Pioneer was selected to manage the regulatory closure of a portfolio of retail gasoline stations located throughout the Midwest that were being sold to a national petroleum retailer who then continued operating the stations. Pioneer coordinated with the various state agencies to develop corrective action plans and implement corrective actions. Since the sites were still operating, the subsurface investigations required specialized drilling techniques and safety precautions to minimize any disruption to the ongoing business activities. Contaminant conditions at the sites varied and required differing levels of corrective action for both on site and off site concerns. Free product recovery systems and dual-phase extraction systems were designed and installed at several locations to remediate the sites as required by the applicable regulations.