Authorities say a plugged line led to the release of untreated wastewater from a central Iowa meatpacking plant into the North Raccoon River.
The Iowa Natural Resources Department says workers at the Tyson Fresh Meats plant in Perry traced the discharge to a plugged line in the plant's treatment system.
Tyson estimated that between 10,000 and 40,000 gallons of untreated wastewater reached the river.
The department says it is monitoring the cleanup and will consider what it called "appropriate enforcement action."
Copyright 2011 The Associated Press.