The International Agency for Research on Cancer historical cohort study of MMMF production workers in seven European countries: extension of the follow – up.

The follow-up of the historical European cohort in 13 MMMF plants located in seven countries has been extended to 31 December 1982. An historical environmental investigation has been conducted in parallel in order to collect information on past working conditions in the plants included in the study in relation to exposure to fibres and to other potential contaminants. In addition to findings which have been reported previously, this paper presents further results in relation to type of raw material used (rock or slag) and to other potential risk factors present in the working environment that could have confounded the association between lung cancer and exposure to MMMF. An overall mortality excess was detected (2719 observed vs 2457.0 expected; SMR = 111), mainly due to deaths from violent causes, the excess being concentrated among short-term employees. After restricting the analysis to individuals with at least 1 yr of employment the Standardized Mortality Ratio (SMR) becomes 102. Lung cancer mortality increased with time since first exposure both in rock wool/slag wool and glass wool productions, the latter showing, however, no overall excess after applying local reference population. The lung cancer mortality excess in the rock wool/slag wool production was associated with the early technological phase which was estimated to present higher exposure levels of airborne fibres. No lung cancer excess was found after the introduction in the process of dust-suppressing agents. An increased lung cancer mortality 20 or more yr since first exposure was associated with the use of slag, but it does not show any relationship with the extent to which slag was used during the early technological phase. No effects could be attributed to other potential risk factors: use of bitumen binders, use of asbestos, exposure to formaldehyde. No consistent mortality excess was found for other cancer sites nor for non-malignant respiratory diseases.