Gulf War Illnesses:

DOD's Conclusions about U.S. Troops' Exposure Cannot Be Adequately Supported

GAO-04-159: Published: Jun 1, 2004. Publicly Released: Jun 1, 2004.

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Since the end of the Gulf War in 1991, many of the approximately 700,000 U.S. veterans have experienced undiagnosed illnesses. They attribute these illnesses to exposure to chemical warfare (CW) agents in plumes--clouds released from bombing of Iraqi sites. But in 2000, the Department of Defense (DOD) estimated that of the 700,000 veterans, 101,752 troops were potentially exposed. GAO was asked to evaluate the validity of DOD, Department of Veterans Affairs (VA), and British Ministry of Defense (MOD) conclusions about troops' exposure.

DOD's and MOD's conclusions about troops' exposure to CW agents, based on DOD and CIA plume modeling, cannot be adequately supported. The models were not fully developed for analyzing long-range dispersion of CW agents as an environmental hazard. The modeling assumptions as to source term data--quantity and purity of the agent--were inaccurate because they were uncertain, incomplete, and nonvalidated. The plume heights used in the modeling were underestimated, and so were the hazard areas. Postwar field testing used to estimate the source term did not realistically simulate the actual conditions of bombings or demolitions. Finally, the results of all models--DOD and non-DOD models--showed wide divergences as to plume size and path. DOD's and VA's conclusions about no association between exposure to CW agents and rates of hospitalization and mortality, based on two epidemiological studies conducted and funded by DOD and VA, also cannot be adequately supported because of study weaknesses. In both studies, flawed criteria--DOD's plume model and DOD's estimation of potentially exposed troops based on this model--were used to determine exposure. This may have resulted in large-scale misclassification. Troops under the path of the plume were classified as exposed; those not under the path, as not exposed. But troops classified as not exposed under one DOD model could be classified as exposed under another DOD model. Under non-DOD models, however, a larger number of troops could be classified as exposed. Finally, as an outcome measure, hospitalization rate failed to capture the types of chronic illnesses that Gulf War veterans report but that typically do not lead to hospitalization.

Status Legend:

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  • Review Pending-GAO has not yet assessed implementation status.
  • Open-Actions to satisfy the intent of the recommendation have not been taken or are being planned, or actions that partially satisfy the intent of the recommendation have been taken.
  • Closed-implemented-Actions that satisfy the intent of the recommendation have been taken.
  • Closed-not implemented-While the intent of the recommendation has not been satisfied, time or circumstances have rendered the recommendation invalid.
    • Review Pending
    • Open
    • Closed - implemented
    • Closed - not implemented

    Recommendations for Executive Action

    Recommendation: The Secretary of Defense and the Secretary of Veterans Affairs should not use the plume-modeling data for future epidemiological studies of the 1991 Gulf War, since VA and DOD cannot know from the flawed plume modeling who was and who was not exposed.

    Agency Affected: Department of Veterans Affairs

    Status: Closed - Implemented

    Comments: In commenting on a draft of this report, VA agreed with the recommendation, but noted that it had already completed studies that incorporated the DOD plume model as part of the parameters. Given our assessment, it is important that VA inform the researchers to include appropriate caveats. VA remains in concurrence with the recommendation, but again pointed out that it had completed studies that incorporated the DOD plume model.

    Recommendation: The Secretary of Defense and the Secretary of Veterans Affairs should not use the plume-modeling data for future epidemiological studies of the 1991 Gulf War, since VA and DOD cannot know from the flawed plume modeling who was and who was not exposed.

    Agency Affected: Department of Defense

    Status: Closed - Not Implemented

    Comments: In commenting on a draft of this report, DOD did not concur with the recommendation. We subsequently clarified the wording of the recommendation to address its concerns. In commenting on the final report, DOD stated that it stands behind the modeling that it did and continues to nonconcur with the recommendation. DOD stated that scientific experts in modeling reviewed both the methodology and results of the modeling and concluded that the DOD work was sound. DOD stated that GAO has ignored scientific fundamentals in its analysis and only evaluated historical models. Thus, any assessments of modeling made by GAO should only be considered as applicable to historical models. It further stated that GAO?s insistence on the value of the Lawrence Livermore National Laboratory modeling was a serious error. It claimed that based on an independent analysis, the Institute for Defense Analyses judged this model to be less capable than other DOD models. In addition, DOD claimed that GAO underestimated the abilities of epidemiologists using the DOD data. The population identified as potentially at risk has been used by various researchers, and, according to DOD, they clearly understand the assumptions made in modeling and the considerations necessary to evaluate the health of this population in comparison to controls. DOD stated that those published studies are appropriately valid.

    Recommendation: The Secretary of Defense should require no further plume modeling of Khamisiyah and the other sites bombed during the 1991 Gulf War in order to determine troops' exposure. Given the uncertainties in the source term and meteorological data, additional modeling of the various sites bombed would likely result in additional cost while still not providing DOD with any definitive data on who was or was not exposed.

    Agency Affected: Department of Defense

    Status: Closed - Implemented

    Comments: DOD concurred with this recommendation.

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