The view of the Congaree River Sediment Cleanup site from the Gervais Street Bridge. Workers removed coal tar and Civil War artifacts from the river bed. (Photo by Sydney Dunlap/Carolina News and Reporter)

The Congaree River has offered a pleasant place to swim, kayak or walk for many Columbians. But until recently, enjoying the river meant that residents had to take a risk.

Reports show visitors stepping on toxic coal tar left behind in the river bed by the former S.C. Electric & Gas Co.

The substance causes a burning sensation when it comes in contact with human skin.

Dominion Energy, the new owner of SCE&G., began an effort to remove the coal tar from two main areas of the Congaree River in May 2022.

Even though it gave itself a three-year timeline for the work, Dominion announced in November it had finished the project – and that it had pulled up hundreds of buried historical artifacts in the process.

Now, these relics are one step closer to being available for the public to view. But it wasn’t an easy process.

Combining the coal tar with the possibility of unexploded ordnance added extra complexity to the cleanup effort, Congaree Riverkeeper Bill Stangler said. Crews had to treat every item like it could be active.

“There’s kind of this lingering question for years of, ‘Does a 150 year old cannonball explode if you hit it with a backhoe?'” Stangler said.

Many of the artifacts from the river come from Union Gen. William T. Sherman’s march through the South during the Civil War, said Allen Roberson, executive director of the S.C. Confederate Relic Room and Military Museum.

Sherman and his troops came into Columbia on Feb. 17, 1985, and threw all the military ammunition and equipment they found into the Congaree River to make the materials unusable for any Confederate troops who returned to defend the city, Roberson said.

Dominion found hundreds of cannon balls, canister shots and a sword stuck under a layer of coal tar.

Crews also found a wagon wheel with burn marks. Roberson said it’s likely from a wagon that blew up during Sherman’s march. The blast wounded 21 men and killed three, including the captain.

The military artifacts recovered were joined by other items, such as an anchor from a steamship that would have traveled up the Congaree to Columbia.

Roberson said the artifacts tell the story not only of the Civil War but of the river and its impact on the city.

Planning for the project began more than 10 years ago.

Recovering the buried artifacts was always a consideration, Dominion Communication Specialist Matt Long said in an email to the Carolina News and Reporter.

Dominion contracted archeologists from TRC, an environmental consulting, engineering and construction management firm.

The company used experts to plan how to identify and remove the artifacts safely.

Crews used metal detectors and large mechanical and hand-held screens to look through sediment and find artifacts, Long said.

Safety buffers were placed around the items to determine if they were explosive or dangerous.

“Safety was a top priority for this project,” Long said. “The presence of munitions required an extensive health and safety plan that include a team of expert, licensed and certified unexploded ordnance technicians.”

The Civil War artifacts were given to the Relic Room, while the non-Civil War artifacts were given to the South Carolina Office of the State Archaeologist, Long said.

Roberson said this is just the start of getting the historical items on display for the public.

He already has submitted a proposal for funds for the Relic Room’s physical exhibit.

But after being submerged in the water for so long, many artifacts must undergo treatment to stop them from rusting as soon as they are exposed to the air.

Experts will use electrolysis to run an electric current through the iron pieces for an extended period of time to remove all the rust and ensure it won’t return, Roberson said. The process could take up to 18 months.

While he is not finished planning the exhibit’s content, Roberson expects it to focus on more than just the artifacts.

He hopes to include photos of the project efforts alongside the items.

“Some of that dig is fascinating,” Roberson said. “I think the archaeological recovery is almost as insane as what you pull out of the river.”

The room that would host the items also will need facility renovations to best accommodate the items, Roberson said. He expects the exhibit won’t be available for another year and a half to two years.

Roberson said he’s happy Dominion completed the project and thinks the cleanup will continue to positively affect the community.

“They did something good for the citizens and out of this project — removing the coal tar,” Roberson said. And “they were able to save these artifacts in time. They could have just said, ‘Artifacts aren’t important. We’ll just tear them up, we’ll just dump them, you know, smash them up with the bulldozers’ – whatever else. But they didn’t. They did it right.”