A MORTALITY STUDY OF WORKERS MANUFACTURING FRICTION MATERIALS WITH CHRYSOTILE ASBESTOS

This is a study of workers at a friction materials factory founded in 1898. Crocidolite was used only during two well defined periods before 1945. Apart from this, only chrysotile asbestos has been used. The mortality study dates from 1942 and extends to 1979. Over 99% of the population have been traced. Ten deaths from mesothelial tumours occurred. An analysis contrasting the observed number of deaths with those to be expected showed a significant excess of deaths from cancer of the lung and pleura in those employed before 1942. Among these deaths were seven from pleural mesothelioma. A case control study of the ten workers dying from pleural mesothelioma showed that all but two of these had definite exposure to crocidolite asbestos. Allowing for concomitant exposure to chrysotile asbestos among both cases and controls, the evidence of an association of the deaths from pleural mesothelioma with an exposure to crocidolite asbestos had a statistical significance level of 0.06.