In 1996, the US government permitted researchers to include patients in medical experiments without requiring their consent. The patients must have a life-threatening condition, be unable to indicate whether they wish to be part of a study, and have no relatives whom it is possible to ask for consent. The experiments must be approved by the Food and Drug Administration.
All but one of eighteen hospital patients knew they were being injected with low-level plutonium by US government researchers after the element was first produced by the Manhatten Project in the 1940s.