Mortality from malignancies of the hematopoietic and lymphatic tissues among personnel of the first nuclear plant in the USSR.

This paper reports results from the study of mortality from malignancies of the hematopoietic and lymphatic system among personnel of the first nuclear reactor and processing plant in the USSR. Two registers have been set up. They include all personnel of the atomic reactor (register A) and of the radiochemical processing plant (register B). The operation of these installations started in 1948, and two cohorts were formed; cohort I includes those who started employment between 1948 and 1953, cohort II those who started employment from 1954 to 1958. The predominant contribution to the occupational exposure was from external gamma-radiation. Adverse radiation situations prevailed during the first years at both facilities, and this resulted in substantial exposures of the personnel. Significant increases of the total cancer mortality rates and the proportion of malignancies of the haematopoietic and the lymphatic system were seen in the internal comparison only in cohort I of male workers from facility B. In the same cohort there was a statistically significant excess of the standardized mortality rates from malignancies of the haematopoietic and the lymphatic system over the population rates in the Soviet Union. Our estimate for the excess relative leukemia risk is 1.45/Gy, which is 2.7 times less than the relative excess risk of 3.92/Gy that was observed for the A-bomb survivors over age 20 ATB (Shimizu et al. 1987).