There is keen interest in oxygen injection systems owing to the increased evidence of in situ aerobic biodegradation of potentially recalcitrant gasoline constituents. Significant remediation cost reductions are possible by stirnulating indigenous microorganisms to degrade contaminants of concern by adding oxygen. Various commercial oxygen injection approaches are being marketed with little credible evidence supporting their claims. A field demonstration of 3 commercial technologies, operating at their highest setting, was performed in side-by-side test cells at the Port Hueneme NETTS field site. Each test cell measured 50- foot by 50-foot and was instrumented with 60 to 80 monitoring wells. These wells were sampled at 4 to 6 week intervals in order to evaluate the oxygen distribution to a medium-sand aquifer. After 1 month of operation, the OPTS test cell showed a 10 to 20-foot oxygen-enriched (dissolved oxygen > 4 ppm) ROI, the C-sparge test cell showed a 5 to 15-foot oxygen-enriched ROI, and the iSOC test cell showed no influence outside the injection well (less than 1.5-foot ROI). After 3 months, each test cell showed essentially stable dissolved oxygen signatures. This presentation will also illustrate the stability of the oxygen plumes in the OPIS and C-Sparge test cells by mapping dissolved oxygen concentrations at 6-week intervals after cessation of oxygen injection.