The long range objective of this research is to reduce the toxicity and carcinogenicity of asbestos by desferroxamine treatment, which neutralizes the catalytic activity of the asbestos-contained iron. In phase I of this project the possibility that desferroxamine treatment can reduce asbestos-caused squamous metaplasia in tracheal organ cultures will be studied. Squamous metaplasia is thought to precede changes that lead to carcinogenesis. In phase I, the ability of desferroxamine to remain bound to asbestos for long periods will also be tested. In the future, under phase II, desferroxamine-treated and untreated asbestos will be administered to rats and the long-term incidence of malignancy will be measured. This study will not only test desferroxamine's ability to reduce asbestos toxicity but will also test a current hypothesis that the toxicity and carcinogenicity of asbestos is due, in part, to iron-catalyzed generation of highly reactive oxygen radicals. This desferroxamine treatment could be used widely as part of the standard chemical washing treatment performed prior to asbestos removal from buildings or prior to working in areas where asbestos is present. This could therefore, if effective, reduce the risk of contracting asbestos-related diseases for asbestos-removal and other workers. Commercially, this could represent a very large market since asbestos removal from schools, homes, and other buildings has become a high priority in many communities.