Abstract: A ventless, combustible waste reduction process and apparatus which can utilize any type of combustion means for disposing of hazardous, as well as non-hazardous, burnable waste. Such wastes include toxic combustible liquids, oil slurries, soils contaminated with dioxin, PCBs, creosote, or any other potentially harmful or toxic combustible material. In particular, the present invention relates to a ventless, combustible waste reduction process in which the operating pressure is slightly below atmospheric pressure and which employs no venting or stack discharge of pollutants whatsoever. The entire flue gas stream is scrubbed, enriched with oxygen and recycled to the combustion chamber in varying amounts in response to pressure and temperature measurements taken in the combustion chamber to maintain the pressure and temperature in the combustion chamber within pre-selected ranges.