Document jmEq6XxzgNJXjeV8kMjBpkwp5

(MMSltts Crweenmental Proteaioo Rmiwh and Development Offieed Health tnj Smnreometnal AiunniM Washington OC 20460 PA^0QS-icO03F Aar. 1991 Project Summary ,*'Wr / Airborne Asbestos Health Assessment Update PLAINTIFF'S EXHIBIT SA-S31 WJ. Nicholson Oats dew taped since the early 1070a, from largo population studies with long tallow-up, hive added to our knowl edge of asbeetos-reisted dJaaaaara and strengthened tho evidence tar asaoda* tiona between aabactoa and specHls typaa of hauKh effect*. Lung eanear and meenth^<-- |p f** "IhffT tainn*t sabeetoe-related ^------ -f d|||h amoria ozpheed Individuate. Cinw oithear wan ltuna hac ataa boon aaaocK atad wnwnaaesbbeeaetoae ae;saoourc. mo a muuud data suggest that tno as riakof lung eanear from aabactoa expoaura la proportional to tho cumulative azpoaura (tho duration times tha Intancity) and tha underlying risk bt tho ab aanca of azpoaura. Tha riak of death from maaotnelloma la appraximataly proportional to tho cumulative azpo aura to aabeetoe and Increases sharply with time shea onset c' .spsaura Animal atudlae confirm tho human apMRinSEiaiea! results and lOdtastaLlftat al rnatoT 4b4ttaivtrtatiaiLMMtoa ham tiaimJi ind maa^'x-'i^* with MiyiUlfRU dlflirenMS tnSttOOflgaaie pflaney. Same mrsaui>manti~flffife_ `Wats uiik MhMatoaUMauuu.azeaadtng to-tlmaa Bldkgrauna-ocaua-ln ikaHWUMtBhll' Invironrnanta. cue- rantly, tha moat Important of thaae nooOdeupananai Jxpdeuree ia tne release of Ifcartfrom aaoeatoe-oomamino aur-- feeing Building mlUMIIs or from, sprayed asbestos nraproouno-in-tuoiv -If aultdlnga.. Extrapolations of risks of aabeatoa eaneara from oeeupatlonal circum stances can be made, although numeri cal estknatae In a spedflo azpoaura ' dreumetancs have a large japprozl- mataly.tanfold) uncertainty. Beccuseof this uneartalnty, caleulatlonaofuhitrlak vatoaa for atbadajjtfL.toaL<ncanira- ttana mud be viewed with caution and ate Wbfrct to the following limitations:- 1) vsrtaourtv In the szposutt-rasdbnsa rmauonahlo at high, exposures; 8) uw. cartalntv In extrapolating taaxpoauraa mog nvvh- imi--f--wtu l ff--,, electron mlcroaronte flhor counts or maaa determinations. 7SST Project Summery wit devef- ooedray EPA'i Envtommeft&fTSHterio _ trid~AtieeiiTont Office, Resrch Tri angle Petit, NG> to oanounee key findtags of tha research project puOUthed, to lig&Uui to kilty documented to e aaparala report at tho earn# title (too Preject Report entering totometbn it boekf. Introduction Tho principal objective of this doeu- ~ mom k to pravdo ihe U.5. Environmental Pmtaaen Agency (EPA) wh a sound a- , otic baas tar rsvlsw and revwen, as appropriate. cf tho nauonal emoson stan dard for asbaatoa, 40 CFR It. subpart 0; aa required by the 1977 Clean Air Act Amendments, Sections 111 and 112. The healh affects bask for designating sbestoe aa a hazardous pollutant and minimiz ing amissions vis the original 1973 Nahonai Emissions Standard for Hazardous Air Poll*arts was sovtinized, at mat urns, during two public hearings and s public qpmment paced. Once a pollutant has been PnnrtC on RrcroeO Piof t designated as a ttaxaidoue* air poftaant, croddoMa.lsu with amosie. and dileae burden of proof piacad on proving withchrysotiie. This suggsstien mu bated iesignauon wrong. ___ . til* original Maaiatt effaeto baai* lor dasignating asbestos as a hazardous f . pollutant was qualitative ew<eoc# astato- tithing asbestoa-asaoeatad carcinogenic on die asaoctation of diseaM with axposuree. No unit exposure risk information exited prior to 1972. Information on exposure-response re lationships for king cancar nsk among vari effects. However, insufficient bases than xistsd by wheh to define pertinent quanti ous exposed groups was scanty. Dtoafrom Canadian mute and mill amploysee deariy tative doae-response retationahrae; La^ unit riak values could not bs eradibiy estimated. The main focus of tfia update documsr* is to dascribs asbastos-ralatsd health affaeta davalopmants sines 1073 and to deter* mins if new data warrant tha specification of unit risk values lor asbestos. Tha docu ment forms part of tha bass to perform a risk assessment. Tha National Aeadamy of Sciences (NAS) in 1983 suggested a definition of nsk assessment as me use of tha factual data basa to define the health affaeta of exposure of indiv^uais or populations to hazardous metarule. such aa asbestos. Therefore, the update document s maaily concerned wsh the excess nsk of cancer from inhalation ot asbestos ftoer*. wsh emphasis placed on the laerature pub lished after 1973. and on those reports that provide information on the nsk horn low-level exposures, such as those en entered in the non-occupational anvi- tenant. indicated an inoaaaing risk with increasing exposure, measured in terms of miSons of particles per cubic foot-years (mppef-y), but data on the risk * minimat exposure were uncertain because the number of expected deaths calculated using adjacent county rates suggested that ail exposure categories ware at elevated risk. A study of retirees of the largest U.3. asbeatoa manufacturer showed king eancar risks ranging from 1.7 times that expected in the lowest exposure category to 5.6 times that expected in the highest. .Exposures were expressed mppef-y. and information on conversion of mppd to tilers per mdUtsr was available only for textile production. Despite the paucity of data, the 1973 re port of the Advisory Committee on Asbeatoe Cancers io the IARC stated. *The evidence... suggests that an excess king carcinoma risk is not detectable when-tite occupational exposure has been tow. These low occupational exposures have almost certainly been much greater than that to the public from general air pollution.* Unt jupatlonai Exposure ied data existed on the association of Qt The Intarnatonal Agency, fpf.Research on Cancer iIAflC3Jt5s asBaitol assflifflg t~carfinoden. meaning that exposure W isSrerirSronogen^riumahs.EPAs gyrielmW^mtia CJIe^QfUe--~ be'stb't as Group A, human earonooen. cancer with asbestos exposure, but the 'excess is relatively smal compared with that for bronchial cancer.* ' The prevalence of asbectoeis. particu larly aa mandeeted by X-ray abnormalities of die pleura or parenchymal tissue, had aansMafK been documented more extensively than ^.rth rv|n mio+\Jf ihHiirle ssheeinsw. the nsk oi the asbestos-related makgnan- rnesomelama. onanchooenxe caronoma. am. in pert mw documentation reacted and cancan ot the gastromtastmal (Ql) from knowledge of this disease extending tract, inducing the esooneaus. stomaea. ' back lb the turn of the oentury, wherean colon, and rectum, tuna cariber m aaaocf- the makgnam potential of aibenoa area ated wsh exposure to four ommd ftom- not suggested until 193$ and not widely maroul varieties of asbestos IPer amotee, approested until the 1940s. Asbestoaif ahtnopnyMse. cnxcoixe. and r6i^khnieL had been documented In a ends'variaevof. Excess taka ot oror "" _ _ worft creumsunoes |r~1 a^SSuWaWfed "m mlne^ end mna. 11 oammewal types of asbestos fibers. manufacturing. arid Ttftd- prixfutdjQSa-(IP*, Among some heavily exposed groups, 50 pbeation of in*;ation'm'arsnafST'S**S^E&^ tt 10 parosrt of mdmdusia employed for Borne-iS a cause atrdsaitranejMU leuury 20 or more years ware found to have Vmployeet, irttUUtah eppfidatort, and- abnormal X-rays cftanctarsae of asbeatoa Workmen emptoyeq i in* mnnq and if. exposure. A lower percentage of abnormal mg or crocioome A much lower nsk of X-rays was present in lesser exposed dsath-from meiotneliome is observed group*. among enrysotae or smosite mine end mil Companr *na supplied to the British employees, and no cues are associated Oocupaicna. r;-ene Society (BOHS) on vrt anthophyiixe exoosure. The IARC Ad- X-ray and time* abnormalities among 290 ^Jbry Committee suggests that the nsk of employees of a large textile production 4Hto`h from masothekema ia greaftal wth feefey x Great Brcaut wars analyzed in terms of a fiber exposure-response reiationahfp. 7he rseuJti wero utifized kt eetabtithing the I960 British regulation on asbestos. These data auggseted that the risk of developing the eariieet signs of aahaeioaia was less than 1 percent for accumulated fiber exposure of 100 ffeeryears/ml (f-y/ml). e.g.. 2 fibers/milliMtar (f/mi) for 50 years. However, shorty after the establishmem of the British stan dard. additional data from the tame fac tor population suggested a much grsatar prevalence of X-ray abnormalities than ww bslaved to exist at the time the British standard was set in 1972. These data resulted from use of the new IntamatxMu! Labour Office (LO) standard dasst'eation of X-rays and the longer tima from onset of employment Of the 290 employees whose dinical data were reviewed by the BOHS, only 13 had been employed for 30 or mare yean;. 173 had lata than 20 years of amptoyment The progression of isbestosi* depends on batit cumulative exposure and time from exposure; therefore, analysis in terms of only on* variable can be mielead-. g- * Environmental Exposure " Several research groups had shown that asbestos disease risk could develop tram other than direct occupational-expo sures. Various researchers in 19S0 have shown that a mesothelioma risk in environ mental circumstances existed in the mining areas of the Northwest Cape Provinos of MM-m nt tfl a 5-vesrBjjgpd-^pughiy hx from occupational sxposure. However, a* but one ct the remainder resuxea imm irpoeure oc-- tying or working in W area ct the mminq activity. Another .study in 198S that showed an extra-occu pational risk investigmed the occupational and reaidantial background of 7< individu- all dacaaaad of mesethefioma in a Lon don hospital. Forty-five of too decadents had been employed in an asbestos indus try; of the remaining 31, 9 Bved wnth someone employed in asbeatoa writ and 11 war* individuals who resided wkhin had a m9* of an asbestos factory. In 1973, tnyeatigiton kfantifiad snyxonmerffH tf" Beatod Ixobsure xi as mesothelioma cases wsheut occupationel exposure who r--rdad near sn asbestos tactory, further dsfining- rasidential risk. A final study, which is par ticularly important because of the size of tit# popultoion impfied to be at risk of ss- beatos disease from indirect occupational exposure in the shipbuidmg industry, was eonductad in 196$. fe dasenbed the prss- no* of asboetesis in 13 individuals and msaothsiioma in S others who were sm- pbyed in a shipyard btrt were not mem* as wail u individuals axposed in occupa- bars of trades that regularly used asbes* tionai drcumsiancss. .tea. Rather, they were expoeed to the dust `craned by other amployaaa placing or SxpamantaI Studies moving insulation. . Evidence of ubiquitous ganaral popuia* tion exposure and snvironmeotal contone- nation from the spraying of aabaatoa on ttia stssf-work of ftqfwaa buildings waa established by 1972. Asbastoa waa com- Experimental animal studies using as bestos (fears confirmed tha risks of lung cancer and mesothelioma from smosSe, eroddoffle. and ehryaotila. in each ease, tha aatabfishment of a risk in animals fal lowed ma association of the mafignaney monty found at concentrations of nano* grams oar cube meter mourn in vimiatfr aif Unitad Stataa cues. and at concentred tiona of mieroomma oar kae fno/tl in river svstams of tha Unaad Statas. Concentre* tiona of hundreds of nanograms par cubic with human exposure. For example, a causal relationship between king oncer and asbestos exposure in humans waa suggested in 193S and confirmed in tha lata isaoa but was not dsaerfeed in the open litstature in animals until 1967. Me matar wars doeumantad at distaneaa up 10 sothelioma. reported in an asbestos worker one-quarter of a miia from fireproofing saaa. Mesothelioma waa acknowiadgad by tha Advisory Commmaa to ba asaoeatad with anvironmantal axoesures. but i suggested that "the avdancs ralataa to eonditiona in 19S3, waa produced in animal experi mentation in 196S. Othar animal axpari* mantaten showed that combinations of asbastoa and other cardnogenie materials produced an enhanced risk of aabaatoa many yaars ago.... There is no avdancs cancer. Asbestos exposure combined with of a risk to tna general potato at peasant* exposure to banz(a)pyrefta waa demon* Analytical Methodology strabfy more eardnogemc than sxposurs to ether agent tiona. Additionsty, organic During tna lata 1960s and sarfy 1970a, and metal compounds asaoeatad with as* significantly tmgrovtd matnodt wars da* vaiopad for assessing asbastoa doease bestos (Stars wars ruled out as important factors in ma carenogsnidty of fibers. and quantifying asbastoa st tha snwon* Uutfy, in 1973 experimentation involving msnt In 1971. a standardized msthedof* ogy waa attabtiahsd. It provtoad a unform tha application of (beta onto tha pleura of animals indicated that tha important (actor ''ntanon for assassmg ma pravafanca of in tha carcinogenicity waa tha length and sbsstos-reiatsd X-ray aenormatsias. width of tha (bars rather than their chemi* Significant advances wara also achieved in the quantifcation of asbestos cal properties. The greater jhr wee reuaedlnffcefem* were lemhew aerosols. In ma lata l960*.-me membrane 2L5um in diameter and lonoer than to um. filter tacftmqua was davaiopad for the measurement of asbestos fibsrs in work* Currant Astestos Standards plies asrosois. While mo procedure has soma bmitatcns, a dd establish a sun* dardtzsd mstnod. usmg simpfa nstrurnsn- taten, mat was far supaner to any that axatad previously. Tha method subes* quemiy ailowsc cdsmotogeaf studiaa is The currant Occupational Safety and Heath Adnureorsuon (OSHA) standards for an S-hourtme-weijhttd average (TWA) occupational axpoaura to aabaatoa is 2 fibers longer than S pm atlength par miHStar of an (2 Vml or 2.000.000 t/m*). Peak ba dona that oasad etposure estimate on exposures of up to 10 I/ml are psrmiosd standardized criterion. Experimental techniques m the quanuheation of asbaa* tos at concentrations of tsrtna of ngnn* of air and tantns of ugh of wsisr wars atao davaiopad. extending the santaway of as* posurs estimstM approxmataly three or* dars of magnitude bstow these of occupational aerosols and alowtng as* s seem ent of gsnsre poputtten exposures. t Finally, tsenneues tor me analysts of as* bestos m lung and ouir body issues ware davaiopad. Test* dgeston tectutfouas and me use of aiactron moosoopy to anafyza fibers contained in me dgssr and in met sactnns of lung tissue shewed that sabea* tos fibers wars commonly present in the -g tissue of general population reetoents for rm more than 10 mat This standard has bean m affect sinoa July 1, 1971, whan a replaced an earlier one of 5 Vrt* TWA. in Croat Britan, a value of 0A Mml is now me accepted level tor ehrymlie. This standard has evolved from recommenda tions made m 1979 by tha Adway Com* mittaa on Aibastos. which also recommended s TWA of 0.S (Ami lor amoaza end 02 Mml tor eroodoiits. Prom 1969 to 1963, 2 (rmi TWA was tha standard for chrysotifa. The earlier Bntsah standard served as a gutoe for tha 1972 OSHA standard. - Tha 1969 8rit*h stone**. -rsa davat* opad speeficaily to prevent aahermsa among wortung poputobone; data thawould slew a dsiarmriatjon of a aandard for canear wara fad to ba lacking. Among occupational groups, cancer a me primary _ eauaa of axcasa dean among workers. 1 hrse lou/tna or mora or asbestos.reUtr**?" Osama era Warn rfiricnancv. Thk fee* um OSHA to propesa a towered TWA stan dard to 03 1/ml (500.000 (An*) in rytctu* 1975. Tha National Inatituta for Occupa tional Safety and Heath (NOSH) antici pated hearings on a new standard and proposad a value of 0.1 (An! in 1976 to an update of their 1972 criteria document In tha discussion of the NIOSH proposal, it was stated mat tha value was selected on tha basis of the practical imitations of ana lyticaltechniques using opticsi microscopy, and that 0.1 tftnf may not neesssanfy pro tect agairnl cancer. Tha preamble to tha OSHA proposal acknowledges that rein-. fomation sxisti _bv which define * threshold tor asbestos carcincosnesia. The usha proposal nas bean wshdrawri. and a new proposal waa submitted on April 10, 1994. In it. OSHA proposed a TWA stan dard of cither 0.2 or 0.5 f/mi depending upon information to ba obtainedTn hear ings {held during tits summer.of 1984). NIOSH reelftimed its position an a 0.t Vml TWA standard. * Tha existing federal national emission standards for asbestos era publishsd to Part 91, Title 40. Coda of Federal Regula tions. til summary, these apply to milling, manufacturing, and fabrication sourcea art to demolition, renovation, art waste dis posal, and indude othar itinitstiona. In ganaral, the standards allow aompiianoa alternatives, either (1) no vmibis emissions, or (2) employment of spsofisd control techniques. Tha standards do not indude any mass or fber count smasion limns- tiona. However, soma local governmental agencies have numencai standards (eg.. New York: 27 ngm*), but thesa have kale regulatory relevance. Otter Rdvicws of Asbestos Health Effects fiscsrely, several government sgsn- das in different countries reviewed tsbestoa haaidi effects. Tha most important of tha reviews outsida the,United Statas are those of ttte Advisory Committee on As* bestos of the British Hsslh and Safety Commission and tha report of ma Ontario Royal Commission. Each of these major reports waa tha rasul of lengthy testimony by many scientists and delberatena by salactad oommittaes over a tong penod of time, in the Unitad States, the NAS has reviewed the non-occupationsl heshh nsk of sabestifonn fbers, and a Chrome Hazard Advisory Pans) convened by the U.S. , f j' ' , i j ; a Consumer Product Safety Commission ra tidier years. Soma diffaranea* between ted on the hazards a# asbeatns. studies may be related to differences in Ther* er* taiga ana* of agreement fiber type, but thaaa ars much tea* than ^td some of disagreement between thaaa those associated with specific processes. reviews and those of the fuH document Four studies provide similar quanta** with regard to the spectrum of asbestos* thro data on tha unit exposure risk for related disease, the models describing as* meeothsfema and six additional studiao bestos*ralatad lung cancer and provide aonebontiv*. but less seaxste, mesothelioma, unit exposure risks in occu quantitnive data. Tha same factors that pational circumstances, possible differ* affect tha lung cancer unit exposure risk ences in eaionoganic potency of different appear affect that ol mcaotoeioma. as asbestos minerals, and risk estimates at th* ratio of a measure at meecthefiom* low. non-oceupational exposures. risk to excess king cancer ride is roughly Summary constant across the ten studies. However, in ether studies the ratio ot number ot .Lung cancer and mesaheltoma are the tiMeathaliema deaths to king eanear deaths mowHCTpcrciTW laPasluseaUiad sauasrof-- among groupe exposed to substantial "death among exposed individuals. Gas*- quantties ol eroddolke is two to four tknea deaths per 100.000 female*. Correspond ing numbers lor males art i.g masoto** Soma d*aths and 1.7 excess kin* eaneer deaths par 100,000 indhriduais. Excess Q1 eaneer mortality is approximately 10-30 percent that of exoass lung cancsr mortaiky. Thee# risks ar# subjective, to some extant, and are also subject to variability in to* *xposur*-r*spons relationship at high exposures, uncertainty in sxtrapoistirg o expoauroa 1/100 as much, and uncertain* ties in oortvarsion of optical fbar count* to electron microscopic fber eounts or mats determinations. Recently, several government agencies in dlferent countries reviewed asbestos health effects. Areas of agreement and disagreement between various reviews are trotnteiunai cancers are also siailsed in most studios of occupatrirteiV sxuuaed worker*. Cancsr it other sites (larynx, kid* nev. ovary) has also bean snown to be higher than among groups exposed pro* dominantly to other fbars. Further, the risk ot peritoneal mesothelioma appears to b* lesa from expesura to chryaoti* than to presented in the full document A compari son of the different risk estimates is also provided. associated with sioecas exposure s* some- ekher croodolke or amoeita, but thta sug studies, but the degree of excess nsk and gestion is tempered by uncertainties aaao* the strengtn or tna assocuatoA VS leu ter dated with the greater possibility ot these and the gastrointestinal cancers than misdiagnosis ot the dUease. for lung cancar or masothalema. The IAAC Animal studies cordirm the human apt- lists asbestos as a greip 1 caicmogen, demblogeai results. Al major meaning that exposure to asbestos is car varieties produce king cancer and mi cinogenic to humane. SPA's proposed toatioma ta flftiy landed ddlsrsc guidelines categorue asbestos as Croup caionogene potency. impurtatxx*~5riri A, human carcinogen. tnjeeuon studies incrw tna icer amen* .Oats from a study of U.S. insulator* ttonaky, riot diartiistryTk tft'S AMtihpOr* ) ,en allow models to be develooed for , time and age dependence of lung can* car and mesotneioma nsk. Thsteen ether studies orovide exposure-response' rrtor- tent Imsataticernniiuced cardnogenicaty. Unq) (>T]un) and thin (el pin) fibers an the most carcinogenic at a oanoer-indue* ble ske. However, the size dependence of L. mauon. fha ^.muunj das suooeet that toe deposaon and migrtmt ot ttoers also lha exeats mix of death Imm lung cancer affects theeeananogame aeuon in humane. trom asoestos exoostrt If PTOPfl*l"',f IB tne cumulative execsure rtfts duraron tones Measurements demonstrate ms* ee. bestos sxocwft t'lgtding 100 times toe the intensity) and the underlying nsk v* the background occur to individuals in son* absence of exposure. me time course of non-occupauonal sattmge- Curraitoy- m. ung carid*r il asiamtrned primarily by the ume course ol tne underlying nsk. How* f important ct theta m Imm immIim. "T ** sver. trie nsk of deam from mesotnekoma ^tpftot-oontamlng surfacing broil nersases very raptoiy after-toe onset ot ing matanals. or from graved rtmts exposure and odeoendert ot eg* and oortiirwwfssoroofroinhs _ cgaretie smoking. As wn lung cancer, a nan potential esea tor future expoeur | the nsk appears to be propertynet to PM. from mawtenancs. reps*. arid removal i cumulative exposure to asbestos at gsrett .tom mtosniBLZl-- penal The dose and time retauonshpe for Extrapotatons of rfcka of aabesaos am other asbestos cancers are uncertaat. . can from oaeupatenal cscumstanees cat Values cnaractennng lung eaneer risk ba made, alhough numerical escmates i obtained trom different studies vary endaly. a speotc exposure areumaance have. Some of the vanaafcty cm be eanbuted to large (approssnetaly tenfold) uncertainty. specific processes. Chrysctie mnng and 8eeauMottoa uneanassy, calcuUaom ot milling, and perhaps frction product manu unit risk values for esbeses a toe low facture. appear to have lower unt expo coneemramu measured in the envson* sure risks than cniysouie textile products** mert mua be viewed with eaubon. The and other uses of asbssoe. Other vanabtty beat etbmaia ot rak to the United States can be associated wan the uncertainties ot general poputaien tor a lifetime oortinu* ^ifi numoers ** eptoemctogcal studies cue exposure to 0.0001 f/mi is 24 mean* ^^kimproper sstimsiss of exposures it toafoma daaha and 04 eaeass iungr 4 ikui GOvswMsnmmccma; i*i/5**-02a/2O206