Abstract: The invention relates to an improved apparatus and method for initiating and sustaining an oxidation reaction. A fuel, such as natural gas or hazardous waste, is introduced into a reaction zone within a pressurized containment vessel. A permeable liner is placed within the containment vessel and around the reaction zone. An oxidizer, preferably oxygen, is mixed with a carrier fluid, such as water, and the mixture is heated and pressurized to supercritical conditions of temperature and pressure. The supercritical oxidizer-carrier mix is introduced to the reaction zone gradually and uniformly, over a comparatively large area, by forcing it radially inward through the permeable liner and toward the reaction zone. A means and method for cooling the exhausted by-products and using them as a cleansing rinse are disclosed.