On page 116 Stat. 2213, the Homeland Security Act of 2002, Public Law 107-296 (enacted November 25, 2002)required that the newly created Under Secretary for Emergency Preparedness and Response in his responsibilities at Section 502 (6) Consolidating Federal Government emergency response plans into a single, coordinated national response plan.
What might be of interest is that as of the date of this post IMO that tasking has NOT been accomplished. Also of interest is that Secretary DHS Tom Ridge did not assign the task to Michael Brown, the Under Secretary for Emergency Preparedness and Response the task but to Admiral Loy then operating in another capacity in DHS and later Deputy Secretary who assigned it under contract to RAND which produced a product largely rejected by management and others interested including the STATE and LOCAL governments. This tasking is also almost exactly the same as the one contained in the Homeland Security Strategy of 2002 (July 2002) and HSPD-5 & 8 both issued in 2003.