Chemical agents at Al Muthanna posed no danger to U.S. troops

WASHINGTON, March 27, 2001 (GulfLINK) - The latest case narrative prepared by the Office of the Special Assistant for Gulf War Illnesses, Medical Readiness and Military Deployments, "The Gulf War Air Campaign - Possible Chemical Warfare Agent Release at Al Muthanna, February 8, 1991," concludes that U.S. servicemembers definitely were not exposed to chemical warfare agents resulting from Coalition air attacks on munitions bunkers at the Al Muthanna chemical weapons facility in Iraq.

"We determined that a probable release of sarin nerve agent did result from a bombing attack midway through the air campaign," said Dale A. Vesser, the acting special assistant. "Using the best information and estimates from CIA and U.N. sources as well as Iraq's post-war declarations, we modeled the potential hazard area through computer simulation. U.S. forces were hundreds of kilometers away from any possible exposure hazard."

Located 80 kilometers northwest of Baghdad, Al Muthanna was the nucleus of Iraq's entire chemical warfare program. The 170-square kilometer site was supposedly established as a pesticide production plant. Because chemical warfare agents -especially nerve agents - and pesticides are very similar compounds, many of the processes and much of the equipment used for pesticides production are also useful for the manufacture of chemical warfare agents.

Al Muthanna housed several facilities used in the research, development, production, and storage of chemical warfare agents. During the Iran-Iraq War Iraq manufactured two chemical warfare agents, tabun and mustard, there. Later, the production of tabun was suspended in favor of the nerve agents sarin and cyclosarin. Tabun was not produced during the Gulf War. Intelligence estimates placed the site's annual production capability at between 2,500 and 3,000 metric tons.

In postwar declarations, Iraq officials stated that chemical warfare agent production and filling of chemical munitions at Al Muthanna was restarted in 1990. U.S. intelligence reports from that period support these claims. Most of the filled munitions were dispersed to other locations prior to the start of the air war and were returned to Al Muthanna after the war.

The Coalition air attacks against Al Muthanna commenced on January 17, 1991, the first day of the air campaign. They continued through February 23, 1991. At least
31 Tomahawk Land Attack Missiles were launched against the site and 87 U.S. F-117 stealth fighter sorties were flown. The missiles were aimed at the more vulnerable buildings and other infrastructure targets, while the F-117s attacked the hardened storage bunkers and other facilities with precision-guided bombs.

In the early morning of February 8, 1991, an F-117 attacked Al Muthanna with a GBU-10 2,000-pound, laser-guided bomb. The bomb struck and penetrated Bunker 2. Gun camera videotape from the night of the mission shows the bomb guiding to, and striking in a crater from a previous bomb attack. It required two strikes at the same aim point to penetrate the 7-meter thick bunker roof. The resulting explosion and fire destroyed the munitions in the bunker. Post-war inspectors confirmed that the contents of the bunker - rockets and packing materials - were totally destroyed.

After the Gulf War, Iraq declared that Coalition air attacks had destroyed sarin-filled 122mm artillery rockets stored in a bunker at Al Muthanna. No chemical warfare agent residue was found in or around Bunker 2, but a low-level vapor hazard, probably emanating from damaged 122mm rockets stored in the open, existed around some outbuildings. The U.N. inspectors estimated that between 1,000 and 1,500 rockets were in Bunker 2 at the time of the attack. Exact numbers could not be confirmed because inspectors decided it was too dangerous to clear the bunker. The CIA concurs with U.N. inspectors' estimates it is likely that Iraq had filled the Bunker 2 rockets' warheads with sarin during the war with Iran, which ended in 1988.

Using the U.N. maximum assessment of 1,500 rockets in the bunker, CIA estimates that the munitions in Bunker 2 contained no more than 8.9 metric tons of sarin and its by-products when they were destroyed.

"The poor quality and short storage life of sarin produced by Iraq caused it to deteriorate rapidly after manufacture," said Vesser. "It's unlikely that
Bunker 2 contained more than 1.6 metric tons of still active sarin at the time it was bombed."

In time between the bomb strike and the resulting fire, CIA estimates a near instantaneous 10-kilogram burst of sarin escaped into the atmosphere. Because sarin also decomposes rapidly at high temperatures, CIA estimates that the fire destroyed the remaining sarin before it could be expelled from the bunker.

Computer modeling incorporating multiple atmospheric and dispersion models and the sarin agent characteristics was performed to project the downwind hazard created by the estimated 10 kilograms of escaped sarin. Because different dispersion models use data in their own distinct ways, the simulations and resulting projections will differ: none more valid than another. To ensure that no potential hazard area was missed, the projections from all of the simulations were combined into single, comprehensive hazard projection.

The level of hazard was calculated using definitions for the general population limit or GPL. The GPL defines the maximum safe continuous exposure for the general population, including children and those in ill health who are more susceptible to chemical warfare agent effects, over a 70-year lifetime. Since the Al Muthanna incident would have been a brief, one-time exposure, we used the GPL for short-term exposure to plot the possible hazard area. Anyone inside the boundaries of the area may have been exposed to a dosage of sarin equal to or greater than the short-term GPL limit. A person outside of the area suffered no such exposure. The resulting hazard area extended to a maximum range of 55 kilometers southeast of the site about 12 hours after the attack. After that time, the models predict that the chemical warfare agent hazard rapidly dissipated and disappeared within a few hours. The closest U.S. forces were 412 kilometers from Al Muthanna and 388 kilometers south of the nearest point of the downwind hazard area and, therefore, safe from any possible exposure risk resulting from the bunker attack. No Special Operations Forces were operating in this area of Iraq on Feb. 8, 1991.

"We're confident that the events at Al Muthanna presented no danger to U.S. servicemembers in the Gulf War theater," said Vesser.

The entire case narrative can be read on GulfLINK. More information or hardcopies of the report are available by calling the office at (800) 497-6261. This report is an interim report and anyone with information that might impact its findings is encouraged to call the special assistant's office.