Iraq actively researched weapons of mass destruction (WMD) and used chemical weapons from 1962 to 1991, after which its chemical weapons stockpile was destroyed and its nuclear weapons program and its biological weapon program halted, in accordance with the United Nations Security Council's Resolution 687. The Iraqi government of Saddam Hussein was internationally condemned for its chemical attacks against Iranian and Iraqi Kurdish civilians and troops during the Iran–Iraq War. Saddam pursued extensive biological and nuclear weapons programs, but did not construct a nuclear weapon. After the Gulf War, the United Nations Special Commission located, confiscated, and destroyed large quantities of Iraqi chemical weapons and infrastructure; Iraq ceased its chemical, biological and nuclear programs.Cleminson, Ronald. What Happened to Saddam's Weapons of Mass Destruction? Arms Control Association. September 2003.

During the Iran–Iraq War, known Iraqi chemical weapons attacks between 1983 and 1988 were estimated to have caused 50,000 immediate casualties to Iranian troops. Civilians were also targeted; between 3,200 and 5,000 people were killed in the Halabja massacre. The attacks were led by Ali Hassan al-Majid, using mustard gas and nerve agents. In the Gulf War, US bombing and post-war demolition of Iraqi chemical weapons facilities, especially containing sarin and cyclosarin, were concluded to be the primary cause of Gulf War syndrome, experienced by over 40% of US veterans of the Gulf War.

False assertions by the US and UK that Iraq continued researching and stockpiling WMDs played a major role in the prelude to the Iraq War. The US and UK carried out the 1998 bombing of Iraq, allegedly targeting WMD facilities. Following the September 11 attacks, the US attempted to link Iraq to alleged WMD pursuits of the perpetrating terrorist group Al-Qaeda. UN inspections resumed between November 2002 and March 2003, under Resolution 1441, which demanded Iraq provide "immediate, unconditional and active cooperation" to UN and IAEA inspections. The US argued that Iraq's lack of cooperation was a breach of Resolution 1441, but failed to convince the UNSC to pass a new resolution authorizing the use of force. Despite this, the US asserted peaceful measures could not disarm Iraq and launched the invasion of Iraq in March 2003.

U.S.-led inspections later found that Iraq had ceased active WMD production and stockpiling. Some have argued the false WMD allegations were used as a deliberate pretext for war.The Iraq Invasion 20 Years Later: It Was Indeed a Big Lie that Launched the Catastrophic War, David Corn, Mother Jones, March 20, 2023. Various unsubstantiated conjectures were put forward that the weapons might have been hidden or sent elsewhere. In July 2004, official U.S. and British reports concluded that spy agencies had "listened to unreliable sources," leading to "false or exaggerated allegations about an Iraqi arsenal."

Iraq signed the Geneva Protocol in 1931, the Nuclear Non-Proliferation Treaty in 1969, and the Biological Weapons Convention in 1972 but did not ratify it until June 11, 1991. Iraq ratified the Chemical Weapons Convention in January 2009, with its entry into force for Iraq coming a month later on February 12.

History Program development 1960s–1980s

1959 August 17 USSR and Iraq signed an agreement for the USSR to build a nuclear power plant and established a nuclear program as part of their mutual understanding.

1968 a Soviet supplied IRT-2000 research reactor together with a number of other facilities that could be used for radioisotope production was built close to Baghdad.

1975 Saddam Hussein arrived in Moscow and asked about building an advanced model of an atomic power station. Moscow would approve only if the station was regulated by the International Atomic Energy Agency, but Iraq refused. However, an agreement of co-operation was signed on April 15, which superseded the one of 1959.

After 6 months France agreed to sell 72 kg of 93% uranium and built a nuclear power plant without IAEA control at a price of $3 billion.

Iraq began a clandestine nuclear weapons program under President Saddam Hussain's directives in late 1969. Iraq's weapons of mass destruction programs were assisted by a wide variety of foreign firms and governments in the 1970s and 1980s. As part of Project 922, Iraq built chemical weapons facilities such as laboratories, bunkers, an administrative building, and first production buildings in the early 1980s under the cover of a pesticide plant. German firms sent 1,027 tons of precursors of mustard gas, sarin, tabun, and tear gasses in all. This work allowed Iraq to produce 150 tons of mustard agent and 60 tons of Tabun in 1983 and 1984 respectively, continuing throughout the decade. Five other German firms supplied equipment to manufacture botulin toxin and mycotoxin for germ warfare. In 1988, German engineers presented centrifuge data that helped Iraq expand its nuclear weapons program. Laboratory equipment and other information was provided, involving many German engineers. All told, 52% of Iraq's international chemical weapon equipment was of German origin. The State Establishment for Pesticide Production (SEPP) ordered culture media and incubators from Germany's Water Engineering Trading.

Iraq used an overlooked method, electromagnetic separation (calutrons), to enrich uranium. Its interest in electromagnetic separation started sometime in 1971. Iraq chose to develop the electromagnetic process over more modern, economic, and efficient methods of enrichment because calutrons were easier to build, with fewer technical challenges, and the components required to build them were not subject to export controls.

Western help with Iraq's WMD program

United States The United States supported Iraq during the Iran–Iraq war with over $500 million worth of dual-use equipment that were approved by the Commerce department. Among them were advanced computers, some of which were used in Iraq's nuclear program.Timmerman, Kenneth R. The Death Lobby: How the West Armed Iraq. New York, Houghton Mifflin Company, 1991. The non-profit American Type Culture Collection and the Centers for Disease Control sold or sent biological samples of anthrax, West Nile virus and botulism to Iraq up until 1989, which Iraq claimed it needed for medical research. A number of these materials were used for Iraq's biological weapons research program, while others were used for vaccine development. For example, the Iraqi military settled on the American Type Culture Collection strain 14578 as the exclusive anthrax strain for use as a biological weapon, according to Charles Duelfer.Duelfer, Charles. Comprehensive Report of the Special Advisor to the Director of Central Intelligence on Iraq's Weapons of Mass Destruction , 30 September 2004, Vol 3, "Biological Warfare", p.21.

The United States government invited a delegation of Iraqi weapons scientists to an August 1989 "detonation conference" in Portland, Oregon. The U.S. Department of Defense and the U.S. Department of Energy conference featured experts that explained to the Iraqis and other attendees how to generate shock waves in any needed configuration. The conference included lectures on HMX, a powerful explosive generally preferred for nuclear detonation, and on flyer plates, which are devices for generating the specific type of shock waves necessary for nuclear bomb ignition. Both HMX and flyer plates were in fact later found at Iraqi nuclear research sites by United Nations weapons inspectors.New York Times, 8 Mar. 1992 "Building Saddam Hussein's Bomb"

United Kingdom

In 1985, the Second Thatcher ministry allowed a German-owned and British-based company, Uhde Ltd, to construct a factory in Iraq which was intended to be used for mustard and nerve gas production by the Iraqis. During the late 1980s, the British government secretly granted Coventry-based engineering company Matrix Churchill permission to sell parts to Iraq for use in their weapons programs, while several UK firms sold components to Canadian engineer Gerald Bull for Project Babylon. In March 1990, a case of nuclear triggers bound for Iraq was seized by HM Customs and Excise at Heathrow Airport. The Scott Report uncovered much of the secrecy that had surrounded the "Arms-to-Iraq" affair, as it became known when knowledge of UK arm sales to Iraq became public.Hidden assets, History Today; March 1994

Iraq's nuclear weapons program suffered a serious setback in 1981 when the Osiraq reactor, which would have been capable of breeding weapons-usable nuclear material, was bombed by the Israeli Air Force before it could be commissioned. David Albright and Mark Hibbs, writing for the Bulletin of the Atomic Scientists, disagree with this view, however. There were far too many technological challenges unsolved, they say.

Iran–Iraq War

In 1980, the U.S. Defense Intelligence Agency filed a report stating that Iraq had been actively acquiring chemical weapons capacities for several years, which later proved to be accurate. In November 1980, two months into the Iran–Iraq War, the first reported use of chemical weapons took place when Tehran radio reported a poison gas attack on Susangerd by Iraqi forces. The United Nations reported many similar attacks occurred the following year, leading Iran to develop and deploy a mustard gas capability. By 1984, Iraq was using poison gas with great effectiveness against Iranian "human wave" attacks. Chemical weapons were used extensively against Iran during the Iran–Iraq War. On January 14, 1991, the Defense Intelligence Agency said an Iraqi agent described, in medically accurate terms, military smallpox casualties he said he saw in 1985 or 1986. Two weeks later, the Armed Forces Medical Intelligence Center reported that eight of 69 Iraqi prisoners of war whose blood was tested showed an immunity to smallpox, which had not occurred naturally in Iraq since 1971; the same prisoners had also been inoculated for anthrax. The assumption being that Iraq used both smallpox and anthrax during this war.