Three above ground storage tanks (containing gasoline and diesel) and associated piping were removed from a DoD site in January 1990. Concentrations of TPHd and TPHg were found in soil samples collected around the former ASTs at concentrations of 140 mg/kg and 9,400 mg/kg, respectively. Groundwater contamination was also detected with TPHd concentrations reaching 21,000 ug/L and TPHg concentrations reaching 140,000 ug/L. ORC was chosen to enhance the aerobic environment within the subsurface and reduce the high levels of petroleum hydrocarbons. Three monitoring wells were installed prior to the application of ORC: MW494A, MW495A and MW496A. These wells were placed in locations based on groundwater flow and contaminant concentrations. Well MW 494A was placed upgradient in an uncontaminated area for monitoring background conditions. Well MW495A was placed in the hot spot and MW496A was placed near the edge of the injection area, downgradient of the source. The wells were nstalled one month prior to ORC injection to allow for the monitoring of baseline conditions.