Mesothelioma: the Wittenoom experience

Abstract

Six thousand five hundred males and 500 females were employed by the Australian Blue Asbestos Company in the mining and milling of crocidolite at Wittenoom in the Pilbara region of Western Australia between 1943 and 1966. This cohort has been traced periodically for vital status and cause of death since 1975. By 1986 there had been 85 deaths from malignant mesothelioma. No such deaths occurred within ten years of first exposure to crocidolite. A survey of dustiness in the industry conducted in 1966 has provided a basis for estimates of cumulative crocidolite exposure of the members of the cohort. Exposure-response relationships have been examined. Mesothelioma incidence rates increase exponentially with time since first exposure and also increase with intensity of exposure to crocidolite. Mathematical modelling of the relationship between mesothelioma incidence and intensity of exposure, duration of exposure and time since first exposure results in an estimate of up to 700 cases of mesothelioma in this cohort by the year 2020.