neglect of ingestion exposures does not have important consequences with regard to estimating credible upper bounds of total doses to the veterans.

The committee has concluded that veterans are not always given the benefit of doubt in developing exposure scenarios and assessing film-badge data. Veterans often were not contacted to verify their exposure scenario, even when such contact was feasible and could have been helpful. In some cases, there was inadequate follow-up with other participants who might have been able to clarify scenario assumptions.

In many cases, considerable judgment had to be used in developing exposure scenarios. Nonetheless, applicable regulations are quite clear that a veteran must be given the benefit of the doubt, which would lead to a higher dose, when there is a question regarding his exposure scenario. Although application of benefit of the doubt would not affect doses in all cases in our random sample, the committee found it to be a frequent problem.

Thus, the committee has concluded that upper bounds of total doses reported by the NTPR program have often been underestimated and therefore do not provide credible upper bounds (95th percentiles) of possible doses.

Question 2. Are the reconstructed doses accurately reported? {The committee interprets this question to be whether the doses that are calculated (regardless of their validity) are being reported accurately to the Department of Veterans Affairs.}

On the basis of its review of many case files, the committee has concluded that doses, as they have been calculated by the NTPR program, have been accurately reported to the VA, and to the veterans. However, the committee believes that uncertainty in assigned doses should be carefully explained and reported to the VA when they are used to evaluate claims for compensation and should be explained to the veterans.

Question 3. Are the assumptions made regarding radiation exposure based on the sampled doses credible? {The committee interprets this question to be whether the assumptions made to define the veterans’ exposure scenarios and the methods and parameters used in dose reconstruction are reasonable and appropriate.}

This question is the most difficult of the four to answer. The committee has concluded that many assumptions regarding veterans’ exposures during atmospheric nuclear-weapons tests are not reasonable and appropriate, given the objective of the NTPR program to estimate credible upper bounds of dose. A large number of separate assumptions are typically required to derive an estimate of dose for most veterans who were exposed. Many of the assumptions being used are indeed reasonable and based on current understanding of the science of historical dose reconstruction. Nevertheless, many key assumptions and methods



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