The Y-12 plant at Oak Ridge, Tennessee, produced nuclear materials for the U.S. goveniment's nilclear weapons program beginning in 1943. Workers at Y-12 Miere exposed to low dose, internal, alpha radiution and external, penetrating radiation, as well as to beryllium, mercun, solvents, arid other iridustriul ugenrs. This paper presents updated results from a long-term mortality study of workers at Y-12 between 1947 and 1974, witli~follow-up of white men through 1990 and duta reported for the first time ,for women and men of other races. Vitcil status wcis determined through searches of the National Death 1nde.r and other records, and the workers' mortality W N S compared to the national population's using standardi7ed mortality rutios (SMRs). Total mortalip w(is low for all Y-12 workers und total cancer mortality was as e-xpected. Among the 6,591 white men, there were 20% more lung cancer deaths than expected ( 9 5 8 confidence interval [CI] 1. 04-1.38). Death rates from brain cancer and severul lymphopoietic system cancers were also elevated among white men, with SMRs of 1.28 and 1.46. Mortality .from cuncer of the pancreas, prostate, arid kidney M-OS similarly elevated. There wus evidence of e.xces.7 hreust cancer among the 1,073 female workers (SMR 1.21, 95% CI 0.60-2.17). Lung cancer mortality arnong these workers wurrants continued surveillance because of the link between internal alpha radiation exposure and this disease, but other agents, notably beryllium, also merit consideration as potential cuuses of lung cancer. Other cancers and agents should also be investigated as part of a conzprehensive study of the heulth consequences ?f the production of nuclear weapons. 0 I996 WileJ-Lib3, IIK.