EAST PALESTINE, Ohio (WKBN) – The National Transportation Safety Board (NTSB) announced it will be launching a special investigation of Norfolk Southern Railway’s “organization and safety culture.”

The NTSB has been conducting an investigation into what caused the company’s train derailment in East Palestine, which led to a leak of chemicals in the area.

The NTSB’s preliminary report indicated that an overheated wheel bearing was being probed as the cause of the derailment. Late last week, the NTSB found new concerns with the aluminum protective housing covers that were used on three of the vinyl chloride tank cars that derailed.

According to the NTSB, those at the agency worried that the covers on some tank cars melted when pressure relief devices (PRDs) vented burning gas to relieve tank pressure. The preliminary examination showed signs that melted aluminum may have dripped into some PRDs, which would have affected their performance.

According to the NTSB, its teams have investigated five “significant accidents” involving Norfolk Southern since December 2021:

  • On Dec. 8, 2021, an employee for the National Salvage and Service Corporation assigned to work with a Norfolk Southern work team replacing track was killed when the operator of a spike machine reversed direction and struck the employee in Reed, Pennsylvania.
  • On Dec. 13, 2022, a Norfolk Southern trainee conductor was killed, and another conductor was injured, when the lead locomotive of a Norfolk Southern freight train struck a steel angle iron protruding from a gondola car on another Norfolk Southern freight train that was stopped on an adjacent track in Bessemer, Alabama.
  • On Feb. 3​, a Norfolk Southern freight train carrying hazardous materials derailed in East Palestine. The derailment resulted in a significant fire and hazardous materials release.
  • On March 4, a 2.55-mile-long Norfolk Southern freight train derailed near Springfield, Ohio.
  • On March 7, a Norfolk Southern employee was killed during a movement in Cleveland, Ohio.

As part of the special investigation, the NTSB will also review the Oct. ​8, 2022, Norfolk Southern derailment in Sandusky, Ohio.

According to a news release from NTSB, it “is concerned that several organizational factors may be involved in the accidents, including safety culture.”

The agency has urged the company to work on immediate safety improvements in the meantime.