Duke Energy confirmed Friday that floodwaters from Hurricane Florence have spilled into a coal ash storage pond near Wilmington and could be washing the toxic waste into the Cape Fear River.
The river had been rising for days, and Duke had issued an emergency warning Thursday that a breech was likely.
The 47-year-old coal ash pond is separated from the Cape Fear River by Sutton Lake, a public fishing lake used as a source of water to cool a coal-burning power plant that was shut down in 2013. Because of rising waters, the river, lake and ash pond are now part of one water system, but Duke has installed a steel barrier at the ash pond to prevent the waste from moving in the reverse direction back into the river.
“Its all mixing,” said Duke spokeswoman Paige Sheehan. “We know that water is being discharged from the ash basin.”
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The extent of the mixing is not clear.
“What we don’t know at this point is if any coal ash has filtered into the Cape Fear River,” Michael Regan, director of the N.C. Department of Environmental Quality, said at Gov. Roy Cooper’s press briefing Friday morning.. “We plan to conduct flyovers and/or partnering with the Department of Transportation to look at driving capabilities to see if we can ascertain that.”
The agency said Friday afternoon that there are numerous breaches in the dam that separates Sutton Lake and the Cape Fear River, but the biggest breach is between 100 feet and 200 feet across. The agency said that there are no structural issues with the coal ash ponds at this time, but it plans to conduct drone inspections to monitor flood conditions.
And the Department of Environmental Quality warned that Duke Energy could be held accountable for any environmental consequences resulting from the leaks, spills and overflows.
“River flooding has also impacted one of two inactive ash basins at the facility,” the statement said. “While the state is currently in emergency response mode, a thorough investigation of events will soon follow to ensure that Duke Energy is held responsible for any environmental impacts caused by their coal ash facilities.
Sheehan said the 1971 ash basin was about 50 percent excavated before Florence dumped more than 30 inches of rain into the open pit. A second ash basin, built in 1984 and also partially excavated, is not threatened, she said. Duke has been excavating the ash from both basins and moving it to a nearby landfill as part of its efforts to comply with a 2014 legislative mandate to store the toxic waste so it does not endanger public drinking water.
On Wednesday, Duke said that about 2,000 cubic yards of soil and ash eroded from the landfill, enough to fill about two-thirds of an Olympic-sized swimming pool. The company said the slurry was trapped in a perimeter ditch around the landfill and did not pose a danger to the public.
Charlotte-based Duke Energy also said Friday that the flooding forced it to shut down its 625-megawatt natural gas power plant at the L.V. Sutton plant in Wilmington. Sutton Lake has inundated Duke’s transmission yard and the company has evacuated employees.
Sheehan said the company believes that the coal ash has remained at the bottom of the ash basin, saying there is no visible coal ash in Sutton Lake. Duke Energy had installed a steel wall to hold the ash in place. The wall, however, was submerged by floodwaters on Friday, according to Duke. Before the flooding, the ash level was at last five feet below the top of the steel wall, Duke said.
Coal ash is a byproduct of burning coal at power plants and contains toxic elements like mercury, arsenic and selenium. The ash is also used as construction fill to build roads, but utilities produced more ash than is needed by the construction industry and stored in open-air pits filled with water.
Coal ash entered the public consciousness here in 2014, when a Duke ash impoundment failed and released 39,000 tons of ash into the Dan River in western North Carolina. In 2015, Duke agreed to pay $102 million in fines and restitution for violations of the federal Clean Water Act.
If the coal ash pond at the Sutton plant were to release coal ash, it would not be a total failure due to collapse, as was the case at the Dan River Steam Station four years ago, where the ash escaped through an opening near the bottom of the pit. In the Sutton facility, the ash is largely settled at the bottom, while water at the top is mixing with the Cape Fear River.
However, ash could be dislodged by the movement of water currents. Environmental activists said the consequences should not be downplayed.
“No matter what, you’re going to have a significant release into the river from an active coal ash pond,” said Kemp Burdette, the Cape Fear riverkeeper. “It is very likely this stuff is going to be stirring up the water.”