Occupational lung disease--past record and future trend using the asbestos case as an example.

Knowledge and understanding of the occupational lung diseases in the post World War II era has come from clarification of the underlying disease mechanisms (attributable to spectacular developments in the laboratory sciences in particular physiology) and from epidemiologic studies clarifying their relationship to occupational exposure. In the case of exposure to asbestos, the risk for all the serious asbestos-related pulmonary diseases (fibrosis of the lungs and pleura, as well as cancer of these organs) has been shown to increase with increasing exposure. However, it is evident that there are considerable differences in risk between workforces, differences believed to be the consequence of differences in the physical (i.e. size) as well as chemical characteristics of the dust clouds to which the different work forces are exposed. Two key questions as yet unanswered are the risk at low level exposure, and the critical characteristics of fibers, physical and/or chemical, which determine pathogenicity. Answers to these questions will determine the future role of this mineral in our society.