Emergency responders evacuated a Neenah plant and several homes located downwind after a Wednesday industrial accident.
Three workers required hospital treatment, but they were quickly released.
Authorities say the problem at the Galloway plant was caused when a tanker truck carrying chlorine unloaded the chemical into the wrong tank, mixing it with acid.
They were worried the chemical reaction would form a dangerous cloud of chlorine gas.
Emergency crews evacuated residents for about two blocks to the north, northeast, and northwest of the plant because the wind was blowing from the south.
The chemical mixture was removed from the area Wednesday night.
