Corrected Feb. 24 | The National Transportation Safety Board released a preliminary report Thursday on its investigation of the Feb. 3 train wreck in Ohio, providing no firm conclusions about the cause of the accident but listing a number of factors that may have contributed, including overheated wheel bearings.

The report comes nearly three weeks after the 149-car Norfolk Southern train carrying 20 carloads of hazardous materials derailed and caught fire, spewing chemicals like highly toxic vinyl chloride into the area around East Palestine, Ohio, and forcing an evacuation of many of the town’s 4,700 residents.

Transportation Secretary Pete Buttigieg toured the accident site Thursday morning and spoke with reporters afterward. Buttigieg and the Biden administration have been criticized for a slow response to the disaster, with many in the community expressing alarm about potential health problems from the chemical exposures in air, soil and water. 

Buttigieg underscored that DOT, EPA and other federal responders have been present since the “early hours” of the accident and added that DOT will not wait until a final NTSB report to “do everything we can to raise the bar on rail safety and to hold people accountable.”

“That’s the other part of my visit here is to make sure that we can assess how to drive the best safety improvements across our national transportation system,” he said. “Any national political figure who has decided to get involved in the plight of East Palestine, I have a simple message, which is, I need your help.”

The safety board’s investigation expands on its previous findings that the accident was caused by an overheated wheel bearing, although NTSB said it had yet to examine the wheel bearing.

According to the report, the train contained a detection system that scans for temperature differences and other mechanical warnings. When it passed the first of three mileposts containing heat detectors, the suspected bearing had a recorded temperature of 38 degrees Fahrenheit above ambient temperature. By the second, it was 103 F above ambient.

By the third milepost, the suspect bearing was 253 F above the ambient temperature. Norfolk Southern’s guidelines say that if a difference between bearings on the same axle is greater than 200 F, the situation is determined to be “critical” and engineers need to “set out” the car for maintenance. 

The report added that when the train passed a milepost on the east side of East Palestine, the detector transmitted a “critical audible alarm message” due to an overheated wheel bearing. The message instructed the crew to “slow and stop the train to inspect a hot axle.”

The engineer engaged the brake application to further slow and stop the train, but an automatic emergency brake application initiated, causing the train to come to a stop. The crew observed fire and smoke and notified the dispatcher of a possible derailment.

Controlled burn, cleanup

Two days after the initial derailment, responders had put out the fire but were concerned about five derailed cars that contained 115,580 gallons of vinyl chloride, a toxic chemical used in plastics manufacturing.

Temperatures in one of those five cars continued to rise, suggesting that it could explode. Responders vented the cars and performed a controlled burn of the substance on Feb. 6 after they expanded the evacuation zone and dug ditches to contain released vinyl chloride liquid while it vaporized and burned.

The EPA, in cooperation with state environmental officials, has been working with Norfolk Southern and community members to test for air, water and soil contamination and start the remediation process. The agency is requiring the railroad company to pay for all cleanup costs, and Norfolk Southern has announced it will provide $6.5 million to help those affected by the chemical releases.

Former President Donald Trump went to the site Wednesday and railed against Biden for not visiting the community. “I would have been here a long time ago,” he said about the president.

Congressional Republicans also have been critical of the administration’s response, aiming much of their fury at Buttigieg, who waited 10 days to address the accident via Twitter.

Buttigieg became more aggressive over the weekend, issuing an action plan for the rail industry to improve safety and blasting Norfolk Southern and other rail companies for lobbying against stronger regulations in recent years.

When asked about his delay in visiting the accident site, Buttigieg said he was “trying to strike the right balance” by providing NTSB time and space to investigate.

“I felt strongly about this, and I should have expressed that sooner,” he said about waiting to comment on the derailment. “Again, I was taking pains to respect the role that I have and the role that I don’t have, but that should not have stopped me from weighing in about how I felt about what was happening to this community.”

Buttigieg also reiterated that DOT is working with Congress on legislative and regulatory fixes, including changing how hazardous materials are classified and phasing in ‘safer’ rail cars. And he added that rail companies need to stop lobbying and fighting against regulations.

“I mean, you see the twisted metal there, you realize the difference between a fortified tank car, and some of the tank cars that don’t have that level of fortification,” he said. “[It’s] why we need to make sure we have the strongest, toughest possible hands when it comes to dealing with these railroad companies.”

NTSB said that it is continuing to examine the suspect wheel bearing, review the accident response and investigate Norfolk Southern railcar inspection practices.

A former federal railroad safety specialist who spoke on background said that since the detection system did not malfunction, it’s likely NTSB will focus its recommendations on the railroad industry taking a more active approach to improve diagnostics on train lines. 

But it’s still not clear what kind of management decisions Norfolk Southern made when the crew first learned of the overheated wheel bearing at the first milepost. The report does not detail if the crew stopped the train for an inspection or any other communication with Norfolk Southern management. 

NTSB has not announced when it will release its final report on the accident, which will include safety recommendations. The Transportation Department’s Federal Railroad Administration will be responsible for enforcing those recommendations.

This report was corrected to accurately reflect the NTSB’s preliminary report on potential causes of the derailment.