Unexpected releases of hazardous materials pose a significant risk to workers and the general public. There are many causes of unexpected releases, such as human errors, equipment failures, or even natural disasters. To protect workers who work with hazardous materials, the Occupational Safety and Health Administration (OSHA) created the Hazardous Waste Operations and Emergency Response (HAZWOPER) standard (29 CFR 1910.120). This module provides an overview of the HAZWOPER standard, who it applies to, and its requirements.