Document xj2Q8J7K21VoZ5vOBOjj2R901

7FOS/T. 60) 3 . ' 3--. --<=n r >ES~ ASA. r\ - Z 1 2 Z , ^ J 7 9. >c 1:: I -2 V 5 CO?;"! U 1 U Z-Z J j C ? V !?. L 2. 2 , Z :' `.o f'-? ;.=-> 2: ssbssaos in gas ': -2 3 3 a r e : 1. Tone-, 7.S.P., Pooiey, F.D. ^nd 3mi:', ?.G. "Factory con un.g study". I.A.R.C. Sc ion t i f i c ?ubi rations Mo. 13 00 117-120 ( 1975) (See paper :v Hobbs ec -.1 July 1979). 7. MoDon:.!', A.D. and McDonald, -7. Corbett. "Monoahi; 1 icma after crocidolits exposure during gas mask manufacture". Environmental Research 17, 3*;0 -- 3-16 (1978) . Copies of both articles are attached. The Jones et al article relates to the use o* Wi t t^ooom crocidolite and merino v;ool for gas masks assembled in Mottingham, v.K. between 19 39 and 1945 . Asbestos =.s used br;?.usn it could form a very tight filter, and most ..'nr 'gases' were in fact aerosols, not gases, i.e. containing fine droplets that could be filtered out. The McDonald article gives derails .of similar activities in Canada. By coincidence, the School of Public Health Tropical. Medicine at Sydney University is at present establish if asbestos-containing gas masks were made Australia. The answer is not known. and trying in to It could be said, of course, that the use of asbestos in gas masks was quite justifiable in 1939-45, in as much as: (1) only asbestosis was known, and the chances of contracting asbestosis from wearing or even assembling masks was probably small (none of the Nottingham mesothelioma cases had asbestosis); and ^ ^* , r\ r srsus a JC 5 S C O C e . : run prooabi1.tv A ~ ' ' ' - ' S t 1'? 1 ' >?t"l Un*?^ ' 3 r.;' 1 3 Or :e -' In ^o" cl i c i fication o irugs, beer Sen '.on? l?n pp 127-1.31} . It it unlibel' :roo Lhol i 13 in uue-i in these apolicacions . vines etc. that 3 . M. At C 376 9 Los i-.z .'zr.e' "OO t 0 l . ^L,.. i .'o _: ,,' C r U J-- hV ;on :t'iv Li z svj:o :. :..' V. .0' t'!-.j:,i:n.i tied c ora-ut: ;or. at :.-.e licf.ir.-.-j tor.' exto:-`c'l frrr 1?2~ - <V:. Tef.-r^-'r-.r c:` V.<* -er-'crr h'-! b.:- n-s:roved but it possible to trace via *.> . i.-- c1 . r.-irzcr t'-rloyec'J : r vo Ivd ;hic -o:.< -t'd ts apprc-i-t'e, i'O. -i,--V. I . _:r.r cf zrr.'rz -ere ct.'.v e-.--_ -..-.in :`or a To- :r a few r.o.-.tr.r, itst oti;rs --.rvei t.-.rcu v.cul t.-.o war. Lee-fas: c`.nr at that f. of aster.-, t:; s, ai.jw-.t," pre-css s~ccrt,4:,.f"i is crcicced chaacers'wata extraction ver.tiIr.tic. ~sac;: production, nairr :.:e zzr.n crocidolite fihrr ie also itr-s-.t. to r.r.ve riser :r. twi Atwr err: ran durirr ".so wap, in f'r-'rten i.Owns a.-.-i ."liicr) are sot nc yet established, but it is ;cr.owr. that tn ntabero at Siroir.^r.sa were rsail. I fiecuUfl: (i) : :o far, 2o.deaths froa scsoth.elioaa have tec:: identified ir. people i w.`:o worked in -1 iii!FL,"'a^iu L?<irH","rAluu'.iO!l wf\o eeitsJ -- ur.dcrt-V.cn (T. Lc I), The tur.ourc have becoae apparent between 20 a.vi ;S years ofroa the tiao f possible asbestos exposure. All tat ono of the eases have i \ .. . i i i --.1 \ "I \M J .co of aeoii.-.clicaa. 4 - if i. i *ILI .ae'.e ... r . ?rir:r*;cr of ;r.o cc/. fcr-'s ..i*re woaer.. .o f rzz . -c loe of :<*r.:y-r,ix caeca, a.-.d rcoidol:to. ~ ; pi'c-is'-C..' f.:.c -i a c r~ is csmcccr.t witn ..*.e appoarar.ee of aaplec ta:br. fr r. *.r.e >5*.err Vcctralt rii crocidoiitc air.o wr.cre the fibre i-.-e*.er -.3 a?-r .c'.tcly A average. The co .cpt: r*.:icr. of f.'.rcr ir. *..'.o .ic;:a'' :.-.c beer estimated or. a -rid area cT^a; : a } a.3.neier -irclo of iur.T v. ::c-.:c cm*. 6 ji tr.ic>:< ..-.c results : -a5 . :vc .e c -.1*. r.is ::o *. j :o .'20 12 100 M3 :p ;*c t I 'c r. ft j.<. The red'.il : -.-oic.-i ? vc c.evcl Cd i r.--cr: d c 119 b i w ) i oJzo 3*rf l C 3` 74 v i.s t.' -C -i 17 v5 50 : Coes i Mgsoihoilcma af:cr Crecjcc:i:s Exposure curing Gas MasK Manuracture1 70 8i Alison D. McDonald Qtpr.rtrreit of Epidemiology c.d iitcith. McG:i( L'oiversitv. Mc/urcai. Canada AND J. Coreltt McDonald TL'C Centenar> fasniutt of Cccapa:.oncl r:cc::`. London Szhoci of Hygiene ar.i Tropical Vea.cir.e, London. England Received January 17, iS73 Of 199 person? employed in the manufacture anJ handling of Canadian rr.iii:ary gas mask canisters containing pure crocidolite, 19j9 :o 19-*C. d;- the end of 1975. 56 had died. 150 were it'll alive. and 23 could r.ct be '.raced. Nine (I597-) of the deaths were probabiy due to ~a. gran; .merothtiicma, sis invoicing the per.torturn. The risk of rr.eso'.r.eiiotr.a after crocidolite exposure appears to be many times greater than that after chrysotiie. INTRODUCTION Evidence has accumulated that the mineral types of asbestos fibre have dif ferent mesothelioma-producing potential--creates: for crocidolite, followed by amosite. chrysotiie. and amnophyiliie (McDonald and McDonald, 1977). How ever. there have been very few studies of human exposure to single mineral types of fibre. For some years we have observed the occurrence and causes of death in a cohort of over 11,000 employees in the Quebec chrysotiie mining and milling industry. About 10vo of this group had worked in a small asbestos products factory in one of the mining towns. Of 10,259 members of the cohort traced to the end of 1975, -247 had died since 1935 and the cause of death was ascertained in 9Sv& (McDonald et al., 1971; McDonald et cl., 1973; McDonald et al., 1974; Liddell et a!.. 1977; McDonald et a:., 1973). Recently v-e identified another cohort of 199 .P.e-C?P_n8J'.v^ y,'erc exposed to crocidolite.bety.eenj.939.and 1942 In three separate &9iQP`c$ including the one in the mining town mentioned aboye:_In twcvplants Alter pads containing, pure crocidolite were made; in a third piant they were packed into canisters which were assembled into gas masks for the Canadian Jirmv^Of the 199 persons, 174 were traced to the end of* 1975--55 were found to have died and the cause of death was identified. This study is described and the pattern of mortality compared with that in the Quebec chrysotiie mining and milling industry. METHODS A malignant pleural mesothelioma was diagnosed in 1974 in a scientific officer who was one of a small group of men in Ottawa responsible for setting up and 1 This work was undertaken with the assistance of a grant from the Institute of Occupational and Environmental Health of the Quebec Asbestos Mining Association. 00l3-935l/7i.0l73-O340902.OV0 Cepi-ngni Q |SJ| tr AcjJmp{ f>rr. ln. All n|hii ot rcproducuoa in ny form mti-cd. 340 WSTTTJTi Or OCCUPATION AND environmental health MONTREAL. CANADA , F.ker r:._> made in two fn::or.es Qui-Awa. CrociuA.:..- -[ were tucy were re ducat: :o the ccrre.t wcic'::: by ;c mo vine some eft he surface tr, cut .rsto canisters. unci tested. There was no special exhaust ventilation but muse wr,o had worked there said that :t k.:j no- npp.'arc.! dusty. The plant w.v- - c'.rat.cn :ro:n the eu_ c:959J'.roecn 1945 bu:_:rcc. Jchte v.n> used oniy_un;i: spr.-.q 19-2. alter wiu'ch -j no asbestos as u<ed in tihav iixter.si-e en.yaines during 19~6 failed to reve.n! any records of civilian aere still held cn military f but provided r.o practice! means of identify:" those v.ho hod or.-ted in tnc plant. Starting with persons .named b> tr.e man .. rii.'.-e _r . u.ugncs.J in l'.'"-. a as; .'.,,t made cfail :r.^:e 'r.o had .. ori-ted .r, the pinn'. w i.'?e names were known. Attempts to trace the 54 persons listed, mainly by p-.rsonai enquiries, revcaied that 25 were alive and 16 dead; 13 could not be trtcai. In the factory a: Asbestos. Quebec, which since the first worid war has pro cessed mainly chrysotile abe?tos produced locally, niter pads were made in the textile cepnrtm.nt from 1959 through 1941. For our studies in the Quebec mining industry, job histories had been extracted from personnel records for ail persons ..ho had wormed for at least one calendar month. It prosed to be impossible to distinguish those who had worked on the gas mask filters, so everyone who had worked in the textile department during the relevant period--1939 through --was assumed to Have been exposed. In view of the conditions current at that time this was not an unreasonable assumption. Tire S4 persons who were bom 1 >91 to 1939 had already beer, traced to the end of 1935; one was lost. 63 were alive, and 21 had died. A further 29 persons, born since 1920. had also been empioyed in the textile department; 23 of these were found alive at the end of 1975 and 6 had died. At a factor,' in Montreal which has manufactured mainly brake linings since I92S, gas mask filters were made from November 1940 to June 1941; this was the only product in which any mineral type of asbestos other titan Quebec chrysotile was used. Paybooks had been kept since the factory was established. These were reviewed with a current employee who had been night foreman on the gas mask filter production. One carding machine was run continuously for three S-hr shifts for the 7-month period. Only those persons whom the foreman definitely remem bered working on the gas mask filters were listed--32 in all. Some may have been C 3775 * ... , . . 7tM.ll .Aits? O.-.iJ \5. AA c:* Montreal '-1 F 0 *! -? -6 A'CCSI-M. "oeocc >! f : -a t5 f ? -! ` ' : ;; F : 5 < Cu ac > * AccxcrMiJ Cs.;:t.c> - *iuh ec;:r. csr. .:*:c:es cc.ac "Cl c: fo-jri. '! F . <j "a i ;} 3 : <\ forgotten. c'-peei:.::;. : esc w.irkin cn a day A-,;:':, and others although not r.::u- : liy u'.: ' : e -ere -r^-Turiv c an os .-a to it. Nine c: 32 coui-i not ce traced. 10 v\<:rc :..; e. and !3 had died. Deal!. cert: fen:.: -..ere sought for nil 56 pers ons reported to ha-- e died and ere obtained for 5? 'Table !). The remaining turcc 'ere reported by a: least :v.o persons to have died aeeidentaiiy (two in road accidents and one by drewningt bat the dates ''ere rot known and the death certificates could not be found. FINDINGS The 53 certified c.v.:cs of death arc shown in Table 2. Of the total of 56 deaths. 23 were from malignant disease including 9 from mesothelioma and S from ion; cancer. Autopsy reports in one case of lung cancer or.d one of generalized car cinomatosis (footnotes h and c in Tabic 2) rc'-caiec the: both had been diagnosed postmortem ns peritoneal mesotheliomas. Enquiries were addressed to pathologists about fb-c other cases of malignant disease. In two. one of iu.rg cancer and another of carcinoma cf pancreas, the certified cause was confirmed but in three (footnotes u. J. and c in Table 2) the diagnosis cf malignant mesotheiioma was preferred by the pathologist to the one recorded on the death certificate. Thus, in 9 (169c-) of the 56 deaths, malignant mesothelioma was the probable cause of death. The intervals between working with gas mask filters and death in these 9 cases lay between 24 years from last exposure and 36 years from first exposure {Fig. 1). Six of the 9 cases involved the peritoneum. Two additional cares of pleura] mesotheiioma were reported in a continuing national survey of mesothelioma in Canada (McDonald and McDonald. i977) in men who had worked at the Montreal factory. One man who had worked there from I92S until his retirement in 1974 died in 1975. The other, who had worked (here oniy from December i940 until April 1941, died in 1970. Thus both men worked in the factory at the lime that crocidolitc was in use and their dates of C 3776 : -/-- , ... ^ . ,,,. . * ntun W-V'ca; S ** *, A<r:.: :s - 1 '..a - i ,. p-c.^r 1 1 Turcrcuicso prrjrv.o:or'.:-:v'. Asbestos S:!:C9S;3 ' i.ljb..U. "C st.icctcberculosisj iivij: ctseus: Other c.r.iscs 10 ;o 3 - * One c:' ?s cono-ered k.. ,*' to ce a pcniors.iJ mesothelioma. " In o.-is cf !bc<c c a p-:n:oi:c..i v.~ ;..oma w.ns diagnosed at aussrsy. ' Per.ion.-::! r.v.ciapnc-*I a; arsy. * F.i' i<w :c *7-. - -{7. J..r:'A v. ho C.rsovi p?r::o(V.-a! "^o:n:horr.a. ' Reviewed b> fv.boiogisi who diagnosed peritoneal mtsot.neiioma. i 1' f 3 /, death were compatible with exposure in 1941 but neither had been induced among the 32 names supplied by the night foreman. Pneumocor.ioiis was the certitled cause of death in four long-term employees. Two cases cf uv-V'tosis were recorced at the Montreal factor.' and one of silicosis and one of sdirotuberedosis at the Asbestos factor.-. In sever, of the nine caces of mesothelioma the total duration of asbestos exposure was short. All four cases in Asbestos worked only in the factory and never worked in the mines or mills. Three were employed only daring the time crocidolite was used, ford months. 6 months, ana 2 years respectively. The fourth worked for a total of 6 years including the 2 years when crociJulite was used. In Ottawa two cases worked for less than 2 years : and the scientific officer was exposed for less than 3 years. | DISCUSSION 1 The mortality findings in the gas mask workers are compared in Table 3 with i those in the cohort of chrysolite miners and millers described above. Comparisons ; of proportional mortality especially for malignant disease must be made with 1 caution because they may be biased by differences in age, in other causes of death, and in length of observation. As relatively few of the gas mask workers have yet died the already high proportion of deaths from lung cancer and mesothelioma may in time increase further. Mesothelioma was some 60 times C 3777 Fic. I. V:r '<i of 4 | 4| 9 r.c >car of oocyrrcnrc of rn^otficliofr.a ;n Nc;:mc*`.m, tnorc in \ ;in :hc chryxrv.jc cohort anJ lent cm:er over l\wcc i.. ; ^a a: '-eu::;.* from . ;:,cr .v.uligrar.: diseases 'irr.iinr in ire f-'-o There n major difference i n the site of the mesoths- !ial tumours; in tre c; wd'hie echo:; *j cf the 9 eases ir.voived the peritoneum compared v.ith only 1 cf the 11 in the chrysotile cohort. A high proportion of peritoneal tumours characteristic of populations with a high incidence of mesothelioma iSeih;>. :f and f la.mmon i, 1975; N'ev. house and Berry, !9T6). The proportional mortality from mesothelioma in Ottawa was 2C~. in Montreal 209?, and in Asbestos 1:27---remarkably similar, though, of course the numbers are small. However, or.iv the Ottawa workers were exposed solely toucrocidoiitc. Some of the employees in the Montreal factory had had long and probably heavy exposure to chrysotile and those in Asbestos to chrysotile and possibly other TABLE 3 Nt.MjuNAxr Djsea'i. in C.-iwt M> i iLr Mim ks *no Millass axo in C*.ociooe:Tj Gas Ma$x F;l:S WokvfKj to the E.\o or 197J Total cohort Traced Dead Cancer of the lung or bronchus Mesothelioma Other malignant disease Crocidohte gas mask filter workers 199 (5<r male) 174 56 7 (I3CT) 9 (I6C7)-' 7 (13*) Chrysot.le miners and mrilers 11.379 (96* maie) 10.259 4.247(since 1935) 242 (6*) 11 (0.26*)*' 632 (U*) * Four certified: two diagnosed at autopsy: three after pathologist's review. * Eight certified, one of which was not thought by the pathologist to be a mesothelioma; three diagnosed at autopsy. * Two cases were common to both series a and b above. C 37?. 1 on u;.s :r rrcfoih-iforna in Lst ;'.poi'.;c'a:'- to !- 35 cj?cs u :ro per::: thib Minus ''as in :h.?-; rf ior.;.a> r ''> :_.rjon:._i:.: :n;er--;.:i c-jtv. con :.-.J ;.n C.mr.do trig. !;. in Cr.r.a-.ia (> of tine <> g/s m:.A/ A jc.-nparej w:;h .'o;`C3 cases in Erghrd. but the tricing of .p:c:a. Second, '.he finding b\ Rub: no <*/ a I. (19771 of one ease Northern ;:ni> pxn.h.A M .ebec expuneucd. A no: her e x r: v ::: of the d:fr. r:n;; rr.cy be reir.: :d : j :he nature of the in bus- r.".:\ n: re ~t. Fibre : j nee::"m an.! dre cjstrfrijiions r*ay differ ;n fac.cr.ee :':r.-\rcz wirr: mints me mtiis. S:uc> of workers exposed oniy to chryso:;!-: i:i .canuf.-.cturing is needed :o resoixe this issue. A.!:hough inform:/.;-.'?, on exposure levels is inching, mesothelioma cler.riy oc curred after very short total exposures to asbestos--r. ft more than 3 years in 6 of the 9 cases at:J .: ~.~d 6 months in two cases. In view of this and the weigh: of other evidence ; .McDonald and McDonald. 1977) the continued use of crociuoiite would appear difficult to justify except under the strictest possible control. acxnov/ledgments This study a is (T-.d; possible by the scientific officer mentioned in the test who de'elvp ;-J a rj'r-;::i:i:.T.v Hu sz - ; - detailed acccun: of how me gas masks w*r* mace and named seme or' me persons who had wc.v-. . m m * p':.-.:. v.- are aiso if ace:cd to the m-racers of '.he tv. o tor.es wr. ere me f.lter pais were ia,.e -to J :o 3 au.moer r :rso*$ *kc w-re <.rr.pic;. eu m as'embiirc nno testing the gas masks in Ottawa, who helped name ar.d trace others who had worked with then. dories. J. S. ?.. F.'O.A.. .-. D.. nEFEr.ENCES o.m.-rh. P. G. (1976) /Actor. p/po.' ;:.-c.ts exposed to crocidclite ' ^asres'.os--a cor.iirum.c survey. MAC Sf.enftf'e Puhhcotom. iSSERSi 52. I 7 - 120. Lidde.i. F. 0. K.. McD.v..-.id. J. C.. i.-.d Tits. inns. D. C. \ ;977X Methods cf cohort a a.*.: y sis: Appraisal cy application to asbestos rrening. J. Roy. Statist. Sac. A. NO. Par: 4. 459-01, McDonald. J. C.. Becklakc. M. R.. Gibbs. G. W.. McDonald. A. D.. and P.ossiter. C. E. (197-;. The health of chryxottie asbestos mine and mill workers of Quebec. Arch. F.n\ iron. Jivalth IS. SI -63. McDonald. /. C.. Lf-'dcfl. F. 0. K.. Gibbs. G. U'., and McDonald. A. D. Dun exposure and mortality in chrysotil* mining. I $: 0 -- T 5. tn preparation. lI McDonald. J. C.. ar.J McDonald. A. D. 11977V Epidemiology of mesothelioma from estimated inci dence. Prev. Mtd. 6. 426-U4A. McDonald. J. C., McDonald. A. D.. Siemiatycki. J.. and Ro-siter. C. F.. {1971>. Mortality in the chrysuie asbestos mines and miils of Quebec. Arr/t. Environ. Hvnlth. 22. f>77-f<Sr.. McDonald. } C., Ross.'.er, C. E.. Eyssen. G.. and McDonald. A. D. (197.1). Mortal;!) tn the chrysoule producing industry of Quebec: a progress report. In "Proceedings of the International Conference on Pneumoconiosis. Bucharest. 1971." pp. 222-237. 79 : -6 oqnai.o wr: v. wO c':: J 'fed. 33. I-'-;?! . .Ss11. r . :*J G. .x<r;%-js n . i'~r?r ;?- ai :;.c P.c-.G f M?.:;c:r.r. - n. /! S'- --?o%x:r. O'- ;r --: a:u:uwH :o occ.siuor/ii hm-ircs f. C . : /*-V `!.!: m r'-*. :i :r\ irc'-i-sriaj /: 'Tr-v . S`:rc*. C. .X . : * J Mr.::r .iJ. P. ': -'O'. C.:Tl .c r S\>t'-U - c s.'cf.i r;/ rvc:r:in.T.3 a.u 3wt',:,n. ] 7. 2-XO-37J. i; 0