This training program in environmental toxicology produces scientists professionally qualified to make original contributions directed at improved understanding of the impacts of hazardous chemicals and other environmental agents on human health. Emphasis is placed on development and application of in vivo and in vitro experimental models designed ultimately to elucidate, in cellular and molecular terms, mechanisms through which environmental and endogenous agents induce their adverse effects. These approaches help to identify health hazards resulting from the presence of toxic agents in the environment;moreover, the identification of biomarkers of exposure provides benchmarks for assessing the effectiveness of intervention measures put in place to reduce human risks. Strong emphasis is placed on the development, validation and application of methodology for detection and characterization of adverse effects. These methodologies improve assessment of actual or potential hazards to humans resulting from environmental exposures. Utilizing biochemical, chemical and biological approaches, the training of doctoral candidates and postdoctoral trainees is concerned with: characterization of the effects of toxic, carcinogenic and mutagenic chemicals at the intact animal, tissue, cellular and molecular levels;development of methods for the detection and quantification of such effects in humans, animals, and other experimental systems;studies of metabolic activation, macromolecular binding and genetic effects;and, elucidation of modes of action at cellular and molecular levels. Training involves didactic courses, formal and informal seminars and other means of information exchange, and laboratory research projects utilizing appropriate model systems for problem definition and solution.