The decision to blow open five tank cars and burn the toxic chemical inside them after a freight train derailed in Eastern Ohio last year wasn't justified, the head of the National Transportation Safety Board told Congress Wednesday. But she said the key decision-makers who feared those tank cars were going to explode three days after the crash never had the information they needed.

The vinyl chloride released that day, combined with all the other chemicals that spilled and caught fire after the derailment in East Palestine, Ohio, have left residents with lingering fears about possible long-term health consequences.

Experts from the company that made the vinyl chloride inside those tank cars, Oxy Vinyls, were telling contractors hired by Norfolk Southern railroad that they believed that no dangerous chemical reaction was happening, NTSB Chair Jennifer Homendy said. But Oxy Vinyls was left out of the command center.

BIDEN ADMIN INSISTS PRESIDENT HAS 'LASER FOCUS' ON EAST PALESTINE DESPITE NOT VISITING FOR A YEAR

"They informed them that polymerization, they believed polymerization was not occurring, and there was no justification to do a vent and burn," Homendy said. "There was another option: let it cool down."

However, that information was never relayed to Ohio Gov. Mike DeWine and the first responders in charge, she said.

Some of this information came out at NTSB hearings last spring in East Palestine. Homendy's comments Wednesday were the clearest yet that the controversial vent-and-burn action wasn't needed. But the agency won't release its final report on what caused the Feb. 3, 2023, derailment until it holds another hearing this June.

DeWine's spokesperson Dan Tierney said it's frustrating to hear now — more than a year after the derailment — that it wasn't necessary to blow open those tank cars.

"The only two scenarios that were ever brought up were a catastrophic explosion occurring, where shrapnel would be thrust in all directions to a one-mile radius or averting that through a controlled vent and burn," Tierney said. "Nobody ever brought up a scenario where if you just did nothing, it wouldn’t explode."

East Palestine Fire Chief Keith Drabick has said the consensus in the command center was that releasing and burning the chemicals was the "least bad option."

But Homendy said they never heard Oxy Vinyls' opinion that the vinyl chloride was stable. Instead, the decision-makers relied on contractors who were alarmed by the limited temperature readings they were able to get, combined with the violent way one of the tank cars released vinyl chloride with a roar from a pressure release valve after hours of calm. Drew McCarty with Specialized Professional Services testified last spring that the tank car "frankly scared the hell out of us."

Republican Sen. JD Vance, who questioned Homendy at Wednesday's hearing, said he wasn't trying to criticize Drabick, DeWine and the other officials who made the decision.

"I think it’s a criticism of the people on the ground who provided inadequate information — and provided inadequate information, I think, to the great detriment of the community on the ground," Vance said. "This is extraordinary work by your team, but this is a really, really troubling set of circumstances."

Norfolk Southern defended the decision again Wednesday and said the plan had nothing to do with trying to get the trains moving again more quickly.

"The top priority of everyone involved was the safety of the community, as well as limiting the impact of the incident," the railroad said. "The successful controlled release prevented a potentially catastrophic uncontrolled explosion."

Krissy Ferguson, 49, has not been able to return to her home that sits on top of one of the creeks that was contaminated since the derailment. She said she was heartbroken to hear the latest updates from the NTSB.

"Is our government going to allow a corporation to get away with it or are they going to act on it? Or is it going to be swept down the polluted creek like everything else is?" Ferguson said.

Misti Allison, who lives with her family about a mile away from the derailment site, said the findings reaffirm what she believed to be true all along: that the vent and burn did not need to happen.

"The only justification was greed, and that Norfolk Southern was putting profits over people to get the train tracks up and running as fast as possible and to destroy whatever evidence was left," Allison said.

And most questions about the potential long-term health effects remain unanswered.

"We need to make sure that health care is available to everybody, not just those who want to participate in a study," she said.

The NTSB has said that it appears an overheating bearing on one of the railcars caused the derailment. Several trackside detectors spotted the bearing starting to heat up for miles beforehand, but the temperature didn't reach a high enough level to trigger an alarm until right before the crash. That meant the crew didn't have an opportunity to stop the train.

Many residents of East Palestine are eager to move forward once the cleanup of the derailment wraps up later this year, but some are still experiencing respiratory problems, rashes and other health concerns.

Norfolk Southern has said that its response to the disaster and the aid it has offered the town has cost it more than $1.1 billion. Now an investor group that's critical of the railroad's response and the disappointing profits it has reported over the past several years is pushing to fire CEO Alan Shaw and take control of the railroad.