Pennsylvania Governor Dick Thornburgh had been in office a mere 68 days when he came face-to-face with the biggest crisis of his professional life. Retired Colonel Oran Henderson, the head of Pennsylvania's Emergency Management Agency, informed Thornburgh of the incident at Three Mile Island on the morning of March 28, 1979. "The minute I heard that there had been an accident at a nuclear facility, I knew we were in another dimension," Thornburgh later recalled. He was a Republican governor of a largely Democratic state, a career attorney who had risen through the ranks to gain national prominence as United States Assistant Attorney General. But in March, 1979, in his new role as Governor of Pennsylvania, Thornburgh would gain a level of media exposure he had never seen before. Thornburgh knew next to nothing about nuclear power, radiation, or evacuation management. Still, he found himself in a position of having to assure the citizens of his state that everything was, or soon would be, under control. Working against him was the fact that he was being given information by officials at Three Mile Island, Metropolitan Edison Company, and the Nuclear Regulatory Commission that was often incomplete, contradictory, and confusing.
On Thursday, March 29, Thornburgh made his first public comments since the accident occurred. "Good afternoon, I'd like to address my initial remarks to the people of central Pennsylvania. I believe, at this point, that there is no cause for alarm, nor any reason to disrupt your daily routine, nor any reason to feel that public health has been affected by the events on Three Mile Island. This applies to pregnant women, this applies to small children and this applies to our food supplies. I realize that you are being subjected to a conflicting array of information from a wide variety of sources. So am I. I spent virtually the entire last 36 hours trying to separate fact from fiction about this situation. I feel that we have succeeded on the more important questions." Thornburgh had dispatched his Lieutenant Governor, William Scranton, to Three Mile Island to bring back a first-hand assessment. Scranton's visit seemed encouraging. He told Thornburgh that the problem seemed fixable.
What little relief Thornburgh felt at hearing Scranton's report, dissolved the next day when it was reported that a large burst of radioactive gas had escaped from Three Mile Island. Suddenly, Thornburgh was placed in the position of having to make a decision regarding a recommendation from Washington, D.C., to evacuate thousands of people from the area surrounding the plant. Adding to the surreal atmosphere in Harrisburg that day was the sounding of an air raid siren that rang out through the capital city. "That siren was like a knife in my chest," Thornburgh recalled. "I thought, 'What on Earth? Where did that come from?'" The ringer of the siren never came forward. Even though the release of radioactive gas was found to have been overstated, Thornburgh, on the advice of NRC Chairman Joseph Hendrie, advised the evacuation "of pregnant women and pre-school age children...within a five-mile radius of the Three Mile Island facility until further notice." Within days, 140,000 people fled the area.
On April 1, Thornburgh accompanied President Jimmy Carter on a tour of Three Mile Island. The outcome of the accident was still uncertain, but Thornburgh and Carter knew that their appearance might boost local morale. It was not until April 9 that the Governor felt confident enough to call back any pregnant women and pre-school children who had evacuated the area.