RALEIGH, N.C. (AP) — Environmental and wildlife officials in North Carolina and Virginia signed an agreement with Duke Energy Monday for the cleanup of toxic coal ash from the Dan River, which flows through the two states.

The agreement requires Duke to pay any “reasonable” cost associated with the Feb. 2 spill at its power plant near Eden, which coated 70 miles of the river in gray sludge. The U.S. Fish and Wildlife Service is also a party to the deal.