COMMITTEE’S APPROACH TO ITS CHARGE
IOM appointed a committee of 14 experts to carry out the study. At its first meeting, the committee decided that its approach to its task would include gathering data from the peer-reviewed literature; requesting data directly from the DoD, the VA, and other experts in the field; reviewing government documents, reports, and testimony presented to Congress; and reviewing relevant NRC and IOM reports and other literature on veterans’ health issues, specific chemicals of concern, waste incineration and combustion processes, and approaches to cumulative risk assessment. The committee also held two public sessions to hear from veterans, representatives of the DoD and the VA, and other interested parties.
The committee decided that the best approach for determining the long-term health consequences of exposure to burn pit emissions was to follow the risk assessment process originally developed by the NRC in 1983, updated in 2009, and used by many federal and private organizations for protecting human and environmental health. The committee modified it to address specific issues necessitated by the statement of task. The process begins with field or laboratory measurements to characterize the nature and extent of environmental contamination. That is followed by an assessment of the magnitude of a person’s or population’s exposure to the contaminated environmental medium (primarily air in the case of JBB) and by a determination of the inherent toxicity of the chemical. All the information is then combined to predict the probability, nature, and magnitude of the adverse health effects that may occur from exposure.
Therefore, the committee focused first on research and data collection related to exposures and health effects reported for the populations at JBB. The committee then assessed health outcomes in other human populations potentially exposed to some of the contaminants found in burn pit emissions. On the basis of the latter information, potential exposures and health effects that might occur in the populations at JBB and other burn pit locations were assessed. Finally, the committee synthesized and summarized key findings and identified data gaps. Using the synthesis, it proposed design elements for a future epidemiologic study.
Several types of data were useful to the committee: information on environmental releases and concentrations of combustion products at JBB, information on possible human exposure at JBB and elsewhere, and the potential for long-term health effects of that exposure. Characterizing environmental releases and concentrations depends mainly on information on pollutant sources, qualitative and quantitative information on the pollutants present in emissions from those sources, and pollutant fate and transport in the environment. It is also necessary to identify exposed human populations and their routes of exposure.
DoD provided raw air-sampling data collected in 2007 and 2009. The raw data were useful for determining which chemicals had been analyzed for at JBB and which ones were detectable in the ambient air. All those detected were considered worth evaluating. The committee asked the DoD for information on the types and volumes of waste burned at JBB and elsewhere in Iraq and Afghanistan, but the DoD was unable to provide the committee with any information specific to the waste stream at JBB; it did, however, provide generic information on waste streams for burn pits at U.S. bases in Kosovo, Bosnia, and Bulgaria.
The committee assumed that deployed personnel were exposed to burn pit emissions mainly by inhalation, although it recognized that some ingestion and dermal exposures were possible. On the basis of the air monitoring data received from the DoD, the committee determined the adverse health effects that might be associated with the individual chemicals that were detected or that otherwise were expected to pose the greatest risk to personnel stationed at JBB. The committee relied on published summaries from diverse sources for health effects information, including IOM and NRC reports; government reports, such as those from the U.S. Environmental Protection