Asbestos: scientific basis for environmental control of fibres.

Any review of the scientific evidence on which public policy is based must commence with a cautionary statement about the quality of the available data both about dust and about asbestos-related disease. Attention is drawn to some of the main problems. It is concluded that, in spite of their shortcomings, the data are sufficiently consistent to be useful in relation to some aspects of the problem of environmental control of the asbestos hazard. The question whether or not there is a threshold dose of fibre below which no biological effect occurs is of considerable importance in framing public policy. The evidence concerning the existence or otherwise of a threshold in relation to the different asbestos-related diseases is summarized. A summary is also given of the evidence about the shape of the dose-response curves for asbestos-related diseases in man. The paper concludes with a note on how scientific data may be summarized in a manner which may be helpful in formulating public policy with regard to a control limit.