(NewsNation) — Members of the National Transportation Safety Board (NTSB) called this month’s Ohio train derailment “100% preventable,” and will host a rare field hearing to investigate the incident and the response. 

“We call things accidents,” said Jennifer Homendy, chair of the National Transportation Safety Board, at a news conference Thursday. “There is no accident. Every single event that we investigate is preventable,”

The announcement coincided with a preliminary report explaining a wheel bearing sounded a safety alarm shortly before the train derailed in East Palestine.

The report — compiled by the NTSB in the aftermath of the Feb. 3 train derailment — found that shortly before the derailment, a wheel bearing on the train’s 23rd car reached a temperature 253 degrees F above its normal temperature. Any difference of 200 degrees is considered critical.

Two prior readings showed the bearing’s temperature was rising, but hadn’t reached a critical threshold. Those standards are set by railroad companies and can vary.

“I will tell you — if there had been a detector earlier, that derailment may not have occurred,” Homendy said.

Norfolk Southern, the company whose train derailed, issued a statement Thursday emphasizing that the crew responded appropriately to the alarm.

“Out of an abundance of caution, Norfolk Southern is now inspecting all of the nearly 1,000 wayside heat detectors on its system – on top of the regular inspection of the detectors every 30 days,” that statement read. “We and the rail industry need to learn as much as we can from this event.”

There are several reasons a bearing might overheat, including fatigue cracking, water or mechanical damage, a loose bearing or a wheel defect. There is no evidence of the train crew “doing anything wrong,” Homendy said.

The bearing’s temperature sounded an alarm to stop the train, which the crew did by applying its brakes according to the report.

Once the train stopped, the crew called dispatchers and warned of a possible derailment, citing smoke and fire.

“The crew applied handbrakes to the two railcars at the head of the train, uncoupled the head-end locomotives, and moved the locomotives about 1 mile from the uncoupled railcars,” the report states.

Safety officials noticed that the temperature of five derailed tank cars carrying 115,580 gallons of vinyl chloride was continuing to rise, suggesting a potentially explosive chemical reaction was taking place.

Responders scheduled a controlled venting to release and burn the vinyl chloride and expanded the evacuation zone.

The tanks cars have since been decontaminated, but an investigation into the situation is ongoing.

The NTSB said last week it suspected an overheated bearing was responsible. Thursday’s preliminary report supported that claim, expanding on what its investigation has found thus far. An official cause won’t be determined until the investigation is complete, which could take 12-18 months, Homendy said.

The board could issue urgent safety recommendations sooner if the investigation reveals something they believe should be addressed immediately.

The NTSB will continue to examine the wheelset and bearing, tank car design and derailment damage as well as the accident response and railcar company practices.

The board is acting independently and doesn’t have authority to enforce safety recommendations.

“We need action on what would prevent that (derailment) from happening again,” Homendy said.