The video first advises public safety agencies to prepare for incidents that involve weapons of mass destruction, which may be chemical, ordnance, biological, or radiological. Such preparation involves sizing up potential targets in a city. These include government agencies, industrial facilities, places of public assembly, infrastructure facilities, and enclosed public spaces. Public safety agencies should familiarize themselves with physical and geographical attributes of potential sites. The video then simulates the Seattle Fire Department's proper response to the dispensing of a toxic chemical agent over a broad public area. The narrator outlines the steps that should be taken in the course of the simulation. The goal for first responders to the scene is to respond safely and decontaminate quickly without becoming victims themselves. The five priorities are to identify the danger, protect the public safety professionals, control the scene, call for additional help, and rescue and decontaminate the victims. Aspects of executing each of these priorities are described.