Document DvbGkKEp5d6O8KVv5Y5reYLLB

FILE NAME: WR Grace (WRG) DATE: April 20, 1983 DOC#: WRG203 DOCUMENT DESCRIPTION: 1983 EPA Status Report ` , t ' TR 2 0 1233 ju&jtcTi : ' t a t u S R e p o r t * 3EHQ-333-0473 MCmiJustine L. V.'e 1ci/'tTeam Leader Chemical Slection and Profiles Team/CHIB TOiFrank D. Kover, Chief Chemical Hazard Id e n tif i c.atio n Branch/ 2.D Sucrai ss ion Descri o tien JUN t h 198J . iyniggs Gtivironmonici Gciencca Div, W. R. Grace ?, Co. (Grace) provided prelimi nary results of an ongoing company epidomioiogy study of pas t./pro sent workers at the Grace venniculite mining and milling operation in Libby, Monta p.a . According to the submitter, the Libby venniculite deposit has been long known to be contaminated with tremolite, an asbestif orm material. w. R. Grace & Co. also reported that in addition to its own epidemic! ogy study, the "National Institute for Occu- ps 11 on a 1 aa ao zv a nd Health (NIOSH), acting at the request of the Mine Safety and Sealth .Administration (MSHA), began a study in March 19o 2 of che effects of tremolite exoosure ucon present and pas t. tinp ]ovoe it Lihbv Tin sub mi ttc-r stated td.at die NI Os'! study is "c;t:'> native o n o r t and statec turtne tha t Grace i made its data ava liable to NIOSH. The submi ttinu corn_eanv_ also reported that it: as "d o vo 1occrd er;t im.atos of historical i.ndivi ua1 wo rker e:<o sure levels" and has recently started to come i.I other employee da ca with tiic se os t irna tes o f ind iv i d ua 1 wo rke r exposure levels. in addition, W. R. Grace & Co. reported that NT OS;! is now in the process of devolopi.ng its own e xpcsure es t mates so r.h.ar N10 SH and the company will he able to use the otiler's estimates for cross-comparison purposes, an activity which Grace hooes will "provide a more precise final product." In its submission, W. R. Grace & Co. reported that the Libby vermiculite mining and milling facility, which has been in operation since the 1930's, was purchased by Grace in 1963 and currently employs 170 people. The submitting company stated that although "dust exposure levels" at Libby were "very high" prior to.1 963, "conditions gradually improved" following the company's acquisition of the operation. The submitter also reported that a 1971 study (conducted by the U. S. Bureau of Mines) si.owed fiber exposures at Libby ranging from 13 to 71 fjLtoers/cubic centimeter (cc) of air. W. R. Grace & Co. stated, however, that following "time-consuming research" in overcoming unique technical design problems, "a new wet milling facility was placed ipto operation [in 1974] followed by further major process and operational NOTE: This status report is the result of a preliminary staff evaluation of inforrr.ation submitted to EPA. Statements made herein ate nor. to be regarded as expressing final Agency policy or intent with respect to this particular chemical. .Any review of the status report should take into consideration the fact' that it mav Ho -- - improvements in the mine, mill and other areas which improved working conditions significant ly ." The submit!: ing company also reported that since 1971/1975, fiber "exposures have been drama tically lowered and at preseat average less than 0.2 fibers/cc (0.01-0.9 fibers/cc range)." With regard to the preliminary results of its own ongoing study, W. R. Grace & Co. reported that the c o m p a n y 's "information indi cates chat of 109 known deaths of former Libby employees, the cause of death for 16 was listed in death certificates or insur ance claim forms as lung cancer, and for two others the cause was listed as me soth eli oma ." The company stated that it did not have "sufficient medical in formation or sufficient occupational and personal history data in these cases to make a judgment as to the cause of these illnesses." The submitting company also reported that based upon "individual exposure estimates, it appears that certain [Grace] employees whose work history predates the new mill and who have a cumulative exposure of less than 100 fiber years show signs o f asbe s to s- re1a ted d is<?ase " and that "all of the.se employees had exposure levels of more than 2.0 fibers per cc for varying periods of time prior to the new mill." W. R. Grace & Co. pointed out "several methodological problems which have prevented [the company] from making any preliminary judgments" based on the reported preliminary information. Firs: trie company pointed out that the information pertains to condi tions which "do not exist in today's workplace environment" and tha t "all of the employees who show signs of asbestos-re 1ated disease 'were employed prior to 197 6 when fiber levels were sig ns ricants!vy nhigohner tmhaann t.hneeyy are tocdaavy.." Tihne company noted that in contrast, its "preliminary data [show that] none of the cur rent employees hired since 1975' have asbestos-related disease. Second, the company pointed out that "there are those who ques tion the validity of using cumulative exposures (averaging periods of significantly high exposure with later low exposure periods) and the fiber year concept as a proper basis for eval uating the effects of asbestiforrn material exposure." Finally, the company pointed out that "the Libby employee population has . history of both a large number of smokers (about 75%) and rela tively heavy individual smoking histories (most employees smoked a pack or more per day)." . W. R. Grace & Co. stated the company believes that the submitted preliminary information "corroborates written scientific opinion on the effects of exposure to asbestiforrn material and that it is within the realm of expectation for a mining and milling popula tion having exposures at the levels which prevailed at Libby in the past." In addition, the submitting company stated that "in some respects, the data are simi-lar to what has been reported in studies of talc mining and milling operations in which the talc contained tremolite and other forms of asbestos." Finally, Grace stated that "despite the uncertainty as to the meaning of the data," the company had submitted the subject preliminary findings pursuant to Section 8(e) for the following reasons: "(1) t/ie. 8 Ey - - 0383-0 4 73 PV i 3 of 5 expressed interest of EPA, NIGSH, OSHA and MSIIA in determining whether the various asbesti form materials induce different medical effects, and (2) ongoing agency investigations as to whether current asbestos exposure standards are adequate." Submission Evaluation It is agreed that the reported serious health effects (i.e., 16 lung cancers/109 deaths and 2 mosotheliomas/109 deaths) are corroborative of written scientific opinion on the effects of exposure to asbesti form materials ami that the effects are, as the submitter stated, "within the realm of expectation for a mining and milling population having exposures at the levels which prevailed...in the past." - In the submitter's study cohort, the proportion of men having smoked was estimated to be 75%, a figure that is consistent with other estimates of the proportion of males who have smoked in the past.(_l) For lung cancer, the estimated probability of death cue to lung cancer in males in the U .S . from age 35 until age 74 is .06 2 or 6.2%. (_2) because this was a working population, it is assumed that the deaths cue to lung cancer did not occur before age 35 and the population was followed to at least age 74. The observed proportion of deaths due to lung cancer 'was 16/109 or .14 7 (14.7 ). Th e re fo r e , the c a 1cu1a ted reiati ve risk wo u1c 1:e approximately 2.4, which is statistically significant at p < 0..01 and is con.cop.5nt wit;!) the known .synergistic effects of asbestos in smokers. For mesothelioma, the sv is no established background incidence for this disease. Hove r, the rate estimates for asbestosrelated mesothelioma ir; .'cr th America in the mid-1 970's were 8 .0/106 for males and shoe 1 2.5/10 for females .(_3) If the incidence of mesothelioma observed in the deceased Libby employ ees (i.e., 2 .mesotheliomas/109 deaths) is projected to a popu lation of 10b , the rate would be equivalent to 18,349 cases of mesothelioma. This finding is quite significant even though the exposure levels between the two groups (i.e., the North American males/f ernales versus the studied Libby population) are not; com parable. In addition, the finding is not necessarily surprising in light of the 13-71 fibers/cc found by the U.S. Bureau of Mines during the 1971 survey of the Libby facility. In addition., W. R. Grace & Co. stated in the submission that exposure levels at the Libby operation were even higher prior to 1970. It would be of interest to know the actual past/present exposure levels for the current Libby emp l o y e e s who reportedly show signs of asbestos-tela ted disease(s), the number of current employees affected, and the nature of the asbestos-related disease(s) that are occurring. In addition, it should be noted that the submit ter's finding that none of the current employees hired since 1975 shew signs of asbestos-related disease is not surprising because inadequate time has passed for the potential asbestos-related diseases to be significantly expressed. 8 Ehr 0 38 3 - 0 4 7 3 P 1 - 4 of 5 The submitter's final comment that W. R. Grace & Co. has "no reason to believe there is any risk associated with the current uses of Libby verrnicu 1 ite-con ta ining prouuc ts" remains to be determined and is dependent upon the potential exposure of users to asbestos from the Libby vermiculite-containing products and the inherent risk such uses impose. Current Production and Use Vermiculite is a naturally occurring hydrated mac nosiurn-ironaluminum silicate (CAL M o . 1313-00-9 ) that when heated (2000F) can expand (exfoliate) from 6-20 times its original size. The known major vermicul. ite deposits are locate'] in South 7-.fri.ca, Wyoming, Colorado, Montana, North Caroline;, and South Carolina. Vermiculite uses include: insulating and: packing materials; fil ler for paints, plastics, and rubber; removal of strontium-90 from milk and phosphates from wastewater; animal feed and fer tilizer additive; insecticide carrier; plant bedding; and general absorbant. Tremol it; (CAS o . 14567-73-8) variety of asbestos wh ich is used p a r 1 u 1s>--11j,. .n paints, ceramics, and acid-resisting ;1 i- cations. Comments / Recomrr.e nd a tio n s W. R. uraco ! c o . reportou that its medical surveillance program at the Libbv . X -ra ys (sin c e 196 4) , annual pulmonary function tests (since 1974), and health status questionnaires (since 1978). The company stated that the results of these tests are made available to individual Libby employees and/or their personal physicians. In addition, the company re ported that "based upon the recognition that, smoking and asbestos exposure can increase the incidence of disease, Grace, in 1978, banned smoking at all Company facilities in Libby." W. R. Grace & Co. also reported that it has initiated a program designed to "help employees stop smoking, and the smoking population has been reduced to 25% of the staff." In addition, the company stated that "all new hires are required to be nonsmokers." W. R. Grace & Co. reported that because of the difficulties in interpreting the submitted information, the company plans to retain Drs. J. C. McDonald and A. D. McDonald (McGill University, Montreal, Canada) to "undertake a thorough analysis of the Libby data" in order to allow Grace "to reach a scientifically sound conclusion based upon [the company's] historical data." W. R. Grace & Co. also reported that the company does plan to continue to cooperate with NIOSH and has sent a copy of the company's 8(e) notice to NIOSH. The National Toxicology Program (NT?) recently completed a life time carcinogenesis bioassay of blocky (nonfibrous) tremolite administered at a 1% concentration in the pelleted diet of male and female Fischer 344 rats (starting with the dams of the test animals). According to the DRAFT NTP Technical Report, "Under the conditions o f 'this bioassay, nonfibrous tremolite was not toxic and did not cause a carcinogenic response when ingested at a level of 1% in the diet of male and female Fischer 344 rats for their li fetime." ' a) The Chemical Hazard Identification Branch (CHIB/AD/EPA) will request W. R. Grace & Co. to report the actual past and present exposure levels for the Libby employees who are reportedly experiencing asbestos-related disease(s), the number of employees affected by such diseaso(s), and the nature of those asbestos-related diseaso(s). The company will also be requested to submit, when available, a complete copy of the results (including methodologies and data) of the Libby data analysis which is to be per formed by Dr. A. D. McDonald and Dr. J. C. McDonald at McGill University in Montreal, Canada. b) The Chemical Hazard Identification Branch will provide copies of this status report to NIOSH, OSHA, CPSC, M S H A , OW/EPA, OSWER/EPA, OAMP./EPA, ORD/EPA, and the "Asbestos Team" (CCD /CT S/ EP A). Copies of this status report will also be transmitted to the Industry Assistance Office (IAO/OTS/EPA) for appropriate distribution. References 1_ Preventive Medicine. 1980. Voi. 9, pp. 747-759. 2_ SEER Report, MCI Monograph 57, June 1981. 3 McDonald JC and McDonald A D . Mesothelioma as an index of asbescos impact. In: Peto R, Schneiderman M (ed), Banbury Report 9, Quantification of Occupational Cancer, Cold Spring Harbor Laboratory, 1981, p g . 73-82. NOTE : In a supplemental submission dated June 7, 1983 (8EHQ-Q683-0473 Supplement), R. T. Vanderbilt Company, Inc. reported that the asbestiform (i.e., fibrous) variety of tremolite is correctly termed "tremolite asbestos" (CAS No. 77536-68-6), whereas the non-fibrous (i.e., non-asbestiform) variety is correctly termed "tremolite" (CAS No. 14567-73-8).