The research of this program grant involves long-term interdisciplinary studies of the toxicological effects of environmental chemicals. Fourteen investigators representing different disciplines direct projects on biochemical mechanisms of toxicity, oncogenesis, and effect on oncogenic viruses, pharmacodynamics, modeling, statistical methods for toxicology, biochemical effects, and physico-chemical relationships of routes and rates of exposure. Examples of the type of work conducted include investigation of effects of halogenated phenols on membranes, oncogenicity of halogenated hydrocarbons and interactions with other carcinogenic agents, covalent binding of toxicants and immunological effects of environmental chemicals. Other studies are directed toward elucidating the photochemistry of environmental toxicants, physico-chemical properties in relation to biological effects and behavior, and mathematical and statistical modeling of the dynamics and toxicological behavior of compounds. Among the compounds under investigation include halogenated phenols containing one to three aromatic rings heavy metals, ethyl nitrosourea, halogenated hydrocarbons, carcinogenic alkaloids, and several industrial and agricultural chemicals of environmental significance.