Three Mile Island, in the Susquehanna River, south of Harrisburg, was the site of the nation's worst accident involving a nuclear power station.
In late March 1979, five years after going into operation, the plant experienced a meltdown in one of its two units, TMI-2.
No deaths or injuries were caused by the partial meltdown, but the accident sparked widespread panic. The fears were fueled in part by the release earlier that March of the film China Syndrome, which was about a nuclear accident and starred Jane Fonda, Jack Lemmon, and Michael Douglas.
The film's title stems from the fanciful but unscientific prospect that a reactor's components could melt through the earth — all the way to China.
Although the accident released radiation, follow-up studies found no increase in possibly related illnesses.
Still, insurance companies paid out about $15 million to settle personal-injury claims against General Public Utilities Corp., the plant's operator.
TMI-2 has been shut down since 1979, and its electrical generator was eventually moved to another facility.
The Inquirer won the 1980 Pulitzer Prize for local or spot news for its coverage of the accident.