On September 16, 2012, 1030am Central Time the U.S. Coast Guard (USCG) on Boat Patrol discovered a sheen on the Illinois River and reported it to the Nationial Response Center. USCG initiated initiated a preliminary investigation and found out that the source of the sheen appeared to be coming from a sewer pipe outfall that is shared by the City of E. Peoria and Caterpillar Co. USCG issued Notices of Federal Interest to both parties and Caterpillar voluntarily installed a containment and absorbent boom at the outfall's shoreline.
On September 17, 2012 at approximately 11am Central Time the USCG notified the Duty Officer at EPA Region 5 and requested that EPA investigate and take the enforcement lead on the oil spill since the source appears to be from land. EPA OSC Mendoza mobilized and arrived at the scene at 4:30 pm Central Time
