Pyrolysis is the thermal breakdown of organic material in an atmosphere with no oxygen, usually run between 300°C and 900°C. Because there is no air, the material cannot burn. Its hydrocarbon content is instead broken into a combustible gas, called pyrogas or volatile organic carbons, plus a solid carbon char and inert ash. Inert matter and heavy metals stay locked in the char in a non-leachable form. Pyrolysis differs from incineration in a few ways. Incineration uses excess oxygen and full combustion to turn waste into energy and ash in one step. Pyrolysis holds the reaction back on purpose so the output is pyrogas and char, both of which can be used later for power generation or further processing.