Transportation Secretary Pete Buttigieg said Thursday that the agency is reviewing its definition of a high-hazard flammable train in the wake of the East Palestine, Ohio, derailment.

Buttigieg made the remarks in response to questioning from Senate Appropriations Committee Chair Patty Murray (D-Wash.) during a hearing on the Transportation Department’s budget request.

“We’ve been here before with crude oil incidents, and I worked with the administration then… to require comprehensive oil spill response plans” for railroads, Murray said. “Could you expand those efforts now for other hazardous materials?”

“The short answer is yes,” Buttigieg replied. “Often what happens is that America learns from experiencing disasters.”

“Questions arose in the wake of East Palestine from those who asked the very reasonable question, looking at that horrific smoke column coming out of the vinyl chloride controlled burn, that if this train did not meet the legal and technical definition of a high-hazard flammable train [HHFT], what would?” he continued.

The derailment, Buttigieg said, “is compelling us” to review and revise the department’s HHFT definitions as well as a broader examination of such definitions, some of which he noted are defined in law. The transportation secretary added the department “welcomes” revisions from Congress in those cases, such as larger fines for safety violations and more specific technical measures.

Buttigieg added that the department is also calling on industry itself to “not wait” for new requirements but rather voluntarily implement new safeguards in the meantime.

The budget proposal for the department was prepared prior to the East Palestine derailment, but Buttigieg said it contained a number of requests that would enable improved rail safety, such as increasing the research budget, which has in the past contributed to technology such as the wayside detectors used in the rail industry.

Murray and Sen. Maria Cantwell (D-Wash.) co-sponsored legislation in 2015 to tighten security procedures for oil being transported by rail following a series of derailments in the state.

The Feb. 3 East Palestine derailment involved several cars carrying hazardous materials, including vinyl chloride, a carcinogenic substance used in the production of plastics.

The Hill has reached out to the Transportation Department to clarify the status of any reviews of hazardous-material definitions.