WINSTON-SALEM, N.C., March 3 (Reuters) - North Carolina regulators have cited Duke Energy Corp for environmental violations at six power plants in a probe prompted by a massive spill at one facility that dumped up to 39,000 tons of coal ash into a river used for drinking water.
The state's Department of Environment and Natural Resources, which is facing scrutiny from federal prosecutors and watchdog groups for its regulation of the decommissioned Eden plant where the spill occurred, said on Monday that Duke failed to obtain federally required stormwater permits at five plants.
The notices of violation followed two others announced on Friday for a sixth plant, the Eden facility, where regulators cited the utility for wastewater and stormwater violations.
The state said Duke, the country's largest electric power provider, could face steep civil fines for neither applying for nor obtaining the National Pollutant Discharge Elimination System permit needed to discharge stormwater from steam electric power generating facilities into state waters.
"Our agency is determined to make sure that all of these facilities are in compliance with state and federal law," said John Skvarla, the state agency's secretary. "We're doing everything in our power to prevent environmental disasters like what we've seen at the Dan River."
The Charlotte, North Carolina-based company has between 15 and 30 days to reply to state regulators investigating its coal ash ponds.
"We will respond to the state," Duke spokeswoman Paige Sheehan said.
State officials said they reviewed the permit status of all 14 of the company's plants in the state after a spill of toxic coal ash discovered on Feb. 2 threatened water and wildlife in the Dan River.
The discharge from the spill, which occurred when a 48-inch (122-cm) stormwater pipe beneath a coal ash pond ruptured, released between 24 million and 27 million gallons (91 million to 102 million liters) of wastewater and as many as 39,000 tons of coal combustion residuals into the river that supplies drinking water to two towns in neighboring Virginia.
State officials found a second leak of arsenic-laced discharge from another pipe during their investigation at the coal-fired plant, which was built in the 1940s and retired in 2012.
Both leaks were plugged. Officials have said treated water is safe for drinking but advised against eating fish from the river or having prolonged contact with the water. Coal combustion residuals from the spill have been identified as far as 70 miles (113 km) downstream, officials say.
U.S. prosecutors opened a criminal investigation into the spill and have requested that inspection records and copies of correspondence between the state environmental agency and Duke Energy be produced for a grand jury later this month.
The five other facilities cited for violating environmental standards are located in the counties of Rockingham, Rutherford County, Wayne, Person and New Hanover, the state said.