Acute Exposure Guideline Levels (AEGLs) Agency for Toxic Substances and Disease Registry (ATSDR) Center for Disease Control and Prevention (CDC) ChemIDplus EXTOXNET Immediately Dangerous to Life or Health (IDLH) INCHEM Integrated Risk Information System (IRIS) NIOSH Pocket Guide to Chemical Hazards (NPG) Right to Know Hazardous Substance Fact Sheets The National Institute for Occupational Safety and Health (NIOSH) The National Toxicology Program Toxic Substances Portal Toxnet