In laboratory microcosm tests, single additions of corn oil, beef tallow, melted corn oil margarine, coconut oil, corn oil, soybean oil, or partially hydrogenated soybean oil supported complete reductive dechlorination of perchloroethene (PCE) or trichloroethene (TCE) to ethene when a dechlorinating population was present. TOC production from the edible oils continued for up to 200 days. More than 250 mL of gas were produced in some microcosms. TCE concentrations as high as 236 mg/L were degraded. Coconut oil was added to a soil column that had been bioaugmented with a dechlorinating enrichment culture to evaluate edible oil-based TCE dechlorination in a flow-through system. Ethene and ethane were the only products found in the column effluent during the 88 days following the oil addition. The 10 mL of coconut oil (1,500 mg/kg) was projected to support TCE degradation for over two years. The edible oils are much cheaper than soluble substrates such as sodium lactate. Operation and maintenance costs for an edible oil based reductive dechlorination system should also be less than for a soluble substrate. The edible oil will need to be added only periodically. This technology should be applicable for source zone treatment.