INTRODUCTION Gasoline leaking into soil will travel downward and diffuse laterally. In the absence of an impermeable layer the limit of downward movement will be the fluid surface of the aquifer. Oncegasoline reaches the aquifer it will spread horizontally and can form a lens on the water table that is large relative to the areal size of the leak near the source. In addition to the problem of ground water contamination@ the gasoline vapor will evaporate and contaminate the soil above the fluid surface. These vapors can diffuse into basements@ storm sewers and underground utilities and present safety and health problems. The work described in this report investigated forced venting as a way of removing these vapors from the underground environment.