Extrapolation from occupational studies: a substitute for environmental epidemiology.

Extrapolation from occupational data to general environmental exposures gives some interesting results, and these results might be useful in our decision-making process. These results could never be observed by environmental epidemiology and this method probably represents the only way of quantifying the health effects of low-exposure levels. Three linear models for extrapolating to low levels are presented--one from Canadian data, one from American data and one from British data. One or more of these is applied to two recently publicized asbestos exposures; exposures resulting from asbestos heat shields in hair dryers and exposures in public school buildings. Predictions are derived as to the effects of asbestos exposures on cancer mortality. A comparison is made between predictions made on the basis of a linear and nonlinear model.