Post-Vietnam Dioxin Exposure in Agent Orange-Contaminated C-123 Aircraft by unknow

Author:unknow
Language: eng
Format: epub
Publisher: The National Academies Press
Published: 2015-05-28T00:00:00+00:00

The committee finds this paragraph problematic in three respects:

The report’s “assessment of risk” could not have been “dependent upon the findings of the National Academy of Sciences’ Institute of Medicine RANCH HAND studies” (USAF, 2012a); that work is officially known as the Air Force Health Study because it was conducted by the Air Force, and is in no way a product of the IOM or any other part of the National Academies.

It asserts that “It is reasonable to assume that any exposures associated with HO [Herbicide Orange] in post-Operation RANCH HAND utilization of the UC-123 would likely be less than exposures associated with HO during Operation RANCH HAND” (USAF, 2012a). The committee agrees that workday exposures during active use of AO were likely greater than post-war exposures on a comparable task basis. However, ORH personnel were in Vietnam for a median of about 320 days (CDC, 1988), and undoubtedly did not access spray aircraft on every day of in-country service. Post-war exposures to AF Reservists would have been generally less frequent on an annual basis, but may have extended for up to 12 years. So some fraction of the AF Reservist cohort could have conceivably spent more time in contaminated C-123s than did some fraction of the ORH cohort (especially if the AF Reservists worked full-time or were scheduled for additional hours throughout the year). In addition, some post-war tasks could have resulted in workday exposures that exceeded the workday exposures of some less-exposed ORH personnel (for example, flight crew officers) in terms of overall duration, more work inside the planes on the ground under conditions of reduced ventilation, etc.

In asserting “Consistent with the findings of the National Academy of Sciences’ Institute of Medicine biennial report ([Update] 2010), it is reasonable to conclude that it is not possible to derive quantitative estimates of any increased health risks [emphasis added] for” the AF Reserve personnel, the AF report (2012a) misrepresents the charge and determinations of the Veterans and Agent Orange (VAO) committee. The second task assigned to VAO committees by the 1991 Agent Orange Act was to estimate risk to Vietnam veterans for each specific adverse health outcome. These outcome-specific risks are what are being referred to in the statement “estimation of risks experienced by veterans exposed to the chemicals of interest during the Vietnam War is not feasible” (IOM, 2012, p. 11). Not only is determination of potency factors from epidemiologic results for each health problem far from being feasible, there are no exposure data to be drawn upon for non–Ranch Hand Vietnam veterans. In contrast, the issue concerning the AF Reservists and ORH C-123s is whether the risk of adverse health outcomes of any sort was elevated among those with potential exposure. This committee considers the sampling data for the AF Reserve C-123 population, albeit limited, to be an adequate basis for a qualitative exposure assessment and for some judgment about the overall health risk from TCDD exposure that the AF Reservists may have experienced, and so finds this justification for not doing so from the authors of the USAF report (2012a) to be invalid.

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