Document qm677b9LD9wKV1ewjMzmYrvXE

December 27, 1943 Dr* Charles H. Sullivan, Jr. Armstrong Cork Company Lancaster, Fa. Dear Dr. Sullivan* IQ ^ & ^ &'**~**~\ I am enclosing a short sketch At' ay serrioea taken From *Who* a V>ho in Industrial fcedluine." Zou may use any part you vlsh in my introduction. Very truly your*. fine. IT. J. McConnell, M.D. Asaiatant Medical Director Director, Industrial Health Section 2337 fl- xwafl ' ~ .. - --- ZJl. v IXii Tu.'. j^... J* . 1* jL jiciioaasii, Lllj V -All *** At striding as the `dvances h-jvj b*>en in na* n thods und tv-v touhniquo in a.jt.-; lining the volatile eolventt in the xsricln^ `nvlron.m---nt c-oring r-cont v-ara, our '^novl-dge of their toxic ctlon hns not gopt pace with the ever-mounting number of newly perfected solvents u:sd in increas ing :;uatity and variety In nearly every manufacturing industry today. Further cifficulties frequently ere experienced In Identifying thtr chemical compositions which are concealed by the use of various trade name. although it is quite well known that the inhalation of concen trated vapors of certain of the voLatlle solvents is dangerous, it too often happens that the danger Inherent in aoae of the nwwor solvents h*a not been suspected until fatal poisoning has occurred or instances of sLclcnass have been traced b&cx to their exposure. Poisoning fros the industrial use of such solvents can be avoided only by sore scientific end, Incidentally, less expensive methods of detersining their toxic properties before use. lespita the fact that the celluler reactions of small laboratory animals. -re not strictly analogous to those ..of nan, exposure of these animals to varying concentrations of solvent materials provide relevant evidence of the probaole effects of these substances on aaa. Rhiie naturally there may be differences, both qualitative and quantitative, in behavior between man and laboratory anlnala, sufficient nanlfestation of the type of toxic action *Read before llth Annual Convention - Greater Mee fork Safety Council, hotels Pennsylvania and Governor Clinton, Aorll 17, 1?40. V 2338 -2- usually can be predicted. bov-ver, It must oe raseebered that the toxic threshold of solvent vapors for asn can only be roughly e sproximated from exposure of aaiafls, ven when aogage Is ctrefully correlated with body weight. Aside; froa iadivlaual variations In the physiological resoont to toxic vapors la aan, these vapors or-iC'-nt a soeclal risk to those Individuals who are either unusually sensitive to poisons or *.r suffering from organic diseases which Increase tnelr susceptibility. Therefore, es desirebLe as some meFFur** of the barafulness of an atmosphere In which aen work undoubtedly Is, our current tables of minimum toxic concentrations must be accepted with due consideration for these variable factors affecting the Individual. after Inhalation, solvent vapors enter Into the generaL circulation end are rapidly distributed to the heart and to the central nervous system, whore they can produce either a general toxic action without hara to the respiratory passages or a mixed effect, being generally toxic and localLy irritant. Seldom do these exert their influence on a single organ. Changes usually are found In the bLood, kidneys, liver, heart, nervous syetea end other organs. A few Irrespirable vapors act so violently Ln tha upper respiratory tract and Lungs that tnelr general toxic effects are secondary considerations. Other avenues of sntranee into the body are by ray of the gastrointes tinal tract and by absorption through the Intact skin. Substances ingested, If they do not initiate voaiting, may be absorbed by the Intestine In varying amounts, depending jn tnelr properties and their reaction on the stomach contents. A major portion of the absorbed material passes Into the portal circulation and nay be satisfactorily handled by the liver. The Lntact skin Is vuLnorebLe to soae of the more toxic fat soluole vapors. Leraatltls may result fro* the contLnual ' 2333 -3- hsndling of slaost any of the*, cither because of tholr frt solvent properties or because of s&nsitlvity, natural or acquired. A few eay sffeet the -yes and any optic neuritis or paraLysis in orlc&re exposed should give rise to inveatl^-tion. Kith f-ew exceotlons, CIL volatile solvents, if inhaled In pufflcient - xncentr&tioa for a sufficient Length of time, .nay be said to be- detrimental to health, altnou^h tneir early effects on the body frequently go unrecognised or are regarded as mLnor aliments of no consequence, because of Inadequate icnowl-dge of tneir physiologic properties. Of tae hydrocarbon groups of solvents 'ncounterid in Industry, the moat Important from the point of vi-?w of toxicity ie the aromatic dries, benacne (benzoL), one of the meet volatile of the group. Is vldeiy used in industry, not only as a solvent end diluent, but in large quantities in the blending of motor fuels and in the cheaical industries. The central nurvous system prlnarily is effected in acute poisoning in contrast to its destructive action on the blood, tiie blood-foraing organs, end the blood vessels In chronio poisoning, high con centrations of bansene ere rapidly fatal, vherees exposures of mod-rote concen trations cause aynptons similar to alcoholic Intoxication t first, but ere followed by syaptoas ot progressive depression, twltchings, convulsions, and paralysis with loss of consciousness. These are not common tyoee of poisoning snd usually result fron an accident or in cleaning vats, tanks, etc. Repeated exposur-s to small concentrations of benzene cause gastrointestinal disturbances, headaches, vertigo, veaicne&a end frequently nosebleeds, and snail heaorrtaages of the guns and conjunctive. The blood undergoes changes as a result of destruction of the blood-forming organs, ineaia is sn important aUgnostic factor. 2340 -4- Khlle tn.=re ai-y be at first a slight Leukocytosis, a rythropenla -nd t LTUXupenis *itn a 3lig.bt reduction in hewogLobln content foLlow. These findings *ru supported oy Lr. ?. a. Li-vis, who r.*:s been observing and examining botwaen o, )dQ~t.nd -7i J3T aen end women wnore work involved cant1, ct with various coapounas containing Deniene for thj lrst twenty years. a n.criit number of th- Journal of Industrial hy^i^ne -nd Toxicology, ho iver, has .-uolished a series of live psp-'ra on chronic Industrial benzene poLconin^ vnich. ctv.-LLcnge, more or lese positively, our present concaotlon of the ci&gnosls, clinical course and pathology of chronic benzene poisoning. Ihile time wlLL not permit a dLacusrion of the controversial factors 'resented in these papers, it ie obvious that the toxic effects of bensane auct be restudied in the light of these new observations. The action of the higher homologues of benzene are also ronewhet controversial, purhapp because in Industrial use benzene frerjently is oresent In the fixture. Under ordinary circumstances, they are obviously l~ss dangerous than benstne because they are less volatile. ToLuene, though more IrrLtsnt .ond exertLng a slightly more narcotic effect on anLmals, at l?*st does not appear to have a destructive effect on the blood and the blood-forming organs so characteristic of benzene. XyLene, which eou-rercialLy Is usually a aixture of three isomeric xylenes, is believed by some authorities, ond denied by others, to bo .aorr toxic in producing narcotic effects than bcnzne snd toluene. Like toluene, Lt does not cause characteristic changes In the blood or Ln the bLoodformlng organs. The uigher hoaologues of benzene, other than toluene and 7ylene, are seldom ueed In pure fora, but In mixtures of verying coaoositlon. Although further V. S3 41. -5- invastigatlon .nay demonstrate toxic properties, '-t oresent they are considered such L',3 dangerous than benzene. Th coal t&r solvent naphthas should be distinguished fro* the petroleum aLstillato naphtha. Crude naphtha consists of a mixture of benzene, toLuone, xylene, tad otfaor Impuriti-e. Coal tar solvent naphtha, though varying in coapoaLtion, consists of xyLeacs - nd cumenes iind snail c;uantitl'ra of hydrocarbons of the paraffin series. aiflash naphtha, according to Lr. Alice HsniLton, ie a mixture of toluene, xylene, tnd the still heavier cumene*. olvnt naphtha consists of xyluiie and nighcr ho^ologues, i.nd is rrlfatlvaly free of benzene und toLuena. These nay procuce acute poisoning in man when severely exposed end death may result from respiratory paralysis. Naphthalene, a distillation product of coal tar, causes local irritation as velL as systoalc toxic effects. It nay causa a rather severe eczema of the cicin and Injury to the cornea. Naphthalene haa been sueoected by a number of observers ss a causu of cataract. Gastrointestinal disturbances and irritation of tha zidney* have been observed fro* inhalation of Lts hot vapor*. The coal tar distillates -"-Iso furnish us with an interesting group of pharmaceuticals, such as aspirin, novocains, end sulphanilaalde, to mention onLy a few. Sulf&pyriuine, which has been so successful in the treatment of pneuaonia, is produced from the tar base pyridine. 3f current interest is the utilization of coal tar derivatives in tha production of'nylon from which textile fibers are now being Jsade. Tha chlorinated hydrocarbon group of compound? ere important because of their anesthetic and poisonous action. The member of this group with which re are all familiar Is chloroform which possesses high solvent powers, but does not find wide application Ln industry because of it* veil known anesthetic -6- propertiea. Tne most widely used solvent of this group Is carbon tetrachloride. It U uaed extensively k.s a cieoning fluid, In fire ext!nguloz.-.-rs, and s a solvcni. lor fata ana oiLg. It hv-s be"n UFf'd vertically rs s vermifuge In hookworm disease. It Is v^ry much Hie chloroform but Is .sore toxic. Its narcotic -'ffecta t>r-> l.;ss asrxed then those of chLoroform, but Lts toxic effects on the liver, h-ert, and cLdn^ya are much non* mold. Iricnlorethylene, b.-cause of Ita solvent action on fata and oils, is useQ t.s a thinner for coatings and vtrnishes, and se a solvent for rubber, replacing carbon tetrachloride in many instances. It Is aarfceted under nany different trtde naaes. Its chief innustrial application, however, is in the -.ot&l industry and is used in degreasing of seta! parts. It is claimed to be even less narcotic than carbon tetrachloride, but its toxicity is in the save ord^r. Because of the lid feeling of intoxication it creates when inhaled in low concentrations a craving for such exposure aay develop Leading to anemia and nervous sequelae. Tetrftchlorethane, which hes a wide field of application on account of ita sigh solvent power, ic the most poisonous of tho chlorinated hydrocarbons. Ita toxic :'fi=cts have restricted its uco In the aviation industry* where it was widely used during tne lorid ter in aeroplsne "dope*. In scute oolconing the symptoms develop rapialy resulting In atrophy of the ILver, Jaundice, tnd fatty changes in other viscera, especially the heart. In chronic esses tha blood chi-nges ?re narked, leading to secondary anemia, hemogLobiaurla and haaolycis. bichlorethane (ethylene a 1chloride) used in the choaical industry and j a c 1,-anlng fluid and in tha extraction of oils and fats, hss irritant and narcotic properties but so far has not given rise to chronic symptoms from prolonged exposure. It is frequently vised with either trichlorethylene or carbon tstracnlorlde. 23^0 -7- CichLorethyl*ne is u?ijc! `r.e a solvent for c^LLulose testate and -3 a dry-clcan'.nt, -t.8at, well .-.s In the rubber -.nd osrfuse Industries. It .:*.e n-rcotlc and irritant prop^rtlfs, but only one fstal esse noted by acuilton In 1914 ns.s been reported from its Industrial use. retracniorsthyL-ne (oerchlorethyl-ne) us.c :r n constituent of toLvant soaps ..no `-a a fat solvent in the orinting Industry and joaetloea -* a dry cleaning a&eat, le a relatively new solvent and Is lea* narcotic then the majority, tLthou*h cyn.oto.ee of drowsiness, headache, gtdcilnscs, vnd a narrowing oi the visual field have bean reported from repeated dally Inhalations. Chlorinated naphthalene products, us*.<t, among oth-rr ways, >-s e f ora of wax In Insulating, have been clearly shown to cause severe eicln troubles and have caused ayaptoms of h&patic disturbances with fstal cases showing signs of toxic Jaundice. It is interesting that thee substances apoaor relatively hnrai- lisa wnen cold, but when heated, despite the fact that they do not decompose, th lr vapors csues acne more or Lass characteristic of wax or tar acne. among the many toric chemicals resulting from the Introduction of suLphur into aliphatic hydrocarbons, c-.rbon disulfide deserves special mention because of its varied effects on the body following repeated exposure to salL concentrations. It is us^d as a solvent for fatty bodies in essential oils end reelns as veil as La insecticides, *nd in the rayon, rubber rnri chemical industries. In :tith concentrations, carbon disulfide fumes affect a person somewhat lilce chloroform and, if exposure is continued, thar fumes esuse complete insenslb'lity, coma and death. Chronic poisoning is chsrecterited by persistent heidache, eonnolence during tne day, elsepleaen-'SE at night, 'nd weakness of the limbs. It Is extr-i-nely v 234< damaging to the nervous system, c?using polyneuritis, visual disturbances, treaor:, o-ntaL confusion, severe psychosis tnd Htarla. An Important character istic >i r*:ia poiaoa.Is its -ff -ct on the higher nerve cantors. Hot only is it damaging to th ^yes, but the a leap-`er.ro ace of the cornepL refle> -s Is said to o-o an orly sign of poLsoning. Recovery If slow ; nd if the poisoning is sov.-re, tnera iay be psrman-.nt Injury. 3nc etteck m^.y predlsrjose to a second. PotroLeua nycroc-rbonc, which represent mixtures f hydrocarbons having no dcflnito composLtioa, are clfflcuLt to appraise physiologically because of Inadequate knowledge ol the source of their product *na the proc'S* of manufictore. Iney nave an extensive use as an automobile lu*l and `-a solvents in the rubber, electrical, paint and varnish, glue, shoe, e.id orinting Industries. They h: ve a mildly fnocthetie action sod In high concentration cauae headache, dixsineae, blurred vision and even loss of consciousness. Generally speaking. It epoars that their toxicity IncraeEes with their specific gravity and boLling oolnt. Any enronic blood damage from this group is controversial and, if found, probably polnte to the advisability of looking for come other exposure or cause, particularly the admixture of one of the acre dangerous types of solvents In the substances handled. I*Lke all the other solvents, th*se can readily cause a dermatitis. Turpentine, which Is a mixture of terpenes, closely related to the broantlc hydrocarbons, is used chiefly ss a solvent or thinner in the paint end varnish industry and to some extent for cleaning type nnd rollers of printing machines end for cleaning fabrics. Turpentine vapors have c direct actios on the stin, csuBing reddening end not infrequently *n obstinate "CscBe. Irrit tion of mucous n-mbranefi and burning of the eyes ere experienced with comparatively low concentrations. The Lnh&lstlon of heavy fua*? of turpentlna Induce symptoms of a mild narcotic ooieoning. Nephritis has been reported from prolonged exposure. 23 4u -9- A iargar group of new=r solvents which is rapidly coming into groater oroalnenca Lc thfc alcohol-etners, or oxides. Often the?* lay be compounded with ohthallc -Cid, joaLlc acid or foraic i-cLd, thereby Introducing the possibility of a second- -toxic agent. Our knowledge of this group If Icrgely b- eed on unlaal experimentation, though a number of crses of incuctrlsl poisoning hbve been reportt-a. ar a group, they ars narcotic or anesthetic, ^nd son* of r.h-oa are known to be toxic in the higher concentrations, but is little Information concern ing their chronic effects or the maxl-aua permissible concentration. The alcohols end their ethers are perhaps the most widely U3d of the vertous classes of solvents. As a group, they are narcotic and Injurious to the nervous systea. The toxicity of the alcohols generally increases with the molecular weight, but whe decreased solubility end volatility of the higher alcohols partially offset the danger of exposure to concentrated vapors. The exception to this rule is wood alcohol which Includes methyl alcohol .nd methanol and is prepared both by aishllLatlon of wood and synthetically from carbon nonoxide ^nd hydrogen, although its narcotic effect Is Lese aariced then that of ethyl alcohol, Lt is a powerful nerve poison which specifically effects the optic nerves und nay result in blindness -no death* using to the accumulation within the body tLssues of its oxiaition products, formaldehyde and formic r.cid, snd its alow excretion from the body, its effects on ths nervous system are has^rdous from continued exposure to iven saall concentrations. Rhlle propyl, isopropyL, Mid butyl aLcohol Eh:re with the other alcohoLa a narcotic effect on thm central nervous structures, their industrial use hp* c.rried little danger for workers. Inhalation experiments with the secondary tnd tertiary alcohols are required to indicate their danger from an Industrial point of view k -10- Iha aost important group of solvent* for nitrocellulose and ceLLuloee acetate are found among the ostare, iceton-8, glycols and their ethore, nai furfurv.L5. All are narcotic Ln sufficiently heavy concentrator ^nd In proportion to their volatilities. fherer.a fetal accidents ore very rare, fivLdance is Beginning to app--ar pointing to their physiologic, affects es being aore dangerous than they were formerly considered. Although the most common effect noticed from the inhalation of s 171 ecstats, known -e "banana oil" and radily recogniied by its sweet, sickening odor, la merely that of Irritation on mucous membranes, one death which ass attributed to ayl acetate intoxication is reported in the literature. A fatal case of acute poisoning by ethyl acetate also has bean reported ln a workman rho was painting the Interior of a tank with oelnt containing 10% ethyl acetate. Methyl, propyl, and butyl acetate are other aembera of the ester group of solvents* ethyl end butyl aeetates are the most widely used of all the solvents of nitrocellulose* Of the ketone group of solvents, acetone, a highly volatile, inflammable fluid, is probably the aost widely ueed, and It is one of the aost powerful sol vents known. absorption taxes place through &L1 mucous membranes and is excreted through the lungs -nd urine. It has a narcotic action sore pronounced than that of chloroform and is irritant to the conjunctive and skin. Several ketones of higher molecuLey weight have been recommended as good solvents for nitrocelluioso, but they hav-i little or no effect on cellulose acetate. The nore important aembera of this group are methyl-propyl ketone, or pttntanone, and methyl-butyl ketone, or hexanoae. Their acute effects on guinea-pigs were studied by lent and his colleagues, who report that death results from a state of narcosis rather than fro* the Lrritatlon of the lungs. All fatalities occurred during the exposure* hen.momentarily exposed to approximately 1.3 and 5 per cent of pentanoae vapor and to 1.23 and 2 per cent of hezaaoae vapor complained 'l 234V -11- of Irritation of tha eyes and natal passage* and of e characteristic strong odor. The gLycols and their derivatives are used in variety of industrial processes. tthyLe-na glycol is sometimes used se a constituent of tntL-freese mixtures tnd the drioicLng of such a mixture has occasioned the only serious cases of poisoning. L>ath appears to be due to respiratory failure t>nd convulsions. The mono--ithyl other of ethylene glycol, or "celLosolve" is en important solvent of this group. It Is a stable Liquid end it is used as a solvent for nitrocellulose snd resins. It offers the advantage over most other solvents of similar boiling point in being nearly odorless n low concentrations. It .aa found by Celts, Patty and lant to be toxic for animals. During the investiga tion two son, who breathed air containing 0.6 oer cent by volume of the vaoors for a f=w seconds, reported tha atmosphere to ha irritating to the "yes and of a disagreeable odor. However, very ILttle evidence of any injury to health froa the use of caliosoLve has been reported. Under certain conditions, the mono-methyl ether of ethylene alycol as found by ureenburg, layers end Sold*star to caure or, at any rate, contrlbuta to abnoraal blood changes, vith or without neurological ~ findings, among a small group of workers In a shirt factory, where this substance was used in conjunction wLth denatured alcohol as a solvent for cellulose acetate. The inhalation of glycol chlorohydrln, or ethylene chiorohydrin, causes local irritation of surface mucous membranes and deeper lung tLcaue. Its toxic effect Ls that of a severe nerve end metabolic poison. Fatal cases of acuta poisoning have been reported. Thi second ether of ethylene glycol, or dioxan, la a solvent of numerous products such as fats, wax, oils, gums, etc. It is ua-*d in the lacquer, celluloid and textile industries and in the manufacture of polishes, shoe creams, glue, t cosmetics and pharaacsutical preparatloaa. At low concentrations, aside froa a , 2348 10 A. J. LANZA AND ROBERT J. VANE workers who have bees exposed to silica dust in these various occupations and are now engaged in other forms of work. OTHER INDUSTRIES OTTERING EXPOSURE TO SILICA DUST The silica hazard, to be sure, is known to be present in mining and manufacturing industries other than those we have mentioned and in the building industry as well. Our survey would not be complete with out giving some consideration to the large number of workers exposed to the hazard in these industries. Bituminous coal-mining, for example, employs 458,000 men, among whom, as among anthracite miners, are a number who are engaged in rock-drilling, and consequently are exposed to silica dust. Among the manufacturing industries with a more or less definite silica hazard, should be mentioned the making of abrasive wheels, sandpaper, hones and mineral earths, employing together about 8,000 men; the manufacture of mineral fertilizers, 21,000 men; of clay products (other than pottery manufacture) 93,000 men; and of cordage and jute- goods manufacture, 19,000 workers. , Many branches of construction work require considerable drilling in siliceous rock. In New York City alone, about 2,000 men at one time were employed at drilling, excavating, and blasting in rock containing a high percentage of free silica. Laborers and helpers in general construc tion and in road and street construction, together with steam- and street- railroad laborers and laborers in public service, many of whom are en gaged in construction work, numbered 1,337,000 in 1930. It is in this class that most of the workers in the building trades exposed to silica dust will be found. The combined total of workers included in this group of miscellaneous industries numbers about 2,000,000. In all probability only a small fraction of this total is exposed to the silica hazard. If, however, we apply even the conservative figure of 5 per cent as our estimate of those who would be exposed to the hazard, we shall have to add 100,000 workers to our general estimate. Our very rough, but obviously conservative, estimate of the number of workers exposed to silica dust to a harmful degree in the United States is, therefore, upward of 500,000. We recognize that the data upon which this estimate is based leave much to be desired. Only the known ex posures could be taken into account. The interesting thing about sili cosis, which must not be overlooked in considering its importance in the nation's toll of ill health, is the unexpected places in which it is being PREVALENCE OF SILICOSIS AND EFFECT 11 Amcovered, and the revelations as to the extent of the damage being done in industries in which the hazard is known to exist .. What does the exposure of more than half a million workers to silica dust mean in terms of the prevalence of silicosis and of tuberculosis? We cannot, fox the reasons given at the beginning of this paper, give a direct . answer to these questions. Many competent students of industrial hy giene, as you are well aware, have shown an extremely high incidence of silicosis in those industries in which they have carried out thorough in vestigations. They have shown, too, how frequently silicosis terminates in tuberculosis. It is not our purpose to review these findings. Valu able as they are, they are entirely inadequate to serve as the basis for anything like a countrywide estimate of the number of silicotics. We think, however, that their findings, taken in conjunction with our esti mate of persons exposed to silica dust, amply justify the assumption that, first of all, a very large number of industrial workers are the victims of silicosis, and second, that these silicotics contribute to the high incidence of tuberculosis and the high death-rates of industrial workers drom this disease, especially at the later ages of life. This latter statement finds partial support in certain mortality sta tistics made available to us. We present two graphs which are interest ing in that they show the age-curve of tuberculosis death-rates for several population groups with varying degrees of industrial exposure. The graph on the right shows how the rates for female industrial policyholders compare with those of male industrial policyholders. The maximum female mortality, it will be noticed, occurs in the age-period 20-24 years, after which it rapidly declines to the age-period 55-64 years. The male mortality, on the other hand, rises rapidly with age, reaching its maxi mum in the period 45-64 years. At these ages, the death-rate for males is three times that of females, whereas at ages 20-24 the female rate exceeds the male rate by about one-third. Graph 1, on the left, compares the mortality of three groups, all males, namely industrial policyholders, representing the greatest industrial ex posure; ordinary policyholders, representing the least, with the males of the general population midway between. At each age, the lowest death-rate is shown for the ordinary policyholders, and the highest rate for the industrial policyholders. The disparity in rates increases rapidly with age from 15 to 19 years, when the rate for industrial policyholders is 28 per cent in excess of that for ordinary policyholders, to ages 45-54, when the industrial rate is three and one-quarter times the ordinary rate. to A. J. IAKZA. JUSD SOBBJCT J. VAKK -These differences: may not be ascribed to industrial influences alone, least of all do they measure the effect of silicosis; The classes vary asrto eczmamicatatus for one thing, which, as has been well established, has an important, bearing an- tuberculosis mortality. The very considerable dif ferences do, however, suggest the influence of silicosis, especially as- the greatest disparity in the mortality rates occurs in those- ages in which ailicnais-.is.mast likely to.show- its effects. TUBERCULOSIS -ALL F0RMS-I93I DEMHRATES PEA 100.000 WHITE MALE* IT ME PERIODS TUBERCULOSIS'ALL FORMS: 1931 OEMMRAHS PER [00000.*YSEX*AfiEPERIOD*. METROPOUTAH mOOSIRIAL P0UCYH01OERS rGraph Graph 2 More indicative of the direct influence of silicosis on the general deathrate.-from tuberculosis is. a- comparison of the. mortality from this cause for men engaged in specific occupations with exposure to silica dust withthe mortality, for. those not exposed. There is, unfortunately, in, the United States no complete analysis of occupational mortality hy which- we might measure: the effect of exposure to silica dust. on. the. health and longevity, of workers. The most, recent data sue found in an investi gation made by twelve life-insurance companies into the occupa tional mortality of persons insured, under ordinary policies (policies of Sl.OOOr.QTi more, payable quarterly or at longer, intervals).. The study PKEVAIEfCE 07 SILICOSIS: AKD SFZECT 13 cnalya&the mortality experience of those insured under policies issued rbirrn^ the.-years 19L5 to 1926. The method employed was to compare tho wtml number of dwttlia, which occurred men engaged in specified occupations, with the expected number of deaths on the basis of death-rates prevailing among standard lives of the same ages and for the same duration of insurance. Although these figures have been pre sented before, they will bear repetition.1 It must be kept in mind that the. standard of comparison is a group of selected lives insured under ordinary policies and not the general population. To offset this, how ever, it should be pointed out that the men in these specific occupations also underwent insurance selection. Table 1 shows the figures for occu pations exposed tn silica dust. Table 1 bears out in a striking way what is implied by exposure to silica dust in terms of tuberculosis. The occupations showing the highest ratios of actual to expected deaths were, in order: underground lead- and emc-miners, granite- and sandstone-cutters, copper-miners and gold- and diver-miners. AlLof these workers are exposed to a serious silica hazard. The ratios of actual tn expected deaths from tuberculosis were, respec tively: 1,833 per cent, 976 per cent, 913 per cent, and 804 per cent. There were actually 60 deaths from tuberculosis among these men as against six expected. Tuberculosis was responsible for one-half of all the deaths of lead- and zinc-miners, 29 per cent of the deaths of copper- miners, and 20 per cent of those among gold- and silver-miners. In all of these three mining classes,, deaths from tuberculosis exceeded deaths from accidental injuries. Among iron-miners, who are, on the whole, probably less exposed to silica dust than are the other mining classes mentioned, we find that the ratio of actual to expected tuberculosis deaths is only 260 per cent. The ratio among quarry-workers was 263 per cent, 7 of the deaths being due to tuberculosis, while 2.7 might have been expected. It was impracticable to separate the granite-quarriers from the limestane-quamers. If we had the figures, we should probably find that the excess among gramte-quarrymen exposed to silica was much greater than among the limestone-quarrymen. This is clearly indicated by the difference in the mortality ratios for the granite- and sandstone- cutters and the marble- and limestone-cutters. The ratio of actual to ^T/mPreusience^)/ Tuberculosis mJndustry vitk Observations on the Dust Hoard: a digest oia^aper by.Doctor A. J. Tania and R. J. Vue, read before the Industrial Hygiene Confer ence, Chicago Tuberculosis Institute, April 25,1930. Published in StatisticalBulletin, Metropotitan Life-insurance-Company, July, 1930, si, no. 7. t 14 A. J. LANZA AND ROBERT J. VANE expected deaths among the former was 976 per cent, while among the latter it was but 294 per cent. There were 16 deaths from tuberculosis among the granite-cutters, as against 1.7 expected; whereas, there were .3 deaths in the limestone group, against 1 expected. TABLE 1 Number of deaths expected from specified causes and number which actually occurred ament persons engaged in certain occupations exposed to silica dust Ordinary department mortality experience of twelve life insurance companies 1915-1926** 1 aasnazrazT Toszacuioss OOCUMVOV Peroeat- Actual Deaths Ex pected Deaths Actual of Ex Aetna] Deaths pected Expected Deaths Percental*, Actual of Expected Metal mine operatives (undertround) Gold and silver mines........................... 44 9.77 450 Lend and zinc mines............................. 22 5.03 437 Copper mines........................................ 83 22.63 367 Tran minfi*............................................. 33 12.12 272 9 11 24 4 1.12 804 0.60 (1) 1,833 (1) 2.63 913 1.44 260 Quarry operatives....................................... 37 22.45 165 7 2.66 263 Stone-cutters Granite and sandstone..... ................. Marble and limestone........................... 29 17.47 166 12 10.55 114 16 3 1.64 1.02 Metal industries Grinders................................................ 46 28.65 161 7 3.33 Buffers and polishers............................ 89 64.10 139 10 6.80 dippers (not ship)............................... 38 14.14 269 8 1.30 Core-makers and sand-moulders.......... 32 22.65 141 3 2.92 Iron and steelfoundries Moulders, founders and casters.., 202 130.14 155 24 13.38 976 294 210 147 615 103 179 Other operatives Drillers, flask-maken, machine-hands, miTers, etc......................................... 45 31.03 145 7 3.03 231 * Compiled from Joint Occupation Study--1928, Actuarial Society of America and Associa tion of Lift Insurance Medical Directors. (1) Approximate figure. In grinding, another occupation in which there is exposure to silica dust, the ratio of actual to expected deaths was 210 per cent and there were 7 deaths from tuberculosis, as against 3.3 expected. Here, again, J 7 1 PREVALENCE OF SILICOSIS AND EFFECT 15 we have a mixed hazard, for the sandstone-grinders, who work in the cutlery trade, have extreme exposure to silica dust and undoubtedly suffer inordinately from tuberculosis, whereas those who work on the composi tion wheels do not have this exposure and probably do not have very high rates from this disease. The only other large occupational groups suffering exposure to silica dust included in the study are certain selected foundry occupations. An interesting feature of the foundry operatives' mortality, not brought out in the table, is that, while deaths from tuberculosis were higher than expected, extreme ratios are found for influenza and pneumonia rather than for tuberculosis. Dust is probably an important factor also in the high nontuberculous respiratory-disease rate. Chippers of metal had very high death-rates from both influenza-pneumonia and tuberculosis. There were 8 actual deaths from tuberculosis, as against 1.3 expected; and 17 deaths from influenza and pneumonia, as against 2 expected. Moulders, founders and casters had 24 actual deaths from tuberculosis, as against 13.4 expected; while there were 61 deaths from influenza and pneumonia, as against 23 expected. There is another important question: What is the effect of silicosis in terms of tuberculous infection among other members of the family? Here again we are confronted by a lack of conclusive information. It has always been the impression among metal-mining communities, where silicosis is prevalent, that there is little tuberculosis among miners' families, even when the miner has died of sflicotuberculosis. McFar land, and also Russell of the Public Health Sendee, have commented that in Bane, Vermont, the amount of tuberculosis among families of silicotics was less than among the general population, which they attrib ute in part to the comparatively late age at which the silicotics become tuberculous. However, Cummings of the Saranac Laboratory has kindly permitted me to quote some conclusions from as yet unpublished studies which he has made. He studied a number of families of individuals with silicosis plus tuber culosis, the diagnosis being made by X-ray. He divided these into two groups, namely, sputum-positive and sputum-negative by guinea-pig inoculation. Over 50 per cent of the children under sixteen, living in contact with a silicotic having a positive sputum, showed X-ray evidence of tuberculous infection. Less than 30 per cent of the children under sixteen, living in contact with a silicotic having negative sputum, showed X-ray evidence of tuberculosis. All of the tuberculous infection shown 16 A. J. LANZA AND ROBERT J. VANE in`these children was of the primary type; there were no-cases of-adult* type tuberculosis. Probably the situation with respect to tuberculosis among families of sOicotics varies with the gravity of the silicosis hazard. When silicosis is severe and the individuals become tuberculous at a period when their children are small, there is naturally more likelihood of contact infection than when the silicosis hazard is less severe and be comes manifest at a later period in life when the children are older -and have perhaps left the family circle. The whole held of family tubercu losis, in relation to silicosis, awaits careful investigation and study. To sum up: There are sufficient data to indicate that, in the United States, the number of industrial workers exposed to the silica-dust hazard is in excess of half a million; that the mortality from tuberculosis-among these persons is appreciably affected thereby; and that the extent of family infection due to silicosis plus tuberculosis is uncertain; but under some conditions, at least, it may be a serious problem. BIBLIOGRAPHY van SicttN, ML: Health hazard Iran duct in the mines and allied industria of theUnited States. Initial survey of the extent and severity. Contribution no.'45, Ameri can Institute of Minin; & Metallurgical Engineers, May, 1933. U. S. Bureau of the Census: 15th Census, 1930: Mines and quarries, 1929, Washington, 1933. Occupation statistics. Gainful -worken by industry and occupation, Washing ton, 1933. Occupation statistics, U. S. summary, Washington, 1932. Pennsylvania Commiarion on Compensation for Industrial Disease: Occupational disease compensation, Harrisburg, Pa., 1933. Lanza, A. J., and Vanx, R. J.: The prevalence at tuberculosis in industry to-day, Metropoli tan Life Ins. Co., Statist. BnlL, July, 1930, p. 6. Russzo, A. E.: The health -of workers in dusty trades. IL Exposure to siliceous-dual (granite industry), U. S. Pub. Health Bull., no. 187, Washington, 1929. McFasland, W.: Silicosis and tuberculosis as seen in the granite workers in Bane, Yt,, Jour. Indust. Hyg., August, 1927, p. 315.