ASBESTOS - PAST, PRESENT, AND FUTURE

Owing to its particular properties asbestos has been widely used for the production of insulating material, for fire proofing, and for strengthening to other materials such as cements and plastics, and thus the story of this mineral was one of progressive commercial success until the middle of this century. However, serious health hazards were realized early: around the turn of the century a progressive form of diffuse fibrosis (asbestosis) in asbestos workers was observed and in 1950 an excess risk of lung cancer, while in 1960 the causal relationship between asbestos and mesothelioma were confirmed. In view of the known potential risks of asbestos and its widespread use in the building industry, more recently asbestos has caused considerable public concern and anxiety. Based on numerous experimental and epidemiological observations, present knowledge of the pathogenic effects of asbestos is sufficient for a number of broad conclusions to be drawn. (1) The amphibole types of asbestos are too dangerous for use as industrial material, and should be banned. (2) Chrysotile can probably be used safely if there is strict control of the workers' dust exposure. (3) It is very unlikely that the general public is at any measurable risk from asbestos in buildings. Exceptions are people working regularly on maintenance tasks involving removing or cutting of asbestos in buildings; such people are properly classified as asbestos workers and should be protected accordingly. (4) The risk-benefit ratio of the removal of asbestos from buildings is not justifiable in most cases, since such endeavours entail significant exposure of workers to the fibre, and since the fibre counts in the room air may be higher in buildings after asbestos removal than before.