Overview of some aspects of quantitative risk assessment.

Use of animal data to estimate the human risk from long-term exposure to low doses of environmental carcinogens poses a number of biological, toxicological, and statistical problems. One of the problems is that of extrapolating animal dose-response relations from the high-dose range, where animal test data are available, to the low doses that humans might encounter. Different mathematical models for extrapolation are summarized, and the procedures for an problems of estimating human risk on the basis of animal studies are evaluated.