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The Defense Threat Reduction Agency (DTRA) traces its roots back to the Manhattan Project in 1942. A mission that began strictly as a weapons development program, expanded during the Cold War and eventually included non-nuclear weapons development nonproliferation efforts. The November 1997 Defense Reform Initiative joined the Defense Special Weapons Agency and the On-Site Inspection Agency with two defense programs: the Cooperative Threat Reduction Program (CTR) and Chemical-Biological Defense Program, Science and Technology component, forming the core elements of the new agency. DTRA was formally established on October 1, 1998. Additionally, the Joint Improvised Defeat Organization joined DTRA in October 2016 and this department was later merged into DTRA 's current Operations Integration Directorate.

DTRA’s rich legacy begins with the Manhattan Engineering District, later referred to simply as the “Manhattan Project,” which was created to develop the world’s first atomic bomb during World War II. Rooted in the success of the TRINITY nuclear test, the first detonation of an implosion-type plutonium device, the Atomic Age was born.

After the end of World War II, the Manhattan Project continued to support atomic weapons testing until the Atomic Energy Act of 1946 split the program into two parts—the Atomic Energy Commission, known today at the Department of Energy (DOE), and the Armed Forces Special Weapons Project (AFSWP). The AFSWP, the military organization responsible for the aspects of the nuclear weapons remaining under military control after the split, was responsible for nuclear weapons maintenance, storage, surveillance, security and transportation as well as conducting offensive and defensive military training in nuclear weapons operations and supporting nuclear tests.

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JULY 1945 - TRINITY, the first implosion-type plutonium device, was detonated in New Mexico.

AUGUST 1945 - The U.S. dropped atomic bombs, “Little Boy” over Hiroshima and “Fat Man” over Nagasaki.

JULY 1946 - MED (Manhattan Engineering District) organized the first postwar atomic test series at the Bikini Atoll in the Pacific Ocean.

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OCTOBER 1953 - The Secretary of Defense directed The Armed Forces Special Weapons Project (AFSWP) (AFSWP) to maintain “a centralized system of reporting and accounting to ensure the current status and location” of nuclear weapons. This critical function continues to the present day.



The AFSWP was re-designated as the Defense Atomic Support Agency (DASA) in 1959 following an expansion of responsibilities. DASA received the majority of the Department’s nuclear effects research and testing funds, and as new technologies were explored, the agency assumed increased roles and missions relevant to the modernization of the U.S. capabilities. DASA was also responsible for coordinating responses to nuclear accidents.

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NOVEMBER 1962 - The Defense Atomic Support Agency (DASA)served as the center for expertise to design enduring communications and systems that could withstand EMP effects.

OCTOBER 1964 - DASA sponsored the McMillan Panel, which advised the Kennedy Administration on nuclear test bans and potential treaties limiting nuclear testing.

JANUARY 1968 - DASA oversaw Service decontamination efforts that removed 237 tons of radioactive ice and debris after a B-52 crash near Thule, Greenland.

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NOVEMBER 1971 - Defense Nuclear Agency (DNA) used satellite observations and modeling to develop steps to mitigate and cope with communications degradation due to nuclear effects.

SEPTEMBER 1972 - DNA-supported OSD site security initiatives following terrorist attacks at the Munich Olympics.

JANUARY 1984 - DNA published the Nuclear Weapons Accident Response Procedure (NARP) manual, providing response procedures still in use today.

MARCH 1987 -DNA developed the foundations of its counterproliferation program following its support of precision strike operations in the Gulf War. In December, U.S. and Soviet leaders signed the Intermediate-Range Nuclear Forces (INF) Treaty. This resulted in DNA developing treaty verification technology.

MARCH 1991 - DNA began what was eventually referred to as counterproliferation initiatives in response to the post-Desert Storm Iraqi quest to obtain nuclear weapons.

DECEMBER 1994 - DNA verification technology expanded to include support to every U.S. arms control and bilateral agreement.

With the rapid military build-up and strategic modernization, the Defense Nuclear Agency (DNA) was established as the successor of DASA in 1971 and soon became the leader for all U.S. nuclear weapons effect tests and other new technologies. DNA also inherited the task of addressing effects of nuclear weapons testing on the health of the general public, test participants and the environment, eventually establishing the Nuclear Test Personnel Review in 1978. In the early 1980s, the resurgence of Cold War tensions and the shift of American Nuclear Policy had a profound effect on the agency, shifting the mission in the direction of enhancing the endurance and superiority of the country’s strategic and conventional forces.

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June 1996 - DNA was renamed Defense Special Weapons Agency (DSWA) as the mission scope expanded to include non-nuclear development activities. DSWA quickly postured itself for success to combat post-Cold War threats.

September 1996 - President Bill Clinton, along with top officials from China, France, Russia, Britain, and more than 50 other nations, signed the Comprehensive Test Ban Treaty at the United Nations.

August 1997 - Following the World Trade Center and Oklahoma City bombing, DWSA supported investigations by providing analytical support and modeling.

DNA transitioned to the Defense Special Weapons Agency (DSWA) in 1996 and gained increased responsibilities. In addition to the agency inherited missions, DSWA was charged with conducting programs associated with the CTR work, arms control technology, and with counterproliferation support. As the Department of Defense assessed the threat of upcoming 21 st Century WMD technological dangers, it became the natural and efficient choice to rely upon DSWA, an agency responsive and agile and prepared to meet the needs of the American people and people around the world.

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OCTOBER 1998 - The Defense Threat Reduction Agency (DTRA) was established, joining DSWA, OSIA, CTR and the Chemical Biological Defense Program.

SEPTEMBER 2001 - The U.S. was stunned by a series of terrorist attacks in Washington, D.C., New York, and Pennsylvania. Immediately following the attacks, DTRA contributed to U.S. Combat Commands and domestic agencies responding to the attacks.

MARCH 2003 - DTRA was named the DoD Executive Agent for WMD elimination operations within Iraq and conducted nearly 70 sensitive site surveys. In May 2003, President George W. Bush launched the Proliferation Security Initiative (PSI), which is now maintained by DTRA.

JUNE 2004 - DTRA partnered with the Department of Energy (DOE) to remove 1.77 metric tons of low enriched uranium and 1,000 highly radioactive sources from Iraq.

Joining DTRA in 1998, the On-Site Inspection Agency (OSIA) was officially 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. OSIA continued to conduct the necessary confidence-building measures inspections servicing the United States and our partner nations. In July of 1991, OSIA became the Executive Agent responsible for supporting the United Nations Special Commission, the organization conducting inspections in raq to determine treaty compliance regarding elimination of Iraqi WMD threats.

The Nunn-Lugar Cooperative Threat Reduction (CTR) program office was founded in 1991. Previously a program within the Office of the Assistant to the Secretary of Defense for Nuclear, Chemical and Biological Defense, CTR became a core DTRA element upon establishment in 1998. The initial CTR program mission was to assist the nations of the former Soviet Union in reducing their WMD stockpiles to comply with international arms control treaties. Based on the long history of successfully strengthening alliances and building partner capacity to eliminate, secure, and provide WMD detection and interdiction capabilities, the CTR program now operates in 32 countries around the world in five program areas. Upon DTRA’s establishment in 1998, the Chemical Biological (CB) Defense Technologies Department transitioned from the Assistant Secretary of Defense, Nuclear Chemical Biological Programs office, as a core element of the agency. The Joint Science and Technology Office for Chemical and Biological Defense was established in 2003 by the CB Department, which serves as a Department of Defense focal point for chemical and biological defense science and technology research and development. CB has supported responses to multiple world crises, including the Fukushima nuclear reactor disaster, elimination of Syria’s declared chemical weapons, the Ebola outbreak in West Africa, and the identification of chemical weapon production areas in Iraq and Syria. Through continued partnerships with academia, industry and government laboratories CB is able to rapidly prototype and transition defense capabilities to our warfighters, ensuring they can survive, fight and win in a CB environment.

In 2005, the Secretary of Defense charged the Commander of U.S. Strategic Command (USSTRATCOM) to lead counter-WMD integration and synchronization efforts. Looking to DTRA for counter-WMD expertise, USSTRATCOM established the U.S. Strategic Command Center for Combating Weapons of Mass Destruction (SCC-WMD) and co-located it with DTRA Headquarters on Fort Belvoir. The DTRA Director served dual-hatted as the Director of both DTRA and SCC-WMD until the WMD integration and synchronization responsibility transferred from USSTRATCOM to U.S. Special Operations Command in 2017.

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MARCH 2011 - Following Japan’s 8.9 magnitude earthquake and ensuing tsunami, DTRA supported Operation Tomodachi providing 24/7 consequence management and reachback support ensuring the safe containment of nuclear materials and preventing a nuclear meltdown. In September, DTRA’s International Counterproliferation Program expanded to include engagements in a total of 88 countries in Europe, Asia, and Africa.

AUGUST 2014 - DTRA led efforts to eliminate 600 metric tons of declared Syrian CW at sea using specialized equipment and the Field Deployable Hydrolysis System.

FEBRUARY 2015 - During the Ebola outbreak in West Africa, DTRA provided transportable diagnostic labs, personal protective equipment, valuable vaccine and therapeutic test results leading to the FDA-approved treatment drug Zmapp.

JUNE 2018 - DTRA collaborated with the Government of Jordan to prevent, deter, detect and interdict illicit trafficking of WMD and related materials and has increased Jordanian frontier border force capabilities.

AUGUST 2018 - DTRA team members were awarded the Secretary of Defense Medal for Valor. The team willingly put themselves at risk, exposed themselves to lethal threats, direct enemy fire and other explosives with one expert single-handedly fending off an insurgent onslaught.


Capping off nearly 20 years of DTRA efforts to counter the deadly Ebola virus, the FDA approves Merck's Ebola vaccine Ervebo. The start of this effort began in 2001, when DTRA and BioProtection Systems first partnered with Canada on tackling the deadly disease.

MARCH 2020

With the rapid worldwide spread of the SARS-CoV-2 virus and its disease COVID-19, DTRA's specialized capabilities were put to the test in many ways. The agency fulfilled the first of more than 40 equipment and training requests from 18 partner nations overwhelmed by the pandemic and is tapped to lead the critical mission of bringing the first shipment of diagnostic kits made in Italy to the United States.

DTRA's special role as the DoD’s dual-hatted Defense Agency and Combat Support Agency focused on countering WMD and Emerging Threats continues to grow. The agency continues to address WMD and CBRN threats it started dealing with years before the agency was established in 1998, and it's unique and specialized CWMD workforce continues to adapt to new and emerging threats and adversaries that are increasing and expanding their WMD, and to identify, anticipate and prepare solutions for the next threat to come our way.



DTRA provides cross-cutting solutions to enable the Department of Defense, the United States Government, and international partners to deter strategic attack against the United States and its allies; prevent, reduce, and counter WMD and emerging threats; and prevail against WMD-armed adversaries in crisis and conflict.  

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