49 CFR defines hazardous material as "a substance or material... capable of posing an unreasonable risk to health, safety, and property when transported in commerce, and [that has been] designated as hazardous under section 5103 of federal hazardous materials transportation law (49 U.S.C. 5103)." Hazardous substances, hazardous wastes, and other materials defined as hazardous in 49 CFR 172.101 fall under the designation of hazardous material. The National Institute for Environmental Health Sciences (NIEHS) Worker Training Program (WTP) awardees include unions whose members load, transport, and unload hazardous materials every day, by rail, air, and highway.

As defined in the Resource Conservation and Recovery Act , hazardous waste is a "solid waste, or combination of solid wastes, which because of its quantity, concentration, or physical, chemical, or infectious characteristics may cause, or significantly contribute to an increase in mortality or an increase in serious irreversible, or incapacitating reversible, illness; or pose a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported, or disposed of, or otherwise managed." Since 1987, the NIEHS WTP has funded non-profit organizations with a demonstrated track record of developing and delivering high quality training to workers who are involved in handling hazardous waste. For more information on related NIEHS WTP training activities, visit the NIEHS WTP Hazardous Waste Worker Training Program webpage.