VOL.: 2 (1973) (p. 17)
Industrial exposures to asbestos have usually been to mixed types of fibre, especially where manufacturing and application are undertaken, for example, textiles, insulation and asbestos cement, and have also occurred in the immediate vicinity. Mesotheliomas have occasionally been diagnosed among families of asbestos workers.
An important excess risk of lung cancer has usually resulted from past heavy exposures. The differences in risk between the several parts of the industry cannot be ascribed to one factor. The type of fibre, past dust levels, the form of dust produced by the process and the length of exposure are all relevant. The risk of lung carcinomas seems to be related to asbestosis.
In manufacturing and application industries mesotheliomas have been caused by exposure to crocidolite, and less frequently to amosite and chrysotile. The period between first exposure and development of tumours is long, usually more than 30 years. The tumours can occur in the absence of other asbestos-related disease.
At the present time, there is no evidence that exposure of the general population to past levels of asbestos dust in the ambient air or in beverages, drinking-water, food or pharmaceutical preparations increased the risk of cancer.
Cigarette smoking enhances the risk of lung carcinoma in asbestos workers to a much greater degree than in the rest of the population.
Subsequent evaluations: Vol. 14 (1977); Suppl. 7 (1987)
See Also: Toxicological Abbreviations Asbestos (WHO Food Additives Series 13) ASBESTOS (JECFA Evaluation)