The National Transportation Safety Board (NTSB) will be holding an investigative hearing June 22 and 23 at the East Palestine High School in Ohio to gather sworn testimonies regarding the February 2023 Norfolk Southern Railway train derailment that caused fires in East Palestine and released hazardous materials into the atmosphere. The hearing is part of a fact-finding step in the organization’s safety investigation.

In a statement, the NTSB said that the investigation will focus on four key points: hazard communications and emergency responder preparedness, the circumstances that led to the decision to vent and burn vinyl chloride, freight car bearing failure modes as well as wayside detection systems and tank derailment damage, crashworthiness and hazardous materials information.

Only NTSB board members, investigative staff and designated parties can participate in the hearings. However, members of the public are welcome to attend and observe the hearings.

Once the hearings are over, the NTSB will use the information gathered to recommend transportation safety improvements. The NTSB said that the full investigation will take approximately 12 and 18 months to complete from the time the accident occurred.

On February 3, 2023, a Norfolk Southern Railway train carrying toxic chemicals derailed in East Palestine, Ohio, resulting in the release of hazardous materials into the air, soil and surrounding creeks. After the derailment took place, emergency responders conducted an hours-long controlled release and burn of vinyl chloride from five tank cars, creating a large ball of fire that discharged black smoke filled with contaminants into the air, according to ABC News.

A preliminary report into the incident, issued by the NTSB February 23, 2023, found that a wheel bearing on one of the railcars overheated and failed just moments before the train derailment occurred.

"The communities most affected by this tragedy deserve as much insight as possible into our investigation, which is why we're holding an investigative hearing in East Palestine," said NTSB chair Jennifer Homendy in a statement. "While we, unfortunately, cannot change what happened that day, our entire agency is committed to carrying out our mission, which doesn't end when we get to the bottom of what happened and why it happened -- we'll also work vigorously to prevent it from ever happening again."

The investigation will take place from 9 a.m. to 7 p.m. EDT June 22 and 9 a.m. to 6 p.m. EDT June 23. The hearings can be live-streamed on the NTSB’s YouTube channel.