DENISON, Iowa (AP) - State environmental officials say a plugged line coming from a holding pond at the Tyson Foods plant in Denison in western Iowa caused partially treated industrial wastewater to be released into the Boyer River.

Officials with the Iowa Department of Natural Resources say the flow was stopped within hours after on-site equipment was used to unplug the line.

The DNR says it will inspect the site and suggest ways to prevent future problems.