Although the proportion of cancer deaths among males is somewhat higher for Hanford employees with recorded occupational radiation exposure compared with males in the general population of the state of Washington, there is no indication that radiation is the cause of this difference. For exposed male employees hired at Hanford from 1944 to 1971, the mean radiation dose increases progressively from 142 mrem in 1944 to 3745 mrem in 1972 (the true gradient would have been sharper); whereas, the percentage of deaths from cancer is 19.85 for 1944–1959 and 20.27 for 1960–1972. For the 1944–1945 cohorts (those hired in 1944 or 1945), the observed dose gradient rises progressively from 142 mrem in 1944 to 3762 mrem in 1972 (with a sharper gradient in true dose), and the percentage of cancer deaths is 20.67 for 1944–1959 and 19.10 for 1960–1972. The percentage of deaths from cancer is 20.36 for exposed males hired from 1946 to 1971 and 20.05 for those hired in 1944–1945 from the time of hire to October 1972. For each year the mean dose level of those who died from cancer is not significantly different from the mean of those who died from other causes. The mean dose level for the majority of those who died in a specific year is lower than the mean for the survivors in the year of death, in the year preceding the year of death, or in the two years preceding the year of death. This is true whether the mean was for those dying from cancer or from other causes. These relationships are similar for female exposed employees and agree with other similar studies. The latest analysis of exposed male Hanford employees vs those nonexposed and the out-of-plant controls from the date of hire to April 1974 shows the following often statistically significant differences: 1. Higher longevity for exposed employees vs the identified siblings of such employees. This advantage of employees over the siblings becomes more pronounced if the comparison is restricted to employees with one or more identified siblings. 2. Exposed employees have higher longevity when compared with nonexposed employees. 3. Exposed employees have higher longevity when compared with their matched controls. 4. Nonexposed employees have lower longevity when compared with identified siblings of such employees. If the comparisons are restricted to employees with one or more identified siblings, the longevity advantage of the siblings over the employees is enhanced. 5. Nonexposed employees have lower longevity when compared with their matched controls. Crude disability claim rates for benefits among the population groups delineated above fully support the findings based on longevity; therefore, all observations available so far give no firm indication of any lasting adverse health effects among Hanford employees attributable to occupational exposure to radiation within permissible limits. Inferentially, these findings are likely to prevail at least until the early 1980's. Adverse effects beyond 36 yr cannot be denied or affirmed at this time.
©1978Health Physics Society