This is Part Four of a 13-part series of modules on HAZWOPER designed to provide the annual refresher training as required by OSHA for all employees affected by this regulation. Part Four covers hazard and risk assessment. Individuals involved in hazardous waste operations and emergency response need to know and understand what hazards they may encounter in their work environment. They must be trained to identify hazards so that they can first assess them, and then take steps to control them whenever possible. This module examines the different types of hazards, their properties, and systems available for identifying them. It also discusses risk and how to assess the scene of an emergency involving hazardous waste.