Updated Analyses of Combined Mortality Data for Workers at the Hanford Site, Oak Ridge National Laboratory, and Rocky Flats Weapons Plant

Abstract

Updated analyses of mortality data on workers at the Hanford Site, Oak Ridge National Laboratory (ORNL), and Rocky Flats Weapons Plant are presented with the objective of providing a direct assessment of health risks resulting from protracted low-dose exposure to ionizing radiation. For leukemia, the combined excess relative risk estimate was negative (-1.0 per Sv), and confidence limits excluded risks that were more than slightly larger than those forming the basis of ICRP recommendations. For all cancer except leukemia, the excess relative risk estimate was 0.0 per Sv, but confidence limits indicated consistency with estimates several times those forming the basis of ICRP recommendations. Of 24 cancer types tested, 12 showed positive correlations with radiation dose and 12 showed negative correlations, as would be expected by chance fluctuation. Cancer of the esophagus, cancer of the larynx, and Hodgkin's disease showed statistically significant correlations with radiation dose (P < 0.05), but these correlations were interpreted as likely to have resulted from bias or chance fluctuation. Evidence of an increase in the excess relative risk with increasing age at risk was found for all cancer in both Hanford and ORNL, and both populations showed significant correlations of all cancer with radiation dose among those 75 years and older. Although this age effect may have resulted from bias in the data, its presence suggests that risk estimates based on nuclear worker data be interpreted cautiously.

Cancer mortality and morbidity among workers at the Sellafield plant of British Nuclear Fuels

“…More precise estimates of the carcinogenic effects of radiation exposure among workers in the nuclear industry will come from combining data for workers in other nuclear plants. Such studies have been conducted for workers in the UK (Kendall et al, 1992a;Carpenter et al, 1994), the USA (Gilbert et al, 1994) and internationally (International Agency (Table III).…”

Radiation-Related Cancer Risks at Low Doses among Atomic Bomb Survivors

“…Although it is often referred to as a high-dose study, e.g. (1)(2)(3), this characterization is only partly true. It is true that exposures were at very high dose rates, and that linear cancer risk estimates are largely determined from the 0.5-2-Sv range.…”

“…It is true that exposures were at very high dose rates, and that linear cancer risk estimates are largely determined from the 0.5-2-Sv range. 2 However, about 75% of the survivors in the significantly exposed part of the population-about 35,000 persons presenting 5,000 cancer cases-had doses in the 1 Author to whom correspondence should be addressed at Radiation Effects Research Foundation, 5-2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan. 2 Some perspective on dose: Whole-body or bone marrow doses of 1 Sv would ordinarily require immediate medical attention for hematopoietic acute effects.…”

“…2 However, about 75% of the survivors in the significantly exposed part of the population-about 35,000 persons presenting 5,000 cancer cases-had doses in the 1 Author to whom correspondence should be addressed at Radiation Effects Research Foundation, 5-2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan. 2 Some perspective on dose: Whole-body or bone marrow doses of 1 Sv would ordinarily require immediate medical attention for hematopoietic acute effects. Annual occupational limits for nuclear workers are 0.02 Sv, with further limitations on cumulative dose, so workers would not routinely acquire 0.10 Sv.…”

Epidemiology of Accidental Radiation Exposures

“…The statistical power of individual studies was, however, low and in most cohorts the confidence intervals of the risk estimates were compatible with a range of possibilities, from negative effects to risks an order of magnitude greater than those on which current radiation protection recommendations are based. Combined analyses of data from some of these studies have therefore been carried out at the national and international levels (4,5,(55)(56)(57) specifically to test the adequacy of existing risk extrapolations. Table 2 presents the results of the International Agency for Research on Cancer (IARC) international combined analyses (5), carried out on 96,000 workers, and compares them to estimates obtained from IARC reanalyses of the atomic bomb survivors data.…”