Figure 33 shows the 1991 and 1992 events resulting from the United Nations Security Council establishing a Special Commission on Iraq.

In April 1991, United Nations Security Council Resolution 687 created the United Nations Special Commission on Iraq (UNSCOM). Its primary responsibilities were to identify and destroy Iraq’s surviving chemical and biological weapons and ballistic missiles, have the weapons moved to an Iraq destruction facility, or destroy the weapons in place.^[148] Almost immediately after its creation, UNSCOM began inspecting Iraq’s facilities and continued through December 1998.

Figure 33. UNSCOM events: 1991 to 1992

May 16, 1991: Iraq announced for the first time that chemical weapons were stored at Khamisiyah Stores during the Gulf War. Iraq declared to UNSCOM that 2,160 destroyed sarin-filled rockets were located at Khamisiyah Stores.^[149] US intelligence analysts knew before Desert Shield/Desert Storm that An Nasiriyah ASP SW was a suspected chemical weapons storage site, and therefore assumed that Iraq had identified the site they knew as An Nasiriyah ASP SW as Khamisiyah.^[150] Furthermore, the name Khamisiyah had no significance to US analysts since they generally did not refer to any of Iraq’s weapons storage sites by that name. Khamisiyah Stores was the site the US knew as Tall al Lahm Ammunition Storage Area.^[151] This confusion over names would prevail within the US government for years^[152] and was one of the main reasons the government did not realize sooner that US forces had destroyed chemical weapons at Khamisiyah. Iraq’s declaration also included "6,240 intact mustard-filled 155mm artillery shells at Khamisiyah Stores (Nasiriyah)."^[153]

October 1991: An UNSCOM team inspected Iraq’s chemical weapons at Khamisiyah. The UNSCOM team inspected what their map depicted as An Nasiriyah Depot SW (Khamisiyah). However, the inspectors were actually taken to Khamisiyah. Here, Iraq told the UNSCOM team Coalition forces had destroyed chemical munitions and warehouses and showed UNSCOM inspectors three sites in and around Khamisiyah that Iraq claimed had chemical munitions.^[154]

Bunker 73.UNSCOM saw parts of 122mm rockets around a bunker Iraq called "Bunker 73" (Figure 34). Since it was too dangerous to get close enough to sample or obtain chemical agent monitor (CAM) readings, UNSCOM could not determine whether the munitions in Bunker 73 contained chemical warfare agents. At this time, inspectors did not document among the munition remnants any identifying traits characteristic of chemical weapons, such as high-density polyethylene inserts, burster tubes, or fill plugs.

Figure 34. UNSCOM photo of remnants of Bunker 73

The Pit. The inspection team found 297 mostly-intact 122mm rockets (of the 1,250 estimated by investigators) containing the nerve agents sarin (GB) and cyclosarin (GF) in an excavated area approximately 3 kilometers southeast of the main bunker complex (Figure 35). On-site sampling and CAM readings confirmed the presence of GB/GF in some rockets. Some were neatly laid out, while others appeared to have been bulldozed into heaps or piles. The inspection team observed and recorded on video plastic inserts and burster rods characteristic of chemical warfare munitions.

Figure 35. UNSCOM photo of pit rockets

Open area. The inspectors found 6,323 intact 155mm artillery shells (a CAM confirmed one shell contained mustard agent because it was leaking) in an open area approximately 5 kilometers west of the main bunker complex (Figure 36). The shells were in good condition but not stored in an orderly fashion.^[155]

Figure 36. UNSCOM photo of mustard rounds

UNSCOM inspectors and many Intelligence Community analysts thought Iraq had placed these chemical munitions there after US forces left Khamisiyah, sometime between mid-April and October 1991. UNSCOM’s report of its inspection in October stated, "It was evident that ammunition had been moved to its current location well after the end of the Gulf War. The reason for this is not clear."^[156] This suspicion of Iraq’s motives would continue to hamper the Khamisiyah investigation for years to come.

By November 1991, the Arms Control Intelligence Staff (ACIS) recognized the error in confusing Khamisiyah and An Nasiriyah ASP SW. During the Gulf War, ACIS was an interagency organization that was the Intelligence Community’s focal point supporting US government efforts in Iraq. Using Global Positioning System receivers and a better description of the facility, ACIS determined that Iraq’s October declaration referred to the Khamisiyah ASP, not An Nasiriyah ASP SW.^{[157, 158]} Unfortunately, the DoD did not make this connection at this time.

On November 12, 1991, the Joint Staff disseminated an ACIS report including Iraq’s claims that the Coalition destroyed chemical munitions at Khamisiyah:

The Iraqis claimed the buildings and munitions were destroyed by occupying Coalition forces. In the team’s estimation, the destruction occurred as a result of locally-placed explosives as opposed to bombing.^[159]

The report was widely disseminated within the Intelligence Community and DoD. On the same day, an internal ACIS administrative cable, distributed within the CIA only, suggested US forces could have conducted demolition operations in the area UNSCOM inspected and could have been exposed to "chemical contamination."

The inspectors also noted that the buildings [at Khamisiyah] were destroyed by demolitions as opposed to aerial bombardment. They also found an empty US crate labeled as M48, which are shape charges used by the US military. [We] notified Army Central Command (ARCENT) of the location and evidence found at Tall al Lahm. We received information from ARCENT to the fact that 24^th Mechanized Infantry Division was located in the vicinity of Tall al Lahm, but we are unable to confirm if US troops did in fact destroy buildings at this particular site. We are sending this information to you in order to take appropriate action as you see fit as the risk of chemical contamination by 24^th ID personnel is a possibility.^[160]

ACIS queried the 24^th Infantry Division at Fort Stewart, Georgia, about the division’s presence at Khamisiyah.CIA documents indicate ACIS contacted a 24^th Infantry Division staff officer on November 20, 1991.^{[161, 162]} In February 1997, Special Assistant analysts investigated this contact and spoke with the person who received the ACIS telephone call. We also contacted the division intelligence officer, division operations officer, and deputy intelligence officer, all of whom did not recall or vaguely recalled the message about their presence at Khamisiyah. They recalled 24^th Infantry Division troops were farther east, but nothing else. We found no evidence of any additional action taken on this telephone call.^[163]

February – March 1992: UNSCOM continued inspections in Iraq, which repeated its claim that Coalition forces had destroyed chemical munitions in 1991. UNSCOM again inspected Khamisiyah from February 21 through March 24, when the team destroyed 463 122mm rockets. The inspection team described these munitions as "fully-, partially-, and un-filled rockets."^[164] During the inspection, Iraq repeated its claim that Coalition forces had caused all the damage to the area.^[165]

UNSCOM interest grew in Coalition occupation activities. After leaving Iraq, an UNSCOM inspector informally asked the CIA for information on Coalition activities at Khamisiyah: "who was there, what actions they took, when they were there, how long they stayed, etc."^[166] UNSCOM never made a formal request, nor have we found any documentation indicating that the CIA took any action. In February 1996, the CIA discovered an undated working paper, drafted in May 1992, in the Iraq chemical weapons inspections file in the Nonproliferation Center.^[167] The paper suggests the possibility that US forces unwittingly destroyed chemical weapons at Khamisiyah. There is no indication that any further action was taken on the draft.^[168]

By the middle of 1993, Gulf War veterans’ complaints of undiagnosed illnesses had gained the attention of the public and government. Figure 37 shows government agencies and Congress creating panels, holding Congressional hearings, and increasing its emphasis on federally funded medical research. Highlights of 1993 include:

• May – The Department of Veterans Affairs (DVA) Blue Ribbon Panel met to discuss the mystery illness.
• June – The House Committee on Veterans Affairs Subcommittee on Oversight and Investigation held hearings on Health Care Issues of Persian Gulf Veterans.
• August – President Clinton designated the DVA as the lead agency for all federally funded Gulf War research.
• August – The staff of the Committee on Banking, Housing, and Urban Affairs (known as the Riegle Committee) interviewed Brian Martin, a former member of the 37^th Engineer Battalion and vehicle operator for the battalion commander. Interviewed by phone, he recounted his numerous illnesses but did not mention the demolition activities at Khamisiyah.
• November – The House and Senate Committees on Veterans Affairs held three hearings.
• November – Brian Martin testified in person before the Riegle Committee; again he did not discuss the demolition activities at Khamisiyah.
• December – John Deutch, Undersecretary of Defense for Acquisition and Technology, established the Defense Science Board Task Force on Chemical Weapons.^[169]

Figure 37. Governmental and Congressional events, 1993-1994

1994

In February 1994, Congressman Browder requested the UN to provide any reports about the disposition of Iraq’s chemical weapons and biological warfare research. The UN response, dated April 5, 1994, listed sites where UNSCOM had found chemical warfare agents and weapons. In Table 2, "CW Munition Storage Sites," UNSCOM listed 122mm rockets filled with sarin nerve agent at two sets of coordinates as destroyed at "Khamisiyah Stores."^[170]

Senior DoD officials’ testimony to Congress indicated a general state of confusion about activities at An Nasiriyah ASP SW and Khamisiyah. On May 25, 1994, senior DoD officials testified before the Riegle Committee about Iraq’s chemical, biological, and radiological warfare programs and their effect on Gulf War veterans’ health. Among those who testified were Dr. Edwin Dorn, Undersecretary of Defense for Personnel and Readiness; Dr. Theodore M. Prociv, Deputy Assistant to the Secretary of Defense for Chemical and Biological Weapons; and Dr. John Kriese, Chief Officer for Ground Forces, DIA. The government’s lack of knowledge about the presence of chemical weapons near US troop units and the continuing confusion over the location of Khamisiyah (Tall al Lahm) versus An Nasiriyah ASP SW were particularly noteworthy. In his opening statement, Under Secretary Dorn testified, "All of the chemical agents and related equipment were found stored at locations a great distance from the Kuwait theater of operations."^[171]

Undersecretary Dorn’s statement referred to known chemical storage sites located in Iraq’s interior and not to the Khamisiyah ASP, which was located in the KTO. Later in the hearing, the Chairman of the committee questioned Drs. Dorn and Kriese about chemical weapons located at An Nasiriyah SW and US troops’ proximity to that location:

Chairman: Now, earlier, you made a statement or a statement was made by one of the three of you that all of the chemical agents and related equipment that was discovered was found stored far from the Kuwait field of operations….

Dr [Kriese]:…I’ll say frankly the word, far, got in the last draft of Dr. Dorn’s testimony this morning. I thought we had that fixed to be stricken from the draft testimony that he was given. It is not correct to say that all munitions were found far from the KTL [sic], sir.

Chairman: Well, that’s an important clarification. So there were instances, then, where some of the munitions were found close to where we had troop deployments?

Dr. [Kriese]: That’s correct.

. . .

Chairman: But in terms of An Nasiriyah here, we did find them there. Do I assume that we continued to use our forces to secure that area as the War went along? We would not have just been in that area and then left, would we?

Dr. [Kriese]: I don’t know those details of how long we were in that area. My understanding is that munitions were found not at the site we bombed [referring to An Nasiriyah ASP SW], but some 15 nautical miles away from where we attacked [referring to the Khamisiyah ASP].

Chairman: How close would US forces have been stationed to that?

Dr. [Kriese]: I think they were across the river. Not stationed, but during the ground force phase of the campaign, that’s as close as we got.

. . .

Chairman: Our troops were right across the narrow river from where we found these things. Is that right?

Dr. [Kriese]: They got that close but I don’t know how long they were there.^[172]

Questions submitted for the record by DoD in September and October 1994 revealed continued confusion over the location of Khamisiyah and its proximity to US forces. DoD’s answer to Question 19 perpetuated this confusion:

Question: Were chemical munitions or binary precursor materials capable of being used in chemical warfare discovered in any area of Iraq, Kuwait, or Saudi Arabia before, during, or after the war by US forces, civilian personnel, or other Coalition participants?

Answer: The Kuwaiti Theater of Operations (KTO) includes southern Iraq south of 31� 00' N [Latitude], Kuwait, and Saudi Arabia. This was the area eventually occupied by Coalition ground forces before, during and after Operation Desert Storm. No chemical munitions, bulk agent, or binary precursors were discovered in the KTO before, during, or after the war by US Forces, civilian personnel, or Coalition participants.... Finally, it has been widely circulated that UN inspection teams found thousands of destroyed and intact chemical rounds in an ammunition depot at Nasiriyah, and that this discovery contradicts our statement in paragraph one of this answer. Nasiriyah technically is outside the KTO, being north of 31� 00' N and the Euphrates River. More importantly, it was not in the territory occupied by Coalition Forces after the war. Moreover, the following points are relevant because UN inspectors did not really "find" the subject munitions. In reality, the Iraqis declared the munitions to the UN and the inspectors eventually went to that location to check what the Iraqis had reported:

1. The UN inspection occurred at least eight months after the war;
2. The location of the "found" chemical rounds was 15 miles from the widely discussed CBW bunkers bombed at Nasiriyah (the site which was originally expected to be inspected). The bombed bunkers were not inspected until one year later in October 1991 and found to contain no chemical or biological weapons.^[173]

Several inaccuracies in these testimonies are evident today:

• DoD stated no chemical munitions were south of 31� north, which was incorrect, since both An Nasiriyah and Khamisiyah are south of 31� north.
• DoD stated thousands of chemical munitions had been found at An Nasiriyah, but did not mention Khamisiyah.
• DoD stated no US troops were in that area after the war, which was incorrect, since elements of the XVIII Airborne Corps and VII Corps both operated in the area in March and April, 1991.

These inaccuracies distorted the history of events at Khamisiyah since, in June 1994, these beliefs formed the basis of information DoD provided to the Defense Science Board Task Force on Persian Gulf War Health Effects. The Task Force report stated in part:

There were also reports of damage by the United Nations Special Commission inspection team that visited a different location [referring to Khamisiyah] in the general vicinity of An Nasiriyah several months after the cessation of hostilities. There are indications that the site visited by the UNSCOM team was not a site targeted during the air war but may have been specially constructed for the UN inspectors.

It appeared this was a separate site constructed by Iraq after the war to show to the UN inspectors. The Iraqis claimed that munitions containing 16 tons of Sarin were destroyed in the bombing….There was also some indication that the munitions were only destroyed subsequent to the ground war by the Iraqis. The uncertainty stems from the fact that it is not clear whether the site the UN inspection team was shown was in fact this subject of bomb damage.^[174]

The information reflected DoD’s, UNSCOM’s, and the Intelligence Community’s suspicion that Iraq had fabricated the entire incident at Khamisiyah to try to conceal their weapons of mass destruction from UNSCOM inspectors.

In June 1994, DoD established the Comprehensive Clinical Evaluation Program (CCEP) to provide an in-depth medical evaluation for all eligible beneficiaries who had health concerns after service in the Gulf and a toll-free information line whose operators assist veterans with care and benefits questions and scheduling examinations for either DoD or DVA hospitals.

Among other efforts of 1995 (Figure 38), with President Clinton’s strong support, DoD announced the opening of two specialized care centers whose major focus was diagnosing and treating illnesses unique to service in the Gulf War, and the addition of $10 million for research to the 1995 Defense budget.^[175]

Figure 38. US government efforts in 1995

In March 1995, Deputy Secretary of Defense Deutch directed the creation of the Persian Gulf Illnesses Investigation Team (later the Persian Gulf Investigation Team (PGIT)), which opened in July. PGIT’s mission was to focus on the causes of Gulf War veterans’ illnesses.

During the same month, the CIA’s Acting Director called for a comprehensive review of relevant intelligence information. The CIA focused on identifying and quantifying Iraq’s chemical, biological, or radiological releases during and after the war that could have affected US forces.^[176] As part of the President’s initiative, the DoD and CIA began new efforts to collect and review operational, intelligence, and medical records from the Gulf War. In April, declassification of DoD health-related documents started.

While these agencies worked closely to identify possible chemical releases through demolition or Coalition bombings, DoD took additional steps to gain more information from veterans.

• In May, Secretary of Defense William J. Perry announced the creation of a toll-free telephone hotline on which all military and civilian personnel who served in the Persian Gulf region could report details of incidents they believed may have contributed to a medical problem they or others had experienced.^[177]

• In August, the President established the Presidential Advisory Committee on Gulf War Veterans’ Illnesses (PAC) to review government activities in determining the health effects of service in the Gulf War.

• In August, DoD announced the opening of its official internet World Wide Web homepage, GulfLINK, which provides immediate, on-line computer access to declassified medical, operational, and intelligence documents, as well as current events and narratives of important events from the Gulf War.^[178]

• Before September, during their re-examination of thousands of intelligence documents, CIA analysts found the UNSCOM Khamisiyah site visit report of October 1991.

• In September, among the three sites—Al Muthanna, Muhammadiyat, and Khamisiyah—it had identified as potential chemical warfare agent release sites, the CIA raised Khamisiyah as a concern because of its more southerly location and its proximity to US troops. In addition, 1991 reporting found by CIA analysts indicated Iraq told UNSCOM that Coalition forces had destroyed Khamisiyah. One week later, the CIA informed PGIT of its concerns and asked what US forces had been at that location and when.^[179]

• In October, DoD researched the newly established Environmental Support Group (ESG) unit locator database^[180] and identified to CIA that some US units were in the area. Specifically, the data had indicated that the 37^th Engineer Battalion and other units had reported location coordinates near Khamisiyah, but no information on their mission (which CIA had requested) was available.

H. Department of Defense Announced Possible Chemical Weapons at Khamisiyah: January – September 1996

Figure 39 shows the events from January to September leading to and immediately after the DoD’s public announcement that the 37^th Engineer Battalion probably destroyed bunkers containing chemical weapons.

Figure 39. Investigation results through September 1996

CIA mentioned the possibility of agent release at Khamisiyah. In January 1996, in a preliminary briefing to the National Security Council (NSC), the CIA mentioned the possibility of agent release at Khamisiyah.^[181] The NSC directed the CIA and DoD to aggressively pursue this matter.

On March 5, the CIA informed a PAC staff member that US troops had been in the vicinity of a probable release of chemical warfare agent. On March 10, a CIA analyst heard a radio talk show on which a 37^th Engineer Battalion veteran described demolition activities at a facility the analyst recognized as Khamisiyah. The CIA informed the PAC that week.

On May 1, at a PAC hearing in Washington, DC, the CIA and PGIT acknowledged that the 37^th Engineer Battalion destroyed munitions at Khamisiyah and the agencies were working together to determine if chemical warfare agents were among the munitions destroyed.

In the spring of 1996, the PAC requested the CIA to examine the potential dispersion of nerve agent from the March 1991 demolition of Bunker 73 at Khamisiyah and at two other sites in Iraq (Al Muthanna and Muhammadiyat).^{[182, 183]} Among other models, the CIA used the US Army’s Chemical and Biological Defense Command’s Non-uniform Simple Surface Evaporations 4 (NUSSE4) transport and diffusion model.^[184]

On May 14, UNSCOM inspectors documented the presence of burster tubes, fill plugs, plastic inserts, and other items characteristic of chemical weapons in Bunker 73 at Khamisiyah. Iraq reiterated its declaration that US forces had destroyed chemical munitions in Bunker 73, and for the first time claimed that US forces destroyed chemical munitions stored in the Pit.^[185]

DoD publicly announced US forces had probably destroyed bunkers containing chemical weapons. On June 21, 1996, DoD announced:

UNSCOM has informed us that, as part of its ongoing effort to verify Iraqi declarations, it inspected the Khamisiyah ammunition storage area last month [May 1996]. During that inspection, UNSCOM concluded that one bunker had contained rockets with chemical agents. US soldiers from the 37^th Engineer Battalion destroyed ammunition bunkers at this site in early March 1991, shortly after the war ended. Based on a new review of the available information, it now appears that one of these destroyed bunkers contained chemical weapons.^[186]

After the June 21, 1996, announcement, the investigation’s focus shifted to better understand two questions:

• First, what was the potential for exposure to chemical agents from the demolition operations at Khamisiyah?
• Second, who might have been exposed?

PGIT began interviewing US soldiers directly involved in the demolition of Bunker 73 to reconstruct such information as the exact dates of the demolition, amount and type of munitions destroyed, and weather and wind direction on the dates of demolition. This information was provided to the CIA to assist in their dispersion modeling of the Bunker 73 demolition.

In July, the CIA briefed the results of its Bunker 73 modeling effort to the PAC and, on August 2, 1996, published their report, "Report on Intelligence Related to Gulf War Illnesses," which identified their modeling assumptions and concluded that any hazard area resulting from the demolition of Bunker 73 moved east and northeast. Among the CIA’s more significant assumptions in modeling the demolition of Bunker 73 were:

• Bunker 73 contained approximately 1,060 nerve agent-filled rockets;
• Each rocket was filled with 8 kilograms of a 2:1 ratio of sarin to cyclosarin nerve agent;
• The demolition ejected 10 percent of the rockets from the bunker;
• Based on US tests, heat from the explosion and burning motors and crates degraded 2.5 percent of the agent in the bunker;
• Winds were light to the northeast to east; and
• The modeling did not include the effect of thermal energy released by the simultaneous burning and detonation of the other 32 to 37 bunkers.^[187]

In August and September DoD attempted a telephone survey of Khamisiyah participants. Because of the uncertainty whether US forces had been exposed to chemical warfare agents, the Assistant Secretary of Defense for Health Affairs designed and conducted a telephone outreach program to contact veterans who may have participated in the Khamisiyah operation. The Defense Manpower Data Center (DMDC) attempted to contact more than 1,100 veterans of units PGIT had determined were in the Khamisiyah area during early March 1991. The DMDC was able to contact 575 of them and asked them to call the DoD hotline to report any medical problems they were experiencing and provide any information they believed pertinent to the Khamisiyah incident. Deputy Secretary of Defense White wrote the approximately 525 veterans not contacted by telephone to urge them to call the Persian Gulf Incident Hotline. This particular telephone outreach effort concluded in October 1996.

The Secretary of Defense widened DoD’s investigation. In September 1996, DoD dramatically increased its investigative efforts. As announced in a news release, Secretary of Defense White:

• Ordered the establishment of a DoD Persian Gulf Illness Action Team "to look across all the activities ongoing in the Department related to Persian Gulf veterans’ illnesses, reassess whether we’re in the right direction with the right amount of resources and level of effort, and asking the right questions."
• Directed the Army to conduct an Inspector General inquiry into events surrounding Khamisiyah and supplement the efforts of the DoD investigation where possible.
• Directed the Assistant to the Secretary of Defense for Intelligence Oversight to investigate US intelligence on Khamisiyah, including how the information was handled.^[188]

On October 2, 1996, the Secretary of Defense named Dr. Bernard D. Rostker, then Assistant Secretary of the Navy for Manpower and Reserve Affairs, to head an action team to evaluate the activities of the DoD related to undiagnosed illnesses of Gulf War veterans. He was to report his recommendations to the Deputy Secretary of Defense."^[189] One month later, the position of Special Assistant for Gulf War Illnesses was established and assumed the team functions.

Efforts continued from fall 1996 to late summer 1997 to resolve uncertainties and complete the initial modeling effort for the demolition at the Pit (Figure 40). Investigators had determined even less about the March 10, 1991, demolition in the Pit than they had about the March 4, 1991, destruction of Bunker 73. DoD and the CIA jointly continued to investigate the activities that occurred in the Pit. Critical uncertainties persisted about such facts as weather, amount and placement of charges, number of participants, and number of events. Accurately modeling the effects of the Pit demolition would be impossible without resolving these uncertainties. Since the two agencies knew little about how such an explosion would react, they decided to conduct field tests to resolve some of these questions. Thus, DoD and the CIA delayed modeling the effects of the Pit demolition until the investigators could develop more information from ongoing veterans’ interviews, document research, and field tests.

Figure 40. Actions taken to resolve uncertainties and conclude initial modeling effort

Fall 1996

DoD announced its intent to survey US troop units within 50 kilometers of the Khamisiyah ASP. After reviewing the CIA’s preliminary work to model the Pit demolition, DoD had considerable uncertainty concerning the fallout from the March 10, 1991, demolition. Therefore, in October 1996, DoD announced it would survey an estimated 20,000 veterans who had been in units within 50 kilometers of the Khamisiyah ASP during the period March 1 – 15, 1991, according to a unit locator database maintained by ESG, now the US Armed Services Center for Unit Records Research (USASCURR).^[190] The survey would be an attachment included in Deputy Secretary of Defense White’s letter to the veterans that would indicate that chemical weapons had been present at Khamisiyah when the demolitions occurred. The letter urged veterans to call the Persian Gulf Incident Hotline with any additional information about the Khamisiyah incident or to report illnesses they attributed to their service in the Gulf War. The letter was not sent to the 1,100 veterans previously identified for the telephone survey. In preparing the survey distribution, DoD carefully selected the dates and distances to be sure to identify and notify units moving through the area between March 1 and 15. The potential exposure assumptions translated into three unit location zones for the survey participants:

• A 5-kilometer zone enclosing the area where chemical warfare agent exposure would have been lethal to any inhabitant;
• A 25-kilometer zone encompassing the area where chemical warfare agent exposure would have produced first noticeable effects, such as runny nose and blurry eyes; and
• A 50-kilometer zone containing an area that doubled the 25-kilometer zone as an added safety measure to ensure including in the survey all US forces in transit through the Khamisiyah area.

DoD also selected the wider range of transit dates for the veterans’ locations because conflicting information existed about the number and dates of the demolitions. An EOD log, dated March 12, 1991, had an entry of a possible demolition similar to the confirmed demolition of March 10, 1991. Since analysts were investigating the conflicting dates, DoD added three days following March 12 as a precaution, making the survey period March 1 – 15.^[191]

The Institute for Defense Analyses recommended numerous changes in modeling the Pit. At DoD’s and CIA’s request, the Institute for Defense Analyses (IDA) convened an independent panel of experts in meteorology, physics, chemistry, and related disciplines. The panel reviewed CIA’s modeling methodology and analysis, which used the analytical linkage between the Defense Threat Reduction Agency’s Operational Multi-scale Environmental Model with Grid Adaptivity (OMEGA) weather model and the Naval Surface Warfare Center’s Vapor, Liquid, and Solid Tracking (VLSTRACK) dispersion model to drive the Army Chemical and Biological Defense Command’s NUSSE4 transport and diffusion model.^[192] The IDA recommended using additional atmospheric models and data sources for modeling the demolition in the Pit.^[193]

DoD established the position of Special Assistant for Gulf War Illnesses. On November 12, 1996, at the recommendation of the Persian Gulf illness action team, the Deputy Secretary of Defense created the position of Special Assistant for Gulf War Illnesses and named Dr. Bernard D. Rostker as the Special Assistant. Dr. Rostker assumed responsibility for the PGIT, which was incorporated as his Investigation and Analysis Directorate.^[194]

1997

The Special Assistant for Gulf War Illnesses sent the Khamisiyah survey. The Special Assistant for Gulf War Illnesses sent the survey, dated January 1997, accompanied by a letter of explanation, to veterans whose units we determined from the then ESG unit locator database were to have been within the 50-kilometer circle around the Khamisiyah ASP between March 1 and March 15, 1991.^[195]

President extended the PAC’s tenure. On January 30, 1997, the President extended the PAC’s tenure until October 31, 1997, with tasking to provide a Supplemental Letter Report and Supplemental Final Report, the PAC’s "Special Report."

The Presidential Advisory Committee on Gulf War Veterans’ Illnesses provided the supplemental letter report. On April 30, 1997, the Presidential Advisory Committee on Gulf War Veterans’ Illnesses provided details of its work in two areas: continuing oversight of the government’s investigation into Gulf War chemical and biological warfare incidents and implementing recommendations of the PAC’s Final Report. Reiterating its January 7, 1997, "Final Report," the PAC stated, "In the face of credible evidence of the presence or release of chemical warfare agents, low-level exposure must be presumed while efforts to develop more precise measures of exposure continue….Troops within the presumptive exposure area should be notified and encouraged to enroll in the CCEP or [VA] Registry." Hence the Committee noted:

DOD should move as quickly as possible toward conclusions about the incidents under investigation and, when in doubt, err in favor of targeted notification of troops about possible health risks and the availability of free diagnosis and treatment programs established by the government.^[196]

The Special Assistant for Gulf War Illnesses and the CIA continued cooperative investigations to reduce the uncertainties concerning demolition activities in the Pit. In his April 24, 1997, opening statement to the House Committee on Government Reform and Oversight Subcommittee on Human Resources and Intergovernmental Relations, Robert D Walpole, Special Assistant to the Acting Director, CIA, stated:

However, when we turned to modeling demolitions at the Pit, we quickly realized we had significant uncertainties regarding how rockets with chemical warheads would have been affected by open-pit demolitions. We were also uncertain about the number of demolition events and the weather conditions at the time of the demolitions. The CIA and DoD have devised a joint plan which will reduce some of these uncertainties in order to more accurately identify the extent of the release.^[197]

Subsequently, DoD and CIA worked aggressively to resolve as many as possible of the following uncertainties surrounding the events in the Pit:

• Limited, often contradictory information from soldiers involved in the demolitions;
• Questions about the demolition date(s);
• Uncertainties about the number of rockets, agent purity, and amount of agent aerosolized;
• Uncertainties about agent release and release mechanisms in an open-pit demolition;
• Limited weather data; and
• No single model that simultaneously ran weather and chemical warfare agent data.^[198]

Interviews with soldiers reduced uncertainties. We located and, with the CIA, interviewed five soldiers who had key roles in the demolition activities in the Pit. These individuals included the 37^th Engineer Battalion operations officer, who initially discovered the Pit and led engineers and EOD personnel to it; two 37^th Engineer Battalion soldiers who placed demolition explosives on the stacks of rockets; the 60^th EOD Detachment soldier who supervised the engineers;^{[199, 200]} and the 60^th EOD Detachment executive officer who inspected the stacks before detonation.^[201] They confirmed the number of stacks of rockets wired for demolition and other information, such as the amount and placement of explosives on the rockets, that proved invaluable to the DoD/CIA team’s field tests discussed in later paragraphs.

Soldier interviews clearly established two large-scale demolitions. An entry in a 60^th EOD detachment field log had indicated a third demolition on March 12. Interviews of 60^th EOD Detachment soldiers revealed the date was incorrect.^[202] This clarification allowed the DoD/CIA team that would model the event to concentrate on one major explosion in the Pit and not two separate events.

The DoD/CIA team estimated the number of 122-millimeter rockets in the Pit to be 1,250. In May 1996, Iraq had declared to UNSCOM that 1,100 rockets were in the Pit at the demolition. The DoD/CIA team used personal interviews, estimates of the heights of the stacks of 122mm rockets, and known data, such as the size of the rocket crates, to develop the estimate of 1,250 122mm rockets. About six months after the demolition, UNSCOM found about 750 of the rockets still contained chemical warfare agent. (UNSCOM assisted Iraq in disposing of these rockets.) Therefore, 1997 assessments concluded that the March 10, 1991, demolition destroyed approximately 500 rockets.^[203]

Test team determined the rockets’ nerve agent capacity. In preparing for a May 1997 field demolition test on the rockets, the test team determined that a single rocket would hold only 6.3 kilograms of agent instead of the 8 kilograms used in the modeling of Bunker 73.^[204] Previous estimates had not accounted for the payload volume reduction caused by the presence of two plastic canister inserts whose total weight was 1.7 kilograms.

The DoD/CIA team estimated chemical agent ratio and purity. The DoD/CIA team estimated chemical agent purity at 50 percent and the ratio of sarin/cyclosarin to be 3:1, based on a combination of estimates taken from UNSCOM samples, Iraq’s chemical production records, and Iraq’s declarations. In their "Modeling the Chemical Warfare Agent Release at the Khamisiyah Pit" document, DoD/CIA stated:

Our best estimate of the agent purity at the time of the demolition is slightly less than 50 percent. Iraqi production records obtained by UNSCOM indicated that the sarin/cyclosarin (GB/GF) nerve agent produced and transported to Khamisiyah in early January 1991 was about 55 percent pure. The agent, subsequently, degraded to 10 percent purity by the time laboratory analysis had been completed on samples taken by UNSCOM from one of the rockets in October. On the basis of the sample purity and indications that the degradation rate for sarin and cyclosarin are similar, we assess that the ratio when the munitions were blown up in March 1991, was the same as that sampled in October 1991 -- 3:1. Assuming a conservative, exponential degradation of the sarin/cyclosarin, the purity on the date of demolition two months after production can be calculated to be about 50 percent.^[205]

The DoD/CIA team confirmed initial wind direction from existing records and photography. The DoD/CIA team used existing data and photography to determine the initial wind direction on March 10, 1991. Very little weather data were readily available for March 10, 1991, so the team determined the weather by combining exact location coordinates of Khamisiyah, general weather conditions during March 1991, imagery from March 10 – 11, photography of soot patterns created by the bunker demolition on March 10^th, and regional scale imagery showing the Kuwait oil field fire plumes for the days immediately following the demolitions. Using these sources, the DoD/CIA team determined the initial wind direction at Khamisiyah to be from the north-northwest, blowing any chemical release to the south-southeast.^[206]

The DoD/CIA team conducted field demolition tests. Since the CIA used test information that did not apply to open-air demolitions to model Bunker 73, the test information could not be used to determine if agent would release quickly or would take a period of days. By April, the DoD/CIA team agreed that field demolition tests were necessary^[207] to determine how chemical agents would behave in an open area similar to the Pit. The team arranged to conduct a series of tests at Dugway Proving Ground, Utah from May 15 to 31, 1997. The DoD/CIA design team developed the Dugway tests (Figure 41) to extrapolate the interaction between the explosives and rockets in an open environment similar to the Pit demolition. The tests determined:

• How the rockets reacted to explosives placed in various locations on them;
• How the nerve agent was released (e.g., aerosolized amount and evaporation rates of spilled agent on soil and wood); and
• How much nerve agent was released.^[208]

For a thorough evaluation of the results of those tests, see "Modeling the Chemical Warfare Agent Release at the Khamisiyah Pit," September 4, 1997.^[209]

Figure 41. Demolition test; picture courtesy of Dugway Proving Ground

The Special Assistant continued efforts to identify troop unit locations. The Special Assistant sent the Khamisiyah survey to veterans identified through an existing database containing unit locations called the Persian Gulf Registry. USASCURR, formerly the Environmental Support Group, derived Gulf War unit locations by reviewing a large number of Gulf War unit records, including unit history data archives, operational logs, situation reports, and after action and historical reports. USASCURR began this review in mid-1994 and has repeatedly updated the database as it obtained additional unit locations.

USASCURR continued recording unit location data in conjunction with the Gulf War declassification initiative the Deputy Secretary of Defense established in March 1995. The declassification initiative decreed a DoD-wide effort to review Gulf War operational records, declassify them, and make them available to USASCURR and the Special Assistant.

To identify veterans who may have experienced low-level chemical exposure, we determined their units’ locations from the USASCURR unit location database for the period March 10 – 13, 1991. Although veterans were either assigned or attached to specific units during the Gulf War, a unit’s location on a specific day did not necessarily pinpoint where an individual soldier was on that day. For example, a precise location recording a soldier on patrol or in transit to another location does not exist.

In April 1997, the Special Assistant and Department of the Army began a coordinated effort to assemble former Gulf War brigade, divisional, and non-divisional units operations officers (G3s and S3s) to verify existing unit locations in the USASCURR database and assist in identifying additional unit locations.

The DoD and CIA linked models to determine the downwind hazard area of the March 10, 1991, Pit demolition. To meet the IDA panel’s recommendations, the DoD and CIA asked other agencies with long-time modeling experience to participate in the modeling effort. The modeling team consisted of scientists from the Defense Special Warfare Agency (DSWA) (now the Defense Threat Reduction Agency (DTRA)); the Naval Research Laboratory (NRL); the Naval Surface Warfare Center (NSWC); the National Center for Atmospheric Research (NCAR); and Science Applications International Corporation (SAIC) supporting the CIA and DSWA. These agencies used existing sophisticated models to develop Khamisiyah-specific potential exposure areas. As the IDA recommended, the team used different combinations of models to reduce model bias. Presenting a composite (union) of the different modeling simulations representing the overlay of the outermost perimeter of all models determines the hazard area.^[210] A general discussion of the modeling process is at Tab E.

The DoD/CIA team announced no US troops were in the area predicted to have noticeable health effects during the time of the event. On July 24, 1997, the DoD/CIA team announced the results of the potential hazard area modeling effort.^[211] The results confirmed no US units were within the hazard area predicted to cause noticeable short-term health effects from demolition activity in the Pit. However, the modeling results did indicate that troops in Iraq and Saudi Arabia were possibly exposed to low levels of nerve agent over a four-day period from March 10 – 13, 1991. Using data on then-available unit locations, DoD identified 98,910 soldiers within the potential hazard area predicted by the models.^[212] From late July through September, DoD sent written notices to two categories of veterans: those in the potential chemical agent hazard area (approximately 99,000) and those who had received the Deputy Secretary of Defense’s letter and survey but were not in the potential chemical agent hazard area (approximately 10,000). On September 4, 1997, the DoD/CIA team published the details of this modeling effort in the document: "Modeling the Chemical Warfare Agent Release at the Khamisiyah Pit."

In response to the announcement of the modeling results in July 1997, various scientific groups recommended refinements to the models and modeling process. After addressing these groups’ refinements, the team decided to generate a new set of Khamisiyah simulations. We have completed these simulations and are publishing the results in this paper (see J. Remodeling Effort: January 1998 – March 2000,) and in more detail in a subsequent technical report.

The PAC issued its Special Report. The PAC issued a Special Report on October 31, 1997, to the Secretary of Defense, and ended its service in November 1997.

J. Remodeling Effort: January 1998 – March 2000 (Figure 42)

Figure 42. Activities surrounding the remodeling of the Khamisiyah Pit demolition

1998 – 1999

CIA released Inspector General report. On February 5, 1998, the CIA Inspector General released its assessment of the CIA’s analysis and reporting of Khamisiyah information from the mid-80s, when Khamisiyah was first identified as a possible chemical weapons storage site, to June 1996, when DoD announced US forces had destroyed bunkers possibly containing chemical weapons. The Inspector General came to two conclusions:

• Information obtained before, during, and after the Gulf War, was not compiled and comprehensively analyzed until the US government focused on Gulf War illnesses in 1995.
• A more vigorous follow-up when questions arose about Khamisiyah might have brought about an earlier realization that US troops may have been exposed to chemical agents.^[213]

Senator Rudman appointed as Chair of Presidential Special Oversight Board.On February 24, 1998, President Clinton named former US Senator Warren B. Rudman as Chair of the Special Oversight Board for Department of Defense Investigations of Gulf War Chemical and Biological Incidents (PSOB). President Clinton established the PSOB by Executive Order to provide recommendations based on its review of DoD’s investigation into possible Gulf War chemical and biological incidents that may have contributed to Gulf War veterans’ illnesses. The board reported to the President through the Secretary of Defense.^[214] Following its appointment, the full board met for the first time in July 1998 and received its first briefing from DoD on the history and background of Gulf War issues. The PSOB reviewed and approved the overall direction of the Special Assistant’s office.^[215] It submitted its final report to the President on December 20, 2000. The PSOB found, among other things, that in each of its case narratives, the Special Assistant’s office made assessments regarding the presence of chemical and biological warfare agents that were consistent with available evidence.

G3/S3 conferences concluded. From April 1997 through June 1998, the Special Assistant and the Department of the Army brought 163 former Gulf War corps, division, and brigade operations officers (G3/S3) to USASCURR to identify and verify their respective Gulf War units’ locations. Successively, Army operations officers from XVIII Airborne Corps, VII Corps, and Echelons-Above-Corps units returned to assist in this effort, which significantly enhanced KTO unit location information. Army operations officers added approximately 390,000 locations to the USASCURR database, more than doubling the locations known before the conferences. Currently the number of locations in the database for all services during the Gulf War period is more than 855,000. Tab F contains details of the development and results of the G3/S3 conferences.

Senate Veterans’ Affairs Committee report released. The Senate Veterans’ Affairs Committee released its Special Investigation Unit’s report on Gulf War illnesses in August 1998. While the report complimented the Special Assistant for his direct approach in dealing with veterans, it also pointed out areas requiring improvement in both the DoD and the Department of Veterans Affairs (VA). In addition, the Special Investigative Unit acknowledged the value of the Special Assistant’s efforts:

Establishment of the Office of the Special Assistant for Gulf War Illnesses in 1996 has increased the flow of information to veterans and the public about various events during the Gulf War that may have affected the health of veterans who served there. OSAGWI has also made efforts to solicit from Gulf War veterans their concerns about their health and possible exposures, and should continue these efforts.^[216]

Panel recommended Remodeling Pit demolition. Following the 1997 Khamisiyah Pit demolition modeling, a panel of modeling experts evaluated the results. This panel approved of the DoD/CIA modeling methodology but recommended a number of improvements, including revisions to the computer models used. The Special Assistant initiated improvements to the 1997 model process to obtain the highest quality of hazard area definition possible. Modeling improvements continued throughout 1998 and 1999 and culminated in redefined potential hazard areas in January 2000.

2000

Independent peer review panel responded. The Special Assistant’s February 23, 2000 report, "Methodology of Refined Modeling of the Khamisiyah Pit Demolition," described revised modeling methodology and improvements. An independent peer review panel found the revised modeling procedures satisfactory but stated that modeling results would "still be on the conservative side; i.e., they are very likely overestimates of the dosages actually received by personnel."^[217] As we did in 1997, our 2000 modeling approach overlaid the outer boundaries of the various modeling results to develop the composite potential hazard area. Our fundamental modeling approach has not changed since 1997:

Remember that this plume [potential hazard area] is the composite of five models; the plumes from each individual model predicted smaller exposure areas. We used the composite approach to increase our confidence that the resulting plume would be our best estimate of the potential area covered, taking into account individual model biases. This approach was critical for notifications and for future epidemiological studies. However, we do not expect that everyone under the composite plume was exposed.^[218]

We recognize that our composite approach methodology overstates veterans’ risk of exposure. Each of the four Khamisiyah model combinations yielded a distinct potential hazard area. However, we cannot say with any degree of certainty which particular model’s potential hazard area or which combination of potential hazard areas correctly identifies military units that may have been exposed. Hence, we used a composite of all four model combinations to reduce the possibility of missing potentially exposed military units. With this in mind, our goal remained the same as it was in 1997: if we erred, we do so on the side of veteran notification. This is particularly important for those veterans who received notice of possible exposure to low levels of nerve agent. (See Tabs E and F.)

Modeling improvements. The 2000 modeling improvements include the following:

• Revised meteorological models. Meteorological model changes were made in: (1) modeling options and input data options for two models: Coupled Ocean-Atmospheric Mesoscale and Prediction System (COAMPS) and Mesoscale Model, Version 5 (MM5), and (2) modeling codes for Operational Multiscale Environmental Model with Grid Adaptivity (OMEGA).

• Reduced amount of nerve agent released. On October 14, 1999, the Special Assistant to the Director of Central Intelligence for Persian Gulf War Illnesses Issues provided revised nerve agent release estimates for several Gulf War incidents to the Special Assistant. All-source intelligence information supported by UNSCOM data generated the revised nerve agent release estimates for number of rockets, quantity of agent, agent purity, and amount of agent aerosolized and evaporated for use in any future ensemble modeling. The CIA revised the Khamisiyah Pit source term data from the estimate used in their 1997 modeling. The CIA also revised source term data for Bunker 73, although we did not remodel Bunker 73 in the 2000 effort. The revised source term estimates quoted from the CIA letter are:

  Khamisiyah Pit – Worst case estimate of agent release: 321 kg GB/GF [sarin/cyclosarin] with the added comment: "New value is 45 percent of the previous assessment based on re-evaluation of number of rockets stemming from UNSCOM excavation in 1998. The new lower release amount and inclusion of environmental degradation [which this document calls "chemical warfare agent decay"] will change exposure limits."

  Khamisiyah Bunker "73" – Worst case estimate of agent release: 51 kg GB/GF [sarin/cyclosarin] with the comment: "New value is lower based on reassessments of rockets and agent fill stemming from UNSCOM excavation in 1998. Winds blow away from troops and release is five percent of release modeled in 1996 that did not expose troops."^[219]

  The revised 2000 modeling indicated a release of 321 kilograms of nerve agent from the Pit instead of the 1997 release of 715 kilograms (a 55 percent reduction.) Likewise, the 2000 modeling revised the total as 51 kilograms instead of the 1997 figure of 1,040 kilograms of nerve agent released from Bunker 73.

  According to the October 14, 1999, CIA estimate, the number of 122mm rockets damaged during the Khamisiyah Pit demolition was 225, instead of the previously estimated 500. Thus, the 2000 source term was 45 percent of the 1997 source term.

• Combined toxicity of sarin and cyclosarin included. The 1997 model treated the source term as totally sarin (GB) because toxicity data on cyclosarin (GF) were not available then. In the 2000 model, we modeled the toxicity of both nerve agents using newly determined cyclosarin toxicity data. Although the amount of sarin was three times that of cyclosarin, the toxicity of cyclosarin is nearly three times that of sarin. Equally important, cyclosarin is less volatile than sarin (i.e., it evaporates more slowly). Modeling the toxicity of both nerve agents produced more accurate hazard areas. As mentioned, the 2000 estimate of agent released was less than half the 1997 estimate. However, the 2000 hazard area did not correspondingly decrease to half the size because of the relative increased toxicity of GF.^[220]

• Atmospheric Removal Mechanisms – deposition and degradation included. We included deposition, i.e., settling to the surface, and degradation, often used synonymously with "decay," in the 2000 model. Both agent removal mechanisms more accurately depict the potential hazard area. Tab E explains in more detail the effects of removal mechanisms on the modeling process.

• Updated unit location and personnel data used. The USASCURR, with more than 855,000 unit locations in its database, maintains two data sets essential for determining veterans potentially exposed to the Khamisiyah hazard area. The first is a registry of Gulf War veterans provided by DMDC and the second is a registry of daily unit locations during the war. The US Army Center for Health Promotion and Preventive Medicine combined USASCURR’s troop locations with the 2000 modeling results to produce graphic representations of the hazard area for March 10 – 13, 1991. We refer to these graphics as the 2000 hazard area results, discussed in the following paragraphs.

2000 modeling estimates of the Pit demolitions that remain unchanged from 1997. These estimates remained the same for the 2000 modeling as the 1997 modeling of the Pit:

• The fraction of chemical warfare agent that entered the atmosphere through instant aerosolization, and the fraction of agent that spilled on wood and soil and evaporated over time;
• The chemical warfare agent evaporation rates from wood and soil;
• The initial ratio of sarin to cyclosarin (3:1) in the agent cloud; and
• Agent purity (50 percent).

US Forces Possibly Exposed. The 1997 possibly exposed troop population was 98,910, compared to the 2000 potentially affected troop population of 101,752. Of that number, approximately 66,000 personnel were in both the 1997 and 2000 modeling potential hazard areas. Table 6 compares the daily differences of those soldiers possibly exposed in 1997 and 2000. Some soldiers were in the potential hazard areas on multiple days, so the total number of possible exposures in Table 6 is not the same as the number of individual soldiers possibly exposed.

Table 6. Comparing the daily differences in possible exposures

Comparing the 2000 to the 1997 hazard areas. Figures 43 – 50 compare and contrast the results of the 2000 models’ and the 1997 models’ potential hazard areas by day for March 10-13, 1991. Figure 51 shows a smaller scale view of the first noticeable effects area for the 2000 model (applies to March 10 only).

Exposure thresholds. We used two exposure thresholds in both our 1997 and 2000 modeling efforts: first noticeable effects and general population limit. We also use these thresholds in our modeling to describe areas of potential exposure.

• First noticeable effects (FNE). This is the dosage expected to cause watery eyes, runny nose, tightness of chest, muscle twitching, sweating, and headache. Dosage is a cumulative exposure—a concentration of a chemical warfare agent over time. Increasingly higher dosages would produce vision impairment, incapacitation, and death.
• General population limit (GPL). The GPL represents the limit below which any member of the general population could be exposed (e.g., inhale) seven days a week, every week, for a lifetime, without experiencing any adverse health effects. Scientists performed exposure testing and computed the GPL from the results of that testing as modified by uncertainty factors such as short-term to long-term exposure, average human to sensitive human population, etc.

Areas of potential exposure.

• Low-level Hazard area. In 1997, we defined the area between the two thresholds as the low-level hazard area, an area where long-term effects from low-level exposure is possible, but symptoms would not exist.
• Potential Hazard area. In 2000, we refer to the area that meets or exceeds the GPL as the potential hazard area, an area where long-term effects from low-level exposure are possible and where acute symptoms might show.

Since the possible chemical warfare agent releases occurred over a four-day period, our 2000 modeling used the GPL based on short-term exposures, as recommended by the US Army Center for Health Promotion and Preventive Medicine.^[221] Figures 43-50 shows the maximum size of the potential hazard area inside which personnel may have been exposed to a nerve agent concentration equal to or exceeding this GPL. Exposure of personnel outside this area did not reach hazardous levels. The dots on each graphic represent a unit’s or part of a unit’s location. The number of units is greater in 2000 because our knowledge of unit locations improved since 1997 due to the G3/S3 conferences.

The 1997 hazard area generally extended in a north-south direction. Based on the wind models, the hazard area extended south-southwest almost 300 kilometers into Saudi Arabia, east of the city of Hafir Al Batin. The 2000 hazard area is divided in two due to slight differences in the wind patterns predicted by the meteorological models but generally follows a north-south axis. The hazard area extends approximately the same distance but to the northwest of Hafir Al Batin. However, the 2000 hazard area extended further to the east and south into Kuwait indicating possible exposure to US personnel not included in the 1997 hazard area. Approximately 70 percent of the 321 kilograms of chemical warfare agent modeled in 2000 had been dispersed into the atmosphere by the end of Day 1.

Figure 43. 1997 Potential hazard area for Day 1: March 10, 1991

Figure 44. 2000 Potential hazard area for Day 1: March 10, 1991

Day 2: March 11, 1991 (Figures 45 – 46)

Both models’ hazard areas have similar shapes. The 1997 model did not consider sunlight effects on the hazard area, but we added these effects for the 2000 modeling at the recommendation of the 1997 peer review panel. For the 2000 hazard area, the dispersion modeling assumed ultraviolet light from sunlight decayed the chemical warfare agent and thus reduced the size of the 2000 hazard area. Improved weather models reflected a shift in the wind to the south, which kept the 2000 hazard area mainly to the north and west of King Kalid Military City (KKMC), unlike the 1997 hazard area, which included KKMC and a much larger area to the west. Later nerve agent emissions evaporating from the soaked wood and soil in the Pit generated the four small hazard areas in the vicinity of Al Bussayyah and around Khamisiyah in the 2000 model. Approximately 89 percent of the 321 kilograms of the chemical warfare agent modeled in 2000 had dispersed into the atmosphere by the end of Day 2.

Figure 45. 1997 Potential hazard area for Day 2: March 11, 1991

Figure 46. 2000 Potential hazard area for Day 2: March 11, 1991

Day 3: March 12, 1991 (Figures 47 – 48)

The 1997 model shows a large hazard area. The 2000 model hazard area is much smaller, due to incorporating two full days of ultraviolet light reaction in the dispersion model. By the third day the chemical warfare agent remaining in the atmosphere, soil, and wood was below the general population limit. Approximately 97 percent of the 321 kilograms of the chemical warfare agent modeled in 2000 had dispersed into the atmosphere by the end of Day 3.

Figure 47. 1997 Potential hazard area for Day 3: March 12 1991

Figure 48. 2000 Potential hazard area for Day 3: March 12, 1991

Day 4: March 13, 1991 (Figures 49 – 50)

A miniscule amount of agent evaporation generated a very small hazard area in both models. Approximately 100 percent of the 321 kilograms of the chemical warfare agent modeled in 2000 had dispersed into the atmosphere by the end of Day 4.

Figure 49. 1997 Potential hazard area for Day 4: March 13, 1991

Figure 50. 2000 Potential hazard area for Day 4: March 13, 1991

First noticeable effects 2000 hazard area: March 10, 1991 (Figure 51). The darker, smaller area on this figure is the 2000 FNE hazard area, and it is within the 2000 models’ M8 alarm hazard area (that area in which the concentration of a chemical warfare agent would be enough to cause an M8 chemical agent detector to detect and sound an alarm for the presence of a nerve agent). Any person in the FNE hazard area would experience immediate visible signs of nerve agent exposure, such as tearing eyes or shortness of breath, and the M8 chemical agent detectors would have sounded a warning to go to a protective posture. No US units were in the first noticeable effects area in either the 1997 or 2000 models.

Figure 51. 2000 First noticeable effects and M8 alarm detection areas

Modeling Khamisiyah. Our modeling does not represent what really happened, but rather what may have happened, given what we know. Our modeling efforts over the past three years have suffered from the passage of time and a fundamental lack of measured data. We overcame some single-model biases by using ensemble modeling techniques—using two or more models to predict the potential hazard area. Though we gained better data on the source term and also had improved models with which to work, we still did not have the accuracy and depth of data the models required to produce an accurate hazard area. Given the limited data we had, we estimated variables such as temperature, moisture, wind speed and direction, and the exact size of the source term. In the end, we again used conservative modeling parameters to attempt to identify the majority of those who may have been exposed in order to protect veterans’ health. Servicemembers should consider their own particular health circumstances and evaluate the information in this narrative, given the uncertainties of modeling the Khamisiyah pit demolition activities.