Cameron-Cole staff developed an investigatory approach and detailed RCRA Facility Investigation (RFI) workplan for a refinery in Montana. The three-volume workplan described the manner by which 21 active and inactive Solid Waste Management Units (SWMUs) were to be evaluated for integrity and their possible contribution to soil, groundwater, and air contamination. As part of the workplan, four of the SWMUs were included for investigation and remediation as one corrective action management area. This approach was designed to streamline the RFI by addressing groundwater conditions attributable to these SWMUs collectively, rather than individually, due to their close proximity and similar source constituents. EPA personnel favorably received the plan.