The Basic Disaster Life Support (BDLS) course presented by the National Disaster Life Support Educational Consortium teaches first responders to use the D.I.S.A.S.T.E.R. mnemonic to help them remember the critical actions they will need to effectively manage a mass-casualty incident. This article describes the components of the mnemonic D.I.S.A.S.T.E.R. which includes: D=Detection--to be aware of all possible threats; I=Incident Command--the Incident Command System (ICS) allows for a flexible standardized system of command and control; S=Safety and Security--the maintenance of scene safety and security; A=Assess Hazards--to be aware and assess potential hazards, such as fire, smoke, gas, and blood; S=Support--to get the job done which entails supplies, facilities, and personnel; T=Triage and Treatment--the sorting of casualties based on severity then sending them for appropriate treatment; E=Evacuation--casualty evacuation and determining evacuation availability via land or air; and R=Recovery--after sorting casualties, time for coroner involvement and Critical Incident Stress Debriefing.