SUMMARY AND SYNTHESIS
Understanding the potential for long-term health effects associated with human exposure to burn pit emissions depends on the reliability and utility of the available data on exposures at JBB and other burn pit locations, as well as exposure and outcome data from studies on other populations exposed to some of the same combustion products, singly or in mixtures. Each of the three main data sources—data specific to JBB, other military reports, and the peer-reviewed literature—provides useful and relevant information, but each has major limitations.
In this section, the committee summarizes and highlights key findings on materials burned at JBB and other military burn pit locations, health effects data on the combustion products detected at JBB, and studies on health effects in non-Balad populations potentially exposed to similar chemicals. The committee comments on its confidence in these findings and on their usefulness in providing the VA with information for medical follow-up and future studies. The committee also considers the possible impact of co-exposure to combustion products from local and regional air pollution sources other than the JBB burn pit.
NEW STUDY DESIGN
The statement of task directs the committee to “examine the feasibility and design issues for an epidemiologic study of veterans exposed at the Balad burn pit.” Two recent IOM reports on other military populations offer useful models. First, a study on depleted uranium in military and veteran populations (IOM 2008) identifies key features of a well-designed epidemiology study of potential health effects associated with environmental exposure.
Second, the review of the DoD’s Enhanced Particulate Matter Surveillance Program (NRC 2010) identifies exposure assessment as a central element in the study design for that proposed study because “if data are not available to characterize exposure, any study of association between health outcomes and exposure will not provide valid results.” Any study of JBB exposures is necessarily incomplete because of the limited exposure information available. Specifically, the military collected environmental samples at fixed locations, but the relation to individual exposures may be difficult to ascertain, be subject to large uncertainties, or both. Since the JBB burn pit was closed in 2009, no additional opportunities are available to collect environmental or personal monitoring data on burn pit emissions at JBB, although it is still possible to conduct air monitoring, including personal monitoring, at other military sites with operational burn pits.
Epidemiologic studies conducted at JBB and other bases with burn pits have substantial acknowledged limitations (for example, lack of adequate follow-up for the diagnosis of conditions with long latency such as chronic bronchitis, emphysema, systemic lupus erythematosus, and cancer). Taking these considerations and the key findings in this report into account, the committee closes with a discussion of design issues for a future epidemiologic study of the JBB population and outlines a proposed approach for that study.
CHPPM (U.S. Army Center for Health Promotion and Preventive Medicine) and AFIOH (U.S. Air Force Institute for Operational Health). 2009. Addendum 2. Screening health risk assessment burn pit exposures, Balad Air Base, Iraq, May 2008. USACHPPM Report No. 47-MA-08PV-08/AFIOH Report No. IOH-RS-BR-TR-2008-0001. Aberdeen Proving Ground, MD: U.S. Army Center for Health Promotion and Preventive Medicine. August.
EPA (U.S. Environmental Protection Agency). 1998. Guidelines for ecological risk assessment. EPA/630/R-95/002F. Washington, DC: Risk Assessment Forum.
IOM (Institute of Medicine). 2005. Gulf War and health: Volume 3. Fuels, combustion products, and propellants. Washington, DC: The National Academies Press.
IOM. 2006. Gulf War and health: Volume 4. Health effects of serving in the Gulf War. Washington, DC: The National Academies Press.
IOM. 2008. Epidemiological studies of veterans exposed to depleted uranium: Feasability and design issues. Washington, DC: The National Academies Press.
IOM. 2010. Gulf War and health: Volume 8. Update of health effects of serving in the Gulf War. Washington, DC: The National Academies Press.