The mechanism of toxicity of arsine gas will be studied in vitro. The effects of this hemolytic agent will be assessed in relation to the possible production of intracellular free radicals and colloid osmotic hemolysis in human red cells. In addition, the effect of arsine gas on DNA repair mechanisms in ultraviolet-irradiated E. coli and tissue culture cell lines will also be studied. Control studies will evaluate levels of arsenite. BIBLIOGRAPHIC REFERENCES: Goldstein, B.D., Benjamin, L.J., and McDonagh, E.M.: Colloid Osmotic Hemolysis Due to Arsine (AsH3) Gas, Clin. Res. 24:309A, 1976 (Abstract).