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Chemical Weapons Programs: History

Iraq started research into the production of chemical weapons agents in the 1970s and started batch production of agents in the early 1980s. At that stage, production was heavily reliant on the import of precursor chemicals from foreign suppliers.

In 1982, early in the Iran-Iraq War, the Iraqis used riot control agents to repel Iranian attacks. They progressed to the use of CW agents in mid-1983 with mustard, and in March 1984 with tabun (the first use ever of a nerve agent in war). The Iraqis continued to use chemical weapons until the end of hostilities in August 1988; in addition they introduced the nerve agents sarin and GF late in the war.

In March 1986 UN Secretary General Javier Perez de Cuellar formally accused Iraq of using chemical weapons against Iran. Citing the report of four chemical warfare experts whom the UN had sent to Iran in February and March 1986, the secretary general called on Baghdad to end its violation of the 1925 Geneva Protocol on the use of chemical weapons. The UN report concluded that "Iraqi forces have used chemical warfare against Iranian forces"; the weapons used included both mustard gas and nerve gas. The report further stated that "the use of chemical weapons appear[ed] to be more extensive [in 1981] than in 1984." Iraq attempted to deny using chemicals, but the evidence, in the form of many badly burned casualties flown to European hospitals for treatment, was overwhelming. By July 1986 it was estimated that Iraqi chemical warfare was responsible for about 10,000 casualties.

Although the Iraqis initially used chemical weapons to prevent defeat and to reduce battlefield losses, they later integrated CW attacks into combined-armed operations designed to regain lost territory and to gain the offensive. Iraq's use of CW in the war with Iran can be divided into three distinct phases:
  1. 1983 to 1986--used in a defensive role; typically to deflect Iranian human-wave assaults. In 1984 Iraq became the first nation to use a nerve agent on the battlefield when it deployed Tabun-filled aerial bombs during the Iran-Iraq war. Some 5,500 Iranians were killed by the nerve agent between March 1984 and March 1985. Tabun kills within minutes. Some 16,000 Iranians were reported killed by the toxic blister agent mustard gas between August 1983 and February 1986.
  2. 1986 to early 1988--iraq adapts use against Iran to disrupt Iranian offensive preparations.
  3. early 1988 to conclusion of the war-- Iraq integrated large nerve agent strikes into its overall offensive during the spring and summer of 1988 leading to the ceasefire.

Iran used chemical weapons late in the war, but never as extensively or successfully as Iraq. The success of Iraqi offensive operations in the southern sector in mid-1988 ultimately caused the Iranians to cease hostilities. The use of chemical weapons contributed to the success of these operations.

The first chemical attacks by Saddam Hussein against civilian populations included attacks launched by Iraqi aircraft against 20 small villages in 1987.

Saddam Hussein's forces reportedly killed hundreds of Iraqi Kurds with chemical agents in the Kurdish town of Halabja in March 1988. The poison gas attack on Halabja was the largest-scale chemical weapons (CW) attack against a civilian population in modern times. Halabja had a population of about 80,000 people who was predominantly Kurdish and had sympathised with Iran during the Iran-Iraq war in the 1980s. Troops from the Kurdish Patriotic Union of Kurdistan (PUK) entered Halabja on 15th March 1988, accompanied by Iranian revolutionary guards. The Iraqi CW attack began early in the evening of March 16th, when a group of eight aircraft began dropping chemical bombs; the chemical bombardment continued all night. The Halabja attack involved multiple chemical agents -- including mustard gas, and the nerve agents SARIN, TABUN and VX. Some sources report that cyanide was also used.

Mustard Blister Agent

In 1981, Iraq started producing the blister agent mustard (HD). Iraq's earlier declarations of 3,080 tons produced have been reduced in the 1995 disclosure to 2,850 tons. The quality of the mustard agent was good (not less than 80 per cent pure) and was such that the agent could be stored for long periods, either in bulk or in weaponized form. Even years after its production, the mustard agent analysed by the Commission was found to be in good and usable condition.

CS Tear Gas

Research into the production of CS was initiated at the Salman Pak site in the late 1970s and early 1980s for the purposes of riot control. It was conducted under the auspices of the Committee for National Security, not the Armed Forces. A few tons were produced at this site. In the early 1980s, military scale production of CS was started at the Muthanna site. The UN Special Commission has been unable to establish how much CS was produced in total. It is known that RPG-7 rocket- propelled grenades, 250- and 500-gauge bombs and 82mm and 120mm mortar shells were filled with CS, but again the quantity of munitions so filled cannot be established. Consequently, the Commission is unable to establish any kind of material balance for Iraq's CS-related activities.

Nerve Gas

Production of the nerve gases tabun (GA) and sarin (GB) started in 1984 and the method of production changed over time in order to resolve stabilization problems. Iraq's latest declarations have reduced the stated amount of tabun produced from 250 tons to 210 tons and of sarin produced from 812 tons to 790 tons.

The tabun produced was poor, being of a maximum purity of 60 per cent. As a result, the agent did not store well and could only be stored for a limited period. Furthermore, Iraq experienced problems in the production of tabun owing to salt blockages forming in pipes during synthesis. Because of these problems, Iraq refocused its nerve agent research, development and production efforts on sarin (GB/GF).

The sarin produced was also of poor quality (maximum purity of 60 per cent when solvent is taken into account) and so too could only be stored for short periods. In order to overcome this problem, Iraq resorted to a binary approach to weaponization: the precursor chemicals for sarin (DF 2/ and the alcohols cyclohexanol and isopropanol) were stored separately for mixing in the munitions immediately prior to use to produce a mixture of two G-series nerve agents, GB and GF. Given that the locally manufactured DF had a purity of more than 95 per cent and the alcohols were imported and of 100 per cent purity, this process could be expected to yield relatively pure sarin.

Over the period from June 1992 to June 1994, the Commission's Chemical Destruction Group destroyed 30 tons of tabun, 70 tons of sarin and 600 tons of mustard agent, stored in bulk and in munitions.

VX Nerve Agent

Iraq also had a research and development programme for the production of a further nerve agent, VX. According to Iraq's 1995 account, VX was the focus of its research efforts in the period after September 1987. Iraq has stated that between late 1987 and early 1988, a total of 250 tons of phosphorous pentasulphide and 200 tons of di-isopropylamine were imported, these being two key precursors required for the production of VX. For the other precursors required, Iraq claims to have used only approximately 1 ton of methyl phosphonyl chloride (MPC) from a total of 660 tons produced indigenously. The remaining MPC is claimed to have been used to produce DF, then used in GB/GF production. The fourth precursor required for VX, ethylene oxide, was generally available, being a multi- purpose chemical.

Iraq stated in 1995 that it produced a total of only 10 tons of choline from the di-isopropylamine and ethylene oxide and approximately 3 tons of methyl thiophosphonyl dichloride from the phosphorous pentasulphide and methyl phosphonyl chloride. From this, Iraq states that it produced experimental quantities of VX (recently increased to 260 kg from 160 kg). Iraq has recently admitted that three 250-gauge aerial bombs had been filled with VX for experimental purposes.

Iraq claimed that further attempts to produce VX were unsuccessful and the programme was finally abandoned in September 1988. According to Iraq's account, the remaining choline from the 10 tons was burned in early 1988 and the remaining 247 tons of phosphorous pentasulphide was discarded in 1991 by scattering it over an area of land and putting it in pits. Iraq also claimed that 213 tons of di-isopropylamine was destroyed by bombing during the Gulf war. However, while the Commission has found traces of these chemicals at the sites at which Iraq states their destruction occurred, it has not been able to verify the quantities destroyed. Thus, precursors for the production of at least 200 to 250 tons of VX could not be definitively accounted for.

The Commission has supervised the destruction, or verified Iraq's unilateral destruction, of 125 250-gauge bombs and several thousands 120mm mortar shells. In its new declaration, Iraq declared an additional 350 500-gauge and 100 250-gauge aerial bombs filled with CS in 1987.


The British government has asserted that Iraq developed large stocks of an incapacitant gas dubbed "Agent- 15". It is apparently a glycollate similar in effect to the agent BZ, an incapacitant once produced by the United States. If this is correct, exposure to about 100 milligrams in aerosolized form would be sufficient to incapacitate. Symptoms, which begin within 30 minutes of exposure and may last several days, include dizziness, vomiting, confusion, stupor, hallucinations, and irrational behavior. The US Army considered BZ to be too unpredictable in its effectiveness to be useful on the battlefield, and all US stocks were destroyed.

Precursor chemical production

In the early stages of its chemical weapons programme, Iraq imported all its precursor chemicals. Over time, however, Iraq sought to obtain the capability to produce indigenously all the precursors required for the production of the agents noted above. Iraq acknowledges that it had or was on the brink of having the capability to produce in quantity the precursors for tabun (GA): D4 and phosphorous oxychloride (POCl3), the sarin/cyclosarin (GB/GF) precursors: methylphosphonyl difluoride (DF), methyl phosphonyl dichloride (MPC), dimethylmethyl phosphonate (DMMP), trimethylphosphite (TMP), hydrogen fluoride (HF), phosphorous trichloride (PCl3) and thionyl chloride (SOCl2). Phosphorous trichloride and thionylchoride are also the main precursors for the production of mustard (HD).

Iraq also had the capability to produce, at least at laboratory scale, sodium sulphide (Na2S) and thiodiglycol (both for sulphur mustard agent production), methyl benzilate (for BZ production), triethanol amine (for nitrogen-mustard agent production) and potassium bifluoride and ammonium bifluoride (for GB/GF production). In addition, Iraq had the capability to produce the VX precursors choline, methyl thiophosphonyl dichloride (MPS) at the least at pilot-plant scale.


Iraq has declared that it weaponized for chemical weapons purposes the following munitions: RPG-7 rocket-propelled grenades and 82mm and 120mm mortar shells exclusively for CS; 130mm and 155mm artillery shells for mustard agent; 250- and 500-gauge aerial bombs for mustard, tabun, sarin and CS; 122mm rockets, R-400 and DB-2 aerial bombs for sarin and mixtures of GB/GF; and Al Hussein missile warheads for sarin. Of these, Iraq acquired the capability to produce all of the aerial bomb types listed and the Al Hussein missile warheads and chemical containers for 122mm rockets. It was reliant on imports of the other empty munitions but had the capability to empty conventional artillery shells and aerial bombs for subsequent refill with chemical-weapons agent.

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Maintained by Steven Aftergood
Originally created by John Pike
Updated Sunday, November 08, 1998 5:34:37 AM