An accident at a nuclear power plant can pose a serious threat to surrounding populations. If people and their government are poorly prepared, as was the case at Windscale, England in 1957, Three Mile Island (TMI) in the United States in 1979, and Chernobyl in the Soviet Union in 1986, substantial exposure to radiation could occur. Much has been done since the 1979 TMI accident to prepare for a future accident in the United States. The federal government now requires approved emergency plans for all nuclear plants and has established minimum specifications for such plans. This paper reports that major questions remain regarding the effectiveness of these plans in an actual nuclear accident, although they have performed well in non-nuclear incidents. Because serious nuclear accidents occur only very infrequently, the plans have not been tested in real circumstances.