Document 8VpNbnE1m1jGXEZgo77aLEJa

ese men there was slight excess risk of lung cancer (SMS - 1.15) and splratory tuberculosis (SKR " 1.14). Since exposures of 20 flbers/cra* e an order of magnitude higher than that experienced now (dust lcvdls r the past few years have been maintained at leas than 2 fibero/cm3), ners working a lifetime under ttfh present dust levels are not expected present any significant health problems relative to those In other nlng Industries. McDonald ct al. (1980) have aloo atudled the health statistics of cohort of 440 women who also worked In the Quebec ehrysotlle asbestos ns end mills. Of the 84 who have died, there was one death due to n{ cancer and one due to mesothelioma. Crocidolite exposure. There Is persuasive data, much already suryed, which shows thst crocidolite asbestoe Is much more hazardous than \rysotile, snthophylllte, and amoslte. Of the mining populations of te world only chose In the crocidolite mining area of the Cape Province : South Africa and at Vlttenoon Gorge, Western Australia, have a sta'.Btlcnlly significant Increase In mortality due to mesothelioma. Also, ssothdloma deaths have been reported among the residents of these areas to ere not employed In the mines or mills. Por example, Webster (1978) rports that the South African Asbestoe Tumour Reference Panel placed 712 iscs of mesothelioma on the register. Which included all the known cases luce 1956. Of these, occupational and environmental background wae itabllehed for 420 cases. Actual mining exposure accounted for 139 of he 420 coses, of which 120 were in connection with Cape crocidolite lalng and two with Transvaal crocidolite mining. There were only four esothellosn ensea in those associated with amoslte mining, and two of hesc had been exposed to Cape crocidolite as well. In the chryaotllc lnlng Industry there was only one case -- a miner from Rhodesia. Of the 06 environmental cases (those not employed In any occupation vherc sbestas la used), 93 ha'd been exposed to Cape crocidolite, two to Trans- .al crocidolite, and one possibly to amoslte. Additional prevalence studies in the Capa Province (Talent et el.. articular occupational or lifestyle hazard. SMR'e are useful to compare otni mortality ae well as mortality related to a particular disease or ccldcnt provided a proper control cohort can be chosen. RQ314 8005 0068 1981) discovered 65 active cases of mesothelioma In people who had pre sented themselves for medical examination. Fifteen of these cases ap peared in two groups, numbering 755 and 947 individuals, who were once employed In the crocidolite mines. additional thirty-eight mesothe lioma cases appeared In a survey of certain patients at the St. Michael's Hospital In Kuruman, Cope Province, who were not responding to treatment for suspected pulmonary tuberculosis. Fourteen of these mesothelioma patients were known to have worked In the crocidolite asbestos mines. Lastly. 12 of the 65 cases appeared In a medical survey of 53 females who. In the past, had hand-cobbed crocidolite asbestos. In contrast to the prevalence of mesothelioma In the Cape Province, this disease Is very rare In the Transvaal, where all of the world's amoslte la mined. Wagner et al. (1960), In regard to their Initial dis covery of the association of crocidolite asbestos with mesothelioma, state (p. 260) "the tumour (referring to mesothelioma) Is rarely en countered elsewhere In South Africa. During the past five years, with the exception of the present series (in Cape Province), no neoplasm of this nature has been diagnosed amongst 10,000 lungs examined at the Pneumoconiosis Bureau In Johannesburg, or In the Pathology Department of the South African Institute for Medical Research. Hlgglnson and Octtle (1957) did not observe a single case In their survey of malignant tumours occurring in the Bantu and Cape Coloured population of Johannesburg snd the North Eastern Transvaal." The incidence of mesothelioma In Zimbabwe (Rhodesia), e country which Is a major producer of ehrysotlle but mines no other fora of asbestos, la very low. In a communication to Mostert and Mclntjes (1979), the Secretary of the Rhodesia Pneumoconiosis Board stated that no cases of mesothelioma were reported In the mining Industry. It Is of Interest to note that two cases of mesothelioma were reported in the Rhodesian railway Industry, a locomotive engineer.and a storeman. The locomotives wero Insulated with crocidolite asbestos to which these two ocn were exposed (Mustert and Melntjes, 1979). Cochrane and Vebstor (1978) report 12 cases of mesothelioma in men employed as Insulators In the locomotive workshops of the South African Railways.' The prevalence of mesothelioma among the miners of Vlttenoon Corgc has been discussed (Table 5, Study VI). The town of Vlttenoon, the 31S PRODUCED BY FORD