Cohort Mortality Study of Vermiculite Miners Exposed to Fibrous Tremolite: an Update

A further follow-up was made of a cohort of 406 American vermiculite mine workers exposed on average to 18 fibres/ml of tremolite. Total deaths to the end of 1999 were: all causes 285 (SMR 1.27), lung cancer 44 (SMR 2.40), mesothelioma 12 (PMR 4.21%). Lung cancer SMRs increased steeply with cumulative exposure (f/ml.yr). These findings show the potential magnitude of the carcinogenic effects of tremolite fibres when contaminating commercial chrysotile, and are relevant to risks associated with tremolite fibres in the general environment.