Residents in El Dorado came outside Tuesday afternoon and noticed Champagnolle Creek had turned turned green.
El Dorado and Union County officials have been working to find out what caused the water to change color.
Crews have built a dam and are pumping the water into tanks.
A green foamy liquid has contaminated the creek and killed the fish in it.
General Manager of El Dorado Water Utilities Mark Smith tells us he has an idea of how this toxin has gotten into the creek.
"We believe these are chemicals that were dumped from a car wash that was being torn down on Main Street, and put down their floor drain, which took that product to the storm drain," says Smith.
Residents have been advised to stay away from the contaminated creek until further notice.
Copyright 2016 Nexstar Broadcasting, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.