Document xXNBVm63KyRozayJ6B046VjQ

deceived API? ~G 19.83 VC U-i'O'xA^y. h A Background PaperPrepared By: i i ! i j; j i The Canadian Centre :forOccupational'Health and Safety 006085 A REVIEW OF FOUR MAJOR REPORTS A Background Paper Prepared By: The Canadian Centre for Occupational Health and Safety for The Royal Commission on Matters of Health and Safety Arising from the Use of Asbestos in Ontario Thir background paper was commissioned by the Royal Commission on Asbestos, but the views expressed herein are those of the author and do not necessarily reflea the views of the members of the Commission or its naff. July 1981 006086 A tieview of FourMijor Reports^on Ue Health Hazards of Asbestos " " : ? k ' * i < j * ~ ' f: f * -a ... !" ' .'! (t r 'flie ROYAL COMMISSION on ASBESTOS in ONTARIO By tlic CANADIAN CENTRE lor OCCUPATIONAL HEALTH and SAFETY 1200 Main Street West He mil ton, Ontario July 1981 This background paper lias been prepared by me Canadian Cfenlre for Occupational Heal in and Safety for tne Royal Commission on Asbestos to survey anti summarize four studies of lle Iiealtn effects of asbestos fibre exposure. The paper does not report on llie Iteanngs on the iiealtn effects of asbestos held during the summer of 19tfl. The views expressed herein are those of the Canadian Centre for Occupational Health and Safely ana not necessarily those of llie Royal Commission or its staft. 006087 This b*etfroad ptptr h*a bo an pripactd by ti Canadian Contra .'for Oecupationa 1 iaa'-ltfa and dafaty for tba *oyal Coaaiaalcn on babastoa -% nmp and annnarisa fear atodiaa of tha haalth -nifniffc-o of Abto libra tspotvri. Tba papar .ton*M^fbo^baaxln-gn on tba botlth offacta of anbaatoo bald `daring aba anaaar t. c.\j; ...> ,V . ,% ii;y: Tba riavs axpraaaad fcarain ara thoaa of tba Canadian Cantra for Occupational Haalth and dainty and aot nacasaarily thoaa of tba ltoyal Coaniaalos or Ita ataff 006088 . , Table olContents . U n: introduction Contents s ,. . `"J- w . . " ' * -.-<* :h*: ;*ji3 >. * * .'T -<*!<_<* : -< *T' i'* ^r: r: :* T , " ' --'C i Section 1 Diseases Caused by Asbestos ?tv sag u V> ic uict srtt a 2 OccurrehceotrDisease s*y /?* >?x ^..JtsKisA *u* #'5og . - ";i ' v fisixoi ysr'J ni if?;!**; .*':*, 'c ^ `^1 3 ' T^tei^tyri^Difi^iit^y^oT^so<^ *> ^ *fg ?c; ; 5.v 'Sh*l^;iDMIte,?ItoseiB^ *--.* %4 Hi '$ it4& :;. :- . ^D-io^tem^o^S^^Ji^hbloidJiBtpSsure^ - *ie '#;&*#*? *# fteE-S ** 6, *.; .iutic. yti&oizy&i m ;&i - -**? ;;:j ' ;7-. iUsk5f^seas^lb^ri#^ '- -'? *'- -44 ;.ai tty* *#%%&&&. y*Cv:0*9; x, '*-*? 8 KiSK^offDrseasesforitiie^iailic J ' " ^ " iO jP'<Xgr}ri$^i; >t' `:c- -fV. 1:.!:' '.- 2J.~ , 9 Chronologyof{Knowledge r - -- 10 Response to the Reports :_r- Appendix A Appendix B Appendix C ~v`... t Extract from the Terms of Keference , Letter of Dr Devid JMuir Chronology of-Knowledge of Asoestos 006089 introduction 1 The Royal Commission on Asoestos invited the Canadian Centre tor Occupational Health and 6efety to undertake a review of four major studies of the health effects of asbestos. This was carried out in the formtrf answers 16 nine questions submitted by the Royal Commission. (1) What adverse health effects in humans are caused by exposure to asbestos? (2) What is the rate of occurrence of these health effects in those who work with asbestos and in the general public? ~ -w (3) Do the major types of asbestos differ in their toxicity? If so{ how? (41 Whet is the shape of4he dose -response relationship?* is it-linear, or some other shape? (5) Is there a sate threshold for exposure to asbestos? (By disease, oy type of asbestos?) If so, what is it? (6) How does the health risk relate to the age oTtheexposed person? How is it affected by othet factors such as smoking? (7) What is the magnitude of the bealth risk froraasbestos for- asoestos workers? (in general -- not in any particular plant, firm or industry.) (8j What is the magnitude of the haalth risk from asbestos for the general population (excluding asbestos workers end those who live in the immediate vicinity of asbestos mines or mills)? (91 What was the chronology of the understanding of health risks from asbestos exposure by the health researchers? The studies reviewed were: (1) Advisory Committee on Asbestos, Final Report, Report to the Health and Safety Commission, 1979, HmSO London.(referreo to as the HSC Report) (2) NIOSH-OSHA Asbestos Work Group, Workplace Exposure to Asbestos; Review and Recon, mendations April, 1984 U.S. Dept, of Health, Education and Welfare, tUi. Dept, of labor, (referred to as the NIOSH-OSHA Report)* (3) National Research Council of Canada, Associate Committee on Scientific CriUena for Environmental Quality, Effects ol Asbestos in the Canadian Environment by Stephen Shugar, 1*79, NKCC16452. {referred to as the NiiCC Report) (4) Report of a Working Group of Experts Prepareo for the Commission of the European Com mumties. Public Health Risks of the Exposure to Asbestos edited by Prof. JLi* Zielhuis, EUR5653e 1977, Perga mon Press, (referred (o as the CEC Report) * A later version of this Report was published in November 1680 as DHHS (NIOSH) Publication Nn.tHDa. Although there is no textual aitference between the versions, page references will difler. 006090 2 ..* ' S-; * > * I,5?* * 7 f. v* We observed that the Reports atfferea fromeech otherinpurpose^atyie, end layout. Therefore, tite conclusions were not always easy to brii^ together in one summary. We found thatJne NIOSH-pSHA ana.RSC Reports were recommendations for d&iiPMnifce& ^ R^ort aeemed Intended solely as a historicalresource to aid in thedcyelopmantof greatest ntimberol prepared which a reportWtiie-Gwiridfl European C*>mmunitjes)wouIdbeprepared. T^ lflC^H^firA- eitec scientific studies frOia 1974MM^ Report represent. eiiw#pW^oS^^r^Sy V NIOSH revisedrecommehitedifti^ '*2*-%* -y&Z&Z&.$ > f *;***?; i.1-5 &&&'*& *;*:i5lC- v.~ In spite of these review as objactive as possible, answered with cited . relative to Questfibiyi8.|| an outside expot*3iw^ ________ _____________________ _____ _ better help clarify thela^if^thel^^^^ Question 4 we felt that the Reports aid not address an important issue which we have therefore detailed. we founo that^forthepurposesofour review, theHSC Keportcarae closest to provioinganswersto all the questions of the Royil Commission on Asbestos. Canadian Centre for Occupational-Health and Safety (CCOHS) personnel wno contriouteo to the preparation of this survey or studies were: Dr Gordon Atherley, prestoent; Barry Spinner, project acientist/asbestos projeetmanagerj wend/King, research officer; Devio Cohen, staff writer/pressoffieet? Lynn Lanie andkita Steimneyer, word processors; and Dr Robert McPaddent project acientl^. 006091 Section it Diseases Gauged toy Asbestos Question 1 WHAT ADVRSE H^TH EFECTS IN HUMANS ARE .j There ere five'diseases which, jn thegeneriJ.j^reementpftbeReporU^ are essoclittc^.^^^y^^^j^^^jQfiilgis^ia^sod cancers of^he^iUhjf^J^^c. jfo<^gasfr^^e|tin^^ -* purposes of tl, ejamirie&uj. - detail and uj^dit00^T^ible 2.j; y*c .< ;; j,?* ;f. 'T, sn t aeiJiulz r,'t , Exposure to ----rr.-TT-.-r^ ~~prr^.^z-zzzr/*___ ..._______ ___ cases of canc^otfpfc4W recording to the'NkCC Repbrt, circumstantial evioence exists connecting asbestos exposure ana other cancers: primary leiornyosarcomaofthe. pj^nragp.j^noc^^ ofthe testis, ovarian cancer and u, - The TteJewiptionM** technical summariesahd m^caldescriptions olthe five a'wmt. CCOHS has%d^i^'^^^^^eii^pQf^^^^^ttj|ii^Jj^n(id|iBpl;.t sum maries ana;e^!m^^^|^'^.be comprehensible,toptrsons- F: without meoidaltirii&ift^ - - - ** . .,.<_? ' f> Seme of the manifestations of asoestos-relataa disease are characteristic. Examplesincludeasoestos.wartsana asbestoshodies. Other manifestalions of asbestostndated,;dUease,suclvasthexyraptoms of coughing and shortness of breath, arecommon feetures of respiratory disease generally and, therefore, their existence does not necessarily indicate asbestos exposure. Generally, the process of diagnosing asbestos-related disease depenos upon the physician's ability to relate various pieces ol' evidence. Often,.evidence characteristic-of asbestos exposure is hard tocome by,leavingconsiderable mom for uncertainty. Generally, the diagnosis of occupational disease, and not. just asbestos-related disease, is a matterbfpresumptionratherthan certainty; often, the diagnosis turnsjm the occupationaltastptygiven to the physician'In responsetb hisquestiociing of the patient. Ana many people have genuine difficulty in recalling all the pertinent details of a worKing lifetime, sometimes extending over forty or more years. 3 Section L- Diseases y Asbestos. , ? V., Question 1 HrHAT lriU .^fCnrAt-S\ s ThootMJ, ^ jn *?* 1*0 K! AJtE There are`Mg# ui n, oik Qt saVtvi9`' ^ re associated with.ex|surelo tK>estc;H* `"`------- --* cancers purposes of deteil and M^le|^^^-Jii)le^r s &b!ew CatUtapstmcO . n .* A-g-u^-ws'Hl'eti Exposure t0 *2blii 3i.&i sTiO^t SOiDllh$ 8|^ilplstes' connecting ttsbestosexposure-anaother-cancersiprimary ]domyosarcm^^h^i|bj^gi^Kt^^^^V|Po^th<ftesti^' ovarian - cancer end ciflrtr^We^^oi^e^i^j .iikcSi ,, <Wi* ,, .- The descriplioniT^TVciVPcbhhC^r&m^tfoijieponu. f.ine.descripVtons-are 4 technical VJ / CCOHShar%a^K|&rStt^^^gggso|aj^,^^|a/crt;,s .;, su.m. ma^ries n.t.oddnenK-n?pCr>ibnHs^.faiJyJfarSdaf5,*t!>ruej,--JC.pms. without meo5iuSaartltrroaainrpinsg^.mi ;u. ,_k. j o<. -- tw^s/ *u >-*<*3j n*<3? - " ,, "... ^SfUiSv rsot*?f.- * ,> Some of the manifestations orasoestos^elateo disease are < characteristic. Other mamfestatlonSTp^iu^tos.^^te^we^eiSuches^he^ymptoms of coughing and shortness oforeatlf, are&dmmon features;.oftiesplratory disease generally and, therefore, their existence: does not necessarily indicate asbestos exposure. Generally, the process of diagnosing asbestos-related disease depends upon the physician^ ability to relate various pieces ol evidence. .pften^wdencejCharacteristicTOf asbestos exposure is hard to; oorhe^by^Mjgng^MjisWewible popm foruncertainty. Generally, the diagnasis^pj occu^ti<^l^$^^ ; asbestos-related diMue, isl|^.i^ter^- j^^^pUon.Wthri|hsn certainty; often? the^d.ii^iwjt'urns^q ,tijjcupa&on^ to the physician'fn wsjSons^to ifts^u^tionuj^^ many . people have genuine difficulty tn recalling 411 the pertinent details of a woricing lifetime, sometimes extenaing over forty or more years. 006093 The following detailed list ot mairifestationtsanc sympttfms Is fodnojn the NtfCC Report. Most are respiratory system sympurintfand t % abiK>rmaliii %hich typically ip&etr in victims of &bestt^^Mha^iyi haa long-terjn^kxposure to theShmi ~ --ftbrbsjs 3f the lung tissue , > , - t*ie^)*|sence of ,asoesU>etpdfos,* in iw % T O* 'V Ct iC* >' 2 g.. - -%asSe*ehinge restrict^^i^| lung * T S' I I 5 sr ? 5 '4 fdetrimo^tal changes imlung^ function, CspecUfly,.:yfUl Cagaei^iVC) ?= -restrictpn oflung expansion ? " " ` fii .;&T ~as W*. *, ? c~ s 7.?.. -T =ft ^ ..~*fte presence ofpleuraBple^U&*** "^feural]efusIons r *"S * -^dysfMiei,.^shortness ofet*ihfc >-3o& lOfSteight -*<^uftgg | | ~g Elf = | =,, -cyanosis {low oxygerQeonfie/jt fblood) w > " ?* i* JS -crepii*U6ns ' -at the.base of theia^ Si^eiSteo byaasdidfaticHT) vas** a #*#* j; rj iiOs-ii - asdesioS wafts ^on thechinos. Generally speaking, scientific iiterature^assumes that readers are familiar witn the relevant medical anoscientific terminology. 3o some extent, the Reports make this assumption,-althoufch the HSC Report does attempt to explain some of the medical and technical-terminology. In the opinion of OCOHS, however, the axpUnations.are ihaoeguate in that they fail to conveyadequately what afoestos-relatea-diseases really are in terms of their effects on human beings. Much of the substance of the Keports will be difficult going for persons without the necessary specialist training, we feel. Asbestos bodies are s1hall:(X>^25;imicrometrel partit_____ t correctly called femaginote-bodies. In and of themselves they do not indicate disiiisei:but?nther exposure to asbestos. Pleural plaques are soft or collagenous tissues which form on the pleura (the membrane lining the walls of the thoracic cavity). Theplaques have been described as being porcelain-like, whitish in colour, and opaque, in contrast to the healthy pleura wnich is pink, transparent and thin. Cancer o f the C astro-intestinal Tract No descriptions given. oz P cn. s (V 8n S' o3' VI OS <a 3 3 c * 2s i*E y a l51 Isa2*!?? SjrSli|3 -5 a ZwfsgtfcCa.-^ 4M^44H?*9*' "|S2,S| * ?1is- s s s ag 'i 3 _ Cl cr * ri S-* 2jf2*a2^ G astro-inteslinal tra c t cancer includes m alignant tum ours ol the stom ach, colon, rectum and the esophagus. IIIIf!|ps;#i *ff *2iS!8 #* M* S'>&##' |$ "I hmhHw lo3*T<|ici!fli: 4 rSl'S- <* 3 t5 io is lr. i* 3* 2--o "l`S?g tg-i TJ * |3 sali^s a. ifiliafsgsSaE- f|B i5s 32.32 *ae a 21 -. S"fFfit-SJaft':Si.-9-?"2rs38 fl"85a 2S-c= I58 ft is *3?nJ3 2j' fo S' :3 B S s 33 cr r. oo 006095 COMMENT BYTCCUtib ON DlSEAbE^CXlMDBY . . -~, -s i : z-. r'.,! V I! Iil1. " The Terms "Asbestos-Related" ano "Asbcstos-lnducad" By 'Wsbestos-related" diseases we mean those which, it is generally greed, are at least partially caused by exposures to asbestos. By "asbestos-*nduced" diseases we mean those which it is generally agreed have asbestos as a predominant cause. We can therefore arrange the diseases as follows: Asbestos-hduceo Disease Asbestos-Kelsteo Disease asbestosis mesothelioma cancer of the lung cancer oElaiynx cancer of the gastro- intestinal(62) tract This distinction, we think, is useful because it points up the fact that mesothelioma ano asbestosis are both typical occupational diseases. otn result from work with asbestos (in the case ol mesothelioma contact with an asbestos worker or proximity to an asoestos fabrication facility can also cause the disease). The Inadequacy of Medical Descriptions of Mesothelioma human pain ano sullerir^ represent factors not always given their due in official reports. Asbestosis is a debilitating disease; mesothelioma is a devastating one. Mesothelioma usually attacks suodeniy, and then over a relatively short period (weeks or months) invades the body as a weed invades a garden. Typically, death occurs within a matter of months after the first diagnosis. This cancer of the chest or abdominal linings causes painful accumulations ol fluid, making the stomach (il the malignancy is located there) rock hard. There are prolonged constipations, swelling of the feet and ankles, great weight loss ano, perhaps most disheartening of all, dramatic and suooen changes in appearance. There is no cure for mesothelioma. Nor for asbestosis. Mesothelioma is spoken about at length in each of the four Reports but without, as inaicatea above, an adequate impression of its seriousness. We assume that physicians, at least, are familiar with mesothelioma and Its effects on the victim and the victim^ family. Nut it is a rare disease, and few physicians will evar have actually encountered a ease, let alone been involved sufficiently to appreciate all its implications. 7 For this reason, CCOHS intends to publish a transcript of a conversation with an individual afflicted with mesothelioma, fie woraeo in asoestes insulation manufacturing in Ontario ano recently oiedaso consequence of this asbestos-inaueec disease. tVe think that this description will convey e filler picture of the natural hittoiy, symptoms, oourse, an<j prognosis of mesothelioma than f^/P|^>he. <i<^riptims in^^RePOrtSi notwithstanding atteT^t4tS<s6ei^yltirf,lhe meSicB'terminoiO^. S&tZ&ZiA* ,'!' et'izA rv.> &' ?s .rioal* ,s vi , Jjreraj ii ?! .5/* norm swr aafe "'be i sun,c> c-53i;s' vU.imJ'l:-** fsasi - -n* ..b^rr*,* .USiT i* 2&3S223 "bSC.i.OC.f a'.:iSCCj-r !.'V v v: <5 :>r . `AU&S ;. arj-r.OOjr:'" O ZCitK-U. i**:*' U#v!iC' -.'-I* :_Dr'JS3i!.v ;>* * ~: o y no '".`itth -V; ie BO 006097 Section 2: Occurrence oT'Disease Question 2 WHAT IS THE RATE OF OCCURRENCE OF THESE HEALTH EFFECTS IN THOSE WHO WORK WITH ASBESTOS AND IN THE GENERAL PUBLIC? The diseases of major concern associated with asoestw; w^u^frj^MN^tosis, lung cancer, mesothelioma, cancer of the larynx, an^an^tfftestlhal cancers. Table 2 describes a categoncationf fodr^yjpes;^ Ikj^ures to asoestos useo in tne CEC Report. CCOHS'uses this catege^wthSilfif^Xafemix C. r>.^; 4*:C ** r;VU5 . *. - V- For groups with occupational exposures fame the various diseases which cause deathjy^eiHSGRep^fllvIifj^^lw^ experience of various industrial populations which workedwi th asbeJto^'&wiilaLorSjf. shipyard workers, asbestos miners, asbestos production workers, efc^'` "...the excess mortality:found in these studierls acTOunt^a^for.inioroefof importance by lung cancer (associated or not usocuLuo. with^asbestosis), asbestosis, mesothelioma, and gastrointestinal cancer." (HSC. page ,48) The oeta on cancer of the larynx indicate that the risk is much smaller-then Tor the other diseases listed. Tables 4 through 8 indicate the comments on this topic bylhekeporU. In the subsections below each of the four diseases implicated in excess mortality (incioence rate of mortality aoove that expected for tne studiec inoustrial populations) is detailed. Asbestos is The Reports generally indicate that asbest nsis has been rarely found in tne general population and is not considered a public health risk. Asbestosis is found only in groups of individuals with long-term exposure to asbestos dust. Specifically, occupational and para-occupational exposures have caused asbestosis. The rates ol incidence and prevalence are defined as follows: Incidence rate is the proportion of persons developing a disease in a given population over a given unit of time, such as the rate of new cases of asbestosis occurring in a factory in a year. Prevalence rate is the proportion of persons with a disease in a given population at a given time. 006093 >9 2*hjfM Ifrpespf Exposure toAabaitca (adapted from the CEO R'eggpjRo^rgt)y-i to wno^ggsgjk.J"-- tSJSJs ID STAS ih'T & fAH* vi D*. H?`U .<>* Ub 3CC/H? HterJ3***3 ja^hso 3h: > ??' .>> aSAPis**^ .!* n* Jabots* iv.frsdoa %a&m :o is^st.a *';; : iar*^d> to '.vA;fa tumosisi teanspbwlt^^g" ,D feuli asi^w.uO W -eW:Oin<6i*#^ v,j ig^ciieqi.* stf#>? too,**: * itJaiw (W. - indtreet^ffeujjtrPy)'Sr-^t-w;? a* j(c):. ^ (a/ domestic '" r *** ^-' 5"-r General^environmehtkl exposure laj water (to) beverages (c) food and drugs (d) air -....-. 006099 10 Various studies oi industrial groups hav examined the percentage oi all aeatns in those groups caused by asbestosis ana other causes ofdeath.. There are problems in comparing the various studies,ana. volume 2 of tne 'HSC Report elaborates these proolems. The HSC Report summarizes the data oi various atuGies for a number .ofbiseases causing death inratable *eproducco>hcre as Table 3 (Table 13,-HSC, Volume ^ page 501. The variousatuoies examined are listed separately. The table shows that asbestosis ctusea, between h Wand-U4R ofrill dealns among workers exposed to asbestos in:,those studie& if^oaicuitteo as s percentage of excess mortality, the values would be.even higher. in its review of,hedatathe NRCGSeportdescribes the range,of-mortality due to asbestosis-as i,03fc~to 10.8% and states that -the fates are probably The incidence rate resbestosisMdifficuitto ascerjtain,tsince the clinical and other signs on whichdiagnpsisisabasediare.nonr^>ec4ficjand subject40 wide variations ininterpreiatiqn. As^wellrcon)parativeiy.little-isRnownr apout the progress! on of the disease.(HSC.,page^M). A .study wasdone of ^ .Bri tish textiie feelory-in-Rochdale where mostly ehiysetile was used.;(Annals of Occ_up^Hygiene,,page?47rllf18681. Thisstuay, upon wnich the i^itish .pccupati{mal.iiygic^<>pciejty;based tnelVogstanciara, used three conditions to measure mofonhty:4a) cectifie<j asoestcsis, (D) possible asbestosis, ano (c) crepitations. Ihe inmdenceHrates observed lor (b) and <c) are higher4han Tor certified-asbestosis. An incidence rata for certified asbestosis of is5* occurs at the level of exposure supposediy equivalent to a lifetime's exposure at 2 fibres/mL.* An update oi this study was done ano later publisned (Berry et al, Br. J. lno. hjeoicine, page 98, 36, lv/9). it concludes that the.incidence rata for certified asbestosis of a3%per year occurred in persons with a cumulative oose of less than XD fiore-years per cc. This is said to correspond to a level of exposure of 2 fibres per cc for a liietime'saxposura sot 50 years.* Usingtne category of possible asbestosis', a detectaole rate oTincidence occurs.-at exposures less than 50 fibre-years per cc. Ano if tne development of crepitations is considered, the average incidence is L2* per year for cumulative exposures of less than 30 fibre-years per cc. According to the HSC Report the only study giving a relatively unbiased assessment of the rate of impairment of lung function (asbestosis) is the updated British study referred to above. * fibres/cc or fibres/m L or f/mL is a measure of airborne concentration, number of asbestos fibres in one millilitre of air. A fibre is defined as being longer than 3 micrometres and with a length to diameter ratio greater than three. 006100 11 Lung Cancer Unlikethetlata onasbestosis from the various stuoiescompaped in Table 3, the information on lung cancer as e eeuse ofdeathis less Clear. Asbestosisisbelifevedto occiironly^inthose exposed toesoestos-dutt, lung eanceH&CcurSinill populations tien^ U>ei>brtlDn-of observed'lung cancer deaths due to asbestos dust alone cannot be accurately measured. * Further, the synerajistic interaction of tobacco smoke and asbestos complicates any analysis bf~the-lfting cahcerdeathsv (See^Sectiort or<a`diictssfbhthe "-'r -9ksx* y'c* e " " '' v '** ' ^. . * ' ,* ^ tT^ i"_ . lr- *' "- ' i - j /*.r T1- ** t< * .J ` " -v'^ The usual approach to dealing with such difficulties is to calculate the mortaiity +itioi T,fti4Ws>beeh`d6he f6r5the>yata^^ble^i;v1^4iumDer of observed (tcttisU 'O': the number of expected deaths in some ^ioup^oj^^abieito tft^tndustruil group due to the same cause is laoellea '*. The ratio Oft is the mortality ratio. For^xampieTor lurig^r^^^deatle^insstUdy5! of T'bie:3,:0--equals 38 - and t equ^^2iiknd*the rn'ortalfty^ratk) <//^expre'ssea aserie&tive risk, is 2.7. This4ndicMtes that'lfihg^danctiriS'a mdre^ikely^cause of<batA*fbr this group than for some comparable5gr^p ^expiOSe'o tdesbestosbust'. for Lhe-various^tudies^ fttWpretatlt^ df SUCh^mparisons isextremely <hfficult -f(^iat^e*5t rfW'oins: the dhdice'OfHiihrch deaffe-id ih&Ude in tne number 'ofoeafhi|;ana ^ife^bisis^Tcarfiulatii^the:xpMtecF'nunitaS^of deaths bf^ome-ckimi^iSli^^#1^TI*e^i^ tififioh^s^emonit^t^^directly in Taole 3-where, frr"study S,^tancefsWthe'larynx ere included "for both observed and expected-numbers bl'deeths. ` Mesothelioma The Reports generally agree that mesothelioma is extremely Tare in the general population in the absence of exposure to asoestos dust. i ** . . < . ^ Even-though the disease is extremely rare, mesothelioma has; been ooservea where neighbourhood exposure-occurs. 'The incidence rate is in the^range i to 5.8 per miliion per year. The HSC Report ranks mesothelioma thiro as the cause of excess mortality in industrial populations. Taole 3 shows tne t mesothelioma causes oetween 0 end 7J% of all deaths among tne workers exposed to asbestos in the various studies summarized. Gastro-lntestinal Cancers The Reports make no comments about the occurrence of gastro-intestinel tract cancers in the general population; insteaa they focus on the association of gastro-intestinal cancers and exposure ol workers to asbestos. The Reports generally agree that an increased incidence of death due to gastro-intestinal cancers occurs in industrial groups exposed to Lsoestos. They note that there is no general scientific agreement on the degree of association of asoestos exposure and gastro-intestinal cancers. Table 3 shows the mortality ratio is in a range as to 3.2. 00G101 1 Section i: Toxicity of -Dlfferart Types of Asbestos IV Question 3 DO THE MAJOR TYPES OF ASbESTOS DIFFER IN THEIR TOXICITY? IF SO, HOW? This topic is controversial, in understanding the contradictory evidence, it is necessary to understand that there are at least four'different commercially important fibre types: chrysotile (whiteaSbestos) and the amphiboles, amosite (brown asbestos), crocidolite (blue csbeiios), and anthophyllite (an asbestos not of commercial concernJvfthin^Canada). Applications often involve mixtures of different fibres. ^UsO/these flores are producedin different fibre sizes and geometries^depending on the proouction process. Hence, differences in toxicity niay occur cue to fibre type, size or geometry. Ordinary air monitoringdoesnot differentiate among these features. The contradictions arise from evidence collected from different sources, either animal experiments or human epidemiological studies. '-Human experience supports:the argument-tnat there:are differences in toxicity. Animal experiments snow the inhalation ot samples of chrysotile produces at least as many malignant iungtumours ana mesotheliomas as the amphiboles,' Apparently this evidence is not applicable to the human situation.- The extremes of-the controversy are clearly demonstrated oy tne following quotations from the HbC ano MOSH-USHA Reports. (1> "As far as mesothelioma is concerned, eviaence from miners; from process workers exposed to a single fibre type; from the aistrioution of neighbourhood ano Domestic cases; and from the geography of mesothelioma, when combined, presents a powerlul case from four different sources that crocidolite has been more dangerous than chrysotile and anthophyllite. The position ol amosite may be intermediate between crocidolite and chrysotile. There is no doubt that crocidolite was used at Rocndale, but the significance of this as a cause of the mesothelioma cases there is not certain. It can be concluded that exposure to chrysotile alone has rarely been shown to cause mesothelioma."(HSC, paragrapn 80, page S3) (2) "...presently available evidence is insufficient to determine the role of specific fibre types (regarding cancer excesses). On the basis of available information,... concluded that there is no acsentific basis for differentiating between asbestos fibre types for regulatory purposes."(N10SH-QSHA. page 3) Tables 6 through 11 indicate the breadth of comment on this topic by the Reports. 006102 Given the contradictory evidence and opposing positions taken Oy the Reports, CCOHS asked Dr David Muir of Metoaster University to provide an opinion on this topic. His letter is attached as Appendix B. The analysis by Dr Muir dearly shows how it impossible for animal experiments demonstrating no basic differences in toxicity to be reconciled with the epidemiologic data. Quite rigntly the focus.for analysis should remain oh the hazard to humanspihaling asbestos fibres and information about controlled toxicity experiments should be viewed in light of their relevance to the hazards of humans. He states that it is necessary to distinguish dearly between differential risKs associated with the use of various types of-fibre in contrast with the risks according to-the measureoairborne concentrations. Slating that he believes animal experiments are of remarkably little help in sorting out the confusing situation, he analysesthe pertinent literature and the reports to determine whether they had a dear understanding of the difficulties in: making the comparison* between liore types and whether they have drawn sensible final conclusions. His conclusion is *1 have little ooubt that exposure to crocidoiiteis associated with an increased risk of mesothelioma." 006104 B 3 So CD Table i> D ifferences In T oxicity 90 O 5| si ! 2 i*2 ST & ,-Mr. *<*! 91 3 S 90 xm 1H S K nX *vo T g 7 3 > soA 8 3 M S *s S o o < s 2H $ 5 2 > o pj CEC Working Group o f Experts: Public H ealth Risks o f Exposure to Asbestos pg. 65 -Asbestosis may develop from exposure to a ll four im portant types o f asbestos, regardless of the tiirpensicns Of the inhaled fiores; tiie longer <xies> hpw evpr, seerp to be m ore pathogenic. 006105 Table Ml D iffe re n ce s In T o x ic ity - LUHG C A N C E R x m 3 m X re H o < a z o z 1 9<*Q> N 3 zz CEC W orking Group o f Experts: Public H ealth Risks of Exposure to Asbestos pe. 65 -The incidence o f bronchial (lung) cancer...does not depend upon the type o f asbestos, but m ainly on the dose level, cz 006106 Section 4- Shape of the Doae^Rcaponse Relation 24 Question 4 WHAT IS THE SHAPE TOF THE DQSE-HESPOHSE RELATION? IS IT 1JNEAR OR-rS0ME OTHER SHAPE? . Preamble - Questions 4 and $ relate' to eAeh other yejry ^ieiy?pecause they are both exploring -the same from slightly different points of vew;^ba^ ^'t|o^^^^iJ^elpp.` much in commonVftls usefurtotjegin the technical terms used in the two questibris. The follo^ir^ Mimitions are presented with acknowledgement to the Uxforo English .Dictionary. The technical terms are: threshold safe threshold dose . respohse.,''' doseTespNonseireiatlor J ' linear relation "" " `dtr^rifilipls;" ' Threshold'limit Value There is an important possibility lor c^usiori' when usuig a technical term with a name which may be familiar to reiders and which contain the word "threshold". That term is "ThresholdJUmit Value" ULV), which is a registeredtrademark of tJ^ American i^nferehce ^Governmental lnoustrial Hygienists. In some respectsTrh^ is relevant to the matters addressed by questions"4lirid 5, ano this is why confusion might arise. A definition of Threshold Limit Value" has oeen given so as to avoid all possibility of confusion between Safe threshold" and Threshold Limit Value". Threshola The everyday meaning is the test guide: the entrance to a house or building. In science, the term was first usee by psychologists to describe what appeareo to be boundaries in human sensation.' For example: {a) "there is e certain limit below which our .~ sensibilities are unable to discriminate. This boundary... (is)... the "threshold", (b) we do not distinguish ... separately ... presentations of less than a certain assignable intensity. On attaining this intensity presentations are said to pass over the threshola of consciousness ... A threshold for exposure to asbestos would be a boundary or limit which marks a clear separation between two different states of asbestos-related disease -- see safe threshold, below. Safe Threshold A threshold of asbestos exposure which separates the absence of ASbAstbs-related disease from -the presence of ^ asoestos-related disease. If a safe threshold existed it would imply .that some degree of exposure to asbestos could be eridured without , the development ol any disease.. If no safe threshold e^t^.itKeni wjoifld have tcTassuine any ^ degree of small, woula c^ citable of producing some disease in some jperiphs., V- , Dose A definite quantity Or amount (of Asbestos! regarded as analogous in some respects to a medical prescription or tomecucine in use or effect. Kesponse Scientific use differs wholly from the everyday use; relative to asbestos, response means that.prppq^ibn of a population exposeo to asbestos which expediencesj specific disease following exposure of tne total population to albestiwjexposure oi a specifiea degree. (This definition was derived from tnat for ''oose-response relationships" arrived at by the'iAskGroup on Metal Accumulation (1973), cited by G. F. Nordoerg.(ed.) "Effects and Dose-response Relationships bf Toxic iMetaJs^ Bsevien OSTfi) Amsterdam.) Dose-Response Relation The correlation, .normally expressed ts a graph, between the percentage bf the. population Affected by the disease in question and the oose.of asbestos. Linear Dose-Response Relation Where the graph relating dose And response is a straight line, necessarily beginning at zero (see figure lb). Other shapes for dose-response relation The graph relating dose to response may be S-shapeo (see figure la), but at least in theory the graph could possess any conceivable shape. Threshold Limit Value Refers to airborne concentrations of substances and represent conditions under which it is believed that nearly all workers may be repeatedly exposed day after oay without adverse effect, because of wide variations in individual auseptibility, however, a small percentage of worxsrs may experience discomfort from substances at concentrations at or below the threshold limit; a smaller percentage may be affected more seriously oy aggravation ol a pre-existing condition or by development of an occupational illness. RESPONSE RESPONSE Figure 1b: S-shaped Relation 006109 47 As pne vipuslyj irdemWk^lor^i^Ho*tlie^merreSf) X6r7erenee of'Goyernmentci Industrial Hygienists, and the definiJioiLjast quoteaU ta*eq froin $eir, booklet Threshold limit Values3f0riGhemicl.Subst*nces and Physical Agents in the Workroom Environment with Intended Changes for 1880'' (Cincinnati: 1880). An additional potential'source of confusion lies in the connection between safe thresholds an&.Tnreshola Limit Values.and Other forms of exposure limit. According tosome authorities.oose-mponse relations should he used in order to deterniiae: that threshold which is to Oe used as the threshold limit value or other Oj^ppsure limit. Accordingly, Question 5 could be interpreted as applying to exposure irmits sucn as Threshold Limit Values and their equiyalentson use in Ontario. We know from the Royal Commission that this particular.interpretation is not intended. Dose-response relations are used for the purposes of risk assessments; for within our terms of reference Questions 7 ano 8 specifacally-refer to matters of risk. There follows a lengthy analysjs^ of-the-Reports-- relating td lhe Sfiape'of iheoose-mesponsp relations. The analysis consists of extracts from the 'Kepom4iW c The gist is that for practical purposes such as-risk assessment the Reports juage tnat the dose-response rtlationsF$<gi$Hii^^ Question 4, once the <k>se4e^iise'^atibns are:oesignated linear with ~ origins at zero, there comes automatically an answer to Question & oy definition, with such linear dose-response relations there can be no thresholds, safe or otherwise. - The analysis is quite Detailed because we have detecteo a fundamental question to which we would like to draw attention; that question is presenteo in the comments oy CCOHS which follow the analysis. 00S110 The N1QSH-OSHA Report 28 The following are extracts from the NIOSH-OSHA kep^rt.ihdicativeol the approach tt> the ^estion 6f the lirtearity or dther dose-response relation. It <^''be'feen\t^.t)^t gt tome uncertainty about thie knapeM|hie. tenor of the Reporti*.aiTaceeptahee^ ,, ri dose-response relation, with ;>o doubt expressed aoout the im{rlance oi dose-response relation relative to decision-making ojijksbestos. . ' Extract 1 . "Evidence availaole to date indicates that a large jdose of asbestos will produce a^igger health hazArd thanf_irsmi$l] dOse. -^i.tfman ist aL U9?), using the lerigth of time worked in tkam^ite asbestos factory as a measurexf the obsige^of'asdeltoSVjre^rjtikiM increased risK ol dyingfromiung cancer withincreSsiog duration of employment. Henoerson ano Lnterline U878), using cumulative dust exposure as an estimate ol dose, reported that the dose-response relationship for lung cancer is more likely linear. They preoicteo the relationship to be biwR= XX) + &6$8 times cumulative dust exposure (mppef-yrs). Lidoei: et al. (1977) also reported a similar relationship, Le., a tendency for the mortality for lung cancer to increase With the dose." (p. 51) Extract 2 "Newhouse and Berry (1973) suggested that the risk of dying from mesothelioma increases with increasing dose. Jones et ali (1879) reported a linear relationship between mesothelioma rate ana length of exposure. In a study of the women workers in a wartime gas mask factory, they found women having a long employment period had a higher proportion of death oue to mesothelioma than those who had a short perioo of employment." (p. 52) 00S111 29 Extract 3 "Although there appears to be little dispute that a larger dose of asbestos will pose a greater nealth risk, the exact nature of the dose-response relationships may oe subject to consiceraole oeoate. This is so primarily because of problems of exposure estimation. Methods of measuring dust have changed over time *itnj*spect to sampling tnstnjmehtfthermal precipitation,"vs. mid^etimpinger vs. membrane filter); location of sampling {personnal vs. areaj, 4ust counting (particles vs. actual'fiDres) and^ eviduatioh j^hju^ues (whole fields vs. 'ey^'ecegiirtimtle).,' oust levels obtained bymcthod^toleyels^^ method is far frdin'fmj^iya3id'')9:fupjbdVio* fto^si<l^|i?|j ' ' Another factor which may lead to dTffererices of opinion on the exact shape of the oose-response curve is the measure of the dose. The commonly used measures of exposure are the cumulative dose and the duration of employment. Since using cumulative dose as a measure of exposure gives equal weight to the concentrations of dust expen encea in each,year. of ;exposure, exposure of many years ago is considered as important4srecent eiqiosure. This practice is unrealistic for the elfopic diswises having/a long-lattncy ^riod. Duration of employment has: alsjb been used as a measure-of exposure under the assumption that increasing the wort time approximates increiasihg the dose. This proceaure nas the same problem as using the cumulative oose. Furthermore, in the absence oi reliaole pest exposure .data, the .duration of employment may not equal the total dose of asoestos." (p.5 2-5 3) Extract 4 "*sith regard to the linear hypothesis, tne britisn Aoviaory Committee on Asbestos, in 1979, stated as follows: Our reasons lor preferring a linear hypotnesis are: (11 It fits the data for occupational exposures, (21 it is the simplest hypothesis and the one most readily useo for extrapolation to the probable effects of low doses; (3) it is likely to leao loan overestimate rather than underestimate of risks at very low ooses. (HSC, Vol. 2, p. 14). Data available to oate provide no evidence for the existence of a threshold level. Virtually all levels of asbestos exposure studieo to date demonstrated an excess of asbestos-related disease." (K1USH-OSHA. p. 53) I 008112 The HSU Report The following extract from the HSC Report (VoL 2) covers oose-response relation in rather more.general terms than >the N1QSH-OSHA Report. The clear assumption is that dose-response relation ls:a reality hot yet fully unoerstood hut the linear form is to oe preferred, f^r the reasons given in the quotation embodied in the NJOSH-ObHA Report. "169 This section, discusses the quantitative evidence aftbbt the relationship between the doseofasbestos inhaled*by'tnemhers of a populat ion ano -the frequency of three-principal biologicai responses - ashestosis, Tung cancer and mesothelioma. No^dati `have1 t^en founa whichpermitianyrquentitative-comment toW-made about the relationship between dose and response for cancer bf thelarynx. That relateo to caneer of the alimentary -tract^is limited to two studi es. The importance of=t5t&>lisftrngjj ifpc36sible,;the nature of the relationship -between doseandbidlogical response is that it may assist in framingpolicyaboutan acceptable level dt exposure. For example if it coula be-aho'wn-that-a leveTof^expdsure exists below which no risk of sickness or death is incurred (a so-calleo threshold) at least such a level would.beiikelytobeaceeptablefromthe medical point of view." (p, 34) "170 Some of the possible relationships between dose and response in connection with the effects of asbestos..^are (a)' a threshold relationship whereby below a certain limiting Value of the oose there is no associates excess sickness or mortality; (b) a (rectilinear relationship whereby the response increases proportionstely-to the dose; (c) a quadratic relationship Whereby the response increases proportionally to the square of the dose; (o) a sublinear relationship where the response increases.proportionally to a power of the oose, the power being less than unity; (e) a cumulative normal relationship whereoy the response increases as if the distrioution of susceptibility levels to asbestos was normally distriouted..." (p. i4) COMMENT faY CCuHS ON SCIENTIFIC NATURE OF THE DOSE-RESPONSE RELATION In our opinion, there are no scientific data in the Reports, or in any tudies rebed upon by them, from wnich any firm conclusions can be drawn about the shape of the dose-response relation. Indeed, the scientific data are so vague that we must ask whether scientific understanding of the dose-response relation is a practical reality and not an unattainable goal of the scientific community engaged ir< certain fields of research. We are collecting data in answer to that question, and some of our preliminary ooservations are presented below. Meanwhile, we would like to bring up for discussion the question: Is dose-response relation a non-measurable concept? 31 From the definition of dose-response relation we con see that it implies a correlation between oose and the proportion of the population aifeetea by whichever asbestos-related disease wel%reLecnsidering. But dose also implies a measurable quantity ~ of asbestos inhaled or otherwise taken in by the people exposed to it. If we accept dose-response relation as a measured concept weareacceptingvineffecvthattiie correlation between dose, of asbestos and the asbestos-related disei&eir.'question is sufficiently strong for-whatever purposesweehoosetd1use dose-response relation for. *4 But the dose of asbestos for human beings at work or in the community at large has never been measurea^directly. * Instead, dost'is inferred ' from the exposure knowriror presumed?forxthe-exposeo^popiiialion"ThUs for practical purples such^ nsk^timationiniconnectidn-^th ` asbestos 2xposuref^tgo.^onaoJb^.sJwng^rr*latrons--have*tb<be' presumed! betWecrj tajjdo^^andje^onseigtnarto^ejgjosureajto odse. If one or both eprrelatiphs .are^weax then'the;ris*c assessments^are-likely to be so uncertai^';^^t>^^i^fgi^;^tiiBioid!ntis that&te-lifcpof^ob''' not deal aoequate^!wi.^^jQss^ue.of4^^^1auonsuma; therfrforej'we woula like tite Cornmi^Vpn'4o'rCoraJderrur.questionsjust'^proposea. ' There follows our preliminary pb^yationsjon doserresponse relation; these are preseht^'M^ ^cKgrpundibjOUTfques.tion..- r - j: Our preliminary conblosions about dbse?response.relaiion He believe that dose-response relation should be seen as an idea which possessed considerable promise when.if.was first mooted, thirty:or soyears ago. Since then, eictensive research^has been.carried out put, apparently, dose-response relation has.nb.better.scientifjc basis.now .than it hao at first.' indeed, surprising!y. little research has-been aimedial producing a secure scientific foundation for it; by far the .major el fort has gone into research-which presumed, its reality, hardly ever questioned its validity, and almost never reported_<adequate.-eyidenee of its existence. To make matters worse (and .this is surprising), doserresponse relation has never been defined in terms which everyone can agree to, and neither nas it been defined in .terms which adequately reflect the acientific complexity of Mose", or "response", doth rf whicn are examined in detail in the HSC Report. A confusion appears to have arisen leading to a widespread and fundamental misunderstanding about dose-response relation. 006114 12 This misunderstanding came about ana is perpetuated because: 0) Researchers report on what they- call ^dose-response relations"* The idea then growsthat ."dose-response relation^represents a scientific reality. The researches not.false: the researchers have successfully demonstrsted -the: axistenceof something which-they term Vxjse-response relation". -><- (2) Individuals andorganizations.concerned with riskassessroent, or other practical matters*' take the researchers*oonclusionaasavalid^ and proceed on the basis that what is needed can be deduced from something the individuals and organizations rcgardas^taosc-responsc relation". (3) No one has established that the two ^methings^coincide scientifically. . 1 ' ,T The meaning of the dose-response relationJn studies reporting its existence. ' Dose-response relations, soroetimes referrea loos exposure-response relations, belongs to one oftwoicategories: 4a)years of exposure, ana (o) years of exposure combined-witfrasbestosleveU. (a) Years, of ^Exposure - in.this category* dose is measurea solely in terms of the years of exposure and no.quantitative .information isgiven about the nature, level, or pattern of the group's exposure to asbestos. Thus, the correlations labelled "dose-response reiations,"are between the proportion of the population experiencing the stated disease aha the years of employment or the exposure (if there is a distinction drawn between the two). For some purposes, these correlations produce useful conclusions. However, the usefulness is limited because years of employment correlate with years of age and, as is well known, the frequency of occurrence of many diseases also correlates with age, at least within certain age ranges. For example, lung cancer is relatively uncommon (though it does occur) before the age of forty; it occurs much more frequently after that age. Asbestos-related cancer and asbestos-related pneumoconiosis display a relation with age and, consequently, in some designs of experiment it may not be possible to distinguish age-related effects from asbesto6-reiated effects. That difficulty becomes clearer when we taxe as an example the latent period of mesothelioma, that is to say, the time elapsing between the first recorded exposure to asbestos and the confident diagnosis of the mesothelioma. There appears to be evidence of latent periods of thirty years or even more. 006115 An example (from studies mentioned in the Reports) indicative of the long latent period is the female workers inCanada and ifcitairvduring the Second World War, who manufactured gas masks. Sue asbestos is said to have been usee lorparts of some oraU of theg*smasks;ifte female workers were employed:on work whichinelUaed.putting iheblue asbestos into the gas masks. Manufacture ceased wittethe ena of Second World War; instances af mesothelioma, began ^ace-noticea in the ISSfe, and continueo to occur through tne 197(s. On thepr^umplioivthat the gas mask blue asbestos was the only blue asbestos to which the workers were exposes,-these instances are ciear evtdenceoflong-latent periods for mesothelioma assoctateO'WttiKbluerasbestos^ ,, For workers in processeswhichwere continuous over Apcriootofrmany years, such as asbestos cement pipe manufacturing in Untario, there would be no such dear end point to the exposure. If these workers also were to develop mesothelioma aftertwenty to thirtynyears exposure, there would be no way of knowing for sure whether all of that twenty ito thirty years exposure was needed to induce the disease, or whether the first few years, few months, few weetes, or even few days were sufiicient to lay an unchangeable-foundation for the mesothelioma which would then develop in its own time. Manifestly, for any diseases with long latent periods, including asi>estos-relatedpneumoconiasis,.'correlationsbetween years of employment and lrequency of-disease -may be misleading where the workers' diseases have developed during theiriperioaof-employment. There may be no way of knowing whether the same workers would have developed the same diseases if exposure/had eeased within days, weeks, months, or years of the atari of exposure. (b) Years of exposure.combined with asbestos levels - This category is represented by those studies in whichthedata are presentee as some combination of asoestos levels anoyears of exposure. Many such studies rely on a measure of dose deriveo from a measure of asoestos levels multiplied oy tne total years of employment of the people exposea to those levels. A common^example of this measure is million particlesper cubic foot x ycarsof eyosureaborcvictco. often, to mppef-yr. Equivalent to this measure iaiiores percubic centimetre x years, abbreviated to (f x y)/v. These dose-response relations may be termed "cumulation-response relations", because the product of the level of asbestos contamination and years of exposure/employment corresponds to a measure ol cumulation. 14 In some studies, the cumulation is calculated from the product of years of exposure end a single Average" level of asbestos during the exposure years. But, thisis not really acumulation-response relation; mathematically,31 is the iamca* the years-of^exposilre Employment-response relatioh, jthat is to ssy category^. Cumulation-response relation applies onlywhere there i* some-variation over the years in the level takehlto typify the asbestos contamination. Nearly all the studies which present cumulation-response relations ire dependent upon asbestos measurements averaged over year-iong ; periods. So far, we have identified not one study witlfedtla reiatingjto averages taken over less than eight hours.' "f " For diseases with relatively long-iatent periods, cumulation-response relations po&sess the same; weaknesses sis years-*)f-exposure/: employmentrresponse relation, the Reports acknowlfdge problems in theinterpretafion of cumflati^^^responserdations, and'critical Consideration of ;ihese factors is evidentin sOme of tne morefecent studies cited by the Reports^ Sb;fsr, however,-we have tricep ho studies which have adequately dealt with the question of fluctuation of asbestos levels from one year to another. And there appear to exist no studies whatever which aoequately deal with the effects of fluctuations in the course of a working day. As stated previously, the data on asbestos levels reported in most of the studies are typically averaged over a period of a year. This averaging implicitly assumes that there are no long-term effects due to short period fluctuations in asbestos levels. However, such effects ere in principle present, ana can be calculated from various mathematical models of the development of disease over time. But the magnitude of effects cannot beoetermined from the models alone. For that purpose, data would be required about the short-period fluctuations in level and, to far as we have been able to find, no such data are available. The procedures used for data^athering up to the present, at least, absolutely preclude the possibility of finding out tne significance of fluctuations over hours or days, a potentially important factor affecting the long-term risk of asbestos-related disease. The prevalence of asbestos-related disease has been shown to increase after exposure to asbestos has apparently ceased. This observation demonstrates that any simple approach based on averages, ano/or years-of-exposure/employment-response relation, and/or the cumulation-response relation are inadequate as an explanation of tne nature of asbestos-related disease. 006117 35 006118 Section 5; Exigence of a Safe Threshold of Expoouro 16 Question S IS THERE A SAFE THRESHOLD FOR EXROSURE TO ASBESTOS (BY DISEASE, BY TYPE OFASBESTOS), ANDTF SO WHAT IS1T? ;^ ?* , .f Tables 13-15 summarize.the salient points from each of theKeports, relative to the notionof safe threshold. ti Overall, the notion offsltfe threshold appears to have 6edn^e>^|u|& by the Reports with the possible excepii&vofcthe position qt fheEHSG Report on asbestosis.7 Ifere, a possibility of a threshold is considered, although the Report cites evidencepointing in the contrary direction. The GEC Report raises the possipjlitypofiQthreshold lOrju^c^icer ana for mesothelioma, ana then it goes onTtbreject it in^bbth instanCes. Tne NIOSH-OSHA Report states therris no safe thresholalfof ^ j asbeslos-relatea disease;without having differentiatedibettteen^the diseases. : " ' 7^ ^ : COMMEhTBY CCOHS^ON SAFE THRESHOLD Z \ The term "threshold" implies a boundary between one state ano another, say, the presence or absence of disease. Thresholo limit Value, on the other hand, implies a boundary not clear cut, oespite the use of limit" in the title. In discussing "safe threshold" we must make clear whether the model represents a threshold in the sense of a clear cut boundary, or whether it represents a vague border zone, as does the Thresholo Limit Value of the ACGIH. The S-shaped dose-response curve (see figure lb) snows a kink which could be interpreted as a threshold -- a threshold dividing these two: (a) asbestos exposure associated with disease in a relatively small proportion of the exposed population, and (b) disease in a relatively high and steeply increasing proportion ol the exposed population. By contrast, a linear dose-response relation give no support whatever to the idea of threshold. At any value above zero there is some asbestos-related disease; the proportion of persons affected increases proport ionately to the-dose of asbestos received. Here one can see wny Questions 4 and 5 are so closely related: if the dose-response relation is linear tor any or all ol.the asoestos-related diseases then, by definition, there can be no safe threshold for asbestos exposure. On the other hand, if the dose-response relation is O-shaped then there may oe a threshold, a threshold which divides a relatively low frequency ol disease from a relatively hign frequency of the disease. Unless the S-shaped curve lies above the horizontal axis at all points apart from its origin then, on strict definitions, that thresholo could not be called threshold because it does not separate the condition of no disease (the safe state, presumably) from the condition of some diseases (presumably, the unsate state). Only if the S-shaped curve cuts the horizontal axis at seme point to the right of the vertical axis can we speak of a "safe threshold". 006119 37 006120 PIMPINGS OP THE REPORTS Agency Report AN ALYSIS POR QUESTION S Safe Threshold fo r Asbestosis FINDINGS OP THE REPORTS Agency Keport A N A LY S IS FUK QUESTION > Sele Threshold lo r Lung Cancer * >O *2 $? 'z* x X o d o V) V O O 38 V I a ee iz & ft. & 2 i * i o M o P ublic H ealth Risks o f Rmosure to Asbestos p g U I (pg. 118) lim it, below which an excess risk is extrem ely sm all. Adequate data to estaolish such a threshold lim it are not available. 006121 FINDING S OP THE REPORTS Agency Report ANALYSIS FOR QUESTION 5 Safe Threshold fo r M esotheliom a 39 m % * >> X V X u H 006122 p g ' 111 to establish such a threshold lim it are not available. -One may even serious!/ doubt the possibility o f deriving a va lid measure fo r e xte rn a l oose as an inductor ol mesothelioma. Section fc Other Factors Affecting Sisk of Dfcetsc 40 Question 6 HOW DOES THE HEALTH RISK RELATE TO THE AGE OF THE EXPOiiED PEltSOH? HCM* IS'll A^FECTED^Y OTHER FACTORS SUCH AS SMOKING? . A variety oi factors affetftu^ the incidence and severity of asbestos-related andasbestos-ii^uce^ '.'..Y ,, ' _ exposurcperioo dose smoking latent period ** pattern of exposure The importance of the degree of^exposure and the dose have been discussed in Section4. Also the uhcert^ of dose have been discussedin Sect{on4.' Other factors which have been identified^ presence of a r history oi tobacco smoking,' the eidstenceol'periods oflatency, thelsge ol the exposed individual; arid the jfcttemof 'e^iqsure. Smoking Table 16 outlines the comments made by the Reports about the effect of tobacco smoking on the occurrence of cancer. Here there is a basic agreement concerning smoking: Cl) The eflects of tobacco and asbestos are known to interact synergistically (cause an effect above and beyono separate effects) in smokers exposed to asbestos ana result in an increased incidence of lung cancers. (2) Smoking has little or no effect on the occurrence of mesothelioma. (3) Smoking has little or no effect on the occurrence of asbestosis, although a smoking history may lean to pulmonary complications. However, whether smoking and asbestos exposure have an aoaitve or multiplicative synergy in lung cancer occurrence is not agreed upon. The NIOSH - Q&HA Report claims a multiplicative relation : the HSC Report claims the relation is uncertain and may be less than multiplicative. 006123 hr sent Period 41 latency, oelay or a lag period" in the appearance bfbiseS5e,i*an important factor relating to the health risks of asoestos exposure. Ail 01 the diseases associated with.asbestos have iatency,periods. There is a delay between first exposureandthe onsetor ' Asbestos is may or may not occur during the tinie While a'Workit is exposed to asbestos. It may appear iong after exposure to asbestos, has ended. The interval is known fo^`/eirt^m'ely ,yji^i^lej`'4J4ntfi^l*if dt,' , months up to decades - epparenUy7dephhdi%bh:th^^^rhC^Br^^surl. Lung cancer has a varying latency period ranging from ten years up_to _ decades after first exposure. Of course, smoking as a factor ma| of N may not complicate the latency period. For mesothelioma the latency' period ranges from ten to sixty years. .___ 3' The implications of the existence of latent periods have been weli^stated in the HSC Report. " s~' !v "liE -- Tnese d^lkysintrdcuce'thefd^ cases of '4s"bdstios'i^i^l>^s'e4la'%ay>dccur inli& years after tne worker has left the relevant job; {2} eases of`diseise''" occurring at present relate to conditions.of.work wiucn are likely to have cha^gedjri tKifintervem trends in occurrence'of a^>estds: relalea'diseise eangive little indication of recent improvements or otherwise (say within the last oecaae) in working conditions: (4) a period ol at least HU years may have to elapse before it is possible to give a definite answer concerning the introduction or control of an asbestos-re latea hazard; (5) in persons currently developing disease, data about the reievanl dust levels is likely to be poor; (6) there is a serious risk among the uninformeo of attributing present disease frequencies to present conditions of work." thSC. page 22) Pattern of Exposure It is recognized that the pattern of exposure, specifically the intensity and time pattern, is related to the health risk. Certain cases of mesothelioma have occurred after very brief yet intense exposures to crocidolite mixtures. (HSC. page 56). As well, similar occurrences ol asbestosis have been aocumentea Traditionally the exposure pattern has been averaged by using the concept of "dose", where dose is the averaged product of intensity multiplied by the periodts) of exposure. As has been discussed in Section 4, this concept has theoretical and practical difficulties. 006124 42 A The importance of the age of thejindividuaj ssan independent factor is extremely difficoltfto analyse, Exposure tO asjstos occureiitaoihe : point iniiime, either itf a aingle exposure or asprotric|ecc*Mt; tit* diseased do hot?oecur\irhmediatel| therafteh.tjn factfweSmonjerit^vHen the disease is considered.to existls never known. The^rtphiegt _> positive diagTiosiS'may tike place^yearsafterthe exislenei^c^the t 5 c disease. Latency^is a Xurther proOlem^which^afiects thejinlerpritatioff I of the factor'-of age; ; " i * *y w I^ ... *m* i i "u fc ' r 5 t ?"% f? /' . ^ ^ .*k *j-y - ^MiffE^Toy cSp^s 4 5 r 1 - ;; ^ The Royil 'Cotntousipa heightened ~ : - ' tusoeptibittty'qf &ukir*n. to asbestos-associat^o^oiseases^ Thi j|biiSheio _ instances of asbestt#-t#||ted disease du^to the;exposifralto.asoestos^of ,7 '.chi loremare rare.^HSG,-page 6^.5HoweVekTtjstcno wri'.that^tHe V T i susceptjpi^yitOsprw^cahcers yanes^ With ^e, the very yotingVoeingit^ ' risK (iwizii^t^tfitipma^ieukerm^.^iwtheraisoestcs^ciateo; vr } malignancies-are similarly relat*d^not'known.:: As welifaihce Children can he expected to live longer than adults, they have more chance of being affected oy cancer-causing substances with long latent periods* of which asbestos is an important example. 1 00612S FINDINGS OP THE REPORTS Agency Report ANALYSIS FOR QUESTION H H ealth Risks R elated to Smoking 43 006126 CEC Working Group o f Experts: Public Health Risks o f Exposure to Asbestos P k - 12 -C igarette smoking is a "highly co n trib u tive 1a c to r, usually in co m b in a tio n w ith e x is tin g asbestosis" , in the developm ent o f lung cancer in asbestos-exposed w orkers. Section 7: Risk of Disease for. Worker* 44 Question 7 WHAT JS THE MAGNITUDE OF THE HEALTH RISK FROM ASBESTOS FOti ASSESTOS ITOkKEKS UN GENERAL* NOTINANY PAKTICULAK-PLANT, FIKm OR INDUSTR Y)? " Some of the Reports attempted to estimate the magnitude of health risks for workers. J ! s 1r In a review of studies of .occu{>at>pnal:popiilationsithfe HS&Repprfi ranked the majorcauses of excess mortality amongasbestas workers where the cause of death was known andisiated the proportion of deaths due to each cause: _ - . [ :*T 3 7 ' 7 ~ lung cancer asbestosis. mesothelioma yastro-intestinal cancer ana ali other causes 404 24*' (3K %*' IS* Surprisingly, a study of fcritish death certificates suggested that asbestos-relatea mesothelioma is a more frequent cause of oeath than asOestos-reiatec lung cancer (HSC, Vol 2, page 22 ano Table 20) The incidence of mesothelioma in occupationally exposed populations has been estimated to be from 2 to 90 times higher than the incidence rate in the general unexposed population. There is a neeo for caution in the interpretation oi instances suen as these Decause of the effects of the various factors which could affect the picture: latent periods changes in work conditions changes in measurement procedures the varying evaluations of occurrence (for example, diagnosis) The NiOSH-OSHA Report made no statements concerning estimates of occurrence, but does state that the present standard (2 fiores/m U appears to cause unacceptable levels of incidence ano prevalence. It then recommends a eonsioerable reduction below the current fibre standard. 006127 006128 f ys ga 0 4> he*; .x v 1fc = 2 S-J? . <A I'i & oo g ' " f c ! WCS g P- T>! E BEPOHTS Agency Report li T, ** X fj A N A L Y S E POK QUESTION 7 Risk o l Disease to r Workers I 45 Section t; Bisk of Pis--scfor the Public 46 Question ft HAT IS THE MAG NITUDE OF THE HEALTH RISK FROM ASBESTOS FOK THE GtNEKAL POPULATION (EXCLUDING AStfESTUtf MfORKEftS AND THOSE WHO LIVE IN THE IMMEDIATE VICINITY HOF ASBESTOS MINES OR MILLS)? ; From the Reports,itif dearthat the magnitude ofxislcs^of .disjWue Xrom asbestos for the generidj>opu|ati(ji|not kMwnwithany^ ,, ... Actual instances of the diseases associated with^nvj^onr^entaiiasbestos . exposure are rare although there have been occurrences in situations of para-occupational and neighbourhood exposures. It is generally accepted that asbestosis occurs only in occupationally exposed groups, although pleural plaques similar to those associated with asbestosis have occirred where occupationally related exposure is unlikely. Hut these pleural changes are only symptoms, or abnormalities, and not firm evioence of disease. The HSC Report states tnat extrapolation from the industrial experience for asbestosis to the public is not possible. There has been no general Reporting of asoestosis in the public. Lung cancer risxs, with the problem of the confounding risk factor of cigarette smoking, as discussed earlier, are not so easliy presented, ine HSC Report states that chrysotile is unlikely to have produced any increase in the risk of lung cancer in the populace. However, for the amphiboies, crocidolite and amocite, the situation is more doubtful tnan for chrysotile. There is a suggestion in the data that the risx of lung cancer may be greater for the amphiboies than for chrysotile, and that an excess lung cancer risk cannot be excluded in those exposed in buildings to amphiboies only. For mesothelioma, chrysotile is believed to cause no appreciable number of cases. The amphiboies are most clearly associated with the majority of Reported mesotheliomas. TYus situation is similar to that for lung cancer. The NIOSH-OSHA Report does not discuss public health risks; it only discusses occupational risks. However, because of the nature of the statements made, certain conclusions can be deduced. "Excessive cancer risks, however, have been demonstrated at all fibre concentrations studied to date. Evaluation of all available human data provides no evidence for a threshold or for a fcafe* level of asbestos exposures." (NIOSH-OSHA, page 4) 006129 47 It cm be^ reasoned that if there is no Vafe* level Of exposure, then exposures to environmental concentrationsrmust have somo risx attached, whether or ootmeasurements oi3fcil&i4kt$9C$M However, the NIOSH-OSKA^Reportdoes not use any extrapolations to The CtC ReporioS"the 6<^u^tio*i datatc health risks. It concludes that: -asoestosis is not'd puhiic health risk -lung cancel eaftnotioO ;etft*pu- xras a^pt^' ~i <vr? tsK*itI'5 'on* n> r*3*is;u '1'. in4 %' 006130 FINDINGS OF THE REPORTS AM ALYSB FOR QUESTIOW t 46 006131 Exposure to Asbestos pg. 12, 96 b ro c h iil lung carcinom a as a public risk. 49 006132 H t seems u n like ly th a t asbestos m in e general atmosphere is s cause d f iW esbtl^hMfta in the general public, (though) more evidence is Section 8: Chronology of Knowledge so Question 9 WHAT WAS THE CHRONOLOGY UF UNDERSTANDING THE HEALTH RISKS OF ASBESTOS EXPOSURE BY THE HEALTH RESEARCHERS? Asbestos has oeen usee a long time. As early as the 1st century AD the Greek geographer Strabo reported that slaves who wove asbestos into prized rpoes ana burial garments for nobility suffered from a "oreatnii^ sieichess". fl>*' in 12th century Europe, CJiariemagne'sbanqufct guests were,treated to arhizing displays of tire-defying tricks periormeo with asbestos ciptrjs. KoW fight hundred years later it is harder to f^'lhitbeinrtty^iuict^^^th'jUtC unusual powers oi what was once called "the magic mineral"." Scientists and medical researchers now ponder the complexities of the pathological nature of the mineral. How does it cause disease? Wno is likely to become a victim? How much dustcanharmaperson exposedover alitctiine of work? how little? Are ail types of asbestos equally oangerous? How can we use our technological know-how to control exposure to the dust? Asbestos has been studied intensively by medical and occupational health researchers. A recent estimate made by CCOHS staff says that one new article on asbestos now appears every day in the medical literature, bn average. For over a century asbestos has been-mined and processed for hundreds of different industrial uses. When workers handling the mineral developed fatal illnesses in the early years of this century, factory inspectors and medical doctors began to make the connection oetween asbestos dust ana disease. Asbestos factory owners were among the first to realize tne danger. Henry w ara Johns, founder oi wnat became the Johns-manville Corporation, dieo of asbestosis in 1898. As early as 1907 at least one French factory inspector ana one British medical ooctor were convinced that asoestos was the cause of oeatn for certain textile workers. (2,3) Twenty years later another Briusn doctor recognized that disease produced oy working in asoestos oust created a previously unknown type o1 lung fibrosis -- he labelled it *asbestosisnl4). In the early WXt it was found that asbestos -related disease couiu strike many factory workers, not just an unfortunate few -- as many as one-thiro of the workers in British plant were alfectec.t5j At the same time doctors at an American clinic found, during autopsy, thst a death apparently due to heart failure was actually due to the suffocating effects of asbestos oust (6). * Bracketed numbers refer to items numbered in Appendix C. 006133 51 In 1931 it was known that an exposure period as short as idne months could produce an asbestosis.(7) People who used asbestos products -- pipe ccverers, boiler maintenance men ana even a clerical worker -- developed asbestosis; it was not limited to factory employees only. That asoestosis and lung cancer could occur together in the same victim was known by 1934 (8); several cases were reported by British ihd American researcrM^Jnihe mtJ i93ft.(9,U,13) During this decade, confusion over the diagnosis of tuoercuiosis in the asbestos-prooucing.region of Queoec became an issue4i4r2,18) By the late 193ft ana early !94ft researchers were preoccupieo with questions about'the link betweehlung capeer and aspestos eptu^.iD|34^Ujlt>,17) Attempts to induce cancers cxpCrimentally'in: mice w^not ooncIusive.U4i hutiierous c&ses ol.aSbestdsis andlungcancers occurrir^ together;had been documented by the midl'94ft oy American, britisn ano Uerraan invest igators.(iy) A consensus on the existence of a causal relation oetween asbestosis and lung cancer was apparently reached in 1949 after a landmark study of 'British asbestosis victims who reporteoior:.eompensaUon.(20) American researchers in the l95ft, howev2r, found reasons to conelude that asbestos wks not re^nslble for causing lung cancer.(21). A major study of English textile employees in the niio 195ft was widely recognizeo as offering the. most sqlid evidence to date that asbestos-exposed. workers ran e high risk of being affcicted with lung cancer as well as asbestosis.(22) Epidemiology, a quan..^tive analysts of disease distrioution and causation, became increasingly popular as a research tool in the 195ft. Studies whten did not incluoe study populations or numbers of victims considered to oe statistically large enough were discredited.(23) In fact the previously accepteo eonnection between lung cancer aha asbestos exposure was refuted in 1961 by prominent American epioemi61ogi$ts.(24) Some evioence appeared irrefutaole, however. It became generally known by the mid 196ft, for example, that insulation worx with asoestos was especially dangerous, and that it caused high excess death rates and gastrointestinal cancer rates -- this from studies in Denmark ana the Unitea States.125,27) Ano by 1965, it was thought that people could develop early signs ox lung disease from asoestos air pollution simply because they liveo in the neighbournood of an asbestos mine(26), ano that both aaults ano eniioren could become victims of mesothelioma lrom contact witn occupationally-exposeo family members (28,29). A subject for investigation in the late 196ft and early 197ft was the question whether or not abnormalities on an x-ray film could signal the presence oi asbestos-related aisease -- some researchers uncoverea disease where x-ray evidence revealed none (30^31). Nevertheless, examination oi x-ray abnormalities by industry personnel in a British factory formed the basis in 1968 for the later universally-applied 2 fibres per cubic centimetre of air stanoard of asbestos exposure.(52) 006134 62 Research on asbestosin the407Qs became more-intensive,!^^ exposure measurement ana'the.nature of asbestos-related.disease more precise., .Numerous import*nta**rtionswere ma^intnein^ of the decaoe --spmemay nqlonger be relevant^jspme have become generally, agreed upon.ano some are stillJhe subject of controversy.- -Among these assertions.are: m, f . * Even low exposuresof.asbestos,can cause cancer.Thetwp fiores per cubic centirnetre^stanaardadppted tc protect British ana American workers:,<$ocs.^j^^nia*|liV|Si0fH6||n^r.~? - * Lung cancer may develop independently of esbestosis, but workers with asbestosis are at an increaseo risk of develop^ lung cancer. * Depending on the medical criteria chosen for diagnosis, the extent of disease reported can vary greatly, especially for mesothelioma. * Gastrointestinal cancer is associateo witn high dust exposures. * The question of wnether or not the difierent types of asbestos are equally dangerous for all related diseases is recognized as a difficult one, although a definite link is suspected between blue asbestos (crocioolite) ana mesotneiioma. * Averaging asoestos dust exposure counts over many years is an unreliable indicator 01 now dangerous the exposure has been, since short but heavy "doses" may carry particular risx of malignancy. * A iacK of oefinite distinctions oetween possiole sources ol asbestos exposure means that greater reliance should be put on biological monitoring than on environmental monitoring. * The relation between biological effect and fiore size is central to the hazard of asbestos. Therefore reporting the fiore dimension as well as concentration is necessary. * Exact dose-response relations cannot be defined; however, there is often a connection between the duration and intensity of exposure and resulting illness. * Exposure to both asbestos and tobacco smoke causes a greatly increased risk of lung cancer, possioly in a multiplicative fashion. * There is no evidence that tobacco smoke is related to an increased risk of mesothelioma. * The time from initial exposure to eventual onset of disease -- the latency period -- can be a surprisingly long period of time lor diseases caused by asbestos; it may be anywhere from lu to 40 years. Tnis fact can greatly complicate diagnosis. * Workers having a long employment period have a higher proportion of death due to mesothelioma than those with a snort period. 006135 93 It should be understood that the brief, discussion hereandthe body of the chronology about ^- In scopes within MMSmibi,0iK ' nil Tc. indicate '-ri$i- have characterized (his field ol research. Ina fewinstancesit wasriec&sary- " cS-..*- to include entriesfromsourcesother than the'f6ur Kep6rtst to fill gaps in knowledge, espfeiifl^fdr';^ j^nod;19EWi6Q? rMchfAi0fc^laili(n6Wi^ag^' of " ^ the hazard including ah awareness of lega^ rija- Tf&i.'j**vgy>-;j ^ prepared by CCOHS. it may provide a useiid coh^ v*-c* Kftt ^eoi^uiaa X$ toMis study. vazT? faofiso ^n**.* 00613i Section 1ft Response to;the Reports 54 Questions: * HAT RECEPTION HAVE THE FOUR REPORTS BEEN ACCORDEDIN CRITICAL REVItWSlN THE MEDICAL JOURNALS? HAVE THERE BEEN FORMAL RESPONSES FROM AFFECTEL PARTiESS UCh-AfirISU&TKY' ORGA'-NIZATIU N S Oa WORKrERS-O&CANIZATIONS? ;^ ^ WHAT WOULD BE A FAIR INDICATION OF THE STATUS A ND WEIGHT-ACCOKDEDTO THESEREROKTS W"THE- ' MEDICAL COMMUHITT^N AMOHG AWECTEtfPAiltfi:^ In general there has oeen very little*esponse-to the four Reports of 1 forniai nature in the meciicaJ,jourriais,jor-in^y;Other puolicatiohs,- jar ^ ^nave been able to determine.; .Most of^the^commenl available Isabout the'Report tc the UK Health-and Safely iCommission (HSGl. Ahere oeiihite responsesto' the Reports were availaole rin .published-formy we relied on^em, twt wherie it was not available^ we have, reported'opinions'conveyed tous by-persons with' some a wareness of. the 'how; the.Reports were received. ` ^ -T ? A book review in the British Journalof-Industrial Meocine~(198a37)savs the HSC Report is "well-presented, comprehensive, ana thoughtful, and repays careful reading. " Dr. M.^L Newhouser the reviewer, credits the HSC Report with providing "very succinct information" on asbestos in the workplace, and says it supportsa/reconimenoation-on-eontrol limits with "very detailed argument".. The one criticism Newhouse maxes in ner review is -- "...it is not too clear what is meant by theJsocial costs' " referred to in theHSC recommendation "that tne Health and Safety Executive take into account the social costs of obtaining, using and disposing of asbestos...". On the wnole the BJliVi review presents a factual account of what the HSC Report says; it offers very little critical comment. Both the BJIM review and an article in the journal Lancet (Oct.lV7 anticipate criticism from industry over the new restrictions for anrasite (brown asbestos) recommended by the: HSC Report. The Lancet article speculates that the JibC Report is likely to oe criticized by environmentalists who regard prohibition as the only Acceptable solution to asbestos-relateo disease, ana it regrets that a consideration ! the benefits of asoestos to health "was unfortunately not within the committee's terms of reference." An article in the publication Health ana Safety at work Uan.lt)8U) reviews the topics of discussion at a major public conference on asbestos sponsored by the Advisory Committee on Asbestos (ACA) in London in November i*79, one month after publication of the HSC report. The major theme of the conference may provide a due to the weight attached to recommendations of the HSC Report -- the theme turned out to be not the numerical value of tne new control limits, but how existing atmospheric monitoring and fibre computing techniques could be used to help achieve compliance with them. 006137 55 At the conference the chairmen of the HSC advisory committee, Hill Simpson, Stressed the report's significance as a pointer tothewayithe HSC-was preparing to tackle all other occupational carcinogens". He stateo that three proposals should be seen as part of a general policy : that users should be obliged to consider substitutes, that the TLV concept should be replaced oy control limi ts, and that control limits should be seen as maximum acceptable exposure levels. Willrea Penny, Director of the Asbestos Information Centre, presented to the same conference the industry's updated estimates of cost of compliance implications of the HSC Report -- considerablereauctions inwhat-had originally been stated were shown. Another Health and^Sefetyat Work article; says, the/ttSC Report's discussion on substitutes for asbestos-are to extensive that industry is concerned that recommendations will be misinterpreteo as a manoalory requirement to substitute.. It also sees tne burden of decisiqmplaced downstream-as *unreasonaoie ar)o unenforcesble". JIhe articie:goeswj to say.iTheaecond industry complaint is of inadequate medical evidr'-ee to support the setting of a 0.5 fibre/m L control lirnit for mosite...industry.claims>that productiorrot the best fire protection-boaros will eeaseandtwo factories dose foliowing implementation of a 0-5 Dpre standard.", Simpson!s reply^reported in:the health ano Safety at Work artide^was that there .wax*: dear medical case for the amosite stanoaro being set lower than that for cnrysotile, aithougn admittedly it was based on vary limited epidemiology. The main concern of industry, accocdif^-to. the samearticle, is the 1 fibre chrysotile standaro which the Advisory Committee on Asoestos proposed shoulo be achieved oy December 1980- The asbestos inoustry in britain complains of being at a competitive disadvantage compered to other iuropean Economic Community (EEC) producers who have several years longer to aoopt stricter control levels. The British magazine Hew Scientist publisned three articles about the HSC Report soon after it was released. In one editorial, the HSC Report is described as an "historic document", not because it recommends stricter safety standards, but because of the maximum "control limit" philosopny behind its suggestions. Author L McGinty says the thirvdng behind the new safety standards for asbestos recommended in the HSCReport "will almost certainly oominate the setting of future standards for all cancer-causing substances in the workplace." He says this thinking is %ew" and that it "closely reflects the philosophy of safety standards forradiation set out by the international Commission on Radiation Protection." McGinty criticizes the HSC Report for ignoring the question of very small asbestos fibres, whicn omc researchers oelieve to be more dangerous than larger ones. He anticipates trade union dissatisfaction with the Report's recommended control limit for chrysotile, which he says would still allow 3Ju of the estimated 25,110 woncers currently exposeo to die from asbestos-causee disease. The Trades Union Congress (TUC) had demanded in its evioence to the HsC before the Report's puolication an overall standard of 01 fibre/ml, and a policy of "gradual compulsory substitution" of asbestos with Jess dangerous materials. McGinty says the HSC Report recommendations fall far short of substitution measures acceptable to the TUC. 006138 A British newspaperrepoeting naafety niattersto industry carriedan article in tiie Octooer 1?7S iasue,-;which<|uotea; consultant's criticisnvoftherHS>c Reportjhesaio therecoromendatkws^were "more of a sop to the emotional environment thanscientificaHy-determineQligures"., and "The figures are a compromise, witnno scientific oesis". . Although directcomment on.the HSCKeportfrom industry and labour representatives was not neeoilyavailaole,a fairly consistent sense I their respect ive positions was obtained. With respect to the NIOSH-OSHA Report, it would besafe^o^conciude that its publication has been received as somewhat less significant oythc parties concerned than waa<heiHSG4leport. id entical commentJn^thrmaaicai literature has appeared, as far as^we can teli- howevar^somi indicationrof response are availeble. ri The Occupational Safetyand Health:Reborte? (<aay 18#Vp.iU8) carried anew* item which^quotes the Asbestbs ihformetiorj Association (AJAlofNorth Amercaassayingithat4heaK10SH^OSHA'Report!isVshort-dighted~ regulatory approach" that?fails to acfcnowledgethat **ocietaUyacceptaole levels of risk can be established."-The association chargedtharthe-Report was not based on any acientific demonstration of the healthful effects of reducing exposure to <U fibres, but instead on NIOSH*s assertion that the (LI fibre level is the lowest level accurately measureablePy-optlcsal microscopy. The association also criticized OSHA and NiOSH for using the concept of dose-response relationship in the development of disease but failing to acknowledge the "correlative rcooclusion" rthat acceptaole i*velsolrisic can be set. A prominent American epidemiologist who has published several articles in the medical literature on asoestos was contacted for his knowledge of how the MOSH-OSHA Report was received. His responsewas revealing -- "i vaguely rememoer tnat report." The same kind of reaction was givenby one of the most influential American labour representatives, out it was clear he was pleased with the Reports call for a lowered stanoardof exposure to asbestos -- "we've been petitioning for this for the last five years.~wetredl for it." One of the medical employees at NlUSh said he thought members of the medical community were generally supportive of the Report, because "they recognize thct asbestos is o huge problem and they areaeeing more ana more evidence of disease". He said hehadtoagree with A1A president I.A. Dougherty that the OlI fibre level was chosen by NIOSH because it was the lowest level accurately maasureable by optical -microscopy. US health and safety government officials announced release of the NIOSH-OSHA Report together with statements about the numbers of workers who might be afflicted with asbestos-related disease: "...restrictions on asbestos in the workplace are 'grossly inadequate* to protect L4 million American workers" -- 'ton estimated Stto 75fiD Americans die each year from lung cancer, asoestosis, mesothelioma arJ other malignancies". The statements ware reported in a New York Times article the day the Report was released (April 11/tQL but notning remarkable was said about the document itself. 57 The Report oftheNational Research -Councilor-CaiMto;lNRUQ).-fls*fm* to-, have beenaceepted-at/ace valueVaceordingto-oneofTthe-jnembeEXofthe NKCC Associate GommiUeeonScientificXJriteria.' AnotherrNKCCofficial, : said the Report received "very littlepublicity**'"we seldomget -hullaballoo afterwards", he said. Re explained that since theaReprt>wentthrough *.. . "multi-stage review", a question about reaction to it after publication was not applicable.- The main-ablhorof the:RRCCTleportiwa54iotwareof^my part icular response!it* partlycbeeeuse he was no- tongerswith/the -.NKOC, out also because no apparent official reactions have beenmsde strongly .or-, openly. No comment or criticism about the NKCC Report, from either Industry orlabour wganizationvwas found. - ,y. -i.* trjn*. h-r^u ti i* ..'nmovi neso c.*t Last, the Zielbuis report,referred to in thissurvey.^^e2yE<2^^orUrtTius document was designed tobeanexaminatiooiofsthepuoti^heaith ri^- ^ associated with asbestos. There is evidence in the Newhouse review.ano in : - status accoroeo to it by BriUsn researchers especially, that the CEC Report is regarded.asamaj9r^stuqyioLone iigportantvespect?offtne-asoestos problem. Its existence Is littledcnojvn in North^Americar^rUhi^rtma|eJty,3t wasbt possible to get any^inoicatiomof European response to theGCReport, beyona the fact that theustudycof^health effectrlnwblume 1c ofrthe HSC Report,~ relerences it as onetoffffour^ecenLexcellent eeviews'. Puolished Comment on.the-Reports : r M L Newhouse, Book-Reviews. iBrilismJoarrtabof Industrial Medicine,. 198&;37t 198-21) Asbestos and-Health. The Lancet, October 27,1979, p.887 Asbestos - putting the legislation into practice, health and Safety at Work. January 1V80, pJ8 HSC carcinogens policy developed in Simpson report. Health and-Safety at Work, January 1984 p. 15 Tighter controls on asbestos recommended. 13 epU979, p.77 Controlling cancer - asbestos showsr-the-way. LhcGinty,25-Oct.l979,p.251 A sale philosophy. L JieGinty, 25 GcO979,p.250 :New Scientist Asoestos: Commission Plans Tough hew Curo. Safety Incorporatingbafetv and Rescue, October 1979, pJ. OSHA-NIOBH Report *5hort-6ightea" New Slenoard-Unjustified, industry Says. Occupational Health ano Safety Reporter, 1 May 198C^ pJJUb Asbestos Industry Finos No Justification for Plan to Cut Allowable Exposures. Job Safety end Health Reporter. May 19ft) Federal Curos on Asbestos Found "Grossly Inadequate". New Yonc Times. 18 April 1980 006140 :? '(if% rr'i ,,*?*-%>$: 4!$- *fe w* r ... - ''. lB53wJaS^' *f*U* .jJl.lt .~M ;s.w- :.': &'* *>S-i?.#Jr *nW&i$r*3 fes% :zh;iJt!*j sdhu* ?0 *,s Eiifeit?? -' ' ^-3-r *& APPENDICES ;.V vv?vir-:/s.; A. . t i*.pC' .'.t.a-j s'S > *r 'r-i- Kferga-*.? ^;^F sSSfSV^-S 006141 APPENDIX A i Extract FromTermrof Reference A Review of Major Studies of the Health Effects of Asbestos (A Surveyof Studies) PURPOSE The purpose of this survey is to review the-njor-stuaitt^the't^ asbestos, identifying the views taken in those four studieis'oh a q_ues-tions. ` x , O^-.- *2 * *K. '. * T * . f *-fe The report is not intenoec to ix ah examination oi t^ exposure and conti^but^icdydf^thetHaJtrieff^ of set of ofasbestos This survey shoulc constitutea^ummary that'is; IntelligiDle to^tne generai'puolic ana conveys to that public a setue of the views expressed in these -major irtuaies. In addition, this survay^ShcHild reyiew the reacxie^if'anyr.tb tnosestuaiesijy the scientific commiimty;rby^n^tptf,by^ :! Out oi this snoulo come some sense of which aspects of the conclusions of'tne studies have been controversial ana which have heen generally accepted. If the CCOHS can contnbute to the resolution of controversial issues with their own views, this would he useful. ' 's This survey is limited to an examination of a specified set of fourpreviousstuoies in order to permit its completion in the time period of three months.' It is anticipated that some of the questions will not he answered completely or satisfactorily in the specified studies, fit such cases, the CCOHS should indicate that the studies do not present a satisfactory answer, ana that further research, examining primary literature Sources Would berieceKsary to find an aiuwer, if the current state of medical research admits anansWerat alL'Atrcm<rlater date, the Royal Commission on Asoestos may commiaiion a study that would examine in detail any questions left unsolved by this Survey, ana Any additional neaitnquestions that might arise. The Koyal Commission on Asbestos may publish the report that results from this survey and distribute it in substantial quantities to members of the general public ana to interested groups concernea with public exposure to asbestos. Tne document may then serve to provide common bacKground information to individuals and groups interested in the problem of puolic exposure to asbestos. 006142 SCOPE OF SUKVEY The survey should review the major overview studies of the. asbestos problem. This wilHnclude: U) Advisory Committee on Asbestos, Final Report, Report to the Keslth end Safety Commicion.i9?Jl(; HmSO London.(referred to as the HSC Report) A (2) NIOSH-OSHA Asbestos Work Group, Workplace Exposure to Asbestos:. Review and Kleccoommrmoeennddaattiions., April 198b..U.S. , DepLof Healthy Education! (refe'r'reo to as the KiDSM^bSHA lle{>Drij (3) National Research Council of ,Canada..tAssociate Committee pn .ScientificC^tmafof.Ei^^nm^tal/6^1ity^Efi^ts,of Asbestos in the Canadfan Environment ~*by Stephen Shugar, 1878, SKCCM4b2.JUeterreo .toMs the NRCC. ReporX) . . (4) Report of a 23 -i 5Ki; :rts IfPrepareo fdr'itifie Cojmmttsipnpf the. Eurpp^an Lfcpmunitijss, ifroiic-Health Risks.oi` the Exposure^to Asbestos ecu By Prof1.2,A3L4L.5Z*i*fe*ib9uis. EUhSbSie l977, Pergamon'Press. (referred lo asfhe etc Report) s. A number of particular questions should be aoaressed in reviewing the major studies. The CCOhS shouid.summahze wjrial the major studies sey about: ........... (1) What adverse health effects in numans Are causes by exposure to asbestos? (2) What is the rate of occurrence of these health effects in those who work with asbestos and in the general.public? (3) Do the major types of asbestos differ in their toxicity! If so, how! (4) What is the shape oftbedose-sresponse relationship? Is it linear,or someother shape? . (5) Is there a safe threshold 'for .exposure to asbestos? (By disease, by..type of asbestosTJIfso, whet Is it? (61 How docs the health risk relate to the age of the exposed person? How is it aflected by other factors such as smoking? (71 What is the magnituoeof the health risk from asoestos for asbestos workers? (in general -- not in any particular plant, firm or industry.) (!) What is the m^pituoe of the health risk from asbestos for the general population (excluding asbestos workers end those who live in the immediate vicinity o! asbestos mines or mills)? (9) what was the chronology of the understanding ol health risks from asbestos exposure by the health researchers? APPENDIX 19i McMASTER UNIVERSITY V200 M<m Street fitu, HimiHun, ftta'w. US 4J9 Telephone. Ant* Code 416 $25-9140. *l 2333,2334 BY Ulv HJI* September 9, 1990 Dr. C.R.C. Atherley President Canadian Centre for Occupational Health and Safety 1200 Main Street Vest Haailcene Ontario L8N 3Z5 Dear Dr. Atherley: SUBJECT: Relative haxarda of different types of Asbestos You have ^asked-me tbmeke^soWreommentsoothe -Approach to this problca as it appears in the following recently published documents. 1. Effects of Asbestos in the Canadian Xnviranaest Associate Committee ooScienclflc Criteria -ior Envlronnental Quality published by the Rational Reaearch Council of Canada. 2. Asbestos - Volume 2: final report of the Advisory Committee published by the Health and Safety Coamiselon 3. Workpiece Exposure to Asbestos: Review end Recommendation* published by M105H-0SHA, April 1980. In approaching thle problem. It ie helpful to remember the esperiencc of the coal mining industry in Britain. In 19*5, it was vail known that most eases of coelworkers pneumoconiosis in Britain occurred in the South Vales area. This wat known to be a mining area predominantly dating with high rank metallurgical coal. Pros this observation it was assumed that high rank coal wet more dangerous than low rank coal. Comparison of the dustiness of the air in these pits by methods used at that time appeared to ahow that they were no more ducty than pita in Scotland where coalworker'a pneumoconiosis vea vary uncommon. Thle remains one of the great epidemiological blunders in the field of occupational health. Ve now know that two factors contributed to this state of affairs. In the first piece the mining techniques used in high rank pits was such that a great deal more dust wss in fact generated then was present In the low rank pita of Scotland. This has got nothing to do with the type of coal hut simply with the mining 006144 -2- 1st Century A;D. PLFN Y Thfc^ElOerconfirms reports Oy^tJ^t^ek^eoi^rsphefrSfraOo, that slaves ^ar#dye<%^SSfeSiitlB>60rAj garments lungs. ifevWe,Wd;'TA$BESYOS?'H INKOR'AjATJQ^JSPHES^OKCE. Cincinnati: i .U^-l^ti'oPiieartit/^Eoueition and Weilare, -1979. - ** , r . V.. .. i -'*; *(WK**-NRCCj (11 190b AURIBAULT, an injector in the -De^V^mehtMf4MoOUr in^Frince, Iuiks 50 : 'Oeatfis^to sex^osure1 to' a"st>erstps ousts in a Aurioaulti M NdfeVur l'hygiene et al lilateurs et 'tisSages b'eftiiantV^ toull'insp. Irav., Paris 14, -lao^usos)' (WAAKlTH] (21 1907 MURAAY in England reports the aeatn of a patient'from asbestos fibrosis of the lungs to a parUamentary committee on industrial diseasewmperisition; The Victim is a 33-year-old man who had worked for ten years in the carding room of an asoestos textile mill. Murray, H.M. REPORT OF THE DEPARTMENTAL COMMITTEE ON COMPENSATION FuR INDUSTRIAL DISEASE: MINUTES OF EVIDENCE. London : Wyman ana Sons 1907. (WKK-OTHJ (51 1917 PANCOAS1 et al reports x-ray appearance of pneumoconiosis ol futeen moiviouals exposed to asbestos. Pancoast, H.K., (et al.j "A Roentgenologic study of the effects of dust inhalation upon the lungs." ASSOCIATION OF AMERICAN PHYSICIANS, 32 (1907k W7H08. (WKK-OThJ 006145 1927 1SJ0 1930 1930s 1S31 -a - Dr. W.E. COUKt reports in lull pathologic*], detail ithe^l'indingSHql' a post-mortem . ' ejwmiiijiM^^^Mlere^eo women wfto ^vefo^'Jisb^tMis.aunnE^0yersoi wore ` ** **ve ;nev |en^ytfungL{^reliel to this in tOipther. Ousts...4* he sey^He-namedfthf-oisessejes&estosis. Cooke, \v.L "Pulmonary, asoestosis." fiftITOH MEDICAL JOUHNAMOdtemoer 3, 49271:- L24-D25. IWKK-NRCCJ (41 .MERE w i^HEKjand.!PjllCEJind about olasbestos ttclQty:$<xker$ ^te2ii)gittQm pulmonary jUupgl tlb/osijk -.f. U'r. ferewethei'j-E.K.A- anoC.*. Price. DUST ON THE LUNQS; ijonaon : h.M.a.O., J930L (WKk-OIHJ (51 talLLS au.thors f raportat-Uve Mayo Clinic victim reveais heart'fahuredutfto ssbestosis. inills, it.G. "Puimonary esoestosis: report of a case.". MINNESOTA MElilCiNE, 13 (1934. (WKK-UThj (61 .Lung cancer isatiU ^relatively uncommon disease.-.. Newhouse, M. "Asoestos in the workplace and the community." ANNALS OF OCCUPATIONAL HYGIENE, 16 (1973): 97HD7. (WKK-HSC) STEwakT at a! find asbestosis in factory workers including one victim .with only nine months' exposure. (Arch. Path., voL 121 IWKK-OTHJ (71 006146 1932 1934 1935 1935 1936 4 ,,1 " VJ . 'll' - , Asoes|psis,4sinot linfitedSOifactory workers. .- Public Kealt/r Servic* eegortsithat.apipecoverer (Proceedings of a Conference Concerning Effects of Ousts Upgp<the>.Jfspiraiory jS .iiut.j ei -d..'.wi-.3ir{L:T WOOD and GluYNE report two cases of lung cancer seen at autopsy in 43 cases of . rtaS!tofiS5f. fjj 3 H ii :j .2 . W39Q^PldWe(hjindrea cases." ......... .*'4NjERr?H$C] (8j * DiO C t > .r. - ' case lung ea^e^ina^uth^e^fina.iUiiA) asoestosis victinji^^a it, rC.>jC'.'-! a-nr Lynct^ jK.ftt. ana -w.A. Smith. "Pulmonary asbestos ill: carcinoma of the lung in asbestos-silicosis." AMERICAN JOURNAL OF CANCER, 24 (1935k 56. iWKR-HSC] (9) iANZAetjil conclude-thatasbestos oust exposure O^rMVpMdispose: to \ *rm<Ktfc. . esbestoeis'as a mliaer CUease than silicosis. Lanza, A.J. "Effects of the inhalation of asbestos oust on the lungs of asoestos workers." PUBLIC HEALTH REPuKiS, 5M (January 4,1935;. (WKR-OihJ Ou) Iwo more cases of lung cancer associated with asbestosis are reported. 006147 1936 1938 1939 -5 EGBERT ana GEIGER ^Egbert* DiS. anaA.4:Geiger. "Pulmonary asb4fcfos-ahdeardn6mi^repprt of a eaae ; witfrnecropsy f&fairtgs.* 'AMERICAN KtVlEW GF^TUBEftGUliOS^ AN D 'PULMUNAKY`I>ISASES,'3ifG936;: 143. ,:GLOVNE '. ' r>* ' -i ^Gloynei^S.K. "A1 Case DToat-ceil carcinoma of thellung occurring in asbestosis." TUBERCLE, 18 0936): lit (WKK-HSCJ (111 DON NELLY finds x^^iylevififence of - ^ asbestosis-imorigr34* oMSi--aSbestos mill ^>^a|^OfActive iubere^Myar^fctond^m^^workers -with -asbestosis. He concludes thattherewas no tenoency in this type of occupation to exacerhate old tuberculosis lesions. Donnelly, J. "Pulmonaryaspeslosis: inei^rfce^ano ^prognosis.*' ilDUHN AL OP iNDUb^iAiPHYGlENE^liri) TOXICOLOGY, 18 U936lfs4i - - u 'IWKtl-O'l h] 021 NGKOaiANN tinas 2 cases of lung cancer in 2 cases of asbesiosis ana conduaes a cause-elfect correlation must be present. Nordmann, M. "Der Herufskreos aer - Usbesiarbeiter.*: ZElfSChklFT FUR KKEBSFUKSCHUNG UND KilNlbCHE ONKOLUGIEi 47 0939k^288. IWkir-HSCJ 031 VORWALD and KARR report negative results in tryii* to show experimentally induced cancer with asbestos. Vorwald, A.J. and J.W. Karr. "Pneumoconiosis ana pulmonary carcinoma." AMERICAN JOURNAL OF PATHOLOGY, 14 U93h 49-57. (EXP-HbC) 041 006148 1941 1943 1943 1943-51 6 NORDMANTf And-SOKGE'report lung -^lirwwi'lh^f^J^e^ic^fesLdti^ from asbestosdust inhalation;'M * .Nordmahn,:Jfc; `ahaJA^So^ge. "Lugenweo* ^Our^h sbistiub'irnAierviTriucn." . iEiTCGHRlFT^K^^B^FOflSCHU N G iJND^iil^lSCHBONROlX.GlL, 51 (194lh 168. : * ,-> .*.o^ ri . .... s .<. 4 Ml .- -C1 `V'!0 '(15) HEUPER con^lwJ&^ariWe Accumulated iliteruw^viisofestds<deiiffiteiy established ^JieopKrelation to BULLETIN 'C0WTROLOF CAHCER, 25 U943); b3. iKKK-HaG] -HuMfiUliGEK`ljjt*a'toUl o;f 22 cases of Uio^CfnCir^ii&^f^is^ctiinsy ana al^ii^l^j^^^^li^belation, says there isstill no del inite answer as to whetngfTpiHmohary-i^eitosls was a c^UMtive^factorririldiigeineer. fiomburger, Fvf ?I^^incidnce of primary Mearaiiiomatdf4he^ungS%rvd'puln)onary asbestosis s analysis Oflitereture." AMERICAN JOURNAL^ OF'?AThULOGY, 19 09431:797. ' JWRn-OTHJ Ub) Studies by WELDER, MERE*ETHER ana GLuY Nt snow that an average 14.7 ol workers with asoestosis also haa cancer of the lung* Welder, h.W. "Uber den lungemcreos bei asbestose." DEUTSCHES ARCH1V FUElt KLINK.HESKA1A MEDITS!NA, 191 0943): 1S9. aserewether, E.R.A. ANN UAL KEPuRT OF THE CHIEF INSPECTOR OF FACTORIES FOR THE YEAR 1947. London : H.M.S.O., 1949. Gloyne, S.K. "Pneumoconiosis: a histoiofr.cal survey of necropsy material in 1205 cases." LANCET, 1 U95Lh *10. (WKR'OTH) 1171 006149 1944 1948 -7 - The Tuberculosis - Asbestosis Survey , jcnc*^:teargy Metropolitan life insurance QoL ainder t^airec(ocshipsof UK. G. linos e tuberculosis mortality increase injjWtfproMines, Quebec, from tfie'jnld l9^/s lftUie^earlyii94l/s to he more than JfflL JThisin-contrastJto a significant decliner(35^irj|theirte-for the province as a/Whole. In his report WHEATLEY says: The obvious existence of a serious tuberculosis problem in Thetforo Mines haslebto speculation regarding the influence of asbestosdustV ' - `I'-i WheatiV.iJBi^BfKOUisOSIS AHD ASBESTOSIS :.MOKTALITYt IN THE ASBLSTOS^MIMING;GGMM UNil Y OF Tfl^QKfl^liESnSiflEtiEC. New York: MetrqpoiitianLife.Insurarice Co., 1944. ' /i r ;1WKK/P-U-OTHj (18) HEUPEK writes that since 1935 a total oi 33 ai^ pEaspwtosxancerofithe lung have peen.reported by -American,; Englisn ana Oermtjvinvestigators... He.repogts-thatoespitealarge numoer of workers exposeaYo asbestos. in the U.S. (over E^aujtheincioenceolasbestosis recoroeo was low. Thisinfermation contrasts Strongly with Germaneesearch oy BOEHME, whO;founa radiological evidence of asbestosis in 29* of 133 asoesios factory workers. Aeuper, W.C. "Environmental and occupational cancer." PUBLIC HEALTH KEPOK1S, supp. 209 (1948). [WKR-OTHJ (19) 006150 1949 1SS2 1953 -- MEKEWETHER compares lung cno pleural (membrane, liningof theJung) cancer In cases ofasbestORis reporieo forcompensation with lur^orpieural cancer in cases el silicons. ENTEKLINE (i78><sees this as the most - Jmpqrtantsingie stuay in bringing about a consensus orrthe relationship between asbestosis ano lung cancer in Great Britain. Mere wether, E.R.A. ANNUAL liEPUKT OF THE CHIEF INSPECTOR OF FACTORIES FOK 'i YEAR 1947. London : fi.to.b-U., 1949. Enterline> P.E. ^Asbestos ano cancer: the international iag.": AtaEdlCAS REVIEn OF RES>PmATOnY<DE>EASE,ii8 (1978). '_ iWAH-HSCj (2U) .SMITH reviews seientific work with asoestos and animals, .conducing mat the study oy NordmannarKLSorge,seems to demonstrate thaLasbestosmo/not^provoKe lung tumours. Smith, W.E. "Lung cancer with special reference to experimental aspects ARCHIVES OF THE INDUSTRIAL HYGIENE AND OCCUPATIONAL MEolClNE, 5 <195Z): 209. SMITH'S views on Noromann's work gains someaceeptanee outsioe Germany. (U.S. Puolic Health .Service, pub. no. 152, p. 35-38 U955J) (Arch. ina. Health, 15,207 (195711 IEXP-HSCJ (211 DR. P. CAnTIEK, in charge ot the Quebec asbestos companies* ineaicai clinic irom 1940 to 1974, explains to a medical symposium in Boston: "Asoestosis remains a disease wnicn can be tolerated for many years'*. Cartier, P. 'Vome clinical observations of asoestosis in mine ana mill workers." ARCHIVES OF INDUSTRIAL HEALTH, 55 C1956E 204-207* (Wkh-OTHj 006151 1954 1955 195b 1956 -9- teRESLOWJs epioemiological survey cites asbestoses^# cause ofiung cancer ana celiea for'further ''intensive investigation". Breslow,L.,(et el.} > "Occupations ana cigarette smoking as factors in lung cancer** - AMERICAN JtfUKN AL OF PUBUC HEALTH, 44 (February 1954): 149-296. tWKK-OThJ DOLL stuaies northern Englutd textile factory-ivorkers with at-least 2u years of exposure toesbestbs. He finds a ten-fold increase; in-theexpectea lung cancer oeath rate among this group. From 1955 on, the concept of a significantly increased risk of lung cancer in workers with asbestosisbecomes more widely accepteo. Doll, Jfc? "Mortality from lung cancer in asbestos urorKers^1 BRITISH JOURNAL OF INDUSTRIAL MEDICIN E,!* 0955): 81. (Wriri-HSC) (22) The epidemiologists Iook forepioemiologic evioence - for example, HAm ftiON L> anu MACHLEsays with regara to a* relationship between asoesios ana lung cancer..."there are at present too few cases ana too little epioemiologic aeta to establisn a significant relationship". Hammond, &C. and w. Machle. "Environmental and occupational iactors" in Mayer, . ana H.C. Maier. PULmuNAkY CARCINOMA, PATHOGENESIS, DIAGNOSIS AND TREATMENT. New York i New York University, 1956. p. 5a (WKr-HSCJ (23) Of SI Danish insulation workers with more than 20 years exposure to asbestos, 19 reveal abnormalities of the membrane covering of the lung (pleura) ana 6 have essential functional changes of the lungs produced by disease. Frost, J., let al.) "Asbestosis with pleural calcification among insulation workers." DA NibH mEDlCAL BULLETIN, 2, 7 (1956): 202-204. [wKk-NaCCJ 006152 1*58 1958-61 I960 -10- The Committee oji.Occupational Cancer of the AMA Council onOccupationaJ Health conclud t^t.in0vjoi^.?^ reports contrioute^ittleto fjigngerstandir^ of Qeeiipiri^^l^eaiHeee^iu^i^hat Specific ihcreases in.a^e^swcjrjap^site-specific cancer irifiiaieinde a^venpimuU^^epresent the only reli^le *yjceiKe. fe)r. the^existence of an occupational cane^rhazara." Occupational cancer: methods of epidemiological stuoy," uOUKNAL OF ihk. American medical association, iso (1958): 217L . 4*KK-hsc) The first,two epidemiologic^studies of Asbestos wo/Kers4n:JNorlhiA.rnerice ao not lung cancer. 4 Ak ^.eeirUjQas WjblJOis.saiajthat "there is no epidemio^^^^%i^nce^of-an association ' t^tweenaspestos.and lung cancer among American Wwk^rs^ , Hraun,'.0/d-:^/T.^^aun^ "An Epidemiological study of lung cancer in asoestosminers." AKCtxIVES OF INDUS'! RIAL HEALTH, 17 (19581: 634. Dunn, *.., (et aLJ "Lung cancer mortality experience of men in certain.occupations m Calilornia." AMERICAN JOURNAL OF public Health; 5| 2.09601:1475. Johnston, K.T. %icIicosls.ano cancer." journal of the American mEuical AssociAi Ion, Hs^Kik is*. ItfKRrHSCj 124) KIV1LUOTU finds farmers and tneir wives in a rural county of Funana witn the seine internal chest scarring as asoestos workers--tney had been exposeo to asoestos air pollution from a mine nearoy. Kiviluoto, R. "Pleural calcilacation as a roentogenologic sign." ACTA RADIOLOGIA, 194 0960): 1-67. INE1-N/OJ (25) I960 1964 1965 1966 -11 WAGNER ct aL finds that oi S3 patients withtoesothelioma 32 tea had contact with All lived in an ^ALsb^stbs `mirfiDn^' n^ioh'. jEJcven of the victims had^o3JCt^fijahaJ exposure. ^WifnerV^id;-, ^Kloiuse pleural : ln^ti^liom#aKi;isSli(os exposure in the BRITISH aOUftNAL-GFTNDpISTKi^L MEDICINE, 17 ' (1960^250. * l"rCs' ^ n c '-`^K/NiJ-CfcCj i2b) 'SEiilKOFF et al find excess oeath rates for lung cancer among Paterson, New Jersey asbestos workers to be seven times the expected rate. In .the stuq*. the ra tes lor ^gasfr^teitnftfean^r'aWthree times that `exp^tifo^e^^cuf^p^ore years after -i expo^fe^^lirtini^iat^tOsmoking. .* ?Overall/fc?5& MgheFfJSh average mortality SelikoilVEJi "Asbestos <*X6sure ano neoplasia.^ ^OSRNAij'oFTHt AmEaICA h MEDICAL ASbd^fXTiClKi.188 U9641: 22. " iWkk-DTliJ (271 SELIKOFF et al find that 4oi New York asbestos workers died of asbestosis ana occupation-related cancer. , Selikoff, LJ. The Occurrence of asbestosis among insulation workersin the United States;* Ah NALS UP THE'NEW YO&tx ACADEMY OF SCIENCE, 132 (1965): 139-166. (WKR-NRCCj THOMSO N'S 1963 study of Cape Town resioents finos an average ol 2c* oi male ano of female) of 6C0 consecutive autopc ^ *ave asoestos fiores emooaeu in their 1. A parallel sstigation carried out in Miami, U.S.A. founa closely matching results. Thomson, J.G. "Asbestos ana tne uroan dweller." ANNALS OF THE Ntiv YORK ACAbfeh Y OF MJILNOL, 13* (lV65h 19&-2J4. lNl-NRCu) 006154 1965 1965 1965-74 1965-79 -12- NEWKOUSEana YMUMFSUNfino, among London hospital'eriesf 76 c*ses, 46 mesotheiiomavictims wno ruio hao no ocla^fi<^!'e^pu^ntO:ii&estos, Out who HyeajwiViih''ilaif.*' hilleorMisOestos .^^{fho^^^oertoa worker.- 'Exposure'*in these 'c&Ses occurs more This study itioftbetween -^iRerWTfouse,1 mesothelioma. Wson. ^M^Uwfi^^r^iuri-^^Seritoneum foliowh^e>q[>ds5& to'^SKlsVocin the Lonaun area." BRITISH ^OtliCNALOF INDUSTRIAL MEDICINE, 22 0965k 261. ` , * it t j^6-HSCJ (28) -OF-EOpapers presentedata-1964 conference in New Cftynio oginionsliissent from - the We^ thit-asoftstps^ii a cause of cancer. Seli>roffj;L3riima 'J.':;eriurg. "Biologic enects A^ftAj&oFTHE new YOKn ACADEMY <)F'SCIENCE, 13z, 1 (December 31,19651:1-766. (WKR-HSCJ 6ELIKOFF reports on the prevalence of abnormal long x-rays in relation to years from initial asbestos exposure in insulation workers. Selikoff, LJ. "The Occurrence of pleural calcification among asbestos insulation workers." ANNaLSOFTHE NEW YORa ACADEMY OF SCIEN CE, 132 0965): 351-367. WALLACE <2 LAN GLANDS report the frequency of x-ray abnormalities among asbestos workers "to be 2U times greater than among non-workers". Wallace, w.F.M. ana J.H.M. Langlanas. "Insulation workers in Belfast." BRITISH JOURNAL UF INDUSTRIAL MEDICINE, 28 (1971): 211-216. (WKK-NBCCJ (3U> X-ray abnormalities are found not to be a prerequisite for diagnosing asbestos-relateo disease. 006155 . ^BAlitK elM notes a eeduction in the vital ^ **y lmpjiary function in " ' YUKK <pp^9io):*&Mu5. Wgffimm'wmmz A,*b iGJAE^l^jm<6 that eutopsy oata on llfiesws:*oricerejreyeal;tnafcin ntearly 30* .of theicaseswilhatleastminimaj asoestosxs, SfMS^^I^j^ti^seasPfepf^iiebec, .... ., ;'<?*; ,;.l -alf&AJteJJilCCj (31) Gases of mesothelioma oeveloping in infancy , or ehiicihooOi probably- asa resuit ol contact with aaU>wtos dust:- conteminatec! lathers, : 0972) - ................ ukUNly ;; Lieben, J. . "Juesothelioma ana asoestos expbsui.t: AH.CH1VJ^^OF . 14 <1967* 559. Grundy, G.W. ^idaiignant mesothelioma in ehiidhooa" CA N Ck, 30(1972): izits. : IP/OtBSCJ U9) 1968 1969 1971 14 , Tne Irtish occupation*! Hygiene Society J^cproraanastte of the ib?e/cn$standard foriasoestos exposure followirnfexamination of x-ray abnormalities in^29u.|Lsoestps factory ivorkers oy industry . x^icvrnaiities totherecorded dust 1|ona|U(^ eonoiud of contracting . 'isbtstasisiitthc-ltffibndeveL ' (B-Oriis.v- ubcnimittee'on*Asbestosis Hygiene Standards forrCnpyifttile Asbestos Dust,>Annal**of Occup.^liygiene, vol. 11 (1968) ^.,47^9)" v ` .0:^1*" ,; < 1.WK**HSC3 (32) BY ROM et ai find that emissions of asoestos ,f^m^^tioni)oMjuid sprayed asoestos are^gwtater tnabjthoaerlound;ih buildings wiULas^t^cemeiif*n**tir^ ana otner ; Whereidryr^rayeoesoestos fibre is exp^a,tu.tne^*nr*siofv oirdir movements, ijfmU^.CxUeVMis) *A-l>ust.survey carried out in^^dir^sincorporating?asoestos-basea materials in tneir construcuon." AN Hals OF OCCUPATlUN AL HYGlfcNL, 12 UV69): 141-145. ItNV-HSC] LANQBR et al confirm that chrysotile fiores or fibrils can4>e identified-in nearly all the lungs of adult .urban dwellers, if the newer techniques of electron microscopy are used, ianger, A.M., (et aLj INHALED PARTICLES, v. 2. Old Mfoicing, Surrey : Unwin, 197L (ENV-HSCJ 006157 1971 1972 1972 15- i tle?flri<litiQinp^&^irticle*^lh ground, 'urfatt^Eriddrin '<)ne^o^>MilIi6n`ffi)^dfile`is{>csto* . , w^uurr ju beer. River u^mWiiS^VfiDresth.n jwater>piss^jthroa ^infiltration from u ' jsa&ftfcbs*^ 5?&* '" .' * i Hind>ft^;;4>omefract. "Asbestos fiores ijv t>4^i|e^iid^3rintdng dM*W2 1<WfcOKt,t232 U871^ 332^ii. (ENY-CECJ ;ju :><m :-.* if -*_ris* ?*`r * tnat o?ftigh'concfcnirttions industry. M EDI tonto OC*VCOUPATIO ft AL IWKRrCEC] SELIKOFF finds measurable but minute mounts of asbestos in air near building sites in New York, where, asbestos spraying is being-done.' *High Wlume semprers ana . electron micrascol^lKrc.iiwa. .Vj SelikOffiLa.^Asbestos eirpoliiition." AitCHIVES^OF'ENVlRONMENTAL KEAETHi 2b (1972); HS. \ (NEl-NkuCj 006158 1972/1979 1873 1973 -16 - Tnereis little: or ho evioenCe thai cigarette -smoicing*is^ated*;increesea risk of mesoUielioma, accordingr-to two studies oy : Hammonds at . v * Haramonu, EiGvt*fr*l.*j^Relation oi cigarettr,smoKing4to^iy<r;of>ci0atr) from iast^Midssoeiitid^iseiise among insulation ivorkersiin the UiS^ThJBogoVikL P-, tet al.j LYON^PalANt^OCTOBBK^Hi, 1972. ; .IARC,publication.no. S. Geneva * Worla Health Organization* 1973. Selixoff, LJ. ano E. Ham mono. HEAL'ffa HAZARDS OF ASBESTOS EXPOSURE. New Yonc: iNew:YorfcAcaofemy. otfScie^e, 1979. . r r,,s*WKiR-N/0] Mortality study by NEW HO USE finds* in a 'Conortol*sbe*tfs*feetory-worKers,*xcess : mortality^roimcancTef'dfrthfc'itmgand other cancer^'even^wltn'idwJtomKSOerateexposure. Hewhouse*'M.f*As6estbsin^theworKpiace ano the community.^ANNALS OF OCCUPATIO N ALHYGINE*>1B (1973h 97-gtf. {WKK-Ho^J BOHLIG ana HAIN mention that tne distributionofmesothelioraasin namourg in 'the- vicinity of-ah asoector'factory is dapehoent upon the prevaiiling wina; a visible *tk>wfalHiXeairpOliution hadbeen emitted from the factory. Bohlig, h. ano E. ham. "Cancer in relation to environmental exposure" in Bogovski, P., let al.] BIOLOGICAL EFFECTS OF ASBESTOS: PROCEEDINGS OF THE WORKING CONFERENCE OF THE INTERNATIONAL AGENCY FOR RESEAftCh ON CANCER* LYON, FRANCE, OCTOBER 2-6,1972. IARC publication, no. t. Geneva : Worla Health Organization, 1973. INE1-CEC) 006159 im 1973-77 1974 -17 - Parlicularlyfor. mesothelioma, findings vary- r - dependingonthe ^medical criteria Chosen for sdiaj^cfi*J-'>2 .s.**vm McCaugney, HLl.-Eiianti P:Di Oldham. ^Diffuse jnesotbeiiomasyobsefver variation ^fmhUtoiogicairdiagnosis?^m^ogovsKi, P.f (et aLj B10i^GiCA^EfiPC3S.GF ASuLSlXJS s F^yGEtDmGS TilE^VUjGtlNG eONFtKEheE^E-,TH<lN<rNATJUNAL . /AiiENEtYTFUKiKaiStAilCHiJ&h CAftGElt, !,Wtl,lF*AW^QTQbI.Vl-, \Wi. JA:C:pupiicattt>a,'no.il; vGeneva :Worla -Health'thrgimi*tion,'4973. ; i K .t c n ^ >The. Advisory-CommitteeomASbestos Cancer UA&Oisays an increaseo risa of cancer resulting from asbestos fibres present in water, beverages, ana looa "does not inoicate-any risk". iwOHW3% vc vbv't -J - The^UEG* report:sayssevidenceson the risk ol -fastrointestinaLexposureis deficient and thatTicausafive/factors:for.fnducing . (astrointes.Unal'tumoursere ndt well . understood!. ' Advisory.Commi ttee on cAabestos. "Report to director of International Agency for Research on Cancer" in BogovsKi, P., let ai.j BIOLOGICAL EFFECTS OF ASBESTOS : PROCEEDINGS OF THE wOAKING CONFEREN GEOF dTttE INTER N ATIO N AL AGRN CY FOli RESEARCH On CA N CEn, EYON,FRAN CE,OCTOeEK-2-6,1972. IaKQ pubiication,no. . Geneva : World EiealthOrganization,1973. - UNV-CECJ WAGNER et al lino chrysotile as potent as crocioolite asoestos in inducing Jun* tumours in rats after inhalation exposure. 006160 -18 - This study is interpreted by the N10iH^SHAiAsirtistds<`a(Vcw,K Group U98U) a* dernonstreting thet *K3hrysotiie appears to bejnuchrmore-fiofogemc and carcinogenic t^nthei^pnil^w^^ amosite and .jsrocidol^t), finct lM concentration 01 dust ^i^t^iunfs.oT.rats exposedto Canadian ~ chrysotile^assQniyiis* -.2% oi tne oust - TO^^tration.in'theJungs of animals exposed '.tjc^amphrooles - yet the lung tumour ' incidences anddegrees of pulmonaryfiorosis were similar in*21 groups". Wagner, J.C. "Mesothelioma in rats alter inoculation? wi ttgasbestbs? and other minerais,"-.tiitl53S.H^&-UKNAu OF CANGERr.i$^imksJS^t: , >. 4 .^oziotts^XP-N/Oj 1974 In a review of 252 cases of mesothelioma with a Known history oi exposure, WhbbTLR fines the same percentage of pest . occupational exposttre{3dr45*j as oi last group had ^^^y4weo^|i|sarLiiiine;pr mill or in towns ^Uuytedin anjasoestos-proaucing area. IVebster.X -^Ine^ngestion oi asoestos fibres!" ENyiRONMEN;TAL HEALTH PEkSPECIIVES,* loecemoer 19741:199. ^-(N.El-CECj 1974 LEW1NSOHN presents review oi studies centreo on the connection bei ween mesothelioma ano type of asbestos. There is general agreement that the risk oi mesothelioma is fibre-relatea in the order crocidolite - tmosite - chrysoliie out the magnitude of 4he difference Oetween eecn type is not well established. Lewinsohn, H.C. "Health hazards of asbestos ta review,of recent trends.!* JOURNAL Or THE SOCIETY Of OCCUPATIONAL MEDICINE, 24 0974): 2. IWKK/P-O-CEC) 006161 1975 1975 1975 1975 KOHL atarshows that when profession*! construction workers sd meteriels similar tooorit-yourseli products, the concentration of as0estos inTelr7exceeds U.S. safety standards oy a^actor'is%rea t as XL >&9htj A.^.^Expoiure to asbestos in the use cl consumer-patbhiihg'ahb taping . compounds." ^GlEN0EfH8S 0975): 551. ; NICHOLSON7 eteWiridsthe level of airoorne asoestoscust^'tf^Kbrnes oi workmen to be IDriflUU hariograrospefciiDic metre. SKIchoison, w.J., tet al.J AbbL&Tub CONTAMINATION OF TiiE Alrt IN PUBLIC BUILDINGS. KTlo report, no. Pd-2ou IP^O-N&CC) `Observations by LlELHUEs et *1 suggest tnei there-is'aiperticdlirriskassociateo with Ifceak? exposUre^lihrels, making asbestos dust -expusure-ievels averirgco -over many years an unreliable'ir^icaXor6(xtiow dangerous the exposure tuts^been. Among 48 mesothelioma caseswithdefimte/probable past exposure, 40s have intensive exposure, out m 71% it is intermittent. (Pleural mesothelioma ana exposure to asbestos; s retrospective case-control study in the'Netherianas. Ini. Arch. Occup. Hlth., U) (WKn-CECj HOWARD et al evaluates the effect of a reduction-in asbestos dust levels due tu technical devices at a KoChdale factory in Britain. There is a oecrease of mortality in workers entering 1950*1954 ana more so in those antenng miter 195U Dust levels nao fallen in the 1953-57 period by approx. SO-tUa throughout tne factory. Howaro, S., (et ai.) A MORTALITY STUdY AMONG ftOKKEKS IN AN ENGLISh ASBESTOS FACTORY :181h INTER NATIONAL CONGRhSb ON OCCUPATIONAL HEALTH. Brighton :n.p., 1973. IWKK-CfcCj 006162 1*76 1*76 1877 1977 -ao- A sury.ey ay.SASTiEN of asoestos in the urbanjiir ot fi^epyrbofgiitwiiaings in Peris, Prance finas concentrations oi ***** to 0 hanograms/cnf3. of air. ^Jollmions *tnjpsp^r=wmiesurbainesjc rasbeste." RtyUFRAN,uAlbi35AiALA^Ii^ RESP^i^dttdS!, $0Bg(i9m 51-62. ....... " '' ' " ' * itNV-N&CL-j SELlKOfF uggetl*.Uiftt 41e Intent period is inv^sgjyj^fi^^^^pse, ihat is-tne lower longer the period"jfrojn i^itiij iwp^iure.to onset of Seltkdf,XJ._*^|i<yioeyr Hsk,<^ asoestos exposure :'paper presentea at Colo Spring Harbdur laoorutones, New Yonc. s.l. m.p., 197a. I*h.K/P-0-HS0j MCDON ALD et alzbow an excess of gastrointestinaijcahcers in men exposeo to the highest doses of dust at Thetforo Mines, Quebec. Mciionalu, J.C., {et *L} "imst exposure ano mortality in chrysotile mining, lflu-1975. Unpublished oata, 1877. IWKa-HSC] "Because of lac* of clear distinctions between the various possibilities of exposure... greater reliance should be put upon oiological njonitoringihan on environmental monitoring". Tne CEC report also states: "uur to tne fact that classification of.the relation between fibre size ano biological elleel is central to the poesiole environmental hazaro of asbestos, the reporting of fiore aimansions in adaition to fiore concentration is imperative." 006163 -21- ZlEHUiS et ai conclude ../."inadequate data existon which tqbase aqoantitative dosfe;irfesportse r^tldnsMpifor - a&j Ontne otoernano.~1here~li often a clear *c(Sri&3on of exposure, typed! jdoiintertfjtyiif. erpo.ure) out qibh^&tionliHtdt a<&fliately possioie." Zielnuis, R.l. PUBLIC HEALTH Rbtt* UP EXPOSURE TO ASBESTOS s REPORT OF A WORKING GROUP Of EXPERT* rti&llskis&PM thecoM^ission of lilR^^K^TE^Gfe^S^^UR SOCIAL SAFETYODIRECTOilA^rE.: `he* Yotk j : - ^ i - 4- "t#lCR/p-o-CRC) 1077 EPLEK and GAENSLEK find 23 shipyard anu manufacturing plant workers ol 763 total nao "pleural effusions" (exudation of Body fluids 'from Vessels!, wniefi.faay.preoispose suojects tb :.s Eprerjr'G'.k. and'E.A. Ga'ensler. "Asoesios effusion." CHEST, 7 2,~ 311977)* 309. `Iwkr-NKCCJ 1077 SARACCI conduces that although the availaole aata uo not allow a otmute answer, the model of muitiplicativejisks of inhaling `asbestos'ano smoking toMicCo appear more plausible than the addilfye fisk model, or One where asbestos his an effect only in the presence ;of smoking. SarScci,'k. "Asbestos ino lung cancer s an analysis of the epidemiological evidence on the asbestos-smoking interaction." INTERNATIONAL JOURNAL OF CANCER, ft 0977X323. (WKK-HSC] 006164 1877 1977 1977-1978 -22- ELIKOFFsurve3* 4*5 ciurreht employees of a<chry*otile'mrineat<Sie Vepte, Netffduhblaria. OverXifcmVC one or more X-t*y*bh6rmilities associated with asbestos TtxpOiiU^e^iiesptte^e^ndrf-^erioo from initial ' '*eij|ibiftir2--i 'tc ''* v>>".s;^n5 tThe?Mti5mai study^team recordea tne `WghestAfrbbrheievel Ofiasbestosdust founa anywhere in the^wbHbit&ere Yerte./ of "i =MlLLERS-iN -BAlE^ERTi, A ot the NATIONALINSTITUTE OF ENVIRONMENT HEALTH SCIENCES, DECEMBER 22, RESEARCH TRIANGLE PARK, N.C. S.L :xup.,J9?4>. > ^ fWARrh/Uj ^ -WEISSreports nounusualmortality -`expeFienee,-overa1^year-period lor a cunort ^workers^mployeoiin'aipdlp ano paper nillbOar-o#plant-using'only enrysoule. weiss^i-JSMbrtilij^ ofa*eo~&ort exposeo to %hrysotiie asbestos;" dOORN A L Pf OCCUPATION AL MLD1G1NE, IS V977k 737. tWKR-N/UJ ELMES ano SltaPSON U9?7) and SEL1KOFF (19?8)econclucie that a-the-past when occupational asbestos exposures were high, aaoestosis was the :e&rlitr?c*use al oealh oniythose whodkrnotsuccumb to its effects Jived long-enough toaequire.-iung cancer. WitlvlOwer4evelsofcasbestosexposure, the earlier caused! -death isiung cancer followeoby mesolhelioma/and only tne survivors of theseaufferifrom the now more slowly developing asbestosis. Eimes, P.C. ano M.J.C. Simpson, "insulation workars in Belfast: a further study of mortality oue to asoesios exposure, 1840-1875." BRITISH JOURNAL Of INuUoTkIAL WEjJlClNt, 34 U977hl74-18u. Selikofl, LJ. ASBESTOS AND DISEASE. New York : Acaoemic Press, 1971. tWRK-NKDC] 006165 PETU finds lhatatthe 2tore/cm* standard, ion* asoestosworker out oij* runs tnc risk ol - dying*premature)y; fcomasbestos-reiated disease. He ^`inas^usoitnft -tne lung cancer piantin Engianu is almost OQuo^t^expecteu rate. Immortality tiucjy Mm&x.worktrs in an -English asfc^stosJaCtpry^ ^hril. J. Ino. tafeQ. Petv <h '"i'nc ;Hygjene*stan^taro for ; chiysotiiejasbestos ;tperaomittea to the Adyisory -Committee on Asoestos." Lancet, 1 , jomhm.: IJtfKltrHSC] < DA1S et al investigate the question of the relative harm produceo oy different types of asbestos fibre. He notes that NAG NEft'S 1974 findings concern only lung cancer, not , rmesothelioma. ilealso^concludes that the relative^pathogemcity^t-thesaiflerent types < of asbestos inay dependupon^the proportion oflipres^reater^thaniaitnicrons in lengtn. Davis^^MiG. 'JMassendmumber of fiores in tne pathogenesis trf asbestos-reiateu lung disease in-rats." ftftlTlSH JGUKNAL OF CA-NCfcJi, S7 UV78h S73-S88. IEXP-NKCCJ ANDERSON et al lino a high prevalence of s?reyiabnormalities ana mesothelioma among householo contacts of former amosite insulatiooplent>employees.. Anoerson,:H.A. "Householoexposure vo asbestorandriskof-subsequent disease" in Eemem R.A. ano J.iw. Dement. DUoTS AND DISEASE; Park forest South, El.: Pathotox Pud., 1979. IP/D-N/OJ - IfisTound oy PYLfcV:thatsynthetic fiores as well as naturally occurring fibres were eaj^inbfenic^'lie'prdducetrmesotheliomas in rtts^iAJtcf4d iithin the lung cavity * fibre, ano primary - UfuhgpiiRndti^ 9#l^^r^amsters injected ' - within*the >cnestdctviiy with a syntnetic J ^cHryS&tBe;^ ** '* -^'Pyl^^lL^ - *r*timiorous lesions, iung anu c* |pjeifl*llitumbui%`iihtfttc^d by%st>estos in rats11 ih^01^IUX-LFFEt;i'S OF MiNKAj. *F1BRB>. yFrinci&AKC, 1979. ^A^tXP-KKCCJ WA'G5N^EK^t;al*shaws*ithat a commercial ' ^aue^f^iisbestcs^^nelmy snort Hurt < ^Canadianf^1tysbtilei^ed primarily for paint > ^irid^S^t^C^ll^fiift,ispc*in induce mesotheliomas wheninjected witnin the j ti(Vi^iffehitfrime 'dT-rat^and`can induce lung - tUnirdUrs'ihebplasinsj^heri1^^ animals inhale Wagner; 4jC7 ^fw5 Comparative eiiects 01 jTthree chrysOUle?by injection and inhalation imrats^in-SIUlkiGTCAL %?FFhuTS Ut MINERAL FIBRES.' -France * IARC, 1979. lEXP^-N/U] HAMMOND'S lb-year followHip study oi 1*4051`asoestosins(Ration workers with *>or more years of work experience obtains compete smoking nistories lor aoout i/4 of the subjects. He ano btUKOFF fino the prooaoility tnut workers' lung.eancer-is oue to asbestos exposure to oe about iVinboth smoaers anu non-emokersalike. Seiko!!, LJ. ana L. Hammona. hEALTH HAZARDS OF ASBESTOS EXPOSURE. New York : New Yock Academy of science, 1979. (WKR-N/Oj 197V . 1979 25- ACHESON ana GARDNER, conclude: aj ficperiraentakwork shows tnat lung CAnc*r,f*^^titAf^nicsotheliomii after -infw^iw^i_tne/l'o^r.i|ypes of asbestos, ... and cnrysotile arc at least as pat/g}gnic.*s the amphiooJes Uncluqing-crpc.y&mej^daahthopnyllitel. t- crocrodlite andamc^tejip^cjmpi^ dangerous in .^ooupwitW SSieer^ano esoestosis . than cnrysotile. cl As for mesothelioma, combined evioence from process workers, from miners ana from;the.jpis.trAbut;ioa.of neighbourfiooa and^rnesUe,,oaseslprt^ents a powerful . -oase.that crocidplile^ias been more r dangeipurjthanisPiys^Ule. s : 3^^^^Q^oc^esiiii9n^Tej(!ie^ab0^ tnat enrysotile Jias r^lyrC|Ui^.mes5thelionna or cancer of the larynx. On the pther hana, the proven capacity of chrysotile to produce mesothelioma inanimals^ifrihe fibre is of a specific configuration, and-the probability that cnry^Uie.is.beconung-increasing!> finely^ivioed ana respirable. should be kept in irnino. Acneson, .11. anu m.J. Gardner. *Tne 111 efiects of asbestos on health" in FINAL J&PUaT*OF *i Ht A>VlbOifcY CUKiMliT.bc. ON ASBESTOS: V.3. Loooon : 187S. p^3. ; . iwivn/P-U-hbCJ JONESetal report that.women in a wartime gas mask Jaciory hdvir^a.iong employment period haves higher proportion of oeath oue to mesothelioma than tnose who hau a short period of employment. 00S168  86 rDc*eHesponseevJdenc*Trm this stuoy agfeeif with thatliem-bfciDMA h U5791, I^DLLetoia977l,BLKKT et al (19791 1W>d 'IWfeW^Otfi>E hQ iiJiiKHi U9? bl. ^owestif.4fcfrr'"^ Coftseqilences of asDestos oiSt^J^lufe^rfa ^arthheitfas ma$x inutory" In'TJi^filOtodlCWJL^EFFEeTS OF ' %imLkift&kESi: motet ia*u. 79. j. 1979 '., among a cohort of^l^en^lth^lrieis^au^ears ol 1979 1979-1980 bEKKY et al followup the 1968 BOHb stuoy of 379 oritisn asoestos textile lactory workers at Rochdale. Of men exposed alter 1954 6.M hau possiole asoestosis after an average followup of 16 years and an average of exposure of 5f/em^. Cumulative oose oaseo on eomoiniiig oust concentrations ma> not be satisfactory. (Asuestosis: A Study ul Dose-Response Relationships in an Asbestos Textile Factory, br. J. ino. Med. 36, 981 (WKR-HSC) McOONALD, LIDDELL et al report follow-up of a cohort of 11,379 workers exposed to chrysotile for at least a month in the mines and mills of Thetlord Mines, Quebec. 006169 Th study results include Tbs ^rnsjor-occupstionsl Hazards of chrysotile Mbestos cxposurtju^respiretory esncar and tliSifiojnpiicstioos of;iHdroofiiiry tiarotis. Excess-mortality |ro^Iungt^tncer is directly -reislcd-to sccumuUtfa^oius^exposure. utng ; were i* ^uiiicisntc^oence to distinguish , bftwffn risk . models, there art no- excesl6uesths from laryngeal cancer. Overall mortality for men isteat Tfttt/oro **<**** McDonsid, *ioriiSjftytn V*fo4ai^-^ millers Of THE teVi&f'`Oust exposure ano 1WH975."