[Artificial mineral fibers and the risk of cancer]

The cancer risk can be reduced by replacing crocidolite and amosite by chrysotile asbestos, by replacing asbestos by man-made mineral fibres that produce less dust, and by nonfibrous materials. MMMF have been found to be carcinogenic in experiments in animals. All respirable mineral fibres that are retained in the lungs are suspected to increase the lung cancer risk, the fibre length and surface properties appearing to be the decisive factors. For most of these fibres, data so far collected in humans are still insufficient to permit definite conclusions to be drawn. There is a certain amount of evidence to suggest that rock/slag wool may be carcinogenic in humans: lung cancer in workers in the production area in the USA was found to be significantly increased (SMR 134%), and in the early phase of European production an SMR of 257% was observed. In the area of glass wool production, exposure to fibre and lung cancer rates were lower, but showed an increasing tendency with increasing time elapsed since the first exposure to respirable fibres. Methodological problems associated with published epidemiological studies are reviewed, and prevention strategies--which need to give consideration to the possibility that the carcinogenicity per fibre could be higher in the case of MMMF than in chrysotile asbestos--are discussed.