Document BykXG3Vjw0bbMRr7Qke3mG2mm

r Frrm Tk* /***+! W 7W > A*** 4. JM4. V*. 1**.f* iS M C4I*igk* i t4, h Am+*tn kU4#f AWcaM Asbestos Exposure and Neoplasia Iminf J. Sofikoff, MD, Jacob Churg, MD, and E. Ctt) tvr Hammond, DSc, Hem York Buildios trades insulation workers have relatively li;lit, imtrsiitlcnt. exposure ta asbestos. Of 632 iaiulation often, whe mured the trad* before 1943 and war*' traced through 1962. forty-five died of cancer of tire lung or pleura, whereat only 6.6 iucb death* were expected. Three of the pleural tumor* were nieihe]iome*{ . there wa* alto one peritonea/ ntetothelio. me.'Four tue*oihclioniaa in a total of 235 death* i* aa exceedingly high incidence for uch a rare tumor. Is addition, aa uncxa pcctedly large number of men died of can- c2y~of the rtomacb, colon, or rectum (27 compared with 9.4 expected). Other can. " ctr* were not increased: 203 were expected. 2J Recurred. Twelve boo died of atbettoaia. ALTHOUCH PULMONARY CARCINOMA had Xl.becn observed is the earliest itvdlct of asbes tos*, association between the two conditions was - wt i);|e<u uf Luwit itu auiitu in tia.' Ad ditional repnrta of tucb aiaocistion followed. Per haps the atnst striking data was proaantwd in the aonual report of the Chief Inspector of Factories of Crcat Britain for 1955.* Every death with asbettosis in th Sles of the Factory Department, frets the first recognition of asbcstosi* aa a disease maty, was studied. Altogether 363 such deaths were recorded (1924-1955). Sixty-lvc or 173% were found to be accompanied by cancer of the hang or pltttnt. DoB.* after reviewing the problem and add ing date of his own. concluded that lung cancer wits a specific industrial hazard of heavily exposed asbestos worker*. X Nevertheless. some investigators have held that, while these observance* might be suggestive, they did not establish aa increased incidence of utrei- -noma of the lung as ptshnonary asbestosis, aad - further, that the association wag unproved. The factor of selection wee considered a poten tial waalsest in evaluating reports of autopsy -series. It was noted that complicated and unucuel -atics would be more likely to come to autopsy, -tfius mising the apparent frequency of associated Jung neoplasms.* Further, it was argued that tu-topey statistics, which dealt with purticul.tr groups -of those who died, do not reflect tntsl population* - of asbestos workers.' Additional reservations Were based on the frequent absence of data, regarding fmm Ow Pl*eMi OrM*1*.** Muknw, . V*4 Mm > exposure, smoking habits, and penonuf history. on the use of series, and on inadequate histological verification in some cates. Within the lust few years e number of additional problems connected with uhestos exposure have appeared, melting clarification and resolution of the foregoing statistical uncertainty i metier of con siderable concern. First, there has been greatly increased use of the venous types of asbestos (a five-fold increase in world utilization of this group of minerals, from 500,000 tons to 2300.000 tons (icr year in the last 30 years), at well us a greatly in creased number and variety of industrial appliesbona of asbestos (over 3,000 such uses now recorded). Second, suspicion has been growing that malignancy associated with asbestos exposure may include neoplasms otlier than carcinoma of the lung Thus, a significant* relationship has been claimed between diffuse mesotlwliomii of (he pleura and peritoneum and asbestos exposure.* This communication is concerned with investi gations undertaken to study tint loltowfog factors: (l) the inridenee of deetlis due to pulmonary car cinoma among a group of workers exposed to as bestos under United States industrial conditions in the past several decades. (2) whether or not such individuals would also be found to have an increased risk of other neoplasms, and (3) whether such risks would be present in an industry other than the asbestos-preducing or asbestos-products industries, with which most reports in tiie past have been concerned but which would not nec essarily represent the most important areas of asbrtof exposure at this time. Furtner, it w as hoped that study of aa Industry with asbestos exposure of limited extent and Intensity w-ould throw same light on the potential problem* aociaied with minimal exposure aabesroe. Materials and Methods Ottr Investigations have been concerned with 1322 members of the Asbestos Workers Union in tiie New York metropolitan ore*, members of New York Load 12 end Newark, N). Local 32 of the International Association of Heat and Frost insuLion and Asbestos Workers. As llw full title im plies,, these men arc itiutUitioa workers. Although tiie union is.cooaidmnl uno of tlw huiUUiy.tr.iiU-. unions, its members dt insulation work in a varietv uf iuduatriiw. iucludiitg sliipbuililinu. Called laagers' in Crcat Britain, tlicy are oftin doigluted 'pipe ewerera,* "insulators,' or '.ubetos workers'in this country. TJs* union is one of tlse oldcvt in t! cx<ntrv. OUP 0 9 3 5 6 9 / DU 037106 Vei 14S, N# 1 ASiESTOS t\ru>U.t->LUKoil' tl At 1 Ttm New York local, is ilk.- *5aijiit.imk-r Amii tiun of Rutter and Htpe Feltm." wa* the first umim Tabic I.-Ms-vma %( Ct*r ..y Asaraisc Wcf*#r Ciposce ! Aabasts* Oust 10 r#.< s Lanfcr at insulation wnrkm in I lie United State*. It amal y.sm gamated vAilfi other kicak ax tlie current Ad**tat Worker* Union in Wli. Tlie viability at tlii uniisi lias been reflected fa tlie stability o( it* memberxlup mil*. "Once a inprenverer. always a pipeem enn" has lieen of epah-miolegiral importance to nr and lias made this group of men partieuLirlv xmtable for tile studv of lone-term effects of bextoi inhalation. Unlike unikillcd workers exposed to asbestos inhalation in poorly paid industries, therr is little labor rumo\er among insulation 1041' 1047 It It ...... 40 44 4f . , ___ 110 am not to S4 . ........... . ioij St to ________ )(IA 40 44 41 *0 271.0 1100 70 74 ___ _ 7SO*0740_.._.._.________ It*__ ______ 11.0 111 t ft 11 ___ i.m.o tfit. iota mo *441 1*4 144 0 100.0 Ml 0 m.i nu 700 tt.i 1.0 2*47M 1001. 1007 19 t i nu 300 0 1140 |44 0 704 0 117 0 701 114 40 IJJ44 mol4i 114 700 1144 Mil ?Ut mo 200.0 107.1 rto m 121 tout workers. Accurate employment records are main- tamed by the union, which hat also been con Of these 632 mm. 239 had been exposed to as cerned with health problems in the industry. bestos dust prior to 19jif In other words, as of Jan The trade was badly hit during the depression: 1. 1943, 2H years or longer had elapsed since these some men had to drop out and very few were 339 men were first exposed. The remaining 293 added during the 1930's. By the end of 1942 the men reached the 20-years-since-first-expoture point union rolls consisted mainly of men with consid at some time after Jan 1, 1943, and before the end erable espehcnce. plus a few who joined in 1940. of 1962. The 33fi men who were first exposed prior 1941. and 1941 Between 1948 and 1962 union to 1924 were counted in each of the 20 years (or membership increased substantially. up to the time of death of those who died). The Source o/ Data.- From union records, a list was 293 who were first exposed in 1924 or later were piepared of every individual who was a member counted only' after they reached the 20-years-since- of either of the metropolitan locals on Dee 31. first-exposurc point (those who died being dropped 15*43, or who joined between that date and Dee 31. at the time of death). When the statistics were 1563. No one was omitted, whatever his subse completed, xve found that e had records covering quent work history. The 1942 list included 633 a total of 8,737.5 man-years of experience of men men. S90 men joined after 1943. with a history of 20 yean or longer since first > Personal data were obtained from union records, exposures asbestos dust. and the work history of each man was detailed, Of the 8,7373 man-years, 1912.0 were in the five- including withdrawal from emniovmens I war ser year period 1943-1947; 2.47S.O were in the oeriod vice, "other employment, retirement, illness). These IJ4S-1S32. 2.336J were in the period 1353-1957; data gave the baseline for calculation of the onset and 2.011.0 were in the period 1958-1962. Table 1 slid duration of exposure. For members w-lio had shows the age distribution of tho mtn-yesrs in tied, records of the Health and Welfare Fund pro each of these 6ve*year periods. Table 2 shows (1) vided date and place of death. Copies of death the average age-specific death rates of all US certificates were obtained on all but one of them. white males during each of these periods, and (2) Autopsy protocols, histological specimens, and hos the average age-specific death rates from cancer of pital records were obtained and rexiewed in those the lung, pleura, mediastinum, and trachea among deaths, approximately one half, in which the ter US white males during each period, as reported by minal illness had occurred in a liospital. the US National Officw of Vital Statistics. .Clatirticel Afiaft/tt*.--Previous studies have sug The mon-ycars were tlien multiplied by tiie cor gested that neoplasia associated with asbesiotis sel responding reported US death rates to ascertain dom occurs until 20 yean after first exposure to as the expected number of deaths under ihe null bestos dust. Therefore, * decided to limit the hypothesis that the death rates of asbestos workers present analysts ff"me* with such an exposure do net differ from death rates of all US white I history. Our comjfleSe records cover all members males (both age and date being taken into consid of the union {indudtnff active and retired mem eration). Tls* results art summarized in Table 3. i bers, both dud end alive) during the 20year Results period from Ja* 1, 1943. through Dee 31. 1961 However, with few esceptiom. the only men with a history of 30 years or longer tinea first exposure Tout Dcef/u.-During the first five yesrs (1943- 1947) only IS deaths occurred among the asbestos ^ -to asbestos were the 633 men on the union roils ee workers, wltenas 39.7 deaths would have occurred of Ja 1. 1943. (The exoeptions war* a few men had their age-specific death rales been the same yvho Joined the union after Jen 1, 1943, but whe had been employed previously as asbestos workers as fee all US whit* males during those yesrs (Ta ble 3). lo otlier words, at Use start of the study, fjsewherej Of these 632 mess, 255 died before Jen the asbestos workers had below txcragt death 1.1961 t rates. This is by no means surprising, indeed, such 0935698 DU 037107 u AjtfESTo* nxroscnc-scuKorr et al MVA. April 6. ISM .TaWa i-Tatai OcaCAs anti DcatAa fram Cinet' at ths lung B'0"chus. Ptur. Mae.ast.num, snd Trjchrj pf 10,000 Whito Moi*9 of Ytr* 194194l 4w **" ms 4*44----------- 7*<A4 1A li lwft C*48t MM I 4949 14 Id---------- ,"" 91 ;1J 9 4 If 19 ___ ___ 194 f IMt----------- m 7 (MV___ 7*74---------- . iii ' IS4 f)t " " TfrTf_____ ITT KB -. "Ttir~ - " 4 I IW *______ _ t.m i ttm________________ JfWJlW Ttl 14 49 71 " li 1*9 711 *\1 09 m 911 J.14* Lweec C8*<rt ... 1 1 10 11 u 18 7 rt ' H" 4} 77 129 17$ >79 419 990 179 IJU " 1.017 ... 1 1 to 14 i) 19 14 22 9 ItlfrlMl r4 >4 4| 70 224 171 177 4ii 407 a iili J4S Cent CjAort " "1 1 S 7 tt 17 ii n 17 ------------ n--------- It *0r.<f 't#| tt r*Mtt4 Aftvfflv fty IN Ut Kt*4*4l 0* * tUfltso A Uvm r'8' *( <* g,q *' fe * Average Hr li'il 1H: t * 1994*1940. >*(l 1HHHJ H * 7t #w*A#N U 1919 eNit*t N*. 19*144 1NH*4ItWM.ittifift, iifNNt. ave<w f k*t (M *#. 47frf vrr li almost always found In the first few years of protpective epidemiological study of this type. T7* es.pl ination is almost ccrtarnlv .is follows: Tlie 413 men to this analysis were actively employed as as bestos worker, in 1943. Sine* disability from illi.ess or other causes precludes employment in a trade of this type, these men were presumably well (or at least not disabled) at the ttart of tlie study perio<L Almost any group so selected as to exclude the ill end disabled has a lower death rate during the ensuing few years titan does tlie general popu lation. sine* ill and disabled persons have extreme ly High death rates. A selective etiect or tnis type gradually wears of with time and largely disap pears within five to tan yean from the time of inItiil selteeioa. Uuring the second five-year period (1WS-1932) the death rata of the asbestos workers was slight ly higher than the death rate of all US white males, ic, 54 observed deaths compared with 50.S ex pected deaths. In later periodt, the death rate of tho asbestos svorkers was proportionately higlier. For the period 1953-1957, there were S5 observed deedis compared with 56.8 expected deaths, and for the period 1953-1902, there were S3 observed deaths compared with only' 54.4 expected deaths. TsWa Obaetved anir Cxeected NgmOet et Oealite Among titt tfecatm weowre Csaeseti te AatMStea Oust 30 Yean ar laager -earners ewai TrW. as runs m7 u\Wm& Ittft 199ft41 \tfUtft5 IuU MSi l 944 1ft9ift au u 84 IIStO Sft4 Ml 49 rO 14 u Xi U 4 4 1 14 29 14 te S4 9 4 . aCam* er se esee.r..w. ten- ft ft 7 U Storm* urtorras rerun LItreaerre (VS eaee mereei ... . 0IrtmeM .. T 41 4 4 4 fTt.9 2SfUt Otorm uimm, renei Cancer of the Lung. Fleur*, and T'achce-la each of the four hve-year periods, far more deaths from cancer of the lung sad pleura occurred among the esbcstoa workers than would have oc curred had their death rates from these diseases been the same as for all US white males (Table 3k Altogether 45 of the 833 asbestos workers died of cancer of these rites, wliereas only 68 such dead* would be expected from general US experience. Of these 45 deaths, 43 were recorded ax due to bronchogenic carcinoma and 3 to neoplasms of tlie pleura. The pleural neoplasms w-ert ah recorded as mesotheliomas. Thus it waj found that the death rate from can cer of the bronchus and pleura -u 6$ times aa high among these asbestoa workers aa in the gen eral US white male population (both age and date being taken into consideration). It may be asked whether tlie high rate of lung canaer among these asbestos workers could pos sibly be attributed to an unusually large proportion of cigarette smokers among them. W cannot in- twer this question directly, since * have not yet -been able to ascertain the smoking habits of the men who died. However, the following pieces of evidence indicate that unusual smoking habits can not account for the high death rate from lung can cer among these w-orken: We have interviewed 320 of the 3n surviving members of the 1943 group. Table 4 gwes a sum-mary of tho smoking habits in this group compared with a sample of men drawn from the general population of 1,121 counties in 23 states.' Tho un ion sample is somewhat inadequate since it does not include tire men who died and does oat in-dude aH of the present living members of the uninn. Nevertheless, it shows that a s.ilntantial proportion of aelwtloa workers never smoked ctuarettes regularly. Certainly live 632 mm itr uur analv- tif of death rates were not all heavy cigarnu: smokers. la die general mat* iJutiuLrtiuu. Imig-t.iiHiT death rates are about ten times as hick among cigarette smokers aa among mmvmnkert; and tl? i g * 0935699 DU 037X08 T V4 l*.*, ,S* l 4 U1 UA ' SJ - TfcU 4.--Hgftitt 4 170 AM4IM t AtNtIM 0v*t 70 rtin , _______________________ C^mpurt Witti Stmin < <*n from in Grwri Population* *4 * * ** 4441 AtbtitM W*e4n. _ %IJ Us* " ' 1*1 (&il ' " 'Ml ....."fli" ' freweafi fi>idltw. % It* It* n jtJ >***!< '.C<,r. **' C [imn iihatw* Waiittq, % 4* 91 10 1 - ns Cooerg4 Aimmnm, * 7.S t# Hi ill mi-- fitheim WtrUft, % 141 It* 4* T u.r1 `tinun u MM III* ||HK MfUtltiM H Of l4 1 death rate from lung cancer increases greatly with the amount of cigarette smoking' However. a large proportion of all mrn in the United States liave a history nf regular cigarette smoking. From data in a prospective study on smoking.* it may be esti mated that if all men smoked a pack or more of cigarettes a day fie. if all the nonsmokers, cigar smokers, pipe smokers, and light cigarette tmolc- ' n had, instead, been heavy cigarette smokers) the ' lung-cancer death rate would be approximately 3.4 times as high as it is at this time. From this tve may conclude that even if all our asbestos workers had smoked a pack or more of cigarettes a day (and, indeed, from our sample we know they did not), and if exposure to asbtsto* were of no significance, then their lung cancer death rate would have been about 3.4 times as high as the rate in the general US male popula tion. Clearly, the smoking habits of the asbestos workers cannot account for the fact that their King- ^--------- Jtamok enaa MM< f 9 Wjojo ee e lljaa mi white males is the general population. 'kGaitteinitttinal Cancer.-Rather to our lurprite. die death rate from cancer of the stomach and the death rate from cancer of the colon and rectum wire higher among the aibeatoa worker* thaa would be expected from the rates reported for the US white male population, calculated in the seme way a.i for lung cancer. Twelve deaths from gastric ` cancer occurred among the asbestos workers, a* compared with only 4J expected. Seventeen deaths from cancer oi the colon and rectum occurred among the asbestos workan, as compared with U expected. Cancer of All Other liter.--The combined death rate from cancer al sites other than lung and pleura, and stomach, eoloe, and rectum was am Increased. Twenty-one suds deatla occurred among ubntos workers, as compared with SU expected ' Atbettoria.-Of the 25a deaths. U was* due to axbestosis (pulmonary insufficiency, ear palmm nale). The lapsed time from first asbestos exposure to death from asbaetoaJs avenged 4SJ years, with a range ef 33 to 39 years. ' Comment ' ' Carcinoma of tho Long.--'The results with regard `to carcinoma of the lung are clear. Industrial ex posure to asbestos by insulation workers, as stud ied here, results in a marled increase in the inci dence of cancer of the lung, approximately six to seven times the expected incidence. Altogether. 45 (17.6%) of 255 men with more than 20 years elapsed since the onset of exposure died of cancer nf the lung nr pleura. These data do not give the 'Incidence of cancer nf the lung In asbestosis." They relate to the spe cific conditions of our investigation: to a group of men with only intermittent exposure to matenals containing limited amounts (often 2% to 20%) of asbestos under working conditions varying from very dusty, as in extracting old Insulation in dosed quarters, to these with little dust exposure, as in building construction in open air. Moreover, they relate to the relatively recent past is a Bede with the shorter work week of tho strong building trades unions, in an era wlien industry ties been aware of potential asbestos hazard and tha working popu- tagitsMH fima t iimi mmig kWi>Mv4tj4Ml 0 m ywatam.w ai* risk associated with dust exposure. These data would not necessarily apply' to asbestos exposure in other industries, such as the factory production of asbestos products, the asbestos textile industry, etc. where conditions of employment might be quite different. Our results do not contradict the even higher incidence of hing cancer suggested m oilier studies *; they are merely a shade less sink-, ing. Difittt* tleural and Peritoneal Malignancy-- .Mesothelioma.--Determining tlte incideoce of dif fuse pleural mesothelioma is complicated by the insecurity of its histological verification. While some pathologists will so categorize s high propor tion of diffuse pleural tumors, in the experience ef others it is s very rare tumor sod may be mim icked by anaplastic peripheral carcinoma of the lung and diffuse fibrosarcoma of the pleura. It Is dilScuk to evaluate completely the published re ports of diffuse pleural mesotlielicma in asbestons in the absence of complete details of each case. To the present time, these has been no informstioa concerning the ineklcnea of diffuse pleural tnfsntlielioma in asbestosis, since the publislied cases are reported w-itiiout reference to a total pop ulation In which they occur. Nevertheless, the -j j 0935700 DU 037109 * ASIESTOS EXPOSURE-SEUKOFF CT At ;ama. asit a, taes {rawing number of report! of individual caul suggests that tltesa tumor* arr perhaps becoming relatively frequent complitatfuna of asbestos ex* pus urn. Oyr observations in thia series are similar!)' sug gestive In three of the 235 dcxtlix among the men whs had worked for 20 years or more, tlw exam* ining natho(ogirt considered the death due to dif* fu*r pleural mesntiiclimna. and in tlie two eases in which we Itave hern able to review tlte histological material the histological appearance wai that of* ten so categorized, and ashestos bodice were pres eat. Thi* incidence of more than 1% of dent ha from pleural mcsothclioms is strikingly high for a turner which is gencrtilU considered to be extreme ly rare. In one cate in our series pathological ex amination suggested diffuse peritoneal mesotheli* orra. Hus single experience is too fragmentary far evaluation. tZastrointestiiutl Careindma -Isolated instance* of gastrointestinal carcinoma in the presence of as* bestosis have been Inown. but there have been no data to indicate tltat these were more than coinci dental findings. Among the asbestos worker* studied here, cancer of the stomach, colon, and rectum waa three times as frequent as expected. These data suggest tltat there may perhaps be an etiotocieal relationshio between industrial asbestos exposure and carcinoma of the gastrointestinal tract. Environmental Asbestos Exposure.-Tha recent demonstration, by South African * tod British * In vestigator* of pleural and peritoneal neoplasms among individuals who had chance environmental . exposure to txbestos many years before raiics the very Important question of possible widespread carcinogenic air pollution. The possibility of en vironmental exposure has long been known. Soon sites the initial clarification of asbestesis as a clinic entity, Haddow ' demonstrated asbestos bodies in a man not employed in the industry but living next door lo an asbestos factory. This finding was later mirrored in tlte finding of chrome benilmm dis ease among residents of a community nr a berylhum factiiry." What is new, however, is an appre ciation of the potential estent of tlte problem. Thomson and associates " have reported the fre quent findings of asbestos bodies in the lungs of urban duellers. Among 6,322 individuals x-rayed in an area about an asbattos mine in Finland, Kiviluoto '* found -103 cas of pleural calcification of the type characteristically seen among asbestos workers, without obvious cause. In a comparxble area without any asbestos mine, no vases were found among 7.101 persons x-raied. It thou Id be noted that these were not people who worked in the mine-none dtd-btit, ratlier. "ere farmers, housewives, and others who lived in (lie general location. In one subject who came to autopsy, polariied-light microscopy demonstrated asbestos fibers in die lung. Similarly, the lung of a cow graz ing near the mine also showed the presence of asbestos. A particular variety of environmental exposure may be of even greater concent. Asbestos exposure in industry still not be limited to the particular craft that utilizes the materia). Tlie floating fibers do not respect job classifications. Tints, for ex ample. insulation workers undoubtedly share their expukute wiu* llmir hui'mimio iu wlm U.dee, intimate contact with asbestos is possible for electiieians. plumbers, sheet* metal w-oektr*. steamfit* tars, laborers, carpenters, boiler makers, and fore men; perhaps even the supervising architect should be ineludeo. I E 100th St. New York 1002S (Dr. Srtikaf). This midy wax lupportrd by the Health Rciearck C* ed af tha City af Nrw Verb. C--pefitmx in the invewigatie* src the bkiiii* *f. Seen af the intemationai Auaciebaa af Heat ane Frets (nsuletan end Aabaeiae IVarken. tVhln*i*a. DC and the oftccrt and membership of the New Teak and Vevaek. N'J. locals ef the Vaioe. > Reftrsi 1. Lynch. KAI. tad South. 'A: Fulmenary Asbestosia: Cucimaia af Lang la AehcstSiUrasft, Acr i Caier 21JA44 (Mari 1S3& 1 Annual Report af Chief tanadar af Factenea (or 7sar ISM. Loada* Her Msisstyi Statianery OCee. ISM. a p 3. Dal. IL: MaruUy Ftasa Uae Caiwar ia Asbmrea -tfCacUs. Ire / M<ar Wad ISJ1UML 19SS. 4. gjiltg, K. sad Jacob. Cu Neua Gesichtapaaiaa W daa LuaeaJusta dar AsbeswWfccr. Otuutk Wad tt'aahr SliMl-CM (Frh 173 lOS*. 9. Inma, DC. ami Town. T.D.: Epabwunlnttiml Study f Laag Cjacer ia A,sheaas Miners, AWA Attk tmhutr Mi ITiffUJril (Jaart IS\1 & Wants. IC; Hem. CA* ami Marchaad. P.: Dtfiua !X(uad Musahiliii-- sad .CdtrUm Eatnaisa ia North tVnirm Cspe Ptamaa. fir* I IxtluMt Wnf ITiItRLITl. I'M*. . I, 7. Ilaaaaaal. E-C. and Ctfliilrl L: SfluaUaa lUbes af iba sad tVasw i .Vac Camer f*r IJ;4I9-M3 (Aug) IUSI. g HunmanJ, E.C, and Hem. D.; Smalms and Death Rates: Report ea Forty-Teux Momht ef Fellow -up af 1ST.* 7(3 Men. I. Total Mortality; II. Deatk Rales by Cmsc. 7AWA 1S6i11M-I171 (Match I); lllf-iJCg iMemh IS) last. t. UcCwsher. W.T.t; Weda. O.U; snd One*. F.Ca Erasure to Asbestae Duet and Diffuse Pleural Mesoahetiw at. fire Wed l t:1397 (Nov If) lHI 1& Haddow. A.C. ia Report ef Annaal Meetm* of Irttah Medical AawvietM, Mandtealee. ISIS. Lances. SJ30-I31 (Aeg 31 IS*. II. dteinee, C. CIiimmc Pulnnurv Cwimhenatmw In Reudentl ef CommunMy Star leryfim* llinc; Thee* Aaattipeinl Caw*. Ants farm Mtxf IS.luLVtiMX (luur) lUVil. It. Theaawa, J.Ca Kusadwtc. H.O.C, end Moathneald. AJL: AOvnlnt cc Modem Urhaa Ibcaid, S A/r Wed I 3T77*ei (Jen ft; Iflta ., 11 Kivlnce, R.I rtmeal Cikitmlh* a R.x*ei-ni*uic stfa cf Non-Oeeupetianul Emtcnua; .VadlmphyBile-AaLca* tews. Arte fierffnf Suppl 194, pp 1-67, 19IRX % 0935701 DU 037110