TOXNET is a cluster of databases on toxicology, hazardous chemicals, and related areas. This system allows searching the nine included databases simultaneously or individually. Included databases are Hazardous Substances Data Bank (HSDB), Integrated Risk Information System (IRIS), GENE-TOX,Chemical Carcinogenesis Research Information System (CCRIS), TOXLINE, Developmental and Reproductive Toxicology and Environmental Teratology Information Center (DART/ETIC), Toxics Release Inventory (TRI), and ChemIDplus. Topics covered include human and animal toxicity, safety and handling, environmental fate, risk assessment, mutagenicity test data,carcinogenicity, mutagenicity, tumor promotion and inhibition, developmental and reproductive toxicology of drugs and chemicals. Additionally, the annual estimated release of toxic chemicals to the environment and drug and chemical structures and other information are available.