An incident (or series of incidents) causing casualties on a scale that is beyond the normal resources of the emergency services. Note: the term mass casualty denotes a major incident potentially involving hundreds of casualties, or more
Cabinet Office, Lexicon of UK Civil Protection: A developing single point of reference for UK Civil Protection Terminology - Version 2.0.1, Emergency Responder Interoperability Lexicon, London, UK 2011. http://www.cabinetoffice.gov.uk/cplexicon, (Emr Mgt - Brit) {545}