The Department of Natural Resources in Iowa says sludge from a northwest Iowa cheese processing plant overflowed from a storage tank and flowed into a nearby stream.
The DNR says the sludge overflowed a tank at the Agropur plant in Hull, Iowa.
The sludge flooded a wastewater treatment building and then flowed into a stream. It moved about three-eighths of a mile downstream before stopping about four miles upstream of the West Branch of the Floyd River.
The company estimates 1,200 gallons of sludge flowed into the stream before workers managed to stop the flow.
Crews were pumping the sludge from the stream and applying it to nearby fields.