"In real basic terms, it means that the river and the lake and the 1971 coal ash pond are all the same thing right now so it's unquestionably releasing coal ash into the river above the City of Wilmington", Kemp Burdette, the Cape Fear riverkeeper, said Friday afternoon as he prepared to launch boats into the river to take samples near the site.
Floodwaters from the Cape Fear opened several breaches overnight in the earthen dam at Sutton Lake, a 1,100-acre (445-hectare) reservoir at the power plant.
Sheehan said floodwaters also had overtopped a steel retaining wall containing one of three large coal ash dumps lining the lakeshore.
Sheehan described the incident as a "developing situation" and said the company can't rule out that ash might be escaping and flowing into the river. Cenospheres are lightweight, hollow beads comprised of alumni and silica that are a byproduct of coal combustion.
The state has been closely monitoring conditions at the facility.
About 3.4 million chickens and turkeys and 5,500 hogs have been killed in flooding from Florence as rising North Carolina rivers swamped dozens of farm buildings where the animals were being raised for market, according to state officials.
As previously announced, cenospheres have moved into the Cape Fear River. Coal ash contains arsenic, mercury and other toxic metals.
Based on the company's current estimate, water and approximately 2,000 cubic yards of soil and ash eroded from the landfill. "Water samples captured on Friday (upstream) and downstream of the Sutton plant site show little to no impact to river water quality".
The area received more than 30 inches of rain from former Hurricane Florence, with the Cape Fear River still rising and expected to crest Sunday and remain at flood stage through early next week.More news: Jaguars add DE Campbell to injury report with knee soreness
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No environmental regulators were at the scene to help catalog the potential harm to the Cape Fear, with officials citing unsafe conditions.
Duke denied a request for an Associated Press reporter at the scene Friday to pass the barricade, saying that the situation at the lake "continues to change" and is "not safe". The company said that because of the high water levels in the river from the hurricane, they do not expect water levels to be affected by the breaches in the dam. The cooling lake water also flowed into the natural gas plant footprint.
FILE - A pipe from the Dan River Power Plant where coal ash spilled is seen along the Dan River in Eden, N.C., February 5, 2014.
Last weekend, coal ash spilled from a landfill under construction onto nearby land.
This is the second time in four years that Duke Energy has suffered a coal ash spill; in 2014, a pipe collapse at a plant in Eden dumped 39,000 tons of ash into the Dan River, contaminating about 70 miles (110 kilometers) of it. In 2015, Duke agreed to pay $102 million in fines and restitution for violations of the federal Clean Water Act.
"We plan to conduct flyovers and partner with the Department of Transportation to see if we can ascertain. whether any coal ash has filtered into the Cape Fear River", Regan said.
Workers were busy digging up one small coal ash spill on the side of the landfill opposite the lake Thursday as Duke employees towed a pontoon boat and a fan boat to the lake to continue examining water quality. "So they have evacuated their employees", said North Carolina Environmental Secretary Michael Regan. The group said the samples would be analyzed by a private lab to determine whether the gray muck contained coal ash.
Santee Cooper spokeswoman Mollie Gore said no significant environmental impact is expected because almost all the ash has been removed from the basin and water pumped in to prevent the dike from breaking.
Sheehan, the Duke spokeswoman, said that any release of coal ash at the Goldsboro site appeared "minimal".