Effects on health of non-occupational exposure to airborne mineral fibres.

The most prominent potential marker of disease-related non-occupational exposure to mineral fibres is mesothelioma. Although many cases of mesothelioma have resulted from occupational exposure to asbestos, some have been associated with para-occupational domestic and/or neighbourhood exposure and have been reported in case series, case-control studies and a cohort study among non-occupationally exposed subjects. However, little information is available on mesothelioma as a direct consequence of general environmental asbestos exposure. Such cases of mesothelioma related to non-occupational exposure to asbestos as have occurred to date are likely to have resulted from past exposures much higher than those prevailing at the present time (in the developed countries); numbers will therefore probably decrease in the future. Very high rates of mesothelioma have been reported as a result of exposure to erionite. No studies are available on the effects of non-occupational exposure to man-made mineral fibres but, among occupationally exposed workers, a risk of mesothelioma is not apparent. There are suggestions of raised lung cancer rates among household contacts of asbestos workers and among individuals exposed to erionite. Non-malignant parenchymal and pleural abnormalities have been observed in subjects exposed non-occupationally to asbestos and erionite, but these are not necessarily associated with malignant lesions. Quantitative risk estimates of adverse effects on health have not been derived from these studies, essentially because of the absence of fibre exposure measurements.