Abstract: A steam injection system for an incinerator. The incinerator includes a housing that defines a combustion chamber, and a plenum is mounted beneath the housing. Air for the combustion process is fed to the plenum and steam is separately introduced into the plenum. The air and steam are mixed and the mixture is introduced into the lower end of the combustion chamber through one or more inlet pipes. The steam acts to reduce high localized temperatures in the combustion chamber to minimize clinker formation, as well as maximizing the conversion of fixed carbon to carbon dioxide.