A major disaster (etymologically, an abnormal star) or an emergency may be defined as: ‘any event that occurs with or without warning, and causes or threatens to cause death or injury, damage to property or to the environment and disruption of the community, and whose effects are of such a scale that they cannot be dealt with by the emergency services, the National Health Service (NHS) and the local authorities as part of their everyday activities and therefore requires the mobilization and organization of special and extra services’. This includes natural disasters – flooding, tsunami, earthquakes; terrorist activity; major public transport incidents (air, train, ships, road traffic); public services problems (gas explosion).

Incidents in the USA are classified according to three ascending levels of scale related to the responses required:

• A Level I disaster is one in which local emergency response personnel and organizations are able to contain and deal effectively with the disaster and its aftermath.

• A Level II disaster requires regional efforts and mutual aid from surrounding communities.

• A Level III disaster is of such a magnitude that local and regional assets are overwhelmed, requiring state wide or federal assistance.

Since the 1990s there have been multidisciplinary plans in place in the UK to deal with emergencies. Recent events like the Asian tsunami and the London bombings have necessitated continual restructuring and reorganization of the Disaster Victim Identification (DVI) response team; the Centre for International Forensic Assistance (CIFA) now works closely with the police, supplying a list of appropriately trained and skilled ‘-ologists’.