The experience of the Balangero chrysotile asbestos mine in Italy: Health effects among workers mining and milling asbestos and the health experienceof persons living nearby

The Balangero asbestos mine is the only chrysotile mine in Italy. In this p aper, we summarize information on work practice, fiber concentration, and h ealth-related effects in the workers and in the population of the area. Min e activity started in 1917 and grew rapidly during the following years. Dur ing the sixties, the number of production lines in the mill increased, and production was between 100,000 and 150,000 tonnes per year. The activity de clined during the 1980s and ceased in February 1990. At Balangero, chrysoti le asbestos occurs in a serpentinized rock; the percentage of asbestos rang es from 4 to 8%, and fiber length is less than 4-5 mm. The ore also include s balangeroite, a magnesium-iron fibrous silicate similar, from a morpholog ical point of view, to amphibole. Until the end of the sixties; mining and milling occurred without any relia ble system of dust control. Dust control through the ore-treatment process was introduced in 1965 and gradually improved until 1982. The main steps in volved filtering, centralized vacuum cleaning, wetting, and the use of air- sealed cabins. Actual measurements of asbestos-fiber concentration date bac k to 1968, from investigations carried out by technical advisers to the com pany. A program of periodic and regular dust-monitoring was initiated by th e company in 1975 and continued until 1989, with more than 2000 samples col lected in 14 years. The cohort of asbestos miners and millers at the Balangero mine (Piolatto e t al. 1990) showed a statistically significant increase in total mortality and in mortality from cancers of the upper aerodigestive tract, pleural mal ignancies, cardiovascular diseases and liver cirrhosis. Occurrence of pleur al malignancies and laryngeal cancers increased with cumulative exposure. W e update in this paper the incidence of mesothelioma in the cohort, on the basis of a search of the Literature and of the files of the Mesothelioma Re gistry of Piedmont. Three additional cases of malignant mesothelioma of the pleura were found with past exposure in the mine, and no evidence of other occupations entailing exposure to asbestos. Cumulative exposure to fibers estimated for these cases was: 340, 319 and 1064 f/mL X years. In the perio d considered, 0.15 incident cases of pleural mesotheliomas were expected. F requency of asbestosis in the Balangero workforce also was very high. Piola tto et ai. (1990) observed 16 deaths from asbestosis in 1946-1987, correspo nding to a mortality rate of 59 per 100,000 person-years. Fifteen new cases of asbestosis were compensated in 1984-1993 among miners residents in one of the four towns surrounding the mine of Balangero (Ispesl 1997). Three ca ses of malignant mesothelioma were observed in the general population, but they were explained by occupational or domestic exposure.