The Defense Threat Reduction Agency (DTRA) is a combat support agency within the United States Department of Defense (DoD) for countering weapons of mass destruction (WMD; chemical, biological, radiological, nuclear, and high explosives). According to the agency's Strategic Plan for Fiscal Years 2018 to 2022, the DTRA mission "enables DoD and the U.S. Government to prepare for and combat weapons of mass destruction and improvised threats and to ensure nuclear deterrence." The agency is headquartered in Fort Belvoir, Virginia. Organizational history DTRA was officially established on October 1, 1998, as a result of the 1997 Defense Reform Initiative, by consolidating several DoD organizations, including the Defense Special Weapons Agency (successor to the Defense Nuclear Agency) and the On-Site Inspection Agency. The Defense Technology Security Administration and the Nunn–Lugar Cooperative Threat Reduction program office in the Office of the Secretary of Defense were also incorporated into the new agency. In 2002, DTRA published a detailed history of its predecessor agencies, Defense's Nuclear Agency, 1947–1997, the first paragraph of which makes a brief statement about the agencies which led up to the formation of DTRA: Defense's Nuclear Agency, 1947–1997, traces the development of the Armed Forces Special Weapons Project (AFSWP), and its descendant government organizations, from its original founding in 1947 to 1997. After the disestablishment of the Manhattan Engineering District (MED) in 1947, AFSWP was formed to provide military training in nuclear weapons' operations. Over the years, its sequential descendant organizations have been the Defense Atomic Support Agency (DASA) from 1959 to 1971, the Defense Nuclear Agency (DNA) from 1971 to 1996, and the Defense Special Weapons Agency (DSWA) from 1996 to 1998. In 1998, DSWA, the On-Site Inspection Agency, the Defense Technology Security Administration, and selected elements of the Office of Secretary of Defense were combined to form the Defense Threat Reduction Agency (DTRA). DTRA employs approximately 2,000 civilians and uniformed service members at more than a dozen permanent locations around the world. The majority of personnel are at DTRA headquarters at Fort Belvoir. Approximately 15% of the workforce is split between Kirtland Air Force Base and the White Sands Missile Range in New Mexico, and the Nevada National Security Site (formerly called the Nevada Test Site), where they do testing and support the U.S. military's nuclear mission. The remaining 15% of the workforce is stationed at locations in Germany, Kazakhstan, Azerbaijan, Uzbekistan, Georgia, Ukraine, Armenia, Kenya, South Korea, Japan,