Three Mile Island
The accident at Three Mile Island Unit 2 (TMI 2) in Pennsylvania in 1979 was caused by misinterpretation of equipment functioning by plant operators when assessing the reactor's condition. A gradual loss of cooling water to the reactor's heat-producing core led to partial melting of the uranium fuel and fuel rod assemblies and the release into the environment of a very small amount of radioactive material. While the TMI 2 accident caused no physical injuries or deaths, it did result in serious concerns and fear and, undoubtedly, was a source of stress to some of the people living close by. Related to the radiation, however, careful follow-up studies showed that the highest dose an individual member of the public could have received would have been about one-fourth of the dose we get each year from natural background radiation sources, even if the individual stood just outside the plant fence during the entire accident. Experts concluded that the amount of radioactivity released during the entire accident was much lower than what would have been released by the station under routine operation during that time.