RALEIGH, N.C. (AP) — North Carolina regulators say Duke Energy illegally pumped 61 million gallons of contaminated water from a coal ash pit into the Cape Fear River, marking the eighth time in less than a month the nation’s largest electricity company has been cited for environmental violations.

The pumping violated the terms of Duke’s wastewater permit at its Cape Fear Plant, State Department of Environment and Natural Resources spokesman Jamie Kritzer said Thursday. Kritzer said the agency has issued Duke a formal notice of violation, which could result in hefty fines.