Abstract: A controlled air incinerator includes a primary and secondary combustion chamber. Combustion by-products from the primary chamber are exhausted to the secondary chamber. In the secondary chamber a source of auxilliary heat is provided to maintain the temperature in that chamber at a point which is sufficiently high to fully combust any particulate and unwanted gaseous matter. The secondary combustion vessel is provided with a baffle means for increasing the residence time of combustion by-products in the secondary chamber. The baffle means comprises an arch preferably oriented concave downwardly, the inlet to the secondary chamber being situated beneath the arch. The baffle means means increases residence time and increases the turbulence of gases passing through the secondary chamber.