Nasty river goo to remain in Congaree for years, as public health threat lingers
It will be at least four years before cleanup crews remove tons of toxic coal tar from the Congaree River, but that’s only if federal regulators cooperate and bad weather doesn’t delay the work, utility officials responsible for the pollution say.
During a public online meeting Tuesday night, officials said the project is an ambitious one that involves building two temporary dams, checking for Civil War-era explosives in river mud and trucking coal tar through city streets to a landfill outside Columbia.
The project has so many moving parts that power company Dominion Energy won’t be in position to build the dams until May 2022, officials said. The cleanup would then take at least two years, with the targeted end of the project in 2025. The project involves digging and scraping tar from the riverbed.
Tar cleanups have occurred in other parts of the country before, but a Dominion official said he doesn’t know of one exactly like the Congaree’s.
“This is a project that’s never been done before,’’ said Thomas Effinger, a top Dominion environmental official. “We are working with a design from world class geotechnical engineers. But as far as I know, no one has ever approached this kind of project the way that we have.’’
Coal tar contains a variety of harmful pollutants, but has been most associated with skin irritation among swimmers or waders who come in contact with it.
Effinger and officials with the S.C. Department of Health and Environmental Control did not provide details on how the project is different from others, but they said the work could be slowed if heavy rains swell the Congaree River so high that the temporary dams are overtopped. River flooding has occurred frequently in the past five years on the Congaree.
The pyramid-shaped dams will be built between the Gervais and Blossom street bridges to dry out the river bed so that coal tar can be dug up. If water pours over the top and into the excavation area, it will delay the project.
“There are certain things that can’t be controlled in this process and Mother Nature is one,’’ said Lucas Berresford, a DHEC official knowledgeable about the cleanup effort.
While weather is a concern, one issue that must be resolved before the project plans go much further involves the U.S. Army Corps of Engineers. The corps must issue a permit certifying that the work won’t cause environmental damage or flooding in the area.
It will be next year before any decision is made, record show.
Coal tar cleanups can be difficult and take years to fully complete, The State reported in 2017. At the time, power companies in South Carolina had spent at least $100 million cleaning up coal tar, the newspaper reported.
Effinger said the power company is committed to the cleanup, despite changes in plans through the years. Dominion’s predecessor, SCE&G, at first planned to clean up the coal tar, then backed away from its plan, only to reverse course again after a public outcry for a cleanup.
“We’re committed to see this thing through and make sure it gets done in the preferred manner,’’ Effinger said.
The project once was estimated to cost $18.5 million. Effinger declined to provide the latest cost estimates but said cost won’t stop the project.
Under the latest plan, Dominion will dig up and remove about 70 percent of the coal tar in the Congaree from two key parts of the river between Gervais and Blossom streets.
Coal tar, a gooey substance similar to soft asphalt, covers about 11 acres of the Congaree River’s floor. Plans have focused on removing some 40,000 tons of the tar, which is mixed in with river mud.
The excavation will be done on the Columbia side of the river, leaving a substantial portion of the Congaree open for boaters to navigate, according to a photograph outlining the excavation area. Tar extends as much as four feet deep in the river sediment, records show.
Trucks hauling the polluted muck will exit the edge of the Congaree below the Gervais Street bridge, traveling along Gist Street and Senate Street, officials said. The trucks would not run after 4 p.m. and would work only on weekdays. The cleanup work must be done between May 1 and Oct. 31 in the river due to environmental concerns, Effinger said.
Before any tar is hauled away, contractors must make sure Civil War explosives don’t exist in the tarry mud. Evidence suggests that Union troops dumped weapons in the river after capturing it from the Confederates, The State reported in a 2015 video about the original removal plan.
Coal tar is a toxin-riddled byproduct of power production in the early 20th Century. Coal tar drained into the Congaree River from about 1900 to the late 1950s, state officials say. It came from a manufactured gas plant that discharged the material into a ditch that ran into the Congaree at the Gervais Street bridge.
For much of the 20th century, little was known or said about coal tar in the river. But in 2010, a kayaker suffered a toxic sting after stepping into coal tar near the Senate Street boat landing. The boater reported a burning sensation on his legs. The discovery eventually led to a DHEC investigation and agency warnings about coal tar in the Congaree.
Tuesday’s public meeting, held via the internet because of the threat of COVID 19, is the first since a session last year about the coal tar cleanup. This year’s meeting drew multiple questions and a smattering of concerns, including from a resident of the City Club neighborhood. Trucks hauling the polluted muck to a landfill would be a constant disruption to the community of 37 homes at Gist and Senate streets, City Club resident Rebecca McMillan said.
“Call me selfish but I am very concerned about the noise generated from those trucks up and down our street,’’ McMillan said. “They will be noisy, the work in the river will be noisy.’’
DHEC is seeking public comments on the cleanup plan until Jan. 15.
This story was originally published November 18, 2020 at 6:06 AM.
