Ohio train derailment tied to overheated wheel bearing, report finds

• The report was released Thursday as Transportation Secretary Pete Buttigieg was visiting the site of the crash.

The latest: NTSB Chair Jennifer Homendy said during a press conference after the report's release that the board will hold a rare investigative field hearing in East Palestine this spring.

• The goal of the hearing will be to inform the public, collect factual information from witnesses, discuss possible solutions and "build consensus for change," Homendy said.

The NTSB found:

• As the crew slowed the train to inspect cars for a hot axle, an automatic emergency brake application initiated, which may indicate the train experienced a separation during deceleration.
• Before starting to slow down, the crew received a critical audible alarm message indicating the temperature of a railcar wheel bearing was greater than 200°F above the ambient temperature at the time.
• "After the train stopped, the crew observed fire and smoke and notified the Cleveland East dispatcher of a possible derailment," the report reads.
• Thirty-eight railcars were involved in the derailment, including 11 tank cars carrying hazardous materials that ignited after the wreck and damaged an additional 12 non-derailed railcars.
• First responders mitigated the fire from the initial wreck on Feb. 5, but five tank cars carrying 115,580 gallons of vinyl chloride concerned authorities because the temperature inside one tank car was rising, suggesting the chemical was undergoing a polymerization reaction and could explode.
• Because of the explosion risk, first responders vented and burned vinyl chloride — a colorless but hazardous and carcinogenic gas — in the five cars after expanding an evacuation zone around the crash site, according to the NTSB.
• The train was travelling around 47 miles per hour at the time of the derailment, roughly 3 mph below the maximum authorized speed of 50 mph.

"This was 100 percent preventable," Homendy said during the press conference. "We call things accidents, there is no accident. Every single event that we investigate is preventable."

• Homendy said the NTSB had no role in the decision to vent and burn the chemicals. Ohio Gov. Mike DeWine previously said he authorized the operation, which occurred after residents of the town were evacuated.

The NTSB said surveillance video from a local residence showed a wheel bearing on the first railcar that derailed "in the final stage of overheat failure moments before the derailment."

• That wheel bearing and other equipment have been collected as evidence by the NTSB for its ongoing investigation, it said.
• Homendy said the NTSB will investigate how Norfolk Southern uses wayside defect detectors (that caused the alert) on its railways, how its crews are alarmed and respond to defect alerts and its maintenance and inspection procedures for railcars.

The big picture: Norfolk Southern executives in an earnings call presentation on Jan. 23 — just weeks before the East Palestine derailment — said the rate of accidents on its railways had increased in each of the last four years.

• The Environmental Protection Agency ordered the company on Tuesday to clean up contamination from the crash under a plan approved by the agency.
• The Department of Transportation on Tuesday also called for multiple measures to increase rail safety and hold rail operators responsible for violating safety regulations.

Go deeper: Ohio derailment prompts calls to investigate federal oversight of trains

Editor's note: This story has been updated with additional details and background.