When the Waccamaw River in Conway crested at nearly 18 feet after Hurricane Matthew's flooding last year, environmentalists and others worried that coal ash from unlined pits at Santee Cooper's adjacent power plant site might spill into the waterway that inspired the city's "Rivertown" nickname.

It was the second consecutive year that historic rains had threatened the dikes that separate the river from the coal ash — a toxic sludge containing arsenic, lead and other pollutants.

While the ash ponds remained intact on both occasions, the outcome could have been disastrous had Santee Cooper not agreed in 2013 to start removing the waste stored at its coal-fired power plants, including the closed Grainger site.

When the floods came, more than half of the ash at Grainger was already gone.

"The Grainger lagoons were very much at risk," said Frank Holleman, an attorney with the Southern Environmental Law Center, which represented a trio of groups that filed a lawsuit against Santee Cooper to force removal of the ash.

"The flooding showed the wisdom of Santee Cooper's decision," Holleman said.

South Carolina's electric utilities, which once fought any effort to remove ash from their sites, now lead the Southeast in their efforts to clean up and recycle the sloshy mess that's long been a source of pollution in groundwater, lakes and rivers.

Santee Cooper, South Carolina Electric & Gas and Duke Energy have combined to excavate roughly 5.6 million tons of ash for use in recycling programs or to move it to safe, lined landfills. Another 14 million tons will be removed statewide within the next decade.

"South Carolina's utilities are proving that excavation can be done relatively quickly and that it creates huge positive results for the environment," the Southern Alliance for Clean Energy said in a December report.

Today, every unlined coal ash lagoon in South Carolina has either been excavated, is being excavated or is scheduled to be excavated for transportation to dry, lined landfills or for use in recycling.

The rest of the South is lagging — about 40 million tons of coal ash in five other states will be excavated while another 250 million tons will be left in place, the alliance said.

"South Carolina as a state — and particularly Santee Cooper and SCE&G — are leaders in the region, if not in the country, in coal ash cleanups," Holleman said. "Our rivers are cleaner and our communities are safer because of that."

More than an environmental victory, the coal ash cleanup has been an economic boon.

"It's good for the environment, it's good for our customers and it's good for the economy because it's providing and sustaining jobs," Santee Cooper spokeswoman Mollie Gore said.

Lexington-based SEFA Group, for example, has invested $40 million in a Georgetown plant that recycles wet ash into a product that's sold to concrete manufacturers.

"Pretty much any concrete you see poured in the state of South Carolina, if the ash is available, it's in it," Jim Clayton, SEFA's chief operating officer, said of the company's product. Concrete made with SEFA's recycled product is stronger and more durable than traditional concrete and has been used for large scale projects like the Ravenel Bridge in Charleston.

With construction booming, Clayton said demand for recycled ash far outstrips supply.

"We're selling everything we can make right now," he said.

Slow to start

South Carolina's utilities haven't always been so eco-friendly when it comes to cleaning up their decades-long storage of coal ash, the waste that's created when coal is burned to produce electricity.

Moncks Corner-based Santee Cooper initially wanted to leave the Grainger ash ponds in place by building a concrete vault around them. The price tag for that project would have been $40 million — about half the cost of moving the ash to an off-site, lined landfill.

Three groups — Winyah Riverkeepers Foundation, the Coastal Conservation League and the Southern Alliance for Clean Energy — filed a lawsuit against Santee Cooper in June 2012, alleging the utility was violating the state's Pollution Control Act.

Santee Cooper fought the lawsuit at first but later relented in the face of public and political pressure, including Conway City Council's unanimous resolution opposing any plan that would leave ash ponds next to the Waccamaw River.

By the end of 2013, Santee Cooper had agreed to remove all of the ash stored at Grainger and pledged to clean up two other facilities — Winyah near Georgetown and the Jefferies Generating Station in Moncks Corner.

"The community made it clear that it wanted its river protected, and Santee Cooper changed its policy," Holleman said of the Grainger cleanup, which is two years ahead of schedule. "They made a 180-degree change and became a national leader on this issue."

SCE&G also settled a lawsuit in 2012 that added a firm timetable to an agreement the utility already had in place with state regulators to remove 2.4 million tons of ash stored at its Wateree Station in Eastover, which had been leaking pollution into groundwater near the Wateree River. The Cayce-based utility also is removing ash from its closed Canadys Station site in Colleton County, "all of which has been recycled for beneficial reuse in the manufacture of cement," SCE&G spokeswoman Ginny Jones said.

"Last year, SCE&G recycled for beneficial reuse more coal ash than we produced, and we will continue to recycle as much as possible going forward," Jones said. 

Duke Energy, the nation's largest utility, in 2015 agreed to remove about 4.2 million tons of ash at its Robinson Plant in Hartsville , but only after environmentalists uncovered documents that showed Duke was storing more than six times the amount of ash it publicly disclosed and had dumped low-level radiation into the material stored beside Lake Robinson. It also agreed to excavate 1.4 million tons of coal ash at its W.S. Lee Steam Station near the Saluda River in Anderson County.

Duke's cleanup in South Carolina is in stark contrast to its actions in North Carolina, where a 2014 spill at the utility's site in Eden fouled the Dan River with more than 37,000 tons of ash slurry. Legislators in the Tar Heel state had to force Duke to remove ash at its sites following that disaster, and the utility has been fined and criminally charges for violations of the federal Clean Water Act.

Environmental, economic boost 

The cleanup at South Carolina sites has resulted in huge drops in pollution.

Arsenic levels in groundwater at the Grainger site, once 110 times higher than federal standards, have declined by as much as 90 percent. Arsenic in Wateree's groundwater is down by as much as 80 percent.

Holleman said it's also led to a change in the mindset of those sitting in the corner offices at South Carolina-based power providers.

"Utilities are large bureaucracies and they are slow to change; very reluctant to change," he said. "But once effective and responsible senior management looked at the facts regarding unlined coal ash pits and realized they all pollute and they are all at risk of collapsing into neighboring waterways — those executives don't want that happening on their watch."

Gore, Santee Cooper's spokeswoman, said the decision to remove and recycle coal ash had more to do with the concrete industry's growing acceptance of using wet ash — in addition to traditional dry, fly ash — in its products. She said the utility had been working all along to line up companies willing to recycle ash from its facilities.

"The key was ... getting them comfortable with the process that would handle the wetter, pond ash," she said. "We had started testing some of the ash at Jefferies as early as 2012, but it was a time-consuming process."

Once Santee Cooper had contracts in place for recycling ash at Grainger, "it opened the door wide to move forward at all of the generating stations," Gore said.

"The settlement agreement (with the law center) only says we have to excavate the ash, it doesn't say we have to take the additional step of reusing it," she said. "The fact that we are able to reuse an overwhelming majority of it is gravy."

Holleman agrees the cleanup efforts serve dual purposes — protecting the environment and creating economic opportunity.

"If the coal ash sits in an unlined pit, nobody gets a job out of that," he said. "But in a cleanup, lots of people get employed. It's been a win from every angle."

There's also the intangible benefit of doing the right thing, he said, which doesn't necessarily show up on the balance sheet. 

"There is a value in not committing crimes, and there is also a value in respecting the communities you serve and respecting the clean water of our rivers," he said.

For Lexington-based SEFA, which patented a process that gives wet ash the strength-producing qualities needed for concrete, the recycling program is a matter of survival.

In the years after amendments to the federal Clean Air Act were passed in 1990, utilities started designing more strenuous emissions controls at their power plants and that degraded much of the dry, fly ash that had been used for decades in concrete production. So SEFA went looking for alternatives.

"We thought: What if we could go out into these ponds and recover material there that could be put through some additional processes that would let us provide our ready-mixed customers with an uninterrupted supply," said Clayton, the company's chief operating officer.

SEFA chose the Winyah site for its first wet ash recycling plant because it already had a fly ash manufacturing facility at the Santee Cooper site. When it opened in 2015, it became the nation's first facility to remediate commercial quantities of coal ash from ponds — taking what had been an environmental liability and turning it into a profitable asset.

"It's a sustainability win for our customers, the environment and future generations," Clayton said.

Reach David Wren at 843-937-5550 or on Twitter at @David_Wren_