Male subjects (26), who worked with Pu during World War II under extraordinarily crude conditions, were given medical examinations periodically over the past 37 yr to identify potential health effects. Inhalation was the primary mode of the Pu exposures. Current estimates of the systemic Pu depositions in these individuals range from 2 to 95 nCi with a mean of 26 nCi. Seven individuals have depositions of 40 nCi or more, often considered the lifetime maximum permissible body burden for workers. Two individuals have died compared to 6.6 expected deaths based on USA adjusted rates for white males. The causes of death were myocardial infarction and accidental trauma. Examinations completed in 1981-82 revealed no cases of cancer in the group except for a history of skin cancers in 3 individuals. The diseases and physical changes noted in these individuals are characteristic of a male population in their upper 50s or 60s. This study yields no evidence suggesting that adverse health effects have resulted from the 36 yr of exposure to intenrally deposited Pu.