From the
Department of Homeland Security Website:
In the event of a terrorist attack, natural disaster or other large-scale emergency, the Department of Homeland Security will assume primary responsibility on March 1st for ensuring that emergency response professionals are prepared for any situation. This will entail providing a coordinated, comprehensive federal response to any large-scale crisis and mounting a swift and effective recovery effort. The new Department will also prioritize the important issue of citizen preparedness. Educating America's families on how best to prepare their homes for a disaster and tips for citizens on how to respond in a crisis will be given special attention at DHS.
Michael Chertoff had "primary responsibility" then on the emergency response to Hurricane Katrina, according to the Department of Homeland Security.
Hat tip to Americablog.