COLUMBUS, Ohio (WCMH) — The National Transportation Safety Board promised a lengthy investigation during a press conference on Thursday to identify all the causes of a train derailment in East Palestine, Ohio.

Defect detectors alerted the crew onboard the freight train of a quick temperature spike that lead to multiple railcars derailing, according to the NTSB’s report released Thursday. The train was traveling about 47 miles per hour when engineers received a “critical audible alarm message” just before dozens of railcars went off the tracks.

“We’ve never seen an accident that isn’t preventable,” said NTSB Chair Jennifer Homendy. “Nothing is an accident. When it comes to preventions, it could be actions on the railroad’s part or maybe not having conservative policies on thresholds.”

View the full NTSB press conference in the video player below.

Homendy explained the organization’s commitment to action and outlined a number of possible outcomes to aid the East Palestine community.

“This is a about a community that is suffering,” said Homendy. “This is not about politics. This is about addressing their needs, concerns.”

The NTSB said the train passed three monitoring systems checking the temperatures of the train’s wheel bearings. The overheated axle was recorded as 38 degrees above ambient temperature at the 79.9-mile post. At the second check, it registered 103 degrees above ambient. A third detector at the 49.81-mile post registered the axle as 253 degrees above ambient and triggered the alarm.

Norfolk Southern had previously established the following alarm thresholds for above ambient temperature:

  • ​Between 170°F and 200°F, warm bearing (non-critical); stop and inspect
  • A difference between bearings on the same axle greater than or equal to 115°F (non-critical); stop and inspect
  • Greater than 200°F (critical); set out railcar

When the crew received the alarm message at the third post, the train’s engineer applied the brakes to slow and stop the train. The crew observed fire and smoke, and notified authorities of a possible derailment.

After the crew made calls to area dispatchers, the crew applied handbrakes to the two railcars at the head of the train, uncoupled the head-end locomotives, and moved the locomotives about one mile from the uncoupled railcars. Responders then arrived at the derailment site to deal with the vinyl chloride and other hazardous chemicals contained in the derailed cars.

The board’s report comes as Transportation Secretary Pete Buttigieg is visiting East Palestine.