Dense non-aqueous phase liquid (DNAPL) at a depth of 20 feet below grade covered a three-acre area of a former manufactured gas plant site, preventing site closure and inhibiting development of the property. As part of site closure, soil and DNAPL were stabilized in situ using a crane-mounted, 10 -foot-diameter auger capable of injecting a 7% cement grout mixture. The auger was advanced approximately 22 feet below grade to extend beneath the DNAPL and key the stabilized mass into the underlying clay layer. In total, 2,256 overlapping columns were advanced over an area covering approximately 144,000 square feet. To demonstrate that performance requirements were met, uncured samples were collected, cured in the laboratory, and analyzed for NAPL saturation. Samples of the soil and DNAPL that had cured in situ were also collected to allow direct observation of stabilized material and to provide additional supporting documentation of the permanence of the remedy. The solidification remedy allowed site closure to proceed, and the construction of two 250,000-square-foot life science buildings is nearing completion. The buildings are scheduled for occupancy in 2004.