The Norfolk Southern crash didn’t hurt anyone, but state and local officials decided to release and burn toxic vinyl chloride from five tanker cars, prompting the evacuation of half of the roughly 5,000 residents of East Palestine, Ohio.

Scenes of billowing smoke above the village, alongside outcry from residents that they were still suffering from illnesses, have turned high-level attention to railroad safety and how dangerous materials are transported.

“I am deeply sorry for the impact this derailment has had on the people of East Palestine and surrounding communities, and I am determined to make it right,” Norfolk Southern CEO Alan Shaw says in prepared remarks released Wednesday, a day before a Senate Committee on Environment and Public Works hearing.

The railroad has promised more than $20 million so far to help the Ohio community recover and announced several voluntary safety upgrades. Senators, however, have promised a pressing inquiry into the derailment, the company’s safety practices and the emergency response to the toppling of 38 railcars. And federal regulators have also said Norfolk Southern must do more to improve safety.

“I want to hear what did they do wrong, what mistakes did they make,” said Sen. Tom Carper, D-Del., the chair of the Environment and Public Works committee. “There’s been a number of criticisms of what they did, and to have him respond to those criticisms on the record.”

The East Palestine disaster as well as a spate of other recent train derailments have sparked a show of bipartisanship in the Senate. The committee on Thursday will also hear from Ohio and Pennsylvania senators — one Republican and two Democrats — who are pushing new safety regulations called the Railway Safety Act of 2023.