On 2016 EPA Region 6 issued an Administrative Complaint (APO) under its authority pursuant to Section 309 of the Clean Water Act (CWA) to Chaparral Energy, LLC (Respondent), located in in Shidler, Osage County, Oklahoma and Gainesville, Cooke County, Texas. The APO was issued in response to violation of Section 301 of the CWA for discharging fluids high in Total Dissolved Salts to waters of the U.S.