Excess of mesotheliomas after exposure to chrysotile in Balangero, Italy

Background: Chrysotile from the mine in Balangero, Italy is considered to be free of tremolite. In a cohort study of miners and millers only two pleural cancers were reported, a finding considered to indicate that chrysotile has a low potency for inducing mesothelioma. However, follow-up ended in 1987 and white-collar workers and the employees of subcontractors were not studied. Methods: To complete the case ascertainment, the study searched the Registry of Malignant Mesotheliomas of Piedmont for records of cases of pleural mesothelioma among the following: mine employees; employees of subcontractors or of other firms transporting or refining Balangero asbestos, asbestos ore or mine tailings; individuals exposed to air pollution from the mine or living with mine employees; and individuals exposed to mine tailings from Balangero. Results: The study identified four new cases of pleural mesothelioma among blue-collar workers in the mine, in addition to the two reported in the cohort study. Thus, six mesotheliomas occurred, compared to the 1.5 expected (p