The U.S. Department of Justice said it’s seeking to hold the company accountable for “unlawfully polluting the nation’s waterways and to ensure it pays the full cost of the environmental cleanup,” in the lawsuit filed Thursday.

It’s asking for fines under the Clean Water Act and for a judgment to hold the railroad accountable for past and future costs.

The derailment in early February led to the evacuation of half of the 5,000 residents of East Palestine when responders intentionally burned toxic chemicals in some of the derailed cars to prevent an uncontrolled explosion.

Chemicals from the derailed cars and firefighting foam seeped into creeks and rivers near the village, with some eventually ending up in the Ohio River. So far, more than 9 million gallons (34 million liters) of wastewater have been removed from the site and hauled to hazardous waste storage sites in Ohio and other states, according to the state officials.

Government officials say tests haven’t found dangerous levels of chemicals in the air or water in the area, but many residents remain concerned about their long-term health.

The Ohio Department of Natural Resources said three weeks after the disaster that the spilled contaminants killed an estimated 44,000 fish, mostly small ones such as minnows.

Norfolk Southern CEO Alan Shaw has repeatedly apologized for the impact the derailment and the company has pledged to pay for the cleanup. The railroad has promised more than $20 million to help the Ohio community recover while also announcing several voluntary safety upgrades.

Ohio filed lawsuit against Norfolk Southern just over two weeks ago to make sure it pays for the cleanup and environmental damage, and pays for groundwater and soil monitoring in the years ahead.