From the 1800s to the 1950s, a goopy black substance dripped and spilled from manufactured gas plants in South Carolina and across the United States as the nation sought to light street lamps and power cities.
But that substance, known as coal tar, was more than a byproduct of energy production. It was toxic enough to people and wildlife that governments began pushing in the late 20th century to clean up the mess.
Now, states including South Carolina are struggling with the legacy of a pollutant that is proving difficult and expensive to eliminate from groundwater and rivers.
Power companies in the Palmetto State have spent at least $100 million on coal tar cleanups since the early 1990s, but records show at least half of those efforts remain incomplete. And at most sites, the costly effects of coal tar could remain for generations to come.
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Among the cities with lingering tar pollution is Columbia, where the noxious goo covers up to 11 acres of the Congaree River bottom. Cleanup work also continues in Charleston, Florence, Greenville, Spartanburg and Anderson. Utilities have been working to stabilize and clean up some sites for parts of 25 years, according to S.C. Department of Health and Environmental Control records.
Power companies, primarily South Carolina Electric & Gas and Duke Energy, are responsible for most of the sites still undergoing cleanup. Much of the work focuses on cleaning up polluted soil and groundwater, but some also involves stabilizing coal tar in rivers. In some cases, major utilities inherited the polluted sites from smaller companies that once operated in South Carolina. The coal tar these plants released to the environment was created by plants that superheated coal to make gas for energy. An estimated 5,000 of these sites, which operated as recently as the 1950s, exist across the country.
While critics say state regulators should have moved more aggressively to get the sites cleaned up, those knowledgeable about coal tar say the pollutant has proven to be a difficult and costly environmental problem across the state and the nation.
“It’s not easy to clean up, for sure,’’ said College of Charleston geochemist Vijay Vulava, who has led research on coal tar pollution in Tennessee. “If you look at other sites where those sorts of cleanups have been done it is not cheap. It costs quite a bit of money.’’
Utility ratepayers are affected because they’re being billed for some of the cleanup work. The public at large is potentially affected because coal tar toxins are hazardous to people’s health, as well as to fish and wildlife.
Unless the coal tar is cleaned up, or at least stabilized, toxins imbedded in the tar can seep into soil, groundwater and rivers. The tar itself can sting or burn people who step into it while wading in rivers, as some Columbia paddlers will attest. In extreme circumstances, coal tar pollutants could cause cancer. Contaminants in coal tar also have caused tumors in fish, research shows.
A costly, toxic mess
Since 1990, SCE&G has shelled out $77.5 million for coal tar cleanups in Charleston, Columbia, Florence and Sumter and expects to spend at least $10 million more dealing with tar pollution. Only the Sumter work is considered complete, according to DHEC, the state’s environmental agency.
Duke Energy, the state’s other major investor-owned utility, says it has spent at least $19 million stabilizing and cleaning up coal tar at four locations in Greenville, Spartanburg and Anderson. Cleanup efforts on three of the sites are not finished and could cost Duke more money, regulators say. DHEC says one of two sites in Greenville is considered complete.
Santee Cooper, the state-owned power company, says it knows of no sites with coal tar pollution.
Cleaning up coal tar can be difficult because the mushy substance oozes like spilled molasses into the soil and contains noxious pollutants that then seep out. Once those pollutants hit groundwater, it can take years to treat the water or pump out the pollutants.
“Groundwater doesn’t get contaminated overnight, and it doesn’t get cleaned up overnight,’’ said Gary Stewart, a pollution cleanup regulator with the S.C. Department of Health and Environmental Control. “It takes a long time to do this.’’
Efforts to address coal tar contamination in the Congaree have been underway since a kayaker stepped in the black muck seven years ago. In the early 2000s, SCE&G did substantial cleanup work on a Huger Street manufactured gas plant site that is believed to have caused the river pollution.
SCE&G originally wanted to dig up the material in the Congaree, but that would have required building a temporary dam to dry out part of the Congaree while excavation work occurred. Company officials backed off the plan after saying the Congaree is too rocky for a dam and because obtaining a federal permit would have been difficult.
Now, SCE&G wants to dump rocks and cloth on the greatest concentration of tar, about 2.3 acres near the Senate Street boat landing. The rest of the 11-acre tar slick will remain uncovered, except for any river sediments that wash over it. Leaving the tar in the river could save SCE&G at least $11 million, records show. It could be two years before the project even starts, officials say.
Environmental watchdog groups say that’s not good enough. The Congaree Riverkeeper organization and the Southern Environmental Law Center filed official notices with SCE&G earlier this month that a lawsuit would be forthcoming unless the tar is removed from the Congaree River.
“These challenges are not generally insurmountable,’’ according to a consulting report commissioned by the environmental group.
Coal tar has been removed from other rivers and creeks, including one in Chattanooga, Tenn., where Vulava did research. Companies responsible for the pollution helped pay to dam up a creek so that coal tar could be excavated and hauled away, Vulava and fellow researcher Larry McKay said.
Bill Stangler, the Congaree Riverkeeper, questioned whether SCE&G would be responsible for future cleanup work if it strikes a deal with regulators, known as a voluntary cleanup contract, to put a stone cap atop the pollution. He also said he wonders how aggressive South Carolina environmental regulators have been at pushing for coal tar cleanups. It’s unknown whether other sites exist in South Carolina.
“It seems to me SCANA is trying to get this done, get all the boxes checked, so they can say they did the minimum and they are no longer liable,’’ Stangler said.
Stangler ought to know about coal tar. Like a handful of other people he has met recently, Stangler has stepped in the stinging muck while working on the Congaree. Others have complained to him about getting the coal tar on their skin.
Last summer, Stangler warned an expectant mother away from a section of the river where coal tar has been found below the Gervais Street Bridge at Senate Street, he said.
“She was pretty upset to hear that,’’ Stangler said. “I also had another woman with two very young children fishing on a gravel bar (near the coal tar). She was really concerned. She said she brought her kids down there all the time.’’
Customers pay ‘pollution’ charge
So far, SCE&G has paid for some of the $77.5 million coal tar work by using insurance payments, but some of that has come from the company’s gas customers, officials said.
The company now charges its gas customers about $3.25 on average per year for tar cleanups at sites it is responsible for. Company officials say that’s a paltry amount, although cleanup charges have been assessed gas customers for years.
According to records filed with the Securities and Exchange Commission, SCE&G will seek to recover more of its cleanup costs from customers. However, in an email to The State newspaper, SCE&G spokeswoman Ginny Jones said the company has no plans to raise rates. The charge to customers has remained the same for more than a decade, she said.
Under fire for billing customers for a nuclear plant it won’t finish, SCE&G concedes that the $10 million it expects to pay for coal tar work, mostly on the Congaree River, is probably low.
“It could be more than that,’’ said Thomas Effinger, SCE&G’s environmental services manager.
Effinger said the company prefers to get rid of the coal tar, but difficulty getting federal permits to excavate the Congaree River is a factor in why the company can’t dig up the tar and cart it away. The matter also is complicated by evidence that some unexploded Civil War-era munitions potentially remain in the river downstream from the Senate Street boat landing, he said.
Effinger also emphasized that DHEC studies have found little evidence coal tar from the Congaree site is polluting aquatic organisms or the water itself. Some questions have arisen about whether coal tar remains a threat to the river since it is believed to have been in the Congaree since the early 1900s.
Even so, the College of Charleston’s Vulava said coal tar pollution shouldn’t be dismissed.
Certain types of toxic pollutants can continue to seep from coal tar if the tar remains in rivers, particularly if the cap is a porous stone covering like one proposed by SCE&G, he said. Imbedded in the tar are numerous pollutants, such as benzene and polycyclic aromatic hydrocarbons, which are toxic to people and wildlife.
“I wouldn’t say they are completely contained,’’ Vulava said of polycylic aromatic hydrocarbons in coal tar. “They are still (seeping) outward – there is a constant flux of chemicals coming out of the massive tar piles.’’
That’s a concern for the health of fish and aquatic life. Some fish exposed to polycyclic aromatic hydrocarbons have developed deformities, such as tumors, research shows. Toxins in the tar also can affect the ability of fish to reproduce, which could deplete populations.
After crews dug up a slick of polluted coal tar in a Chattanooga creek, Vulava and McKay found pollution remaining in the sediment well after the cleanup ended, according to a 2016 study they published. They also found it in a flood plain where polluted sediment from the river washed during times of heavy rain and high water.
“We could be talking decades or even a century,’’ McKay said, for natural processes to get some pollutants out of sediments.
If capping must occur, it would be better to use a synthetic type of liner similar to what is used in landfills, said Vulava and consulting engineer Randall Gracheck, who was retained by the law center to assess the issue.
Charleston’s coal tar problem
On the Congaree, coal tar apparently drained along a low spot below the manufactured gas plant on Huger Street, adjacent to what is now the State Museum, Effinger said.
After tar began to leak from the Huger Street site in the early 1900s, it gradually built up in the Congaree. Some people raised concerns in the 1950s about encountering coal tar, records show. It’s unknown how state officials responded in the 1950s, long before DHEC was founded. The agency began investigating the river tar when a kayaker stepped in the material in 2010. SCE&G had previously worked to clean up the mess on the Huger Street site.
But the expense in Columbia to clean up coal tar, so far, is much less than what SCE&G spent to address the problem in Charleston. The power company spent more than $50 million in a decadeslong effort to make property along the Cooper River useful for redevelopment.
In the 1990s, the company began digging up soil along the river bank and treating groundwater to kill the coal tar pollutants. The company also reached a nearly $4 million lawsuit settlement with the U.S. Attorney’s Office in 2011 to reimburse the federal government for cleanup work it had done on the property.
By many accounts, the cleanup has been a success. The S.C. Aquarium was developed on the site and other parcels have been identified for development after the company removed 63,000 tons of sediment from the river bank.
Part of the solution included dumping layers of sand on coal tar that dripped into the river in an attempt to cap it off. SCE&G later installed a stone and fabric cap over the coal tar in the Cooper River – like what is proposed for the Congaree. DHEC reports no problems from the coal tar since it was capped.
Even so, SCE&G says it still must pump tar away from the site and send it to a licensed disposal site.
“There is a lot of tar in there with a lot of construction debris,’’ Effinger said, referring to an area near a company substation. “So we are pumping tar. It’s like molasses.’’
Tar at Greenville school
SCE&G’s other coal tar cleanups have occurred in Florence and Sumter. Neither involved tar in rivers, but they cost the company about $9 million.
Duke Energy, headquartered in Charlotte, has had plenty to deal with in its Upstate service territory.
At one site near the Reedy River in Greenville County, a 1920s-era gas plant released tar into ditches nearby. In 1988, the state learned that some of the wastes lay deep below a landfill that had its own pollution issues. The discovery forced Duke to remove 61,000 tons of tar and polluted soil and replace it with clean dirt.
But the site is still under investigation and more cleanups may be necessary. At the corner of Bramlette Road and West Washington Street in a low-income area of Greenville, the site lies across the street from an elementary school and from a row of modest homes.
Sites in Spartanburg and Anderson aren’t as far along and more work is necessary, according to DHEC. Polluted groundwater is flowing toward a creek near the old Spartanburg gas plant site, records show. A site in Rock Hill, whose owner was not immediately known, also has not been cleaned up.
“We have carefully designed our work plans to assure the health and safety of the public and our personnel by minimizing any possibility for contact with the residues,’’ Duke spokeswoman Danielle Peoples said in an email.