Mortality of workers in the man-made mineral fibre industry

A cohort, consisting of 7049 males who worked for one year or more as production or maintenance workers during the period 1945-1963 in one of eight US plants producing man-made mineral fibres, was followed for deaths through 1973. Standardized mortality ratios were elevated for major causes of death for men with 20 years or more since first exposure and were high when compared with those of men with less than 20 years since first exposure. None of the excesses was statistically significant. Since many causes of death were involved, the excesses observed are probably unrelated to exposure to man-made mineral fibres. Data for the three mineral wool plants included in the study could not be interpreted due to the possible use of asbestos in one or more of these plants. For the five fibrous glass plants, there was no evidence of an excess in malignant or nonmalignant respiratory disease related to exposure to respirable fibrous glass. Estimated historical respirable fibre concentrations to which workers from fibrous-glass plants were exposed were very low, less than 1/100th of the standard proposed by the US National Institute for Occupational Safety and Health.