Defense Threat Reduction Agency
A U.S. Department of Defense organization, the Defense Threat Reduction Agency is concerned with reducing the threat of weapons of mass destruction, through specialized military training, work in arms control, and now in research and development for neutralizing WMD threats. Nuclear weapons expertise has been shared with the U.S. Department of Energy and its predecessors. DTRA is simultaneously the Center for Combating WMD of the United States Strategic Command, acting as a field-oriented Combat Support Agency.
It also absorbed the On-Site Inspection Agency, "formed in 1988 to carry out the on-site inspection and escorting responsibilities of the U.S. government under the Intermediate-Range Nuclear Forces Treaty." DTRA also obtained received the functions opf the Cooperative Threat Reduction program office, which transferred from the Office of the Assistant to the Secretary of Defense for Nuclear, Chemical and Biological Defense Programs. Its mission was to implement the Nunn-Lugar program to assist the nations of the former Soviet Union in reducing their weapons of mass destruction subject to international arms control treaties."
"For a time, the Director of DTRA was also dual-hatted as the director of the Defense Technology Security Administration, which was formed in 1985 as a field activity under the Office of the Under Secretary of Defense for Policy to manage the Department of Defense’s license review process for the export of dual-use technologies and munitions. That organization eventually returned to the Pentagon." 
Nunn-Lugar Global Cooperative Initiative
Arms Control and Verification
DTRA manages the OC-135B Open Skies bilateral inspection aircraft.
Research and development
It supports a wide range of research programs. For Fiscal Year 2007, the major projects were:
- Continue cooperative testing of technologies with the Russian Federation to enhance security and accountability of Russian nuclear weapons.
- Continue an academic program to investigate active interrogation and explosives detection.
- Instrumentation for radioactivity
- Continue development of portable high-resolution gamma ray detectors without the logistical burden of cryogenic cooling.
- Continue development of highly efficient portable neutron detectors for the detection of radiological or nuclear weapons.
- Continue program for developing systems exploiting advances in solid state nuclear detectors, processing electronics, analysis software, identification technology, and combination nuclear/biological/chemical sensor technology.
- Continue development of individual dosimeter and nuclear radiation exposure monitoring equipment for use in operational environments.
- Continue development of high intensity, highly directional neutron source for active interrogation.
- Continue development of a microsphere neutron detector.
- Continue evaluation and development of a thermoelectrically cooled portable, high-resolution gamma-ray detector.
- Continue an industry-based development of high-resolution gamma-ray detectors without the logistical burden of cryogenic cooling.
Chemical and Biological Defense
Nuclear Deterrence and Defense
Nuclear Deterrence and Forensics
- History of DTRA, Defense Threat Reduction Agency
- Office of the Comptroller (December 2005), Exhibit R-2a, RDT&E Project Justification, RDT&E, Defense-Wide/Advanced Technology Development, U.S. Department of Defense