Mortality patterns of rock and slag mineral wool production workers: an epidemiological and environmental study

An epidemiological and environmental study of rock and slag mineral wool production workers was undertaken at a plant that has been in operation since the early 1900s. Size characteristics of fibres produced by each process at the plant and data from industrial hygiene surveys were used to evaluate current and past exposures. These data suggest that the average historical airborne fibre concentration probably did not exceed 2.5 fibres/cc before 1935 and 1.0 fibre/cc after 1935. A retrospective cohort mortality study was designed to assess mortality patterns. Detailed occupational histories were compiled on all plant employees. All jobs in the plant were assigned to one of eight potential exposure categories to assess the extent and severity of mineral wool exposure and the effect of other significant exposures on employee mortality. Findings included an increase in the number of deaths due to cancer of the digestive system and non-malignant respiratory disease among workers who had over 20 years' exposure to mineral wool or who had survived 20 years since their first exposure to mineral wool. These findings are not inconsistent with those of Enterline's (Symposium on Biological Effects of Mineral Fibres, Lyon, France, September 1979) in the Thermal Insulation Manufacturers' Association's mortality study of men employed in four mineral wool plants.