State environmental officials are looking at a plan to remove coal tar from the Congaree River in downtown Columbia by mid-2017.
An $18.5 million cleanup outlined Thursday would close an informal float trip ramp on Senate Street for three years once work starts in the summer of 2014, officials said.
Riverkeeper Bill Stangler favors the plan but wants to make sure the river is minimally impacted by the work.
The tar was discovered in the summer of 2010 near the Gervais Street bridge, coating the bottom of the river with a goo that swimmers found difficult to wash off.
It is a byproduct of a coal gasification plant that was operated in the Vista by a utility later acquired by South Carolina Electric & Gas Co.
Removal of the tar from the river is challenging and will proceed slowly, cleanup project manager Lucas Berresford said.
It will require building a temporary dam around the area with the tar.
SCE&G will pay for the cleanup, with company environmental services manager Tom Effinger pledging minimal hassles for nearby residents as work occurs.
The project will be an inconvenience but we want the river to be fixed, homeowner Mary Langston said..
It was typical practice for manufacturers to dump waste into the river prior to standards that ban it today, Berresford said.
The amount of tar put into the river for about 50 years in the early 1900s is unknown, he said.
Contact with the tar can cause skin irritation but it is not considered dangerous, state environmental officials say. Still, a no-swimming advisory remains in effect in the area.
The tar varies in depth from an inch to a foot in an area extending nearly a half-mile downstream from the bridge, a study says.
View Proposed coal tar cleanup in a larger map For more information on the problem and cleanup plan, go online to