonokoniosis with tuberculosis. The names were justified both by clinical and pathological observation for it has been subse quently shown tliat. in silicosis at least, a super-imposed tuberculosis may cause death In perhaps 75 per cent of the cases. Some observers even go so far as to state that silicosis itself does not develop unless the lungs are previously damaged by a latent tuberculous infection. This is probably an exaggeration, for typical' silicosis can be produced in the experimental animal by the inhalation of siliea without infection. T!k role of asbestos dust as an excitant of tulierculous infection is not as clear cut as that of pure silica. White there are numerous reports of death in asbestoxis due to a terminal tuberculosis, nevertheless surveys of living workers have failed to demonstrate any excess of such' infection. Simple anthracosis is said to prevent the progression of tuberculous infection. Statistics from coal mining districts do show a tuberculosis rate much lower titan that "normal" for the ace group. As yet corrobo rated experimental proof of protective action of coal against tuberculous infection is lacking. Not only the tubercle baeillu* but other bacteria seem to develop with special facility in the tissues previously damaged by silica. For example, the pneumonia rate among silicotic native laborers of South Africa is many times that in rton-siiicotie natives living under similar conditions. In coal miners, likewise, pneumonia is a common and often fatal complication. What lias been said of the enects of inhaled inorganie dusts would Indicate that the reaction of the tissues is not merely a response to mechanical irritation by par ticulate matter. Today it is generally accepted that the injury is chemical in nature and that only certain of the common types of industrial dusts ix>sscss properties capabic of exciting reaction. In the eases of silica and the silicate of magnesium or asbestos the slightly alkaline body fluids probably effect a slow solution of the dust particles liberating silica in colloidal form. This substance irritates the connective tissue cells which respond by multiplying. The result is-an overgrowth of the sup porting iramework elements at the expense of the more delicate cells specialised for specific functions. For these two types of dust the diaracrer and form of the pathological cliangcs has been carefully worked out. In silicosis the essential tissue chance consists of nodules of connective tissue which develop first in the lynipoid tissues situated in the drainage apparatus *ot the lungs. These nodules interfere with the physiological removal of foreign bodies and subsequently iultalcd particles accumulate in the framework of the lung itself. Such reaction gradually decreases the norma! elasticity of the organ and encroaches upon its functional elements. As a result the cardinal symptom of the disease, dyspnoea or shortness of breath develops. Because of the excessive amounts of scar tissue formed in the lungs the right side of the heart >r m i *i, 11 r.-d* :d .lisfch W,1; Hi1 p's r v. :f $Z* ; l !* `i .i'r*> Twenty-first Cotujress--National Safety Council encounters increasing difficulty in forcing blood into the organs. In an attempt to compensate the overworked heart muscle Incomes thicker and heavier and unless infection intervenes the time eventually arrives when the heart fails and death occurs from this cause. The reasons for the prevalence of infection in the silieotic lung are not altogether clear. It is obvious that when tiie drainage system is so obstructed by nodules of scar tissue that more dust particles can only be removed with difficulty, the same must be true of bacteria which nay lie iniuled. As a consequence they remain in the lung and set up progressive infections. But this is not the whole story- The silicotic tissue apparently otters a peculiarly favorable soil for the continued multiplication ot tubercle bacilli and perhaps other bacteria. Experiment has shown that even al ternated organisms of this type will produce rapidly fatal tuberculosis in a silicotic guinea pig. Furthermore, inhaled silica dust will cause a pre-existing latent tuber culous focus, harboring a few attenuated bacilli, to become progressive and spread. The cause of this effect upon tuberculous infection has not yet been ascertained hut probably it is in some way associated with the death of tissue caused by the toxic silica. Associated with this factor is an increased activity of the phagocytes which 'are stimulated by the irritating silica so that these cells tend to migrate rapidly and carry tuherele bacilli into previously uninvolved portions of the lung. 'Asbcttof dust, perhaps because of its fibrous structure, is not transported very far within the lung. It tends to lodge along the walls of the finer tubes and little of it is removed by the lymphatic drainage system. Tissue reaction, probably initiated by the solution ot the fibers, occurs in their immediate vieinity. As in the case of silica this reaction consists of an overgrowth of the connective tissues which is later transformed into leather-like scars. - Aluminum oxide wilt serve admirably as an example of a nou-siliccotts dust whose particles are as hard and slurp as those of crystalline silica. When a measured quantity of such particles. I to 3 tntcra in diameter, are injected into the ear vein of a rabbit the majority of them come to rest in its liver and spleen. There they remain, apparently harmless, collected in large phagocytic ceils and producing no reaction of the connective tissues for at least two years. Injection of the same quantity of the same sized quartz particles excites the iortnation of so niudi scar tissue tiiat tltc functional elements are almost completely destroyed and the organs are reduced to nodular masses of leather-like consistence. Carborundum, the carbide of silicon, when iniuled by guinea pigs for periods as long as four years, likewise fails to excite significant overgrowth of the connective tissues. It- produces only a low grade inflammatory change with no nodules. Instances such as tiiose cited constitute the liasis for believing that, the cellular response to dust particles is not due to their hardness and sharpness but to chemical substances liberated by the action of the tissues upon them. The case for solubility las not been proven directly, for the detection of soluble silica in the tissues offers technical difficulties which tmlay are tmsurmotmtahle. Nevertheless this substance is known to lie a cell poison and in weak concentrations it will provoke an overgrowth of the connective tissues. Mention should he made of the effect of inhaled coal dust. Most city dwellers breathe in sufficient quantities of this material during an average life-time to pigment considerable areas of their lungs. Deposits of grey or black dust will be found alone ' the course of the lymphatic drainage system but this pigmentation is associated with little or no new growth of connective tissue. The coal miner's lung is much blacker hut in most instances it also develops no deforming scars. When such reaction docs occur analysis usually reveals appreciable amounts of silica in the lungs. The presence of excessive quantities of carbon dust apparently influences the localization of mod erate amounts of silica so that the latter is not deposited in nodules as in pure silicosis but in streaks along lymph vessels as pure coal would localize. Coal miners' fibrosis, due to relatively small amounts ot silica, is therefore dif- terent excess pure s variet> siliceoi FIna slowly to the But it at leas: high ec develop * gestion trations This . attention to an in of that < in the p should b The .ST Sanita The <r capacity chemical the dust One o: dust inha health ha maining c example, such as .c with tuh^mttclt less true of ci marble dn little lung quartz co: readily. So far : . for any g parenchyrr. It is know by the hu of the With re apparent t. greater qu. of the atm tsnicil In an attempt to arier and unless ,.i and death occurs < are not altoectiter acted by nodules of cully, the same must they remain in the story. The silicotic .inied multiplication shown that even atttulosis in a silicotic listing latent tulxrressive and spread. been ascertained hut mused by the toxic he phagocytes which migrate rapidly and lung. transported very far es and little of it is lohly initiated by the ?he case of silica this .* is later transformed siliceous dust whose When a measured to the ear vein f a There they remain. ' :cing no reaction ot -tne quantity ot the scar tissue tltat the .-rans are reduced to :gs for periods as of the connective - :io nodules. ng tltat the cellular .jess but to chemical ease for solubility in the tissttes otters Vs this substance is soke an overgrowth Most city dwellers life-time to pigment > will be found alone n is associated with -.ng is much blacker t such reaction docs lungs. Tlte presence `<aiization of mod:-s as in pure silicosis - **a, is therefore dit- i t t Industrial Health Section 53 ferent from tltat of the pure quartz worker. When the amount of inhaled silica is excessive, the effect of the coal is negligible and the reaction approximates tltat in pure silicosis. There is said to be more reaction to hard coal than to the bituminous variety but there is evidence to suggest that this is due to the greater amount of siliceous rock which must be worked in mining anthracite coal. Finally, consider the silicosis of granite cutters. This develops sotnewliat more slowly titan that of the pure quartz miner and it lias been maintained that this is due to the relatively small amount of uneombined silica in granite (25 to 40 per cent). But it is believed tltat other components of the glomerate granite may neutralize or at least inhibit the effects of the silica so that only after prolonged exposures to high concentrations does significant reaction occur. While typical silicotic nodules develop in guinea pigs inhaling pure quartz ior a year, not even the earliest sug gestion of nodules have appeared in the lungs of animals inhaling comparable concen trations of granite (40 per cent silica) for four years. This brief discussion of some of the problems involved in pneumonokoniosis draws attention to the limitations of our present knowledge. It indicates that the reaction to an inhaled dost is determined by the chemical and prohabiy physical composition of that dust. It emphasizes the need to further study of different types of dust both in the pure state- and in mrasored combinations. Tlte ultimate aim of such a study should be the neutralization of die toxic action of such dangerous substances as silica. .* .' . 3 -t.A**YsuL The Dust Content of the Atmosphere in Various Dusty Industries By J. J. BLOOMFIELD - Sanitary Engineer, United States Public Health Service, Washington. D. C. Tlte speaker said in part: Tlte properties of a given dust which determine its capacity to produce pulmonary pathology are. tlte nature of the dust, that is. its chemical and mincralogical composition, its particle size, and finally the quantity of the dust dispersed in the atmosphere. One of tlte outstanding results of the last 20 years of research in the field of dust inhalation is the demonstration of the fact that, in general, the degree cii health lutzards associated with tlte inhalation of any dust, all other factors re maining constant, is dependent upon the mincralogical composition of the dust For example, it is now well established tltat - the inhalation of certain types of dust, such as granite dust, will in time produce fibrosis of the lungs, at times associated with tulierculosis. In other cases exposure to (last may result in the production oi much less fibrosis without notable tendency toward subsequent tuberculosis: this is true of cement dust. And finally, there arc certain types of dust, as typified by marble dust, which in the quantities and lengths of exposure so far observed produce little lung fibrosis. In general, it has liectt fmiud that those dusts which are high in quartz content are the ones which produce a disabling fibrosis of the lungs most readily. So far as the sire of the dust particle is concerned, it ts apparent that in order for any given dust to produce injury to tlte lungs, it mtist gain access to tlte jiarcnehyma of the lung, the site where the harmful effects of the dust take place. It is known that not all of the particles of inhaled dust gain access or are retained by the human lung. In this connection it is of importance to have regard to tlte size of the dust particles present in the industrial atmosphere. With reference to the quantity of dust present in the air of a workroom it is apinrent that when the dust concentration is high the exposed person will inhale a greater quantity in a given period of time than he will when the dust concentration of the atmosphere is relatively low, and since the rate of production of the fibrosis l i ii l i < I <i ! i 1i tr F 54 Ttt'fitty-firsf Congress--National Safety Council is partially dependent upon the rate in which the dust is inlialcd. this latter item piavs an important role in predicting the relative dancer of different environments. Hence the need for the evaluation of the quantity of dust in the industrial atmos phere is obvious. Research on the problem of industrial dust inhalation has indicated tint so far as their fibrosis produrine qualities are concerned, dusts may be divided into three 'groups: (1) those composed completely of combined silica, tliat is silicates, such as pure asbestos: (2) those containins free silica in the crystalline form known as quartz, (granite contains approximately 35 per cent of quartz): and (2) dust con taining free silica in a non-crystalline form such as diatomaceous earth. In'general, it has bees found that the harmfulness of a quartz containing dust is in direct proportion to its quartz content For this reason, in attempting to evaluate the harmfolness of a dust it is oi the utmost importance to ascertain its exact min eralogies! composition. It lias been our experience thaf to determine accurately the exact mineralogical composition of a dust one should resort to a combined chemical and petrographic analysis. By no oilier method have we found it possible to determine the amount of quartz present in a given sample. In certain instances, such as when one is dealing with a mixture of quartz and pure potash feldspar, it is possible to deter mine the amount of qtartz present in such dust merely by a chemical analysis. However, most dusts which come into question are mixtures of quartz and silicates. Take granite for example. The average granite is made up chiefly oi three min erals in about the following proportions: feldspar 60 per cent, quartz 30 per cent, and mica 15 per cent. Chemical analysis shows tliat this average granite contains 70 per cent of silica. Of this 70 per cent. 30 per cent is present as quartz (free silica) and the other 40 per cent is present as combined silica, in chemical com bination with the other minerals that make tip granite: it Ts possible to determine these proportions only with the aid of the petrocraphic microscope. We find in practice tliat samples of dust settled out of the asmosphere at the breathing level of the worker serve admirably ior both chemical and mincralogical determinations. Table l presents tiie qtartz content of dusts obtained in various industries which we have studied. TABLE 1 Percentage of Quartz Present in Various Industrial Dusts Kind of Dust Percentage oi Quartz Rod; drilling dust (bituminous ccal mine}........................ Granite cutting dust.......................................... Rock drilling dust (anthracite coal mine)........................ Brass foundry dust................................................................ Dust from raw mills in cement plant................................ Slate mill dust (Vermont red slate)................................. Silverware polishing dust...................................................... Anthracite coal dust.............................................................. Bituminous coal dust......................................................... Cement dust .............................. Slate mill dust (Vermont green slate)............................... Talc mill dust.......................................................................... Marble cutting dust............................................................... 54.0 35.2 31.0 10.0 6.5 . 3.0 1.7 1.5 1.2 1.0 trace none none It is evident from this table that rock drilling occupations in the coal mining industry and certain occupations in the granite tuning industry ami in brass foun dries would he in the hazardous class as judged by the proportions oi quartz in the atmospheric dust. \ \ i- It has fx microns in larger pan greater tha: lower sizes, trate to the ourselves w mension. In order access to th in the dust -may be obta instrument pheric dust slip may the In another : tion: the pa means of a measurements may be grou curve is easii As pointed atmosphere i> the injury wi. From the , quantitative i: .size range oi requiring car* will depend the refractive observer. \V< industrial hyg the dust come and certain it. This different one-half and : such normal mination the in alt air. So far as ! by the South dimension are, size limit of p. who examinuu silicotic lung. i. and about 36 *. majority of tlu The n.edian si. in comparing f tides measures mills, found a by Navrogordnt In connecticr.: nifieancc the t'c or indirect of * this latter item it environments. industrial atmos- ;cd that so far as divided into three : U silicates, such form known as nd (3) dust con* irth. In general. lust is in direct a to evaluate the tin its exact min* _ * \act mineralogical : and petrographic mime the amount i as when one is possible to deter'hemicaV analysis, nrts and silicates, i- fly of three min, art* 30 per cent. * granite contains as quartz (free ..v chemical com* hole to determine i;nosphcre at the :.nd mineralogical mined in various sts -cottage of Quartz 54.0 3S2 31.0 19.0 6.5 3.0 17 IS 12 1.0 trace none none the coal mining M in brass foun:ions of quartz in . I | } I * j j i J J ' I : Ii l . > 1 t r j i I \ \ { I l j J f Industrial Health Section 00 It lias been demonstrated that particles oi dust of a size greater than 10 to 12 microns in longest dimension are very seldom found in the lungs. This absence oi larger particles is partly due to the fact that the numbers of such particles greater than ten microns in size present in industrial air is. as compared with the lower sizes, comparatively small; furthermore, these larger particles do not pene* trate to the terminal portions of the respiratory tract. Hence we need only concern ourselves with those dust particles that are less than ten microns in longest di mension. In order to ascertain whether or not an industrial dust is -capable of gainingaccess to the lungs, it is necessary to know something of the size of the particles in the dust' tinder consideration. In practice the samples for particle size studies may be obtained by the use of the Owens jet dust counter. The advantage of this instrument over other devices is that the Owens apparatus projects the atmos pheric dust in unaltered condition directly on a microscope cover-slip. This coverslip may then be properly mounted and examined by any one of several methods. In another method a microphotograph of the dust is made at a high magnifica tion; the particles revealed on an enlarged print or screen may be measured by means of a millimeter scale. Xo matter which method one uses for particle-size measurements the results may be treated in the customary manner. The-particles nay be grouped in classes according to size, from which a percentage distribution curve is easily obtained. '* As pointed out earlier, a knowledge of the quantity of dust dispersed in the atmosphere is very important since with any given dust the rate of production of the injury will be dependent upon the total quantity inhaled. .... From tUft. practical hygienic viewpoint, the particle count is at present the best .<quaatitatice index of the degree of atmospheric pollution. The decision as -to the size range oi die particles which should be included in the dust count is a question requiring careful consideration. Obriously the size of the smallest visible particle will depend on the magnification and type of illumination used in the microscope, the refractive properties of the dust and to some extent on the visual acuity of the observer. Wc must bear in mind that our chief interest in this problem is in the industrial hygienic aspect. Primarily we are interested in differentiating between the dust content in the ordinary normal atmospheres, not yet known to be harmful, and certain industrial dusts which are known to be associated with lung damage. This difference is sharply marked so far as the dust particles between approximately one-half and ten microns in diameter are concerned; but the difference between such normal and abnormal air is masked and lost when we include in our deter mination the particles of ultra-microseopic site which are present in vast numbers in all air. So far as the upper limit of particle size is concerned it has been demonstrated by the South African studies that particles greater titan ten microns in longest dimension are, as a rule, of negligible importance. The data concerning the lower size limit of potentially hazardous dust is not so conclusive. Moir of South Africa, who examined microscopically 120 dust particles obtained from two specimens of silicotic lung, found that only 13 per cent of the particles were less than Oj microns and about 36 per cent of the particles were less titan one microti in diameter. The majority of the particles. 60 per cent, were between one and three microns in size. The median size ot the dust was found to be 12 microns in diameter. Drinker, in comparing the size frequency of the particles measured by Moir with the par ticles measured by him of the dust iotind in the sputum of men employed in ore mills, found a close correspondence. These findings have also been corroborated by Navrocordato. In connection with the lower limit ol -particle size of dust of pathological sig nificance the following pertinent question arises: Aside from the evidence direct or indirect of the non-retention 0f minute particles of dust by the lungs, what Ttvcnty-firsf Cantjrcss--iWuiotuil Safety Council TABLE 2 Average Dust Counts in Certain Dusty Trades Industry and Occupation Dust exposure in millions of particles per cubic toot Average per cent ot quartz in dust Tale Mining and Milling: Jack-hammer drillers .......................... .................... Packers ............ ........................................... Muckers ..................................................... Crushcrmctt and cvlindermen.................. .................... Slate Finishing Mills: Floormen ................................................... Loaders ....................................................... Disc crasher operators........ . Quartz Grinding Plant: Mill operators ........................................... ..................... Laborers ................................ ............... Packers ...................................................... .................... Granite Quarrying and Finishing: Levner drillers ......................................... Jack-hammer drillers .............. .......... ........................ Hffod poeunnjfTi tool finishers............ .. Machine pneumatic tool finishers.......... 1. Plug driller*........ ....................................... Attendant labor (indoors)................. ..................... Anthracite Coal Mining: Miners and hel(iers .................................... ................... Attendant labor ........................................... EUuminws Coal Mining: Coni cutters and loaders. Attendant labor .......... ... Marble Cutters ...................... Cotton Cloth Manufacturing: Carders ............................ Weaver* and spinners.... Silverware Manufacturing: Dusty trades ........... Non-dusty trades . ........ 2,1(30 14 173 55 112 17 232 112 4' 23 9 5 None None None None None 3 3 3 3 09 99 '99 99 35 35 35 55 35 35 35 1.5 1.5 1.5 1.2 1.2 1.2 None Nonr X*e S'... - i.r 1.7 1.7 evidence is there that appreciable percentages of ordinary industrial dusts ever fragment into those minute sues less than 0-S microns in diameter: The best answer to. this question would be data of actual measurement of such dust. Un fortunately we have but scant published data on the particle size frequency of dusts in the air of industrial establishments. In 1929 Fchnel made sonic particle *ize measurements in connection with, the dust study of hard rock drilling in New York Gty. He reported the findings on three samples, which showed the dust which was less than 1 micron in size to vary from 1 to 15 per cent. Most of the dust in these hard rock drilling operations was between 2 and S microns in size. Badliam. in studying the dust hazard among sandstone workers in Sydney, Aus tralia. measured some 16,000 particles of dust in the air of work places ami found that 67 per cent of these particles were about 1 micron in size. In a particle size stu> ma< speOni thar 1 a. F corn limit metlof d high finds Heal. beine Du .'t hazar sumn - indust * 9 mine* indusi grindi tries most i #; < Si It v in the more y ard. lead, a their *. known Thv tors ot . -Jnhatwdollar ization. Mine* compe/. mg to otiter r1 against has gri ll is pay m.i: Strar.i /mlustrial HecdtIt .Section 57 study of twenty-five samples of cleveti different kinds of aerial industrial dusts i made by the filar micrometer method at a magnification of 1.000 diameters, the j speaker found that practically all of the dust was less than 5 microns m size. Only 2 per cent of the particles were less than 0.5 microns. 21 per cent were less :re Average i than 1 micron, and the majority of the dust. 71 per cent, was found to be between * per cent of { 1 and 3 microns in diameter. * quart* in From all of the evidence therefore, and in the absence of conclusive proof to the 't dust contrary, it is apparent tliat we need only he concerned with those dust particles None None None None None 3 3 3 3 99 99 99 99 ' 3S 35 35 35 between oue-lialf and 5 microns in size, and from a practical standpoint the lower limit of particle size to be counted may well be taken at about 1 micron. Many methods have been devised and used for the purpose of determining the quantity of dust in air. Suffice it to say tiiat for the purpose of dust sampling in either high or low dust concentrations, the Grcenburq-Smith impinger apparatus now finds universal favor. This instrument has been used by the United Suites Public Health Service in all of its dust studies during the past nine years and is also being used by other workers in this field in this country and abroad. During tlie past nine years the writer- has made numerous investigations of dust hazard in many industrial establishments throughout the country. In Table 2. l. summary is presented of the average dust content of the air in a few of these dusty industries. This table clearly shows that the highest dust exposure was In the talc mines, slate finishing mills, quartz grinding plant, coal mining and granite cutting industries. Owing to the high percentage of quartz present in the dust of the quartz grinding and granite cutting plants, as compared with the dust in the other indus tries listed in Table 2, quartz grinding and granite cutting are revealed to be the. most hazardous of the occupations we liave studied, - 35 35 35. ' 1.5 I i Clinical' ana Statistical Aspects of Silicosis By ALBERT E. RUSSELL, M. D,, F. A. C. P. 1.5 1.5 1.2 1.2 1.2 None None None None 1.7 . 1.7 177 Surgeon, U. S. Public Health Service: Surgeon. U. S. Bureau of Mines. Washington. D. C. j It would be difficult to estimate with any degree of accuracy the number ni people in the United States who are engaged in dusty trades. It is evident, however, that more people are exposed to dust, which constitutes the greatest single industrial haz ard than is generally supposed. Certain dusts contain poisonous elements, such as lead, arsenic, mercury, ctc^ which give rise to general conditions resulting from i II their absorption. This paper .however will deal only with those dusts which arc known to. be direct factors in the production of pulmonary diseases. Economic Aspects of Silicosis The economic problem presented hy silicosis is tremendous. The .'tillering and loss of life due to it cannot l adequately measured. In the gold mining area around s ial dusts ever j Joliatmcsburg. South Africa, during the period 1911 to 192V. more than .-3 million ter? The !>est nch dust. Unijcney of dusts me particle size rilling in New vrtved the dust *. Most of the microns in sire. Sydney, Aus"aces and found a particle size 1 j } ! J I dollars liave been paid in compensation alone. The costs of medical care, hospital ization. and legal proceedings further augment this enormous figure. Mines in Australia arc reported to have been liankruptcd hy payment oi silicosis compensation. I know of a company in our own country which has claims amount ing to more than a million dollars for disability due to dust inhalation. There are other plants in the East which will 1>e bankrupted it all the claims which are filed against them are allowed. In most of the industrial states the number of claims filed has greatly increased in recent years. It is clear tliat dust-prevention work. like any health-promoting activity, would pay many times in money, good health, and efficient operation. Strangely enough, only during the past 25 years has dust received much attention ! j'd}; oners silicomyonejoi^the^nosilimppciam^quStioris md^idoaiilwbbihAvrlworkeci '* 1 N. jg&SS? sS3.;4-i 3gs& Out-;-^;' i;.<S?:^1 isagel &*&*;.* 4 . -:?':-J -.T -.~t---.;r^ 3&?iS ? $D uu (333'^ :.a?3g# 3 O'X* aa>^3 jTvfu a <SJ ..,, : iV.: ] ;rrvi * / < /ir/7 in? them with the ipmesit. ..,-e figure* can ho not only be Mmlied tier memlxrs of the . department. They r. The C'Wi should Iictwecn companies. hy iitchiiliiuf uci> > salary. It to explain ail the ey, Newark Mate Compensation .I* connect ion. He -4tey payments made >e |*crcemaee*. as rc. the next listtrc* Mows: We hut it requires :.ty alxmt jer?*m.nl ati/iit. . Ie sc little c>* s could ikk exist, p and revert to the :t of* Imtuiry" pro* Safety hjieiiKvr. sr playlet depietiue 1-mi of an industrial characters." were he UuhiKT Section TIFEXTV. FIRST ANNUAL SAFETY CONGRESS NATIONAL SAFETY COUNCIL ?tea Safety Section, A.R.A.--Steam Railroad Section, N.S.C. Section Officers 1931-32 Chairman--C. T. Eailev. Ctiei Safety Agent. Oregon Short Line Railroad. First Tier-Chairman--C. E. Hitx. General Safety Agent. New York Central Lines. Second I'icc-Cliaimutn--C. L. LaFountaixe. General Safety Supervisor, Great Northern Railway. Secretary--). C Cavxstcn*. fXOTE: The jolloz.'ina fopcs contain. 4 condensed abstract of the records of the sessions of the Scietr Section. .AR.A--Steam Railroad Section. XSC. as published in full by the American Raihvcy .Association in a booklet entitled. "Proerediitas of the v 12th Annual Meetina of the Safety Section. If'ashinatan, D. C* October 4 to 6,1932.") TUESDAY MORNING SESSION October 4, 1932 The sessions of the Safety Section. American Railway Association--Steam Railroad Section. National Safety Council, convatetl in the Hotel Washington with Cltairman C. T. Dailey. Clnei Safety Agent. Orecon Short Line Railroad. Salt l-ake City. Utah, presiding. The invocation was given by L- G. Bentley. Chess/wake & Ohio Railway. Report of Committee on Relations with National Safety Council By ROBERT SCOTT Director. Insurance and Safety, Atlantic Coast Line Railroad Mr. Scott said in part: Your committee dads pleasure in reporting tint much satisfactory proercs# has been made itt the direction of co-ordinating the work of both sections with the view of avoiding duplication of effort and expense and to the end that the cause of safety might be advanced. The first annual meeting cf the Steam Railroad Section. National Safety Council, was held in Philadelphia in October. 1915. while the Safety Section ot the American Railway Association held its first special session in Boston in September, 1921. Both of these sections have been functioning properiv and well ever since they came into existence, and have been a powerful force in tiie reduction of avoidable accidents. On September 2, 1931. a mectinc was held in Chicago at which there were present members oi the committee on- relations and omeers oi both sections. At this meeting Ii m .i :i::N Vl.-'w * It** *'i 5 :.! *l Siar/S 412 Tzvcnty-jirxt Congress--A'otional Safety Council in the stress of economy it lias been necessary drastically to restrict all expenditures, and dark because the economic depression kept our backs and shoulders bowed to the storm which has raced around us--4>ut durinc all this stress, you cemlcmcn oi the Safety Section have carried the banners oi saiety and safety rirst dying. and your shock troops have been sttpportirig and defending them and there has been no let-up. Wliile there have been let-ups in other directions, there has been no let-tip in this saiety movement, even with vour depleted forces. Now. as we approach the crest of the hill, the slogan "33 hy *33** floats down to our ears from the throats of tltousauds whose lives have licet: spared by the drive for saiety. I see the lisht crowing clearer ahead and as we lift our heads and throw back our shoulders. I see a smoother, broader, lighter pathway with more moderate slope stretching away to the green meadows above. The storm clouds are breakinc. the warm rat's of the economic sun are gradually coming through: doubt and despair are nearing their end. TUESDAY AFTERNOON SESSION October 4. 1932 Report of Committee on .Prevention of Highway Crossing Accidents By H. A. ROWE ...Manager^CUims Department. Delaware. Lackawanna & Western Railroad. " New York City TIte speaker said in part: The Committee is again gratified to be aide to announce a further reduction of grade crossing accidents, fatalities, and injuries it l3l as compared with 1930. Thus tve hare had three consecutive years n progress in the curbing tt crossing crashes, the records being as follows: l`'.l. total accidents 4.100. kilted l.Sll. injured 2.057: 1930. accidents 4.S53. killed 2.030. injured 5.517; and in 1929 there was a slight reduction. The year 192S was the peak year in railroad crossing fatalities, since which time the reduction oi such fatalities lias been 757 per year, the 1931 record being but on-.* more killed than in 1922. when tlie careful crossing campaign was inaugurated. The outstanding accomplishment of crussing accident Reduction can he better grasped when ue note tint motor vehicle fatalities on streets and highways iu 1022 were 13.074 but iu 1931 there was an increase of 18.913 deaths or 139 jer out. During this same 20-ycar ~errod there w an mrrease o: but one death at railroad crossings. A very important feature oi the committee work has been the careful crossing campaign which has cmutiuied to enlist the interest and cooperation of many organi zation* and the general puhlie. Tins has been furthered hv general publicity, the regular posters initiated for this special campaign and other liter-lure. . During the past year the National Safety Council lias been active in its educational campaign tor the prevention of accidents, and in its May. l`>52. i#tm oi the Kati/mal Saiety .Wter contributed a most useful and illuminating :ror.:i.ip:ece. The crossing accident situation was stressed in the same issue ot the After, and in many other respects the National Safety Council lias shown deep interest in cooperating in the prevention of crossing accidents. Opportunity is presented tor a fuller enjoyment of the facilities offered by the 41 Community Safety Councils associated with the National safety Council. Codec-' lively. 30 Councils reach 803.000 school children throtich 3.141 meetings. Railroad safety representatives, cooperating with such local Councils, have an excellent oppor tunity of extending the gospel of careful crossing over railroads. These Councils hold vast numbers oi other meetings and should be regarded as fertile soil. eiJ Safety Section, A.R.A.--Steam RoUrond Section, XS.C. 417 'ial WEDNESDAY MORNING SESSION October 5, 1932 Jfaj'o Railroad years of railroad Report of Committee on Train Service Accidents ;ion to safety into By D. G. PHILLIPS inherently safe taj convinced him* Superintendent of Safety, The Wabash Railway melt does not need t-mistic and who is The speaker said in part: In the year 1931. out of 5.099 fatalities and 35.556 per* sons injured, according to reports to the Interstate Commerce Commission. 4.624 of online service are say their home work any mental t their duties, and not become easily to face any shtu* -) per cent ot die lien but that they - problem we have. anything occurring king, employees of -life and the things wt with all. Their They seem to get Ipless. these fatalities and 1S.S49 of the persons injured occurred in train service accidents. While it is true tliat a large proportion of these fatalities occurred in grade crossing accidents and to trespassers, it is also true tlut over half of the fatalities to employees on duty occurred in what is known as train service accidents and about one-third of the injuries to employees occurred in train service accidents. We ieei. therefore, that we are justified in saying that (he prevention of train service accidents is probably the most important safety problem confronting us today, i as far as accidents in and around railroads are concerned. -Under the heading "coupling or uncoupling cars or locomotives'* in 193! 12 persons were killed and 394 persons injured. This may be compared for the year 1930. when 30 persons were killed and 604 injured. The year 1931. therefore, shows a decrease l of 60 per cent in the number of fatalities and 35 i>er cent in the number of personal i t i injuries: and these may be compared further with the record for 1920. when there were .151 .fatalities and 2.430 injuries due to this cause. The pncipaf reason for personal injuries under this heading is due to employees stepping in between moving cars, usually at a time when coupling is about to`be nude, to determine if the knuckle lias fully opened, to adiust location of couplers, nt efforts of those safety campaigner or to adjust the coupling or uncoupling lever, with the result tliat they are caught between the couplers; or perhaps due to tripping or falling while performing this xork. to constantly act. and arc thus run over by the car. Our remedy for correcting this dangerous practices. These ' (he unsafe. ' ird as the fatalists m all to itself. . ... intensive and Hf tiut any large *ve censored m>*sclf "'if type, because in T la the service. due *rje about this type *.f to the possibility practice is for each and every railroad to make a positive and definite, rule prohibiting employees from going between moving cars when nearing each other, to examine the >) t employees to see tlut the rule is understood by them, and tlut supervisory officers see that the rule is enforced. Under the heading "coupling or uncoupling air or steam hose."* in 1931, 13 pvrsons were killed and 1/5 persons injured, which may be coittfured with the record for 1930, when 7 persons were killed and 232 injured. The increase of 86 per cent iu the number of fatalities is decidedly regrettable, although the record sitows a decrease or 24 jnrr cent in the number of injuries. The principal cause of employee injuries under this head is due to their failure to protect themselves by performing this work- in accordance with the rules. The remedy for this class of accidents where car men arc employed rests in a Tcristies. Generally iitMghxs are alone sful individual. with h his private habits rady response from '-.dongs. hit iamily. reach him through . the success ot these :*<r supervising officer safetv to his gang, -elf. full and complete enforcement of (he blue signal rule which i? quite uniform on all- railroads. Railroad managements should improve this blue signal so as to nulcc it as efficient as posssihle. The rule should also govern- the placing of the blue signal so as to make sure that it is in a location where it will serve the best purpose as a 1 signal to warn train, engine and yard men who might lw guided by it. Where en } ) gine is coupled nto ears and trainmen arc peri..rming this work without blue, signal protection, they should not permit themselves to get info a place where an unexpected movement ot the cars might cause an accident, without first notifying the engine man and fireman so as to be fully protected. Under the heading "operating hand brakes." in 1931 there were 18 fatalities and S34 persons injured, as compared with the record tor 1930 when 26 persons were killed and 1.154 injured. The year 1931 shows a decrease ot 31 per cent in