The Accident at Three Mile Island

Abstract

On March 28, 1979, one of the reactors at Three Mile Island, a nuclear power plant near Harrisburg, Pennsylvania, overheated. A combination of human error and a string of technical failures triggered a partial meltdown of the plant’s radioactive core and the consequent leakage of radiation into the environment. In the dramatic days following the accident, engineers, scientists and mechanics worked to minimize further release of radiation and to prevent a total meltdown of the core. Meanwhile, state and federal government officials hurriedly tried to come up with emergency response measures. Two days after the accident, Governor Richard Thornburgh advised preschool children and pregnant women within five miles of the plant to evacuate the area. Residents within a ten-mile radius were asked to stay at home, turn off their air-conditioners, and close their windows. Confused and frightened by conflicting information and sensationalist media reports, more than 100,000 people fled the area. Twelve days after the accident, the Governor declared the situation under control. According to officials, “no significant amount” of radioactive iodine and cesium had leaked into the environment; a considerable amount of radioactive noble gases, however, had been released into the air.(1) An extensive clean up of the highly contaminated plant took more than a decade. The radioactive debris and the melted core were shipped to Washington State and Idaho. Three independent government commissions investigated the accident, and several public health studies were conducted. Most studies found no increase in cancer mortality rates of the population living within a five-mile zone of the plant, though an epidemiological study published in 1997 concluded that cancer rates among the population downwind of the plant have increased since 1979. The debate over the medical effects of the TMI accident continues.(2) The TMI partial meltdown, which was the worst accident at an American commercial nuclear power plant, both altered nuclear regulation policies in the United States and shook the public's confidence in nuclear technology. Echo developed an online survey, which invited people to share their thoughts about the TMI crisis. We aimed to collect entries from a broad spectrum of people, ranging from residents who lived near the plant to people who lived in a different part of the country (or in another country) and followed the events through the media. Our aim was to build a free and public archive that serves as a resource for activists and scholars alike. As part of the Echo Project, this website was intended to collect and preserve the public memory of the nuclear accident at Three Mile Island. Hosted at chnm.gmu.edu/mars/tmi.