Military Participants at U.S. Atmospheric Nuclear Weapons Testing—Methodology for Estimating Dose and Uncertainty

Abstract

Methods were developed to calculate individual estimates of exposure and dose with associated uncertainties for a sub-cohort (1,857) of 115,329 military veterans who participated in at least one of seven series of atmospheric nuclear weapons tests or the TRINITY shot carried out by the United States. The tests were conducted at the Pacific Proving Grounds and the Nevada Test Site. Dose estimates to specific organs will be used in an epidemiological study to investigate leukemia and male breast cancer. Previous doses had been estimated for the purpose of compensation and were generally high-sided to favor the veteran's claim for compensation in accordance with public law. Recent efforts by the U.S. Department of Defense (DOD) to digitize the historical records supporting the veterans’ compensation assessments make it possible to calculate doses and associated uncertainties. Our approach builds upon available film badge dosimetry and other measurement data recorded at the time of the tests and incorporates detailed scenarios of exposure for each veteran based on personal, unit, and other available historical records. Film badge results were available for approximately 25% of the individuals, and these results assisted greatly in reconstructing doses to unbadged persons and in developing distributions of dose among military units. This article presents the methodology developed to estimate doses for selected cancer cases and a 1% random sample of the total cohort of veterans under study.

Mortality among military participants at the 1957 PLUMBBOB nuclear weapons test series and from leukemia among participants at the SMOKY test

“…A cohort comparison with the entire 114,270 atomic veterans in the Eight Series Studies was also conducted based on the NuTRIS doses. A comparison between the NuTRIS doses and the subcohort doses (which were based on a comprehensive dose reconstruction) [17] showed a strong correlation with only a scaling factor of about 0.64 needed to bring them into close alignment. The pattern of leukemia risk over categories of NuTRIS bone marrow dose is similar to that seen for the case-cohort analysis (Table 3).…”

“…In accord with the case-cohort study design, dose reconstructions and categorization was for all cases of leukemia and a random sample of all veterans in the Eight Series Study. The detailed dose reconstruction methodology for nuclear weapons test participants was reported by Till and colleagues [17]. …”

“…Much of the detailed information available, i.e., the NuTRIS doses, had been compiled to support estimation of dose for compensation programs for exposed veterans [5, 6]. The subcohort of 1,076 randomly selected participants formed the comparison group for which comprehensive dose reconstruction was performed for the case-cohort analyses [17]. During the dose reconstruction [17], it was found that the NuRIS dose [5], available for the entire cohort, could be adjusted with a scaling factor to bring them into close alignment with the dose estimates for organs where internal exposures from weapons fallout were negligible.…”

“…The subcohort of 1,076 randomly selected participants formed the comparison group for which comprehensive dose reconstruction was performed for the case-cohort analyses [17]. During the dose reconstruction [17], it was found that the NuRIS dose [5], available for the entire cohort, could be adjusted with a scaling factor to bring them into close alignment with the dose estimates for organs where internal exposures from weapons fallout were negligible. The NuTRIS doses available for the entire cohort of atomic veterans are for external radiation and do not consider internal radiation, but since any intakes of radionuclides would contribute only a negligible dose to red bone marrow they would be of little consequence.…”

“… ^ Referent Category a The subcohort is an approximate 1% random sample of all participants in the Eight Series Study for which comprehensive dose reconstruction was performed [17]. The full cohort is everyone in the Eight Series Study with a NuTRIS dose, adjusted to be comparable with the subcohort dose.…”