The Maine Department of Environmental Protection is taking Canadian Pacific Kansas City to task over the cleanup following a freight train derailment and fire.

Commissioner Melanie Loyzim sent a letter Thursday telling the railroad that its good faith efforts have failed to meet the agency’s expectations with regards to response and timing “to effectively mitigate impacts to the environment and public health.”

Two concerns are a failure to move a pair of rail cars containing hazardous material farther away from the site in a timely manner, and the failure to remove diesel fuel from the locomotives’ saddle tanks, causing a diesel fuel spill, the agency said. An estimated 500 gallons of fuel spilled.

Three locomotive engines and six train cars carrying lumber and electrical wiring went off the tracks April 15 in Somerset County, sending three people to the hospital.

Canadian Pacific Kansas City, created by a merger of Canadian Pacific and Kansas City Southern that was completed the day before the derailment, is leading cleanup, salvage and repair.

Derailments and railroad safety have been a growing concern nationwide since the fiery Feb. 3 Norfolk Southern derailment outside East Palestine, Ohio released chemicals, that forced evacuations and creating lingering health concerns.

The Maine derailment happened near Rockwood, a town of about 300 people on Moosehead Lake, about 90 miles northwest of Bangor.