MALIGNANT MESOTHELIOMA AFTER ENVIRONMENTAL EXPOSURE TO BLUE ASBESTOS

To determine the magnitude of the population at risk from non-occupati onal exposure to crocidolite at Wittenoom, Western Australia (WA), a c ohort of 4,890 residents who never worked for the mining company Austr alian Blue Asbestos (ABA) has been assembled from all 18,553 available records: the local school register, hospital attendances, the WA elec toral roll, birth certificates, workers who answered a mailed question naire in 1979, participants in a cancer-prevention programme using vit amin-A dietary supplements, and other sources. The majority of subject s were relatives and friends of ABA employees, and nearly half the coh ort were either born at Wittenoom or first went there as children unde r 10 years of age. As most residents were at Wittenoom when the mine a nd mill were in operation during the period 1943 to 1966, 82% were fir st exposed to crocidolite 20 or more years ago. The proportion of othe r workers (i.e., not employed by ABA) and their families increased onc e the mining operations ceased. To date, 24 cases of mesothelioma have been reported in this cohort: 9 males and 15 females. Time from first exposure to diagnosis ranged from 23 to 44 years and residence in Wit tenoom ranged from 6 weeks to 11 years. (C) 1993 Wiley-Liss, Inc.