Evaluates the risks to human health and the environment posed by the production and use of fully halogenated chlorofluorocarbons. Eight different commercial compounds, some of which are known to contribute to ozone depletion, are assessed. The opening section summarizes the unique chemical and physical properties that account for the commercial importance of chlorofluorocarbons and explain why their degradation in the upper stratosphere destroys ozone. Subsequent sections summarize data on the global distribution of chlorofluorocarbons and evaluate the strength of evidence suggesting that increased ultraviolet-B radiation, resulting from ozone depletion, will endanger terrestrial and aquatic biota. The report concludes that even small increases in ambient ultraviolet-B exposure can result in significant ecosystem changes.