Santee Cooper has enlisted private contractors to help secure its coal ash pits in Conway after Gov. Henry McMaster raised doubts about the utility’s ability to protect them from rising floodwaters and a potential environmental disaster in the wake of Hurricane Florence.

Santee Cooper insists it is as ready as it can be for the deluge heading toward the riverside pits. But the utility’s chief cautioned that floodwaters will likely top protective dikes if current forecasts hold true, raising the risk that ash will escape from the site.

The pits, adjacent to the swollen Waccamaw River, contain some 200,000 tons of ash, a potentially toxic remnant from coal burned at the Grainger Generating Station to produce power. A failure in the earthen berms could unleash a plume of ash laced with chemicals such as arsenic, lead and mercury.

James Brogdon, Santee Cooper's interim president and chief executive officer, told McMaster Tuesday that the dikes were never intended to handle the trillions of gallons of water that Florence sent cascading downstream from the storm’s epicenter in North Carolina. Current forecasts predict the river will rise to a record-shattering 19.9 feet on Sunday — nearly 9 feet above flood level.

“It is evident that Hurricane Florence impacts will be measured well above design standards for an event that is expected to occur every 1,000 years,” Brogdon wrote. “Let me be clear, if the current river level projections are correct, Santee Cooper’s dikes at the former Grainger Station will be subject to overtopping. Overtopping does not necessarily mean that the dikes will breach or that significant quantities of ash will be released, but it increases the risk of a breach or a release.”

Santee Cooper opted to bring in outside help after a three-hour meeting at the Grainger site Monday with representatives of state agencies.

The gathering came after McMaster voiced concerns that the Moncks Corner-based utility lacked the plans and the resources necessary "to ensure the structural integrity of the coal ash ponds." The governor indicated in a letter to Brogdon that he planned to send in the South Carolina National Guard and state emergency management officials to assist with securing the site and coordinating help from other state agencies.

Santee Cooper officials have maintained they are doing everything possible to prevent a breach from the Waccamaw, which drains an area the size of Rhode Island as it snakes roughly parallel to the coast near Myrtle Beach.

The utility sent workers to the site about a week ago to begin preparations after learning of Florence's potential to wreak havoc along the coast, Santee Cooper spokeswoman Mollie Gore said. Amid the storm's driving rains, workers dug in to keep the dikes from failing. Workers mobilized excavators and bulldozers in case of a breach. They filled giant bags of rocks. A heavy-lift helicopter was placed on standby to drop the bags in any holes that form. Utility workers also pumped water into the ponds to equalize pressure on the berms as the river rises next to them, she said.

Still, concerns have elevated in recent days amid reports from North Carolina of floodwaters invading a coal ash landfill at a retired power plant near Wilmington and three old coal ash dumps capped with soil in Goldsboro. Duke Energy, which owns both sites, has maintained neither location poses an environmental threat. 

Governor voices concerns

McMaster initially reached out to Brogdon Sunday, urging Santee Cooper to “act immediately and take all appropriate measures” to protect against a breach or possible ash spill at Grainger. He specifically called for large sandbags atop the dikes.

Brogdon wrote back Monday, indicating that Santee Cooper already had a plan in place and that its crews were working around the clock to protect the ash ponds.

Brogdon also expressed concern about the state’s plan to use barriers to prevent the Waccamaw River’s floodwaters from spilling onto U.S. Highway 501. He said that could back up river water into the ash ponds, potentially compromising the dike structure and creating “the possibility of ash backflow into the Conway community.”

McMaster countered with another letter raising doubts about Santee Cooper’s plans to address the situation.

"We must work together to protect the people of South Carolina and our shared natural resources," McMaster wrote. "Our precious environment should not be subjected to a 'wait-and-see' approach; rather, Santee Cooper should take all appropriate measures to effectively mitigate the risks associated the GGS ash ponds."

McMaster also noted that "the fact Santee Cooper finds itself in this situation is troubling in many respects; however, now is not the time to assign blame. There will be ample time in the future to assess Santee Cooper's level of preparedness."

Utility officials ultimately ended up meeting at the Grainger site with engineers and other representatives from the state National Guard, Emergency Management Division, Department of Transportation and Department of Health and Environmental Control. A number of options were discussed, including placing sandbags or mesh basket barriers atop the dikes, Gore said.

Those options were ruled out because the tops of the dikes are too narrow — 10 to 12 feet across — to maneuver equipment needed to put bags or barriers in place, Gore said. They eventually settled on bringing in private crews to install 3-foot silt fencing along the dikes to help contain the ash, Gore said. The utility also has containment booms to catch any spillover, she said.

At a news conference Tuesday, Adjutant General Bob Livingston said the National Guard is providing floating bridges “that we would use to cross a river in combat operations” to assist Santee Cooper in its pumping operations at the pits.

DHEC Director Dave Wilson said a primary concern is "making sure no drinking water sources are impacted." He said the Grand Strand Water and Sewer Authority and Georgetown are "looking at that and making sure they can provide uninterrupted service."

The material at the site represents about 10 percent of the 1.5 million tons of coal ash that once resided at Grainger, Gore said, and the remainder should be gone by early 2019. The utility began the cleanup in 2013 after settling a pollution-related lawsuit filed by the Southern Environmental Law Center. It accelerated the ash removal after Hurricane Matthew’s floodwaters threatened to swamp the site in 2016.

McMaster said Tuesday the plans now in place ensure all parties are doing everything they can to safeguard the public from the current threat posed by flooding as well.

“We have high confidence in what we’re doing, but we also have high confidence in the strength and power of the flood that’s coming,” he said.

Seanna Adcox contributed to this article. 

Reach Glenn Smith at 843-937-5556. Follow him on Twitter @glennsmith5.