An ICS divides an emergency response into five essential functions: Command, Operations, Planning, Logistics, and Finance and Administration. At the top of an ICS structure is the Unified Command (UC) or the Incident Commander (IC). Federal officials transitioned ICS into a national program called the National Interagency Incident Management System (NIIMS) in 1980. In 2004, the U.S. Department of Homeland Security specified ICS as a subcomponent of the National Incident Management System (NIMS).
