Well before Operation Desert Storm or the U.N. inspections that followed it, Iraq had already begun to build chemical weapons. After launching a research effort in the 1970s, Iraq was able to use chemical weapons in its war against Iran and to kill large numbers of its own Kurdish population in the 1980s. During the first Gulf War, there were fears that Iraq would launch chemical-tipped missiles at its neighbors, particularly Israel, but Iraq refrained for fear of U.S. retaliation. During Operation Iraqi Freedom, coalition troops again feared they might be hit with chemical weapons, though this did not come to pass.
By 1991, the United Nations had established its Special Commission (UNSCOM) and charged it with the task of destroying, removing, or rendering harmless "all chemical and biological weapons and all stocks of agents and all related subsystems and components and all research, development, support and manufacturing facilities."
By the time UNSCOM left Iraq in December 1998, it had eliminated a large portion of Iraq's chemical weapon potential. UNSCOM had overseen the destruction or incapacitation of more than 88,000 filled or unfilled chemical munitions, over 600 tons of weaponized or bulk chemical agents, some 4,000 tons of precursor chemicals, some 980 pieces of key production equipment, and some 300 pieces of analytical equipment. Notwithstanding these extraordinary achievements, there remained important uncertainties regarding Iraq's holdings of chemical weapons, their precursors, and munitions.
I. Chemical Agents
CS and Mustard Gases
After a successful research effort in the 1970s, Iraq began producing tear gas and mustard gas in the early 1980s. Tear gas is not lethal; its chief use is riot control. It causes pain to the eyes and nose, and uncontrollable coughing. Iraq first produced several tons of CS tear gas at its Salman Pak site, and by the early 1980s began military-scale production at the al-Muthanna State Establishment.
Iraq also began to produce sulphur mustard blister gas (HD) in the early 1980s, and by 1983 was able to employ it in chemical munitions against Iran. The primary effect of mustard gas is skin and eye blistering and lung irritation. Heavy exposure to an aerosol of mustard gas causes the lungs to fill with fluid and "drown" the victim. Mustard gas has a low death rate; generally only 2 to 3 percent of its victims perish.
Iraq initially told UNSCOM that 3,080 tons of mustard gas had been produced, but in 1995 Iraq reduced this amount to 2,850 tons. UNSCOM found Iraq's mustard gas to be at least 80% pure and determined that it could be stored for long periods of time, both in bulk and in weaponized form. In its distilled form, mustard gas has a long life, and can be stockpiled for decades. It is relatively easy to produce and load into munitions. Iraq admits filling some 550 artillery shells with mustard gas but says it misplaced them shortly after the first Gulf War.
Nerve Gas: Sarin and Tabun
Iraq moved up to producing the nerve gases sarin (GB) and tabun (GA) in 1984. These gases are highly toxic compounds that can penetrate the body either through contact with skin or eyes, or by inhalation. Just a few droplets will kill within minutes if inhaled or within hours if absorbed through the skin. The initial effects depend on the amount of contact with the agent and are almost immediate. Chemical nerve agents tend to have little or no incubation or latent period in the body. These agents act by attacking the central nervous system, causing rapid paralysis, respiratory failure and death by asphyxiation.
According to Iraq, the sarin and tabun it first produced was of poor quality. It was unstable, and the effectiveness of the agents diminished quickly after production. Iraq claimed that its production methods were later changed to eliminate the stabilization problem. Iraq argued that the tabun it produced was of such poor quality that Iraq turned its research, development and production effort to prolonging the viability of sarin instead.
Iraq adopted the "binary" method of weaponization, in which the components of sarin gas are stored separately until use, when they are mixed. The components of sarin are DF 2 and the alcohols cyclohexanol and isoproponal. Iraq manufactured DF 2 with a purity of 95%, and imported alcohols of 100% purity, so the detonation of its munitions could be expected to yield relatively pure sarin.
At first, Iraq told UNSCOM that it had produced an estimated 250 tons of tabun and 812 tons of sarin. In 1995, Iraq changed its estimates and reported it had produced only 210 tons of tabun and 790 tons of sarin. Thus, it is still uncertain how much tabun and sarin Iraq actually manufactured.
Nerve Gas: VX
Iraq appears to have turned its research efforts toward VX nerve gas in 1985. VX is the most toxic of all known chemical warfare agents. Its effects on the body are similar to those of sarin and tabun, paralyzing the nervous system and causing convulsions and rapid death when contact occurs. A very small amount on the skin (10 milligrams) is enough to kill a man. VX is an oily liquid that may persist in the environment for weeks or longer, thereby posing a major skin absorption risk.
Iraq admitted that it had six or seven research teams working on VX, and production is known to have taken place in 1987-88 and possibly until 1990. A team of U.N. experts concluded that there was clear evidence that Iraq had the capability to produce the agent because the Muthanna State Establishment, as early as 1984, had done industrial scale organophosphorous synthesis, a process much more difficult than that required to produce VX. One plant, in Dhia'a, was reconfigured to produce necessary components for VX by 1988. Iraq also admitted producing and procuring vast amounts of precursor agents for VX, including 58 tons of the chemical choline, a key VX ingredient. Iraq claimed that nearly all of its precursors had been destroyed by aerial bombing during the first Gulf War, and that what remained was secretly destroyed in the summer of 1991.
UNSCOM estimated that by 1991, Iraq could have produced between 50 and 100 tons of VX gas. By 1998, UNSCOM estimated that Iraq was capable of producing 200 tons. Iraq at first told UNSCOM that it had only produced 240 kilograms of VX, but in 1996 admitted that it had produced 3.9 tons. Iraq provided documents stating that 2.4 tons of VX were produced in 1988 and the remainder in 1990. Iraq explained this low volume by claiming that it had scaled-up all its chemical weapons processes at al-Muthanna except VX, a claim UNSCOM rejected as incompatible with Iraq's massive R&D efforts. Iraq also claimed that it later abandoned the VX project because the gas was of poor quality and was unstable. Iraq never backed up its claims with verifiable evidence, so the total quantity of VX that Iraq produced is not known.
Total Chemical Agent Produced
Iraq claimed that its chemical weapons program yielded a total of 3,859 tons of useable agents. Iraq insisted that it only weaponized 3,315 tons and consumed 80% of those weaponized agents during the war with Iran. The true extent of Iraq's production and holdings of chemical agents has never been fully verified.
II. Precursors
Chemicals that serve as ingredients for making chemical weapon agents are known as "precursors." In the early stages of its chemical weapon program Iraq imported the necessary precursors. However, from 1986 to 1990, Iraq constructed and operated numerous plants and facilities (such as Fallujah 1, 2 and 3) for producing precursors on its own. Iraq told UNSCOM that during Iraq's entire chemical weapon program, which lasted from the mid-1970s through at least 1991, it produced and procured 20,150 tons of key precursor chemicals. Of that amount, Iraq claimed to have used 14,500 tons to produce chemical agents or other key precursor chemicals, leaving 5,650 tons of precursors unaccounted for. However, Iraq also claimed that only 3,915 tons of precursor agents remained inside the country as of January 1991, a noticeable discrepancy. Of that 3,915 tons, a total of 2,850 tons were destroyed under UNSCOM supervision and the rest was said by Iraq to have been destroyed during the first Gulf War or destroyed by Iraq unilaterally.
III. Weaponization
After a chemical warfare agent is produced, it is loaded into a munition so that it can be fired at an adversary. This step is called weaponization.
Tear Gas and Mustard Gas
Iraq admitted that it deployed CS tear gas in both RPG-7 rocket propelled grenades and in 82mm and 120mm mortar shells. CS was also used to fill 250- and 500-gauge aerial bombs. In addition, Iraq admitted that it used both 250- and 500-gauge aerial bombs for mustard gas deployment, as well as 155mm artillery shells. Documentary evidence was found showing that Iraq also filled DB-2 aerial bombs with mustard gas, although Iraq claims that it filled only a few bombs for testing purposes. UNSCOM managed to destroy 12,792 of the 13,000 155mm artillery shells filled with mustard gas that Iraq had declared as remaining after the first Gulf War ended; however, Iraq also declared that it had lost 550 of these shells. UNSCOM was never provided with any substantial evidence to corroborate this claim. A few such shells were destroyed by subsequent inspectors in 2002-2003, but many were still unaccounted for after the second Gulf War.
Sarin
Iraq filled thousands of munitions with sarin or its binary components. These included 122mm rockets, DB-2 and R-400 aerial bombs, and thirty special warheads for the domestically produced Al-Hussein missile (a SCUD variant). The Al-Hussein warheads were discovered and subsequently destroyed under UNSCOM supervision. Iraq also claimed that it unilaterally destroyed 45 additional special warheads that were filled with chemical agents, including binary sarin components.
VX
Iraq denied ever having weaponized VX. In June 1998, however, UNSCOM found evidence of VX contamination on fragments of missile warheads. Iraq never provided an adequate explanation for this evidence, insisting instead that weaponization never occurred. Iraq did admit filling three aerial bombs and one 122mm rocket warhead with VX, but claimed that this was only for storage and corrosion tests. Iraq said that the tests were failures due to the low purity and poor stability of the gas. U.N. experts concluded, however, that weaponization of VX presented no technical difficulty for Iraq and may have been done.
Total Munitions
Iraq declared to UNSCOM that at one time it held over 200,000 special munitions, either filled or unfilled, specifically designed for chemical or biological weapons. These included grenades, mortar shells, aerial bombs, artillery shells, rockets and missile warheads. Of those, Iraq claimed that it used or disposed of approximately 100,000 munitions filled with chemical weapons during the period of its war with Iran, which ended in 1988. With regard to its holdings as of January 1991, Iraq asserted that 127,941 filled and unfilled special munitions remained in the country. During the first Gulf War -- according to Iraq -- 41,998 munitions were destroyed by Allied bombing, and Iraq also said that it unilaterally destroyed 29,662 munitions after the first Gulf War. The remaining 56,281 special munitions were either destroyed or accounted for under UNSCOM supervision.
Iraq gained the ability to manufacture R-400 and DB-2 aerial bombs, chemical containers for 122mm rockets, and Al-Hussein missile warheads. Iraq had to import all other munition shells, but UNSCOM believed that Iraq also had the ability to empty conventional artillery shells and aerial bombs and refill them with chemical agents. Iraq had a wide array of munitions specially designed for chemical use, and some of them were used for more than one chemical agent.
Nose cone for chemical munitions
An Iraqi worker climbs into a chemical agent missile nose cone to open it for sample-taking
Deployment
The role of the military in Iraq's chemical weapons program remained a secret. Iraq never disclosed any information to UNSCOM concerning deployment, military requirements, firing or bombing tables, field manuals on the use of chemical weapons, or the chain of command for chemical weapons. According to Iraq, there were never any field manuals specifically for chemical weapons, nor were any specific military units trained to use them. Iraq said responsibility for the planning of combat use for chemical weapons was handled at the Muthanna State Establishment by a special tactical group, but refused to provide any further information.
IV. Manufacturing Plants and Equipment
Although Iraq developed and produced chemical weapons at several secret locations, the main work was done at the Al-Muthanna State Establishment (MSE). It was the principal manufacturing site for both agents and munitions. It also served as a storehouse for precursor chemicals, filled chemical munitions and warfare agents in bulk. The MSE consisted of the Al Muthanna production facility, three precursor production sites at Al Fallujah, and munition stores at Muhammediyat. The Samarra site, also part of the MSE, was the prime production facility for Iraqi mustard gas and nerve agents.
Iraq also produced chemical munitions at a large complex known as Al Taji. UNSCOM found at Taji 6,000 empty canisters designed to be filled with chemical weapons for use in 122mm rockets.
In addition to its work on chemical agents and munitions, UNSCOM attempted to find and destroy hundreds of pieces of production equipment. Iraq admitted that 553 pieces of equipment located at 15 production plants had either made chemical precursors, agents or munitions or had been bought for that purpose. Nearly all of the equipment came from foreign companies. Most of it was at the MSE, including the facilities at Al-Fallujah. UNSCOM, in accounting for this equipment, reported that it was destroyed either as a result of the first Gulf War or under UNSCOM supervision. UNSCOM also destroyed an additional 197 pieces of glass production equipment that MSE had procured.
V. The Situation Prior to the Second Gulf War
After UNSCOM inspectors left Iraq in December 1998, U.S.-led forces bombed many sites believed to be chemical weapon plants. After the bombing, reports emerged that Iraq had rebuilt many of those sites, and that the sites appeared to be operating. It was inferred that Iraq had resumed its production of chemical weapons, and was adding new elements to the portion of its previous stockpile that had never been accounted for. No evidence confirming these inferences has emerged to date.
