Abstract: Apparatus for burning waste polymers of selected combustion characteristics. A vertical or horizontal combustion assembly includes a base cylindrical portion having water-cooled walls to maintain a selected temperature by removal of the heat of combustion, a plurality of pipes for injecting combustion air tangentially into the interior space, a loading port in the wall of the base section and a burner for igniting the waste matter injected through the loading port. Downstream of the base section is a ceramic choke which has an axial opening therethrough of lesser diameter than an internal diameter of the base section followed by an afterburning chamber, which like the base section, has a plurality of air inlet pipes tangential to the chamber and a burner port for igniting vapors in the upper chamber. Combustion air is controlled so that less than stoichiometric air is injected into the lower chamber to provide a reducing atmosphere, with excess combustion air in the afterburning section.