Federal authorities on Thursday pointed to an overheated wheel bearing on a Norfolk Southern train that derailed and released toxic chemicals earlier this month in Ohio.
The preliminary report from the National Transportation Safety Board did not offer an exact cause of the East Palestine, Ohio, derailment but outlined several operational concerns.
"Surveillance video from a local residence showed what appeared to be a wheel bearing in the final stage of overheat failure moments before the derailment," the report said. "The wheel bearing and affected wheelset have been collected as evidence and will be examined by the NTSB."
In a press conference Thursday afternoon, National Transportation Safety Board Chairwoman Jennifer Homendy said "it was the combination of the hot axle and the plastic pellets which started the initial fire."
Homendy said roller bearings typically have a finite life of between 100,000 and 300,000 miles. Overheating in roller bearings could stem from fatigue cracking, water damage, mechanical damage, a loose bearing or a wheel defect.
"It is recognized in the railway industry that wheel set roller bearings can fail catastrophically in as few as 10 to 15 miles on a train traveling at track speed," Homendy said. "You cannot wait until they fail. Problems need to be identified thoroughly so something catastrophic like this does not occur again. This of course was much earlier than 10 to 15 miles, so we're going to look at that."
Future investigative activity will focus on the wheelset and bearings, tank car design and maintenance procedures, derailment damage, inspection practices and a review of the accident response, the NTSB said.
At about 9 p.m. local time on Feb. 3, an eastbound Norfolk Southern freight train derailed, including 11 tank cars carrying hazardous materials that subsequently ignited. These chemicals included vinyl chloride, a highly flammable carcinogen. Thirty-eight railcars derailed in the incident, according to the NTSB report.
According to the report, the train was traveling about 47 miles per hour at the time of the derailment, below the speed limit of 50 miles per hour. The train's positive train control system, in place to prevent over-speed derailments, was operating at the time of the derailment.
After the train passed a wayside defect detector, it transmitted an alarm message instructing the crew to stop the train to inspect the hot axle. The Norfolk Southern train was equipped with a hot bearing detector system, designed to detect overheated bearings. These detectors are located on the ground pointing up, using infrared technology. NTSB has not identified any operational issues with the wayside defect detectors, nor any track defects.
However, authorities noted a shorter distance between sensors may have helped.
"Had there been a detector earlier, that derailment may not have occurred. But that's something we have to look at," Homendy said.
At the time the train was instructed to stop, the bearing's temperature recorded a temperature of 253 degrees hotter than ambient temperatures, above a threshold of 200 degrees at which point temperatures are considered critical, according Norfolk Southern criteria. At the previous detector, it recorded a temperature of 103 degrees above ambient temperatures. The report said temperatures between 170 to 200 degrees require a stop. Each train company creates their own thresholds, Homendy said, though the NTSB will investigate if warning thresholds need to be changed.
"We have no evidence that the crew did anything wrong," Homendy said.
Homendy said there are federal regulations stating that train cars need to be able to be cooled for 100 minutes, though the fire lasted for well longer than 100 minutes. This means the train car's insulation kept the cars from cooling.
A one-mile evacuation zone was implemented after the derailment, impacting up to 2,000 residents.
Two days after the derailment, temperatures continued to rise within five of the derailed tank cars carrying 115,580 gallons of vinyl chloride. Due to the possibility of a catastrophic explosion that could have sent shrapnel up to a mile, Norfolk Southern carried out a controlled release three days later. The NTSB had no role in the decision making or carrying out of the vent and burn.
No fatalities or injuries were reported.
Homendy said the NTSB will hold a rare investigative field hearing in the spring in East Palestine to collect information from witnesses and discuss possible solutions.
"We've never seen an accident that isn't preventable," Homendy said. "I don't like the word accident, I hate to use it. Nothing is an accident."
Working on cleanup
Norfolk Southern CEO Alan Shaw told CNBC in an interview that aired Tuesday he believes it's safe for families to return to East Palestine. Officials reported air levels are safe and the town's water is free of harmful levels of contaminants.
"Our focus right now is on environmental remediation, cleaning up this site, continual air monitoring, water monitoring, financial assistance to the residents of this community, and investing in this community so that the community in East Palestine can thrive," Shaw said.
However, residents continue to express skepticism. Ohio opened a health clinic Tuesday to address growing reports on headaches, nausea and rashes in the community, and some residents have reported dead chickens and fish near the site. A number of residents who fled their homes have sued Norfolk Southern.
On Tuesday, the Environmental Protection Agency ordered Norfolk Southern to handle and pay for all cleanup efforts.
Shaw told CNBC that Norfolk Southern has reimbursed or committed $6.5 million to East Palestine and will continue to provide financial assistance to residents.
The town has become a political hotspot after former President Donald Trump, a Republican, paid a visit on Wednesday to meet with first-responders and local elected officials. Trump, who won Ohio in 2016 and 2020, suggested that the Biden administration had shown "indifference and betrayal" in responding to the crisis — in addition to promoting his name-brand water.
Trump did not mention on Wednesday his administration in 2018 scrapped a 2015 Obama-era rule mandating advanced braking technology on trains transporting hazardous or flammable materials.
The Thursday report comes the same day that Transportation Secretary Pete Buttigieg visited the site. Buttigieg sent a letter Sunday to Norfolk Southern, warning that the company must "demonstrate unequivocal support for the people" of East Palestine.
Buttigieg has drawn criticism from Republican politicians for his response to the crisis. Sen. Marco Rubio, R-Fla., has called on Buttigieg to resign or be fired for "a gross level of incompetence and apathy." Buttigieg acknowledged in a CBS News interview Tuesday that he "could have spoken sooner about how strongly I felt about this incident."
In the press conference, Homendy said this investigation is "not about politics" and that the goal is to issue safety recommendations guided by facts.
"This is a community that has been devastated," she said. "They deserve to know what happened, how to prevent it from happening again. They deserve to have the right solutions."