HARRISBURG – “The China Syndrome” debuted in move theaters nationwide on March 16, 1979.

It told the story of cover-ups about safety at a nuclear power plant and the potential for catastrophe posed by a possible meltdown.

Twelve days later — 40 years ago today — the Hollywood thriller came perilously close to reality at Three Mile Island, the nuclear power plant 15 miles south of Harrisburg.

A series of human and mechanical failures played out over five days as plant operators and government officials scrambled to understand the situation and neighbors fled while people around the globe watched the drama unfold.

The incident largely gave birth to the anti-nuclear power movement that has stymied the expansion of the nuclear industry in the U.S.

Now, four decades later, as the plant’s current owner threatens to shutter the power plant, Three Mile Island is one again the focus of controversy.

State Rep. Thomas Mehaffie, R-Dauphin County, has introduced legislation that would allow nuclear power plants, like Three Mile Island, to tap into incentives created for green energy sources.

The current owner of Three Mile Island, Exelon, has warned that it will close without the state aid.

Opposition has come from a variety of groups, including TMI Alert. The watchdog group was created in 1977, inspired by “growing environmental awareness” of the danger of nuclear power, said Eric Epstein, who has been involved with TMI Alert since 1984 and is now chairman of the group.

He said that the state aid is unnecessary because all of the other nuclear power plants in Pennsylvania, except Three Mile Island, are profitable.

“TMI is an aging and small reactor that can’t compete,” he said.

How the trouble began

The issue that made the words Three Mile Island synonymous with nuclear plant problems started just before 4 a.m. on that Wednesday when water pumps failed at the power plant.

After the pumps failed, employees opened a valve to relieve pressure. That valve should have closed when pressure fell, but it got stuck open though indicator lights suggested it had closed.

That meant that workers inside the power plant weren’t aware that coolant was being released. Efforts to contain the situation were complicated by other confusing readings from instruments. This ultimately resulted in the water level in the reactor to drop so that the top of core became exposed and led to a partial meltdown, according to the Nuclear Regulatory Commission’s account of the incident.

How bad was it?

John G. “Jack” Herbein, now retired and living in Johnstown, was vice president of generation for Met Ed, the company that then owned Three Mile Island, in 1979.

He said that mistakes made throughout the crisis and the full scope of the damage inside the reactor didn’t become clear until years later when investigators could get inside.

Ultimately, he stressed, the amount of radiation released into the atmosphere was minimal. At the gate outside the plant, the radiation was “not anymore than a dental X-ray,” he said.

Arnie Gundersen disagrees.

He spent more than 40 years working in the nuclear industry, but he’s now chief engineer for Fairewinds Energy Education, an anti-nuclear power advocacy group. Gundersen said that the the plant’s air monitors weren’t all functioning so the information about how much radiation was released was incomplete.

From what’s known, he said he believes it’s clear that there was more radiation released than the power companies or government regulators have said.

At the time of the incident, Gov. Dick Thornburgh said that only pregnant women and young children within 5 miles of the nuclear power plant should evacuate. That didn’t stop thousands of others from fleeing. Research cited by the Federal Emergency Management Agency estimated that as many as 144,000 people fled the area around Three Mile Island.

Gundersen said those who left were right to do so.

“I truly believe no one should have been in those communities” near the power plant, he said. “There were dozens of indications that by 10 a.m., they should have called an evacuation.”

Communication problems

Gundersen said he doesn’t think there was a conspiracy to cover-up events as they happened. But he thinks that individuals involved at times withheld information that would have shed more light on how dangerous things seemed to be.

For example, he said transcripts of conversations between Nuclear Regulatory Commission officials and workers inside the plant captured a telling exchange. The NRC officials asked what the temperature in the core of the reactor was. The workers inside the plant replied that they couldn’t say because the printer was spitting out a page covered in question marks.

Gundersen said the workers knew, but didn’t say at the time, that the question marks indicated that the temperatures were over 700 degrees, meaning the core was heating up dangerously.

Herbein said that officials were providing the best information they could. A part of the challenge was that as workers made sense of what of was transpiring, they realized some of their initial interpretations were inaccurate.

“We were being misled” Herbein said. And on top of that, as more information was gleaned about the incident, the picture kept getting bleaker.

“We seemed to be in a cycle where things just kept getting worse,” he said.

That translated into public tension with the media and public officials.

By the middle of the morning on the first day of the incident, Lt. Gov. Bill Scranton met with reporters and assured them: ““there is and was no danger to public health and safety.”

Hours later, he changed his tune: “This situation is more complex than the company first led us to believe,” Scranton said in a 4:30 p.m. press conference.

A multi-day crisis

While the event started on March 28, the tension wound up over days with Friday, March 30 being the climax. By Friday, it had become clear that a hydrogen bubble had formed inside the reactor. At the time, government regulators were concerned that the bubble might explode releasing even more radioactive material.

Robert Swift, now a reporter with Capitolwire, a news service focused on state politics, was 26 and five weeks into his stint as the capitol correspondent for Ottaway Newspapers when the crisis at Three Mile Island played out. The Ottawa newspapers then included the Sharon Herald and the The Daily Item in Sunbury, now owned by CNHI.

By March 30, Harrisburg was largely empty because most people had fled. But the area and the Capitol were swarming with reporters.

The United Press International had a teletype machine in the Capitol newsroom, Swift said. In the middle of the afternoon on Friday, bells on the teletype machine began to ring as it spit out an urgent bulletin: “The Nuclear Regulatory Commission said Friday the Three Mile Island power plant faces the ‘ultimate risk of a meltdown.’”

The UPI news alert wasn’t the only scary moment on Friday. That morning, a Harrisburg fire official decided to sound the air raid siren. It was intended to remind people to stay inside, but at the time, no one knew why the siren was being going off, sending reporters in the Capitol scurrying to the governor’s office for answers, Swift said.

Swift said that he took his cue about whether it was safe to stay by watching the UPI and Associated Press reporters. He figured they’d learn before him if it was too dangerous to remain at the Capitol.

“If they were gone, I was gone,” he said.

With so many wire service reporters around, Swift spend some of his time focusing on the number of evacuees streaming out of south-central Pennsylvania north to the hotels along the commercial strip on Routes 11-15 in eastern Snyder County.

With the Susquehanna Steam nuclear plant under construction while the Three Mile Island crisis was taking place, there was also a lot of interest in what impact the incident would have on the future of the Columbia County power plant, he said. The nuclear plant in Berwick opened in 1983, one of the last nuclear plants to open in the U.S.

Plant workers deflated the hydrogen bubble from March 30-April 1 by “by periodically opening the vent valve on the reactor cooling system pressurizer,” according to a summary of the event by the World Nuclear Association.

Immediate aftermath

The crisis was largely over by April 1, when the hydrogen bubble had been deflated, but it took until almost the end of April before the plant operators had gotten the reactor into “cold shutdown, according to the World Nuclear Association’s recap of the events.

Confusion and fear over the health effects caused by the incident lingered for years though. Because of those concerns, the Pennsylvania Department of Health for 18 years maintained a registry of more than 30,000 people who lived within five miles of Three Mile Island at the time of the accident, according to the nuclear association. The state’s registry was discontinued in mid-1997, without any evidence of unusual health trends in the area.

There are two nuclear reactors at Three Mile Island. Reactor 2, the one involved in the meltdown, has never been restarted since the 1979 crisis. Reactor 1 resumed operation in 1985 and continues to operate today.

While the crisis seems long ago, the environmental legacy of the incident remains and will remain for generations, said Epstein at TMI Alert.

Epstein’s group still monitors activities at Three Mile Island, as well as at the two other nuclear power plants along the Susquehanna River — Susquehanna Steam in Columbia County and Peach Bottom in York County.

“Nuclear power accidents are catastrophes without ending. (The damaged reactor) is still a high-level waste site,” Epstein said. “This started in the 20th Century and it will still be in full force in the 22nd Century,” he said.

Epstein said that federal safety regulation of the nuclear industry was heightened after Three Mile Island, but over the years he feels like it’s slowly withering away.

“I have as much faith in the NRC now as I did 40 years ago,” he said.

Anti-nuclear movement

Over the decades that have followed, Gene Stilp has become one of the most prominent activists in Harrisburg. In 1979, he was a law student at George Mason University when the Three Mile Island incident happened.

The issue drew him to a gathering to plan a protest in Washington, D.C., in response to the Three Mile Island.

“They asked if anyone could get permits, I said, I could do that,” Stilp said. “That was my start, I haven’t stopped.”

He filled out permits indicating that the group expected 25,000 people to show up but 125,000 people turned out. He was later involved in organizing similar mass demonstrations in New York and went on to lead anti-nuclear protests in the Harrisburg area.

“If you wanted to have a nuclear accident where people wouldn’t fight back, it was in central Pennsylvania. People believed the government,” Stilp said.

He will be at the 40th anniversary vigil outside the Three Mile Island plant Thursday morning.

Stilp said he will likely get arrested.

“I get arrested about every five years just to give an example for the next generation” of protesters, he said.

Stilp is also proud of the fact that he claims to be the first person arrested protesting outside the Susquehanna Steam near Berwick, which was under construction when the Three Mile Island crisis took place.

Activists like Stilp note that construction of nuclear power plants in the United States ground to a halt after Three Mile Island.

Ongoing controversy

Lobbyists for the nuclear industry and labor organizations representing workers at the state’s nuclear plants are pushing for a change to state law to allow nuclear to tap into financial incentives intended for green energy.

Exelon, the company that now owns Three Mile Island, has announced plans to close the power plant by September unless the incentive proposal becomes law. In western Pennsylvania, Beaver Valley is also on the chopping block, as FirstEnergy, its owner, has threatened to close that power plant by 2021 without state action.

The idea faces stiff opposition from a diverse variety of groups, including other utilities, large electric customers and the AARP, which has opposed the plan over concerns about how it could lead to increased electric prices.