ABSTRACT: Subsequent to initial source area excavation and backfill, residual xylenes and naphthalene were treated via a biotic and abiotc approach. The remedial technology utilized free radical chemistry, oxidation chemistry and facultative biological oxidation. These processes extended the oxidant and free radical residuals while enhancing the in-situ environment for biologically based attenuation. The three remedial approaches were combined to achieve synergistic chemical and biological removal of dissolved and sorbed compounds at the site. The chemical oxidation process causes a large and fairly complete removal of targeted compounds, while biological processes refine the site and allow for the further reduction of concentrations of targeted compounds. The remedial program resulting from the data collected incorporated hydroxyl and sulfate radicals and a zero valent iron catalyst to remediate the site. Ferric iron and sulfate species were relied on to promote facultative anaerobic mineralization of the residual targeted compounds. A second oxidation event followed the primary event in which only the oxidants were applied allowing for a conversion of the ferrous species back to ferric iron while achieving additional oxidation of entrained xylenes and naphthalene. Through this combination of remedial techniques, compounds of interest in the source area have decreased by as much as 98%.