“As a result of this incident, hazardous materials vented into the air and spilled onto the ground. These substances contaminated local waterways and flowed miles downstream,” the prosecutors wrote in the suit.

Norfolk Southern spokesperson Connor Spielmaker said the company was “working with urgency, at the direction of the U.S. EPA,” at whose request DOJ brought the lawsuit, on “cleaning up the site, assisting residents whose lives were impacted by the derailment and investing in the future of East Palestine and the surrounding areas.”

“That remains our focus and we’ll keep working until we make it right,” Spielmaker added, repeating a refrain that Alan Shaw, the railroad’s CEO, has said many times in his recent appearances before Congress, in which he’s apologized for the derailment.

The derailment, involving a freight train traveling near a small town along the Pennsylvania-Ohio border, sent 38 cars off the track, spilling hazardous chemicals. Some of the tank cars had been compromised and required a controlled release of toxic vinyl chloride, which was burned off and forced the town’s evacuation.

Federal officials have insisted that the area and its water are safe now, but residents continue to complain of foul smells and worry about long-term health concerns, as well as depressed home values.

The company has come under intense scrutiny from the industry and lawmakers, who have pressed for more stringent safety precautions as they suspect an overheating wheel caused the derailment. Norfolk Southern has since announced a handful of new safety measures, as has the industry as a whole.

Lawmakers from both parties, including a heavy contingent from Ohio and Pennsylvania, are pressing forward with legislation intended to shore up rail safety, but so far have yet to gain broad traction.

Tanya Snyder contributed to this report.