Officials with the Iowa Dept. of Natural Resources said Thursday, that a plugged manhole at the Smithfield Foods plant in Denison, sent some rinse water to the Boyer River early Thursday morning.

Smithfield crews noticed the discharge around 3:30 a.m., about 15 to 30 minutes after they think it started. An unknown amount of final rinse water flowed across the property, then entered a storm sewer that flows into the river.

In less than two hours, a construction crew built a small dam, stopping the flow into the river. Another crew began vacuuming up the rinse water. DNR staff were on site before 8 a.m., checking on the cleanup and the river. DNR will continue to monitor cleanup efforts and consider appropriate enforcement action.