COUNCIL BLUFFS, Iowa (AP) — MidAmerica Energy has contacted Iowa environmental regulators to alert them of a sheen noticed on Mosquito Creek that appeared to be coming from a storm water drain at the Walter Scott Plant. The Iowa Department of Natural Resources said in a news release Friday that booms and absorbent material were immediately deployed.

An unknown amount of the unidentified substance entered Mosquito Creek. The company has a contractor at the site cleaning out the storm drain and stopping any further release. No impact was observed on the Missouri River and no dead fish were observed in Mosquito Creek.