Abstract: The method of incinerating hazardous materials and fluidizable wastes, such as liquids, gases, entrained solid particles, fumes and slurries, utilizes an incinerator in the form of a sudden expansion burner. The incinerator has a relatively small diameter cylindrical inlet pipe connected by a circular plate to a relatively larger diameter elongated cylindrical combustion chamber. A waste injection line passes into the incinerator adjacent the inlet pipe for transfer of incineratable waste therethrough and into the upstream end of the combustion chamber. Air inlets connected to a blower also terminate adjacent the inlet pipe for supplying air at a high flow rate to the combustion chamber. One or more fuel nozzles extend through the plate into the combustion chamber to provide an overstoichiometric concentration of fuel adjacent the plate. The fuel is ignited through an electrically powered, fuel supplied ignitor extending into the combustion chamber through the inlet pipe.