On Mar. 1, 2004, the National incident Management System (NIMS), developed by the Department of Homeland Security (DHS), was released.

It established a uniform set of processes and procedures for emergency responders at all levels of government to use in response operations. NIMS was the first-ever standardized approach to incident management and response.

Since 2006, the NIMS document has been revised to incorporate best practices and lessons learned from recent incidents. The NIMS revision also clarifies concepts and principles, and refines processes and terminology throughout the document.