State authorities are looking for the source of an "oily" chemical that may have been dumped illegally into the city's wastewater treatment plant.

A dark brown oily substance with a citrus odor was reported at the plant Thursday afternoon. 

Missouri Department of Natural Resources representatives collected samples at the city's wastewater treatment plant south of Highway 50 off Highway 47. 

Investigators have located the area where the chemical may have originated.

City officials said the chemical could kill enzymes that breakdown waste in the treatment plant. There is no danger to residents. 

See the Weekend Missourian for more information.