The document outlines the roles and responsibilities of the Incident Safety Officer (ISO) and Assistant Safety Officer-Hazardous Materials (ASO-HM) at hazardous materials incidents. Key duties of the ISO include ensuring safety zones are established, monitoring operational effectiveness, and maintaining incident command. The ASO-HM assists with technician-level operations and evaluates personal protective equipment and decontamination. Safety issues that require close monitoring include control zones, accountability systems, rehab, and traffic control. The ISO must apply an action model involving risk evaluation, reconnaissance, resource evaluation, and reporting requirements including federal site safety plans. Unique considerations for clandestine drug labs and weapons of mass destruction incidents are also discussed.