This list includes 25,043 entries; approximately 11,000 main entries are accompanied by a description of the substance, information on its toxicity and references to existing USA standards and criteria documents, the remaining 14,000 entries being synonyms and cross references. The specific data provided on the toxicity of each substance related to: route of administration, animal species involved, type of exposure reported (e.g. lethal), dose which caused the toxic response (usually milligrams per kilogram or parts per million), and body system affected. The bibliographical sources from which the toxicity data were extracted are all listed. Absence of a substance from the list does not, imply that it is innocuous.