Discusses research findings about malathion, a widely used insecticide, concerning potential for human exposure; how malathion works and is used; toxicity; carcinogenicity; mutagenicity; associated birth defects; reproductive effects; effects on vision, diet, behavior, and immune systems; contaminants and analogues, synergists, residues, inert ingredients; persistence in soil and water; and water, air, and fog contamination. (121 references) (MCO)