Terrorism poses a clear and present danger to civilian populations. Although terrorist cells may gain access to traditional chemical weapons,there are literally thousands of other industrial chemicals to choose from. Common chemicals used on a daily basis in an industrialized society can be readily obtained from the local shopping center, rail yard. or from nearby industrial parks. and terrorists may choose to use these agents in an attack. The medical implications of a major incident involving the accidental or intentional release of a dangerous chemical are significant, and all healthcare facilities should have a plan in place to manage the casualties of such an event. This plan should include event recognition, crowd control, primary triage, emergency treatment, decontamination of injured and uninjured patients, and secondary triage. Emergency health care providers should be prepared to respond to classic chemical agents such as mustard,chlorine, and phosgene and must also work carefully with law enforcement and public health agencies to keep abreast of new threats. The ability to recognize an event promptly, triage patients, decontaminate casualties,administer antidotes when available, and provide best supportive care will minimize the adverse outcomes.