Reconstruction of historical exposures at a Welsh nickel refinery (1953-2000).

Past epidemiological studies of workers in a nickel refinery in Clydach, Wales, have shown evidence of large excess respiratory cancer mortality risks [lung cancer relative risk (RR) ≈ 3; nasal cancer RR ≈ 140] in those employed prior to 1930, with risks dropping dramatically in workers hired subsequently. The pre-1930 risks have generally been attributed to high exposures to mixtures of nickel compounds. More recent studies of this refinery's workers have focused on those first hired in 1953, when many of the operations that presumably gave rise to the high exposures were no longer in operation.