Abstract: This specification teaches a method for treatment of exhaust gases which if left untreated can generate, upon full oxidation, temperatures in a range of from about 1600.degree. F. to about 2700.degree. F. over an oxidizing catalyst. The method has the following steps. An internal combustion engine (10) is operated under conditions in which there is insufficient oxygen to oxide all the hydrocarbon present in the fuel. The exhaust gases so-developed are passed into an exhaust manifold (12) and then through an exhaust pipe (14) to an oxidation catalyst (16) whose primary oxidation catalyst is palladium. An air pump (20) generates a supply of oxygen which can supply up to about 80% of the oxygen required to combust fully all of the hydrocarbons and carbon monoxide contained in the exhaust gases when the internal combustion engine is operating in a wide-open throttle condition.