The Charlotte-based Catawba Riverkeeper Foundation has settled a lawsuit over coal ash storage at S.C. Electric & Gas’ Wateree power plant southeast of Columbia.

SCE&G agrees under the settlement, announced Monday, to remove all coal ash from ponds at the plant and recycle or place it in lined landfills. The settlement makes binding and accelerates an agreement signed last October between the utility and the S.C. Department of Health and Environmental Control.

Coal ash contains metals that can be toxic to wildlife and people in high concentrations. The Riverkeeper Foundation, in a lawsuit filed in January against SCE&G, had argued the plant was discharging contaminants without a permit. SCE&G says its has corrected seepage from a pond dam but that no contamination reached the Wateree River.

Contaminated groundwater has also been found around the ash ponds at Duke Energy’s power plants on the Catawba River, which flows north of the Wateree. N.C. officials have said the contamination might come from natural sources.

N.C. situation called ‘very similar’

“It’s a very similar situation” to the S.C. contamination, said Rick Gaskins, executive director of the Riverkeeper Foundation. “I would argue the situations on Mountain Island Lake, Lake Norman and Lake Wylie are in some ways higher priorities because they’re a source of drinking water.”

Duke has 23 ash ponds at its Carolinas plants, according to its website, and landfills at seven plants.

North Carolina officials are being “extremely cautious” in investigating contamination near Duke’s plants, Gaskins said, apparently because of recent legislation forbidding the state from imposing environmental standards more stringent than the federal government’s.

The Environmental Protection Agency has delayed action on the first federal rules on coal ash. The most stringent option it is considering would close ash ponds and replace them with dry landfills.

Under the S.C. settlement, SCE&G agrees to remove 240,000 tons of ash from the Wateree plant’s ponds within three years. All ash will be removed by the end of 2020, a year ahead of the timetable laid out in its agreement with the state.

SCE&G has already converted five of its six South Carolina coal-fired power plants from ponds to landfills, said spokesman Robert Yanity. A landfill at the 700-megawatt Wateree plant, the utility’s largest, opened in 2010. The utility serves 669,000 electric customers in South Carolina.

“Our hope would be that other plants would see what SCE&G is doing and see it as the handwriting on the wall,” Gaskins said.