(Reuters) - Exxon Mobil Corp reported a minor release from an unknown vessel caused a petroleum sheen on the Des Plaines river in Illinois on Monday, according to a filing with state pollution regulators.
Exxon's Joliet refinery personnel were working to clean up the release, the filing with Illinois Emergency Management Agency said.
The filing did not say how long the release lasted.
Exxon runs the 238,600-barrel-per-day Joliet refinery in Channahon, Illinois.
(Reporting by Koustav Samanta in Bengaluru)
