Document 7OVgmddjdooXL7XVd3z3ZZVXe

1V2_ JC U. S. TREASURY DEPARTMENT rum.tr health service Public Health Bulletin No. 241 Aofont 19.1R A STUDY OF ASBESTOSIS IN THE ASBESTOS TEXTILE INDUSTRY nr WUHFMAR C. DREESSEN. F*m4 AmMoiH SoffMN S. M. DALLAYALLR. P*ed SonlUrr Enrlneef THOMAS t. EnWAROR. TttS*lr Ertllftt i. W. MILLER. rHhf*l*tirt R. R. SAYERS. Senior Sorfeoii With the ftMlflUn^e of H. P. EASOM. M. !>.. Dlreor M. P. TRICE. Entlneer rKO ('ar+llttm Ai* ttf From the DMlon of tnrfsalrUI Hrfiene Notional tfiflOtnle mt Health nei*jny3).",*cv mhEcnoN nr tWe ry*'<)r.r>t* r.r.nrmt. t'WtTf.n states GOVERNMENT TRINTINO fimffl WASntNCTONt JJ . . fW U iV. u, / . r-- A STUDY OF ASBESTOSTS IN THE ASBESTOS TEXTILE INDUSTRY INTRODUCTION u*e in industry. As everyone knows, it is noneombustible and nn excellent insulator against bent nnd electricity. Fewer people seem io be nunre that it* fibers nre sufficiently long nnd flexible to be curded, imn. nnd woven like wool, flnx, or cotton. Utilizing tliee properties of nsheatos, industries have been developed in tins country which employed more thnn fi.OOfl men nnd women in slightly more thnn 60 rth)i*bnicnts in 1D36. Another property of asbestos hns been discovered more recently. When asbestos dust is inhnled dnily, yenr in and year out, a lung disense termed nshestosis may develop. In many respect* asbestosis resembles silicosis, but it differ* from silicosis in several important particulars which will be discussed in the medical section of this report. The first rerord of a ease of nshestosis seems to have been mndo by Montague Mnrrnv in 1000. Tho first complete description of tho disease nnd of the "curious bodies'* seen in lung tissue nnd sputum appeared in 1027 when Cooke (0) nnd McDonald (22) reported two rase* of nshestosis nnd listed their reasons for believing that nshestosis bodies originate from asbestos fibers that renrh the lung*. The pub lication of their papers aroused gcnernl interest in the subject nnd numerous papers appeared soon afterward. Hoffman (40) appears to hare been the first American to call attention to the magnitude of the nshestosis problem. In 1018 he reported that 13 deaths from al>efttosi* bad occurred among asbestos textile workers, and about the same time Pnnenost, Miller, and Landis (20) reported on 17 cases of nslustosis. Mill's (26) paper was the first pathological report on nshestosis published in the United States, nnd in the same year, 1030, Lynch and Smith (3S) reported on asl>e*tnsis bodies found in tho pot urn of n*he*tos worker*. Bemuse several sntisfnrtorT literature rrviews of nshestosis hnvo appeared in rerent years there seems to be no need to present a com plete literature review in this report. Some of the more useful literaiure rrviews have been listed in the annotated bibliography. In Merrwether'a (26) review emphnsi* is laid on the relation of nshestosis (!) 2 to working conditions. The clinical aspect* of the subject urn well treated. Cdoyne's (!G) discussion of the pathology of usbostosis is particularly helpful. Middleton's (47) Miiroy lectures on pneumo coniosis contain ft section on ashestosix. Egbert (15) tins smiinmrizcil the literature reports on 28 fatal ruses of asbostosw. "Active pul monary tuberculosis was present in G instances of the total 28 cases; the fatal outcome was primarily the result of tuberculosis in 3 instances." OBJECTIVES or THE STOUT The Public Health Service was requested by the State Board of Health and the Industrial Commission (administrator of the Work men's Compensation Act) of North Carolina to assist them in mnking an engineering and medical study of health hazards in the asbestos textile industry.1 The objectives of this study were threefold: (1) To make a medical study of tho effects of long-cominued inhalation of asbestos dust on the human body; (2) to identify the manufacturing processes that create dust and to recommend practices and, when necessary, equipment that will reduce the dust exjuisure of workers; and (3) to find out what concert trillion of aslantos dust ran i>e t oirmied without injury to health. 1 Thii tvprwMU oo* of ih* nm <>< SuOol fund* f.< **.^*f*ti< jiruVrt m> n* i>t *.r>* Public SmIOi Scrrlcw ihJ Side fiMlth i !"(,tment. W1.TIIOIW . The ev In nlf li of ItV the D fill* Div'c Therefore report. The sin -111 Cl'V de ll mrhnle the (lull's m/inlier o hnnnury tnniU'. li IllllONIlI of the it)f>*n tire n>ed to umIIou. iiu- -liilii' lulu rhrxl ctinnt Appro'in is ohtititiei Av/.ivi\>v n I Illlillfl Soil Much of ttsW'Slos tc of cot ton u prejmfntin/ marhini's, s|Hwilinj (a devices. The foin into two <1 cotton inf rfcMMki PfCT E 3". 4ut v lia in nr<\ rforc. 1 vpe irlir*. (.. orrr'l t- INTTDFNCE OF AS8RSTOSTS Preceding sections of this bulletin have, stressed the importance of the X-rny findings in establishing a diagnosis of asbestosis. Tbo reason, of course, is that X-rny examination is the most direct means now available for detecting the primary effect of inhaled asbestos dust on the body; namely, initiation of interstitial fihrosis o( lung tissue. Classification of nsbeslosis into a series of stapes which follow on another in their development is a difficult matter because it depends to a treat decree on the interpretation of relatively minor changes in the lung-field markings. Other investigators have encountered the ame difficulty. Lanza, McConnell, and Fchncl (17) and Fulton, Dooley, Matthews, and Houfz (15) set up a category of doubtful cases of nhrfosis. Stage 1 in the accompanying tabulation more or less corresponds to their category of doubtful cases. It comprises cases in which diagnosis rests largely on X*rny evidence. Stage 2 represents early eases of nshestnsjs, and stage .1 designates moderately advanced eases. More advanced eases (stage 4) are relatively infrequent. Stage 5 was reserved for bed-ridden cases. TaSi.S 4t.--*-Rrlntian nf n*hr'tn*> In lung-field tnarfcmpt Table 41 illustrates the relationship of stages of nsl>estoeis to the X-rny findings. Although diagnoses of early stages of nsbesfosis were occasionally made in the absence of definite ground-glass lung-field markings when rough, dyspnoea, and objective findings were present in sufficiently advanced degree, diagnoses of the later stages of asbestis were not made unless unmistakable ground-gloss markings were present in the lung fields. The incidence of nshestosis increases rapidly with increasing dust exposure. A fifth of the workers with an exposure of 50 to !)f) million pnrtiele years, and half of the workers having an exposure of more than 10f) million particle years had ashestosis. In comparison with anthraro-silirnsis these are exceedingly low diist-exposum values (*9) 90 The relation of ushesiosis to dust concentration and length ( em ployment, in table 43, is of grrut practical importance because it allows wliut working cuuditiun* nre most likely (o cause a.-d>es|isi- and how long a period of exposure may elapse before the disease becomes evident. Table 42 -- Relation of aabtslvti* to total dull apomrr 1 2:.y37 > T portam Fiov*iprvure-oul4 out b*Uw*l*do<l tpenons uifcttUv*|inlmfiMy lubcuMluvihtt* b*M leludtd (ram tnu ubl*. Table 43.--Occurrence of atbettoax* in relation to duel concentration and length of employment PBRCRNTAOK WITIt AHOBSTOSIS Dnt irpmn, mltliia pt'Uctat pet cmMe tool Yno Ni kIirmi IimIiWt 0 ti 4 t * In** Over Ml $to M___ Qv Jt.,, UVrnl**....................... M n o% 1)4 IV r it% tt tt% A 0% 14 r; The percentage of persons with asbeatosia increases greatly with in creasing length of employment. Lanza, McConnell, and Kclmcl (I?) reported a similar trend; their percentage values are higher than these. There are two explanations for the small numher of person* employed IS years or more. This group of asbestos textile factories has tveen in operation from 6 to 1G years, and bocuusc of tho relatively short life of the industry in this section of tho country comparatively few persons have boon exposed to ndvestos dust fur a long time. Another explanation is suggested by the fact that almost three-fourths of the workers employed moro than 15 years have the early stages, at least, of a disabling disease, asbestoais. Since there is no satisfactory* way of locating and examining persons who drop out of an industry liecause of disability incurred therein, tho pcrccntugc values of tho foregoing tables are necessarily minimal estimates of the prevalence of asbestosis. Tint rnl.iii li-lll-vl . found centra rent of p.irtiH Kroir mt-dieu workin ronreri would during as in in very ficentral prrdih-ri define t for the ( <luta an In mi exjjosnr safe lim vidunlb unusual 2.r. mili offcri ii central! iisliestof employ* in the r: Reem icntnili liny we per cubred>e**U>- tn nr have \nnn oslx* recently reduein; to less l PI TU** ineidenre nf nhcsinsi increases with increasing dust roneentrrumn. In their report nf n similar study carried on in Pennsvlvnnin nhotos textile factories, Fulton. Donley, Matthews, and Iloutz (15) found Umt $ percent nf the workers exposed to an average dust coo* cmtrMion of 5 million particles per cubic foot hod nshestosis; 22 per cent of (he 17-miHion-particle group; and 57 percent of the 44-milIionpnrtirlr croup had oshestnais. THnrsHoc.n concentration or a.srrstos oust From n practical standpoint. one of the most importnnt results of & medical ond engineering study such ns this is the definition of snfft working conditions in the industry under study. Ideally, ft threshold concentration of dust should be the highest dust coneentrfttion that would not produce pneumoconiosis in originally healthy workmen during their entire working life, Tlio chief difficulty in this study, n in mot of the earlier studies of the Public Health Service, is that vrrv* few workmen nro exposed for a long period of time to low ronrenfrntioos of ashestos dust. Because of the importnnee of tbo problem, it seems to be desirable to use such data ns are at hand to define tentative safe working conditions that may serve as stnndards for tlie guide nee of factory managers nnel engineers until more rnmplete data ore nvniluble. In mi iiniilvd" nf lids kind the cases that, neeur at relatively low dust, exposures are of especial signifiraneo because they indicate what th safe limits of exposure may be. These raws must be examined indi vidually, ns well ns statistically, in order to be sure that there are no unusual features that would complicate statistical analysis. Below 2.5 million particles per rnhic foot, the interpretation of tahie 43 offers no diflieuttieM. None of the 30 persons excised to dust con centrations lielnw 2.5 million particles per cubic foot had a case of ivdirstost*, although, as ft mntter of fnrt, only 6 persons had Keen employed more than 5 years. Three doubtful cases of nshestosis fell in the rnnge 2.5 to 4.!) million pnrticles. Because clean-cut cases nf asbestosis were found only in dust con centrations exceeding 5 million partirles per rithie foot, and bceausa they were not. found nt lower dust concent rat ions, 5 million pnrticles per cubic foot muy ho regarded tentatively as the threshold value for ashesles-dust exposure until better data are nvnilflble. In order to find out the levels to which ftsbe*tos-dust concentrations have been reduced in prnetiec, an engineering study (7) was made in an ashestos textile factory in which dust control equipment has been recently installed. This shows that means arc already available for reducing the dust exposure of a majority of ashestos textile workers to less than 5 million particles per cubic foot. IP 92 The data of table 43 provide a simple means of comparing nsbestosis with other pneumoconioses. In a previously reported study of the Public Health Service (31) it was found tlmt workmen in unthruriio mines could bo divided into three groups which differed with respect to the nature of the dust to which they were ex|*wed. The perrent- TaBLI 44.--Ptreenlngri nj \tatktt* rxpatnl to certain rftnrfntrnlitm* n/ ilut in ntbrtla* tritil' fnrtnrt't ichrrr cnritrnl mtnnurr* nrr ,,<</ In n limit,tl ,chnl unit tit factor nt u-Aert 'Jfi etiee ihint c,itrnl it fjrucUml irnti1 In , rile | n -- irl I Th 1 II-hi" Dtnr enneentmtmn million f-uHirl.-i (t culilc <>( Ue af cm\f>\ tnevurc*1 F.itrnfit- 1lfr*<UIill* O-olfl itli^-ufr- * Ow 10................... llo*.W.................. J J III............... i:irlvr *............... ,, * 1% 9 T IT 3T ' n.u from ut>l* fl. 1 Du liore O). ages of men having any stage of an thrum-silicosis (1,2, or 3) have been tabulated sepuraudy for ouch group in relation to average dust eoncentration and length of employment. In passing, it nmy be of in terest to call attention to the difference between the pneumoconiosisproducing power of the three kinds of dust encountered in anthracite mines. If one compares groups of men with the same dust exposure and tbo some length of employment, in general the percentage of men with anthraco-sdicosis increases with the free silica content. Table 45.--Ptrcmlagt of mm having anthraco-uhcotit ' ; Ac und ' fii-hrCXpi*Mirlii' -tody detu-e these of till Shull I ii lien: | IHTUf j iKSllM 1 the <11 ; -tudv j Hutrv ob<ec inn 1 Oltft mnl In million |m/. lletn (* pulilf l.CJ ftihraetw minm rifaii u> <tiut (iki. lunml k- Ot<\ J iwm frte silif* Y nun In iii'ltiMff Hfl rtvm ntifikifrl Iff luiiiJ*rr* who ffa ri(>ai| In r4>nUJ^ft( IJ [rrcrtit fr< julfen Ynrt In Irolnwrr 111 nk v*ki-r *-f. pnv-l loiluit r-MXmniir l*nii U i*pooi Ifif nlifn hi iinhnirf (hn It (II }4 f)rrr it thn IX in 14 tlm n i.-- ll.-.o 13 ISI..TI lut C. fl' ..f u lois 1>. rnny I ii l<->ti M*l). : "The plove* 6tii n c 71 i t> f) tn uiiost |nirlc I rnnti UMa.ia P. 7Q, 1`nWle Urll* Mnll.-Un No, Ml. * La ifi*n 10 ion naiuiixd. -i-vnil* | m-g'it. As in asbestosis, the incidence of pneumoconiosis among anthracite rando miners increases with increasing length of employment. There is a j in the much more definite incrouso in the incidonco of uuthrueo-silicnsis with the ft increasing dust concentration than thoro is in uslnTiUwis, probably . nri*iK Q .) irfA*i of ill'' Ihrnciie TCM'ect i i. '...I c lioori :f rnM- of in* r iri*rur m-ure .f ITICII w il h f 2o40 93 hrm-in men wore exposed in a murh grenter range of dust coneentrillions in anthracite mines than in asbestos textile factories. In comparison with tlic three kinds of dust encountered in antbraoiir mino, relatively low concentrations of asbestos dut and rela* livrlv slmri lengths nf employment in the asle*to* textile industry result in pneumoconiosis. There wns no free silica (quartz) in the dust encountered in the asbestos teyttle factories. According to fable 43, Jfi.3 perrent of C.9 former asbestos workers and 373 men and women employed at the time of the study in three asbestos tertile farinries had asbestosis. (Versons who were not exposed to appreciable quantities of asbestos dust have not been included.) Eight percent of the 378 workers employed at the time of study hail nshestosis. This does not completely represent the inci dence of nshestosis because about ISO employees were discharged from these factories 13 months before the present study was made. Many of the discharged asbestos workers had asbestosis, ns the reports of Shull (31), Ponnelly (12), nod MeVhceter* (23) show. Although an attempt was made to examine as many ns possible of these discharged cases, only f>n muld he examined, 43 persons of whom had asbestosis according to the diagnostic standards employed in this study. If one assumes that the number of persons employed in these factories was ihr aitine before llieso 130 persons were discharged a* it was when thn study was made, and if one assumes that 02 percent of a]) the dis charged chwhi )md nshextiwis, /hen 30 cases of aslu'stoxi* esca|>cd ol*-crvntion. Adding 1luse to the 73 that were found, dividing the sum hy 447, and niui/iplytng by Iflrt gives nn estimated percentage of 27.3. This is not. an unusual jierrenfagn value. In numerous atmlirs of /he dutv /redes /lie percentage of workers with pneumoconiosis has Iveen found to be between 20 and 23 percent. Two such studies may be mentioned. Of 7,722 miners and men seeking employment in lend anil zinc mines at Virlier, Okie., who were examined in 1027-28 (49), 21.3 perrent. bad silicosis. In ft study of anthracite miner* (30. "The previiirnrr of onthrneo-*ilieosi* among the entire group of em ployees was found to be about 23 perrent.'* Other irivestigntops have rejiorted thft incidence of asbestosis in nsbestos te.riilc factories. Ijinzft, McConnell, and Fehncl (17) re ported, "Of the total of 126 X-ray examinations, 4 were diagnosed as second-degree asbestosis, 03 a* first degree, 39 ns doubtful, find 20 ft* negative." The persons be studied "were selected more or les* at random from among those having more than 3 years of employment in the industry." Since l/anza did not. examine fill tho employees in /he fartorics he studied, percentage values calculated from his data are not directly comparable with rate of incidence for the present study. 94 Fuhon, Dooley, Matthews, and Houtz (15) noted that ``A.-hvaUi-.i.s was found in 14 perrons (12 men, 2 women), or 25 permit ol UKexposed group." sncioknci or auucstobuj in dotzuznt occupations The percentage of perrons nffoctod hy nsbe*tosis varies in different occupations. Tho numbers of persons employed iu mmiv of Ujo occupational groups are so small tlml motion must be exercised in making comparisons, but tho data scum to bo of sufficient interest to warrant publication. Classified by departments, the preparation department has the highest percentage of aslx-stolic persons. Curd* ing is the principal occupation in this deportment. Although only 8 of tho 72 carders had boon employed more than 10 yours, 20.2 per cent hud osbcHtnsm. Klovnn curdeot lmd mivniiml nslx-slowis. i\n other occupational group hnd so large u proportion of advanced cases. Tails iQ.--fr'umbrr and peretntagr of v-nrkrr* haring a*ht*ioait, elntti/ird nteorrl\ng la rfrjKirtmmt nn{ t*ru)>nit Dpnnat ud oerunUon Nuinlwf wiih ulanmi piomym* } will* Sun 1 su3 Xlnvr* 3 ml 4 I'.r Liu. |,n I"" mil of nut [>lu: in a ili*i I im *1 sag; (MIS' It shnv of fi * CTVir*wkuwrtiwfcrnsk..t.K..a. l.o..t.m.....r.i.t..i........................................ Immtiw. wliiibnn. mm! ....... . 43 14 14 31 -- M t 14 !......... 3 "* * 4 0i ( i # - it 11 4 In the spinning, twisting, and winding department, the mule and ring spinners lmve a higher proportion of asbrslotic perrons than fho average, 24.0 percent. Twenty of tho sixty-five mule nnd ring gpimicrs had been employed more than 10 years. A third occupation with an excessive prevalence rU for nsbesWwis is cloth weaving, in wiiich 25.6 percent of the workers are affected. Only 3 of the 43 workers had been employed more than 10 years. < i TlM M. of nrllfV the dust of Hi try. i lion* quite here mg t 'Mi*-: wy.Wi'.T" 'ctnaj? ef the I _M. _t trtC't CfUu- nly 5 y. pcr- Xo cases. i<W- 'o* ne* i IB-' n i ) ti ; and \ the ring tosts ?ted. C 2841 1 05 Asneatosis ry crcat rrita/k and ts thc cyrrm states Lanza (18) has rolled attention to rv point of interest, namely, that British investigators have found nshr*tosts more severe and menacing than it ww in the United States. He adds that this difference is probably more apparent than real. Lynch and Smith (2b) have re ported 3 fatal case" whose duration of employment in asbestos textile mills was 11K, 17, and 21 years in occupations having dust exposures of the order of dry weaving. Stock (32) reported a fntol enso in a man 27 year? of age wlo worked 8 years as a carder in an Asbestos plant. Egbert (13) has also given complete findings of similar case in a man 30 years of age who had worked 13 years as a carder and who died 4 years after onset of symptoms and 3}f years after discon tinuing work. These examples of American fatalities, somo in young individuals, suggest that the period of dust exposure before disability or death ensues is ns short ns is the ease in silieosis. Bridges (fi.3) in the factory inspector's reports of Great Britiin has shown from, year to year (table 47) that the duration of employment of fatal rases with nsbestosis ifc\ onl*T half that of eases with silieosis. TauM! *7.--XiliftiAt* c*h**tif*i* in G**nf N'ltmhp* A' r DontlBn lmpl<)iiim Umi. mum MinU mnm A*m^ TTrun** MS..*........................................................ Hu M.* 12 SlIimH with ........ ................ . aw ? ....................................................... At * * Ahm,,l (llh ntfuwiWI,............. .............. v* n.t JB i* V l It.* ,i ji. r .in l More than 00 pereent of the raw mineral used in the manufacture of asbestos textiles in this country and Great Britain is Canadian chrysetiie, indicating that very little difference is to bo expected from the standpoint of biological reaction in the two countries. As near as dust concentrations in the various operations of asbestos manufacture of British practice can be compared with results obtained in this coun try, no greater differences arc found than exist in the inherent limita tions <of tho dust-sampling devices. It would seem, therefore, that quite negligible differrnres exist in the manifestations of the disease here anti abroad with the possible exception of associated oreomplicating tuhrrculosis. ni \ l l \ \ SUMMARY OP MEDICAL FINDINGS Only tlr borderline less than 5 had duste 5 million A medico] examination was made of each employee in three asbestos v' asbestosis textile plants employing/423 men and 118 women. These persons * in asbe>tf were much younger thpn the average industrial employee and they eiigineerir. bad been employed in this industry for\relatively short lengths of complish*-. time. -Almost half of these workers had'been previously employed in cotton or woolen textilo mills. Only 23 persons had hern em ployed in a trade in which workers ore known to bo exposed to inor r ganic dust, and only 1 of these 23 persons had pneumoconiosis.' -For this reason, it is believed, asbestos-dust exposure can be held respon- eible for the cases of pneumoconiosis that were found in these three factories. Asbestosis is a form of pneumoconiosis caused by long-continued inhalation of asbestos dust. The primary effect of asbestos dust on the body is to set up an interstitial, pulmonary fibrosis. This may bo seen at autopsy, and reports on three cusos apjHMir in the patho logical section of tins bulletin. This type of fibrosis may also be detected by X-ray examination of the chest. On the X-ray film the shadows cast by tins type of fibrosis resemble ground glass in appear ance and usually extend over the lower portions of the lung fields, frequently being heavier on.the right side. Unlike silicosis, nodular fibrosis has not beeo detected in asbestos workers. As in silicosis, the chief symptoms of asbestosis are progressive dyspnoea,. variable cough, substemal chest pain, decreased ' chest expansion, emaciation, weakness, clubbed finger tips, and*curved finger nails. Most of these symptoms seem to bo the result of the pulmooary fibrosis set up by inhaled asbestos dust, anti the con comitant pathologic changes, such os emphysema, bronchiectasis, and bronchiolectosis, wluch can be demonstrated at autopsy. The percentage of persons affected by asbestosis or by any one of t ^ these symptems depends upon the dust exposure. In all cases the percentage of persons affected by any given sign or symptom of asbes- tosia is greater than in control groups of industrial workers who were ot exposed to inorganic dust. A characteristic of asbestosis is tho finding of osbestosis bodies in the lungs and in the sputum. Although it does not appear from these data that a finding of asbestosis bodies can bo used to establish & diagnosis of asbestosis, nevertheless it is ovidence of asbestos exposure. (116) C 2843 1\1 m m ia .f*mmmss&&s&ms^'&* 1 trtey '.h* of- n em> inor* For sponthiro inued t on may vthoi \ u -`eareMs, svc heat reed lh conanri o of the he*'cro s in icse ha ire. . <t f r m Only three cases of nshrstnsi?. all of Ihem dincnosed n* doubtful of borderline rases, found tt> bn exposed to dust concentration* of less than 5 million particles per cubic foot. (Thr*t> throe individual* hnd Huf exposures of ahout 4 million particle per cubic foot.) Abnv# 5 million particle* per cubic foot, numerous ewes of well-marked asbestos?* were found. Tt would seem that if the dust concentration in n.be*t/* fartnrir* coulrf ho kept Mow 5 million particles (th onpineprinc section of thi report has shown how this may bo ac complished), new cases of a*hf*tesi probably would not appear. This'page and the preceding eleven (11) pages constitute the Annexere marked with the letter "I" referred to in the Affidavit of''Bernard Ctminic Brassil sworn this 15 March, 1985 before me: ii / * }' /