In 2000, after decades of denials, the US government conceded that workers who helped to make nuclear weapons were exposed to radiation and chemicals that produced cancer and early death. Among 14 plants, according to a report, 22 categories of cancer, ranging from Hodgkin's lymphoma and leukemia to cancer of the prostate, lung, bone and bladder, occurred more often than expected. The cancers were found among nearly 600,000 people who have worked in nuclear-weapons production since the start of World War II. The report also raised the prospect that there are workers who are not yet sick, but will get sick, from past exposure.
In 2000, it was the first time that the US government acknowledged that people got cancer from radiation exposure in the plants. Until then, in the 57 years since the Manhattan Project began processing radioactive materials to make bombs, the government minimized the hazards of radiation and chemicals, criticized epidemiological studies that raised disturbing questions and spent tens of millions of dollars defending itself against lawsuits charging that the bomb plants had made workers sick.