You could look out Suzanne Machita’s kitchen window and see them, the four cooling towers of the crippled nuclear plant that for a decade had seemed so quiet, so innocent, so much a part of her neighborhood in Middletown, Pa. But that afternoon, 30 years ago, those towers took on a frightening look in the sunshine of early spring, and Three Mile Island looked like an abandoned fortress.

It was the day the radiation poured out of the plant behind Machita’s ranch home. She couldn’t see it, feel it or hear it. But she sensed that afternoon that her domestic tranquility had been shattered, and pulling the curtains shut didn’t begin to shut out the fear she felt.

“I can’t stand the sight of the things anymore,” Machita said to me that afternoon.

I called her up the other day, and together we relived the frightening time we shared so long ago. Machita is now 67, a retired secretary, and what she said was eerily similar to her remarks three decades earlier: “I couldn’t stand the sight of the towers.”

As news of the accident circulated, Machita and her family packed their suitcases in their home by the Susquehanna and fled — her neighbor told me she was more afraid of the panic than the radiation — and a year later they sold the place, just to get away, moving about 15 miles north. But the story of Three Mile Island, and the spring when technology seemed to turn from wonder to threat, never fully left her.

Machita, her husband and her daughter all developed thyroid problems. Proving causation in these cases is a difficult task, but, she said, “I think it is unusual three members of the same family have this and it is not hereditary, not in our family.”

And Machita was left with a lingering doubt about the people, then and now, who are supposed to know and understand what she doesn’t know and understand. “You couldn’t trust what anybody said, the government or any authority,” she said last week.

Three Mile Island was a technological failure, a political challenge and a cultural marker. It was that moment when the word “meltdown” was transformed from metaphor to menace. Those who were there, and those who watched in fear from afar, were shaped by the notion that nuclear accidents could be real and imminent, not simply the stuff of movies like “The China Syndrome,” the Jane Fonda and Jack Lemmon film that was showing at the East Five theater complex only miles from the nuclear plant that week. One line of dialogue stuck out to everyone who crowded into the special 11:30 p.m. showings: “It could render an area the size of Pennsylvania uninhabitable.”

Three Mile Island didn’t do that, of course. But it chilled a nation, and it chilled the nuclear-power industry for decades. It also showed the power of rumors and news snippets to produce mayhem.

When reports circulated that an expanding bubble of hydrogen gas could lead to an explosion in the damaged reactor, waves of panic surged through the Harrisburg area, prompting Gov. Richard Thornburgh to call an unforgettable midnight press conference in his office.

“I appeal to all Pennsylvanians to display an appropriate degree of calm and patience,” he said, as anxious reporters, worried about their Sunday-edition deadlines and about whether they might soon be dead, crowded around his desk.

Thornburgh exuded calm. He later served as U.S. attorney general and today is a Washington attorney. Last week he was a featured guest at a Nuclear Regulatory Commission session on the accident. His topic: emergency management.

It is important to remember that the accident in the Pennsylvania countryside came only five years after Watergate and only four after the end of the Vietnam War. The president of the United States at the time was a nuclear engineer. All these factors combined to underline the toxic mix of betrayal, distrust and skepticism that Three Mile Island fed upon — and fostered.

Government had recently left Americans disappointed and dispirited. Two presidents in a row, Lyndon B. Johnson and Richard M. Nixon, were found to be mendacious. The military had been discredited in Vietnam. The clergy was under siege. Universities had become ideological battlegrounds. Now technology was being revealed as, to borrow a poignant phrase from the Cold War, the god that failed.

“The first lesson learned is to expect the unexpected when you are dealing with technology, particularly one that has the potential of being life-threatening and ecologically disastrous,” Thornburgh, one of the few heroes of Three Mile Island, said in a conversation last week. “You should never say ‘this can’t happen here’ and you have to have a healthy skepticism toward technology.”

No one knows how many, if any, people died because of Three Mile Island. No one knows how many cancers were caused by the accident. But no one can doubt that American innocence, already on life support in 1979, died on the banks of the Susquehanna, and no one can doubt that the cancer of cynicism, already a feature of our body politic, has metastasized since then. Huge, uncontrolled plumes of it spew out of our culture every day.

Our historical canon of the modern era has several landmarks: John F. Kennedy’s assassination, followed by that of Martin Luther King Jr. and Robert F. Kennedy. The Gulf of Tonkin Resolution. The Civil Rights Act. The lunar landing. Woodstock. The killings at Kent State. Gas lines. The helicopters on the roof in Saigon. The seizure of the hostages in Iran. The Reagan revolution. The death of the Challenger astronauts. The fall of the Berlin Wall. The emergence of the Internet. The impeachment of Bill Clinton. The overtime election of 2000. The terrorist attacks of Sept. 11. The inauguration of Barack Obama.

Surely there are others — perhaps the appearance of the Beatles on “The Ed Sullivan Show,” perhaps the first Super Bowl, perhaps the advent of conservative talk radio or hip-hop music, perhaps the premiere episode of “Seinfeld” or “Sex and the City.”

Three Mile Island is the forgotten cultural totem. But it lives with Suzanne Machita and Dick Thornburgh and with us all. Forgotten, but not gone.

— David Shribman is executive editor of the Pittsburgh Post-Gazette.