A sheen on Wilson Park Creek was reported to the National Response Center on May 1, 2017 at 18:26 CDT. Shortly thereafter, the Milwaukee Fire Department (MFD) Hazardous Materials Team contacted EPA about suspected jet fuel in the outfall leading from General Mitchell International Airport into Wilson Park Creek. OSC Halbur responded and coordinated response efforts with MFD, Milwaukee Airport Fire Department (MAFD), Milwaukee County, the Wisconsin Department of Natural Resources (WDNR), and SET Environmental. Booms were placed at the outfall and along the creek to contain the release.
The source of the sheen was identified at approximately 09:00 CDT on May 2, 2017. Jet Fuel from a leaking valve at an inactive airport gate entered the airport’s storm sewer system. The pipeline feeding the fueling station was isolated, stopping the release. Over the following weeks, the pathway from the leaky valve/containment area to the sewer was identified and cleaned. SET maintained booms in the airport's storm sewers, the outfall, and Wilson Park Creek until July 10, 2017. The response was deemed complete after two successive rain events with no visible sheening and clean confirmation samples in the storm sewer, at the outfall, and in Wilson Park Creek.