The U.S. Department of Labor, Occupational Safety and Health Administration (OSHA) under 29 CFR 1910.120 Hazardous waste operations and emergency response requires workers who work at hazardous waste sites who may be exposed to safety and health hazards1 to receive initial and refresher training from qualified instructors. Initial training must be completed prior to work on hazardous waste sites. The following training discussion follows OSHA guidance in interpreting the standard. OSHA-approved state programs, however, may have differing interpretations or regulations.