In the case of a radiological incident, the Federal Radiological Emergency Response Plan specified federal leadership coordinated by the US Nuclear Regulatory Commission and Federal Emergency Management Agency. The national emergency management team that responded to the terrorist attacks of September 11, 2001, was not the product of unilateral federal action. In New York City and Arlington County, Virginia, incident management commands were led by the city and county fire departments, respectively, and organized under the incident command system. The initial response to the attack on the World Trade Center in New York City was made by the city’s fire and police departments, emergency medical system, Office of Emergency Management, and Department of Design and Construction, as well as by the New York/New Jersey Port Authority police. The restructuring of the National Response System had produced both intended and unintended outcomes, all of which would become apparent during the response to Hurricane Katrina in 2005.