Document 4aoXa4e9kQbNkEwrynOMywygG

14256997033 2002-02-26 19:09:21 (GMT), page 8 7 Crocidolite Studies published in the late 1970s by J.C. McDonald et al. offered yet another explanation for the non-carcinogenicity of chrysotile. (McDonald and McDonald 1978) They claimed that most of the mesothelioma cases from the Asbestos, Quebec mines occurred as a result of exposure to amphibole crocidolite (also known as fibrous reibeekite), which was allegedly imported from Australia for use in gas mask manufacture at the factory located "adjacent to" the Johns Manville Jeffrey mine during World War II. The QAMA-McGill researchers postulated that this use of crocidolite in filter pad manufacture from 1939-1941 accounted for increased mesothelioma and lung cancer rates among miners and millers at the Jeffrey mine even though none ofthem had ever worked in the factory. It is interesting to note that there are no citations to interviews with workers or correspondences that prove imported crocidolite was ever used for this purpose at the mine location. British regulations specified the used of either chrysotile or crocidolite for WWII gas mask filters. Why would QAMA members producing gas masks import crocidolite from Australia, past Japanese submarines and battleships, past other filter factories in Ontario that used crocidolite, to fill gas mask filters at a factory adjacent to the largest chrysotile mine in the world? Furthermore, Begin (1992) reported that mesothelioma rates were not as elevated as one would expect if crocidolite was used at Asbestos in gas-mask manufacture. (Begin et al. 1992) He revealed his own doubts about the presence of amphiboles at the factory by stating that amphiboles "may have" been used there and noted that there were no cases ofmesothelioma in other departments that were nearby such as quality control. Because the QAMA-McGill longitudinal cohort mortality was a follow-up of a birth cohort, most members of the cohort had worked at the mine or mill during this two-year period that gas masks were produced. However at the time the McDonalds initially suggested that this 7