Oxidation of dilute TCE vapors in a foam reactor using Fenton's reagent was investigated. The new process relies on rapid mass transfer from the gas undergoing treatment to a fine aqueous foam and oxidation by Fenton's reagents. Laboratory investigations demonstrated that TCE elimination capacity was as high as 56-61 g TCE m -3reactorb -1 with a removal efficiency of 62% and TCE mineralization of 83% at gas retention time of 30 s and TCE inlet concentration of 0.6 g m -3. Compared to oxidation in wet scrubbers packed with commercially available plastic packings and using the same composition of Fenton's reagents, the foam reactor configuration provided a higher rate absorption and greater elimination capacity of TCE vapors. The treatment performance far exceeded those of current bioreactors and was comparable to those of advanced oxidation techniques such as TiO 2/UV and ozone/UV, suggesting that Fenton oxidation in foam reactors may be a promising technique for treating TCE and other recalcitrant vapors. © 2007 American Institute of Chemical Engineers.