RALEIGH -

Federal environmental officials have reached a deal with Duke Energy to clean up its mess from a massive coal ash spill into the Dan River.
   
The U.S. Environmental Protection Agency announced Thursday it had finalized an enforceable agreement with the nation's largest electricity company over the Feb. 2 accident. The spill coated 70 miles of the river in North Carolina and Virginia with toxic gray sludge.
   
EPA will oversee the cleanup in consultation with federal wildlife officials under provisions in the Superfund law. Duke will reimburse the federal government for its oversight costs.
   
Duke has already begun vacuuming out three large deposits of ash found in the river. The byproduct left behind when coal is burned to generate electricity contains numerous toxic substances, including arsenic, selenium, chromium, thallium, mercury and lead.