Document 2qpNzew2Jvz3VR7VzaBKJXG97

PRODUCED BY FORD xposure for many years. Thus far only about 10 or 12 deaths among nthophylllte and chryaotlle miners hare been attributed to this disease. There Is seme question as to the relationship betveen exposure! to nosite asbestos and Incidence of mesothelioma. Transvaal amoalte miners cem not to show this disease, whereas, according to I.J. Sellkoff and owcrkers, fourteen men exposed to amoalte during World War II at a ntterson, Sew Jersey, factory have died of pleural or peritoneal mesohellora (Sellkoff ct al., 1980b). It ahould be noted, however, thae nly one mesothelioma case was noted on the death certificates. The hlrteen other deaths were recorded by Sellkoff from a postmortem "best stlnatc." Such "adjustments" of death certificate data make It lmposlblc to compere different epidemiological studies or to compare to control" groups. In addition, there are two other observations relating o anoslte asbestos that Sellkoff does not address: (1) the very lov eeothellomn rates In the Transvaal nnoslte miners and (2) the strong osslblllty that many of the Patterson factory amoalte workers had prevlus work experience In Hew Jersey factories that processed eroeldollte sbestos. McCullagh (1980) In a review of the Patteroon workforce sugests that "something like one-third, or some 300 members, of the Patteron cohort may have been occupationally exposed to asbestos before ntcrlng the cohort." Chrysotlie asbestos, which accounts for about 95 percent of the ?bcstos In the present market. Is much less harmful to miners than is rocldollte and probably amoslte. McDonald et al. (1980) found that for cn exposed for over 20 years to chryaotlle dust averaging 20 fibers/cm3, he total mortality was less than expected (620 observed deaths, (59 -peeted deaths). Risk of lung cancer was slightly Increased: 68 deaths served, 42 deaths expected. Exposures to 20 flbere/cm3 are an order of gnltcde greater than those experienced now (generally less than 2 :bers/ca3); thus, chryaotlle miners working a lifetime under these pretnt dust levels ahould not be expected to suffer any measureable excess incer. 10 10If there Is no threshhold below which there la a zero risk of -vcloplng eoneer from exposure to a carcinogen (many believe such a hreshhold exists, many do not), then even exposures to ehrysotlle !PQ3T8 8005 0070 epidemiological evidence does not exist to assess the health effects of tremollte or actlnollte asbestos. The minerals cumralngtonlte, gtunerlte, and hotnblende, which are sometimes considered to be asbestos-llke, have been shown not to 4au#e^ashescos diseases In miners. ACXHOWLEDGMEKTS 1 thank David B. Stewart for n helpful review of this paper. asbestos as low as two fibers per coble centimeter could cause a few cancers to develop within a significantly large work force. Tet, the same also can be oald of the human cost of operating heavy mining and manufacturing machinery; there will be some accidents resulting in In jury and loss of life no matter how carefully the aafety procedures are designed end followed. If, as some propoce, society Is to abandon the use of ehrysotlle anbestos despite the eptlnlstle health picture for the present Quebec asbestos miners and millers, we should first be able to answer these questions: (1) Vhat will the health rlok be to those exposed to the asbestos sub stitutes? (2) Will the substitutes be less effective for fire protection, for braking efficiency, ond lor strengthening materials, resulting In In creased Injury and Xosa of life? (3) Will the coats of the substitutes prevent their use, for example, as replacement material for asbestos In cement water pipe and reinforced construction cement? 319