VOL.: 14 (1977)
The size and shape of the fibres influence the incidence of tumours; fibres less than 0.5 mm in diameter are more active in producing tumours. Glass fibres and nemalite of a similar size can also produce mesotheliomas following their intrapleural or intraperitoneal injection in rats.
Occupational exposure to asbestos may occur during the mining of fibrous minerals, as well as of minerals embodied in rocks, which may contain asbestiform fibres as a contaminant.
Both cigarette smoking and occupational exposure to asbestos fibres independently increase lung cancer incidence, but when they are present together they act in a multiplicative fashion.
The general population may also be exposed to asbestos fibres in air, beverages, drinking-water, food and pharmaceutical and dental preparations and by consumer use of asbestos-containing products. The presence of asbestos and asbestiform minerals from natural sources in the environment, other than mines or quarries, has only recently shown itself to be a further potential problem.
At present, it is not possible to assess whether there is a level of exposure in humans below which an increased risk of cancer would not occur.
Previous evaluation: Vol. 2 (1973)
Subsequent evaluation: Suppl. 7 (1987)
See Also: Toxicological Abbreviations Asbestos (WHO Food Additives Series 13) ASBESTOS (JECFA Evaluation) Asbestos (IARC Summary & Evaluation, Supplement7, 1987) Asbestos (IARC Summary & Evaluation, Volume 2, 1973)