The Federal Emergency Management Agency, or FEMA, is an agency of the United States Department of Homeland Security. The purpose of FEMA (begun by Presidential Order on March 30, 1979)
is to coordinate the response to a disaster which has occurred in the United States and which overwhelms the resources of local and state authorities. The governor of the state in which the disaster occurred must declare a state of emergency and formally request from the President that FEMA and the federal government respond to the disaster. The only exception is when an emergency or disaster occurs on federal property or to a federal asset, for example, the Alfred P. Murrah Federal Building in Oklahoma City, Oklahoma, in the 1995 bombing, or the Space Shuttle Columbia in the 2003 return-flight disaster.
References
Other websites
DHS organization
FEMA Field Operations Guide Including descriptions of markings on evacuated and searched buildings FEMA website A History of FEMA