In situ vacuum extraction, air or steam sparging, and vitrification are widely used methods of remediating soil contaminated with volatile organic compounds (VOCs). All of these processes produce a VOC.-laden air stream from which the VOC must be removed before the air can be discharged or recycled to the generating process. Treatment of these off-gases is often a major portion of the cost of the remediation project. Carbon adsorption and catalytic incineration, the most common methods of treating these gas streams, suffer from significant drawbacks. Membrane Technology and Research, Inc. (NITR) proposes an alternative treatment technology, based on permselective membranes that separate the organic components from the gas stream, producing a VOC-free air stream. The technology we propose to develop can be applied to all of these off-gas streams and is not tied to a particular off-gas generating source. We propose to develop a completely self-contained system because remediation projects are frequently in remote locations where access to trained operators and utilities is limited. The system will be a turnkey unit, skid-mounted and completely automatic, requiring power but no other utilities. The system will process the off-gas, producing a concentrated liquid VOC stream and a purified gas containing less than 10 ppm VOC that can be discharged or recycled to the gas-generating process.