The site of the Norfolk Southern railroad derailment in East Palestine, Ohio

Washington (AFP) - The US transportation regulator announced a special investigation Tuesday into the safety record of Norfolk Southern Railway, a month after one of its trains derailed and released toxic chemicals in an Ohio town.

The National Transportation Safety Board (NTSB) announced the probe following the death on Tuesday of a Norfolk Southern employee in a work accident – the company’s third such incident since late 2021.

The NTSB said it would investigate the railway’s organization and safety culture, “given the number and significance of recent Norfolk Southern accidents.”

It pointed to five serious accidents: the three work-related deaths since December 2021 and two derailments this year.

The company drew widespread criticism for its February 3 derailment in East Palestine, Ohio, where a freight train spilled hazardous materials, including the carcinogenic chemical vinyl chloride.

The accident sparked a fire that released dangerous smoke and gases into the community.

Authorities were forced to conduct a controlled release of the vinyl chloride to avoid a possible explosion.

Critics called the accident preventable, and called for a probe of the company, which has more than 18,000 employees and 19,300 miles (31,060 kilometers) of rail.

Another Norfolk Southern train derailed on March 4 near Springfield, Ohio.

“The NTSB is concerned that several organizational factors may be involved in the accidents, including safety culture,” it said in a statement.

Norfolk Southern chief executive Alan Shaw said in a statement that the cause of Tuesday’s accident is not yet known but the company will “cooperate fully” with the NTSB.

He said he has emphasized to top management “the urgency of finding new solutions” on safety issues.

“Tomorrow we will hold safety stand-down briefings reaching every employee across our network,” he added.