CANCER MORTALITY AND MORBIDITY AMONG WORKERS AT THE SELLAFIELD PLANT OF BRITISH NUCLEAR-FUELS

The mortality of all 14,282 workers employed at the Sellafield plant o f British Nuclear Fuels between 1947 and 1975 was studied up to the en d of 1988 and cancer incidence was examined from 1971 to 1986. This up dates a previous report on mortality only up to the end of 1983. Ninet y-nine per cent of the workers were traced satisfactorily. Cancer mort ality was 4% less than that of England and Wales [standardised mortali ty ratio (SMR) = 96; 95% confidence interval (CI) = 90,103] and the sa me as that of Cumbria (SMR = 100; Cl = 94,107). Cancer incidence was 1 0% less than that of England and Wales [standardised registration rati o (SRR) = 90; Cl = 83,97] and 18% less than that of Northern Region (S RR = 82; Cl = 75,88). Cancer mortality rates were significantly in exc ess of national rates for cancers of the pleura (nine observed, 2.6 ex pected; P = 0.001), thyroid (six observed, 1.8 expected; P = 0.01) and ill defined and secondary sites (53 observed, 39.2 expected; P = 0.02 ). There were significant deficits of cancers of the liver and gall bl adder, larynx and lung. Among radiation workers there were significant positive correlations between accumulated radiation dose and mortalit y from cancers of ill-defined and secondary sites (10 year lag: P = 0. 01) and for leukaemia (2 year lag: P = 0.009), but not for cancers of the pleura and thyroid cancer. Previous findings of such associations with multiple myeloma and bladder cancer were less strong. There was a significant excess of incident cases of cancer of the oesophagus (P = 0.01), but this was not associated with accumulated radiation dose. F or cancers other than leukaemia, the dose-response risk estimates were below those of the adult atomic bomb survivors, but the 90% confidenc e interval included risks of zero and of 2-3 times higher. For leukaem ia (12 deaths, excluding CLL), under an excess relative risk model, th e risk estimate derived for the Sellafield workers was about four time s higher than that for the adult atomic bomb survivors with a confiden ce interval ranging from a half to nearly 20 times that of the atomic bomb survivors. Overall, however, there was no excess of leukaemia amo ng the workers compared with national rates.