A full-scale in situ enhanced bioremediation program targeted petroleum contamination at a school bus maintenance garage in Otego, NY. After the removal of the leaky USTs and contaminated soils in 1998, in situ enhanced bioremediation was proposed as a cost-effective alternative to conventional ex situ remedial methods because ongoing site use limited the available space for aboveground structures associated with conventional ex situ cleanup. PermeOx(R) Plus, produced by FMC Industrial Chemicals, was selected as the enhancement product. The compound provides oxygen to enhance the biodegradation of petroleum hydrocarbons through a reaction of the specialty formulation of calcium peroxide and water. In July 2002, total BTEX mass at the site was estimated at 4.7 kg. PermeOx(R) Plus was injected in 200 x 80 x 8-ft-deep treatment zone using a direct-push drill rig at 107 locations within the plume area. In addition, Bioblend(TM) M-4, a blend of petroleum-degrading bacteria and nutrients, was injected into the contaminant plume. By December 2002, total BTEX mass within the plume was reduced to 1.7 kg. A second PermeOx(R) Plus injection was conducted in a 140 x 70-ft area at 55 locations. This presentation discusses the use of PermeOx(R) Plus to introduce oxygen into the site's ground-water contaminant plume and the overall effectiveness of the remedial program for reducing the levels of dissolved-phase and sorbed-phase petroleum hydrocarbon concentrations. For more information on PermeOx(R) Plus, contact FMC Industrial Chemicals at 866-571-6007 (PA), or national distributor Panther Technologies at 609-714-2420 (NJ).