Senators attacked Norfolk Southern Corp.’s response to last month’s toxic chemical spill in Ohio in the first congressional hearing about the accident. The company’s chief executive officer apologized and vowed to help local residents. 

The railroad showed “an apparent lack of transparency” immediately after the Feb. 3 incident, Senator Tom Carper, a Delaware Democrat who leads the Environment and Public Works Committee, said at the hearing on Thursday. He chided the “mistrust” the railroad created with local residents.

Norfolk Southern CEO Alan Shaw faced heated rounds of questions that ranged from safety to the railroad’s policy about staffing and sick leave. Shaw said the company is making some changes, including hiring more staff, but he stopped short of promising everything that the lawmakers asked for.

“You sound like a politician,” Vermont Senator Bernie Sanders, an independent, told Shaw at the hearing.

The incident set off a political inferno and has led federal agencies to open broader reviews of the railroad’s safety practices. While no one was directly injured by the train wreck, it forced people to temporarily evacuate their homes and has raised tough questions about the way chemicals are transported across the US.

Shaw told the committee that the railroad has committed to $20 million in reimbursements and other payments in East Palestine, Ohio — the site of the derailment — and is urgently working to remove waste from the area. 

“To date, nearly 600 homes have been screened; none of the results indicate a health risk from incident-related substances,” Shaw said. “We are committed to this monitoring for as long as necessary.”

Dozens of rail cars jumped the tracks in East Palestine after a wheel bearing failed, prompting a fire and, days later, the burning of toxic vinyl chloride to prevent an explosion. A string of other accidents, including a fatal wreck involving a Norfolk Southern train in Cleveland on March 7, have raised more questions about the company’s safety record.

Several lawmakers called for passage of bipartisan legislation tightening rail safety standards. Shaw said the company supported the “legislative intent,” but he didn’t offer a full endorsement of the bill.

Shaw told lawmakers that the railroad operator is funding a center to assist more than 4,200 families as well as reimbursing firefighters and making payments to local schools.

The company is also working to improve its safety based in part on findings so far in the investigation by the National Transportation Safety Board, he said. He defended the engineers on the East Palestine train, saying they were operating below the speed limit and followed proper protocols.

Analysts at UBS AG said in a research note Thursday that there’s “significant momentum” in Congress to pass legislation tightening safety at freight railroads, but details of such a measure remain unclear.