Exposures to released hazardous materials (HAZMAT) pose an increasing threat to individual and public health, particularly in high population density. Any incident causing casualties on a scale which threaten or causes overload of the available resources of the emergency medical services (EMS) or associated systems (EMSS), constitutes a major incident (MI). Emergency services, including the EMSS, have a statutory duty to develop a comprehensive, integrated and flexible all-risk Major Incident Plan (MIP) for such an event. The MIP should also include developed management provision for HAZMAT incidents and in particular provision for safety and protection of both casualties and the EMSS personnel and systems, from secondary contamination by persistent, transmissible HAZMAT agents. This paper offers an outline review of contemporary policy and practice guidelines for the management of HAZMAT incidents and major incidents, with emphasis on the following: strategic and tactical preparation, integrated modular planning, communications, evaluation, training and equipment, including personal protection. In addition organisational aspects of the safe management and protection of the EMSS and personnel at the incident site, during transportation and at the receiving hospitals are considered. Safe and effective management of casualties requires adequate protection from further exposure, triage and synchronous decontamination and life support. Finally, the implications of conventional and unconventional conflict including terrorism and current unsolved problems are discussed.