OMAHA, Neb. (AP) — Construction workers cleaning out tubs filled with concrete say they accidentally turned a nearby Omaha creek red.

Greg Armstrong, owner of Swain Construction, says his employees were cleaning the tubs Friday afternoon about 70 feet from the Little Papio Creek in Omaha. Armstrong says three to four gallons of the dye leaked into the creek in the process, but the water has since been cleared.

The Nebraska Department of Environmental Equality and county officials were called to test the water.

A supervisor with the state agency says officials are aware of the issue, but had no further information.

Armstrong says the dye isn’t harmful to fish or other wildlife.