The Iowa Department of Natural Resources says Houston, Texas-based Enterprise Products reported a drop in pipeline pressure early Saturday. The affected section runs from Decatur, Neb., to just west of Onawa.
The company shut down the pipeline on both sides of the river, and an estimated 140,000 gallons of gasoline is being pumped out.
Crews on the ground, by boat and by plane are searching for the leak. As of Sunday afternoon, the source had not been found but is suspected to be on the Iowa side. Divers may be deployed in the next few days.
The leaked gasoline is expected to have floated downriver. Officials in Council Bluffs and Omaha, Neb., have been warned.