COLUMBIA (WACH) -- The investigation into a black sticky substance found in the Congaree River continues.
Earlier this week, swimmers notified WACH Fox News about the problem.
Environmental officials say they still don't know what the substance is, but they're looking into it.
Thom Berry with South Carolina DHEC says they've taken additional samples and will be posting signs urging people not to swim at the old boat launch near the Gervais Street Bridge.
Boating and surface activity is still safe, but out of caution DHEC decided to place signs notifying swimmers to avoid the area before entering the water.
Some are connecting the problem to road work on the bridge. They say tar from construction has fallen into the water. Others say that's not possible.
WACH Fox News will continue to follow this story. Keep checking back for updates.
Related Stories:DHEC investigates black sticky substance in Congaree - Wednesday, June 23, 2010Swimmers report finding a black sticky substance on their hands, knees and feet after emerging from the Congaree River. Swimmers find black sticky substance in river - Tuesday, June 22, 2010 Swimmers taking a dip in a section of the Congaree River Tuesday came out of the water not only wet, but what appears to be tar stuck to parts of their body.