One prominent hypothesis about illnesses among Gulf War veterans is that some of the reported symptoms are the result of exposure to chemical warfare agents. During and after the Gulf War, some veterans reported that they had been exposed to chemical warfare agents. To investigate these incidents, and to assess the likelihood that chemical warfare agents were present in the Gulf, the Department of Defense developed a methodology for investigation and validation based on work done by the United Nations and the international community. The criteria include:

While the methodology (Tab D) used to investigate suspected chemical warfare agent incidents is based on these protocols, the passage of time since the Gulf War makes it difficult to obtain certain types of documentary evidence, and physical evidence was often not collected at the time of an event. Therefore, we cannot apply a rigid template to all incidents, and each investigation must be tailored to its unique circumstances. Accordingly, we designed our methodology to provide a thorough, investigative process to define the circumstances of each incident and to determine what happened. Alarms alone are not considered to be certain evidence of chemical warfare agent presence, nor is a single observation sufficient to validate the presence of a chemical warfare agent.

After following our methodology and accumulating anecdotal, documentary, and physical evidence; after interviewing witnesses and key service members; and after analyzing the results of all available information, the investigator assesses the validity of the presence of chemical warfare agents on the battlefield. Because we do not expect to always have conclusive evidence, we have developed an assessment scale (Figure 1) ranging from Definitely Not to Definitely, with intermediate assessments of Unlikely, Indeterminate, and Likely. This assessment is tentative, based on facts available as of the date of the report publication; each case is reassessed over time based on new information and feedback.

Figure 1. Assessment of chemical warfare agent presence

The standard for making the assessment is based on common sense: Do the available facts lead a reasonable person to conclude that chemical warfare agents were or were not present? When insufficient information is available, the assessment is Indeterminate until more evidence can be found.



The Office of the Special Assistant for Gulf War Illnesses undertook this investigation because some Gulf War veterans expressed concern that they may have been exposed to chemical warfare agents released into the environment by a bombing raid on Iraq’s Al Muthanna chemical weapons storage site. This narrative describes how we investigated this concern and presents our assessment of the threat to veterans.

The State Establishment for Pesticide Production at Al Muthanna, near Samarra on the Tigris River, north of Baghdad, was the nucleus of Iraq’s entire chemical warfare program. By 1985, Iraq referred to the installation as the Muthanna State Establishment. It consisted of the Al Muthanna main site and three other sites near Al Fallujah, west of Baghdad. At Al Muthanna, the chemical warfare agent production and munition filling facilities were separate from chemical munition storage where Iraq stored chemical munitions in the open and in large, structurally hardened bunkers built in the form of a cross.

Early in the Iran-Iraq War, Iraq manufactured mustard and nerve chemical warfare agents at Al Muthanna and filled bombs, artillery shells, and rockets with them. Before the Gulf War, Iraq halted production of the nerve agent tabun, but produced the nerve agents sarin and cyclosarin instead. In mid-January of 1991, the Defense Intelligence Agency assessed that Iraq transferred chemical munitions from Al Muthanna during the week before the air campaign started. Nevertheless, because of its history, Al Muthanna and the rest of the Muthanna State Establishment were major targets in the air campaign of Operation Desert Storm.

Iraq’s response to United Nations Resolution 687 after the war declared that air attacks on Al Muthanna destroyed sarin-filled 122mm artillery rockets stored in a bunker there, but did not damage 122mm rockets stored in the open. United Nations inspectors estimated that, at the time of the bombing, the bunker, identified as Bunker 2, contained between 1,000 and 1,500 leaking or problem-plagued sarin-filled 122mm rockets, probably left over from Iraq’s war with Iran. The Central Intelligence Agency accepts the United Nations estimate.

Our research determined that an F117 attacked Bunker 2 at Al Muthanna early in the morning of February 8, 1991, with a laser-guided bomb. Although the bomb caused little external damage to Bunker 2, it destroyed the sarin-filled 122mm rockets stored inside the bunker. Iraq reported that an extensive fire in Bunker 2 caused by the air attack consumed all the rockets and associated packing materials. United Nations photographs taken after the war confirmed this report.

The Central Intelligence Agency estimated that Bunker 2 contained 1.6 metric tons of viable chemical warfare agent at the time of its destruction, and that approximately 10 kilograms of the sarin escaped from Bunker 2 into the atmosphere in the first few seconds after the bomb exploded. After that time, the extreme temperatures inside the bunker destroyed all the remaining vaporized agent before it vented into the atmosphere.

We used a combination of meteorological and dispersion models as recommended by the Institute for Defense Analysis to estimate the dispersion of the sarin vapor cloud possibly released by this air attack. Using the Central Intelligence Agency estimates of the size and character of the chemical warfare agent released, our modeling shows the maximum downwind hazard extended approximately 50 kilometers to the southeast of Al Muthanna.

On February 8, 1991, the closest US forces were 412 kilometers south of Al Muthanna and 388 kilometers south of the nearest point of the downwind hazard area that might have resulted from the attack on Bunker 2 at Al Muthanna. Therefore, we assess that the hazard area of the possible sarin release at Al Muthanna definitely did not extend far enough to reach any deployed US forces, and any chemical warfare agent released from Bunker 2 at Al Muthanna definitely did not expose US servicemembers to hazardous levels of contamination.

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