Upper bounds of doses from external exposure to gamma radiation are often underestimated because of questionable assumptions about a person’s locations and durations of exposure.
Upper bounds of doses from external exposure to neutrons are always underestimated by a factor of about 3–5, but few participants received much neutron exposure.
Skin and eye doses from exposure to beta particles do not always seem to be credible upper bounds, and skin doses from radioactive particles on the skin do not seem to have been taken into account.
Methods used to estimate doses due to inhaled radioactive materials involve many assumptions that are subject to error because of a lack of data to monitor exposures. Nonetheless, in some exposure scenarios, estimates of inhalation dose appear to be credible upper bounds. In other cases, the estimates are too low but credible upper bounds would still be small doses. However, there were scenarios involving some maneuver troops and close-in observers at the Nevada Test Site in which upper bounds of inhalation dose were underestimated by large factors, and the doses in these cases often could be important. Large underestimates of inhalation dose were due mainly to neglecting the effects of the blast wave produced in a detonation, which could have caused resuspension of large amounts of radionuclides that had accumulated on the ground from previous tests.
Dose reconstruction has not routinely included exposure from ingestion of radioactive materials or contaminated food, but the committee does not believe this was an important source of radiation exposure for most participants.
In developing exposure scenarios and assessing film-badge data, veterans are not always given the benefit of the doubt and often were not contacted to verify their activities, so underestimates could have occurred in individual cases. The veterans themselves are a valuable resource that has been underused.
Because of problems of scenario development and estimation of external and internal doses, total doses do not always provide credible upper bounds, and the resulting underestimates often are substantial. Methods used to estimate doses and their uncertainties should be re-evaluated, and the requirement to give the veteran the benefit of the doubt should be applied more consistently in dose reconstructions.
Interaction and communication with the atomic veterans should be improved. For example, veterans should be allowed to review the scenario assumptions used in their dose reconstructions before the dose assessments are sent to the Department of Veterans Affairs for claim adjudication.
Dose reconstructions have been accurately reported to veterans, but uncertainty should also be reported and carefully explained to VA and the veterans. Also, since some changes in the dose reconstruction program could have made a substantial difference in some earlier dose estimates, veterans and their advisors should be notified when changes are made and that they can ask for updated dose assessments and re-evaluation of their prior claims.