In the pyrolysis process, the whole or shredded tire is heated in a reactor vessel under an oxygen-free atmosphere. The rubber melts in the reactor. The rubber polymers break down into smaller molecules which eventually vaporize and exit the reactor. These vapors may then be burned to produce power or condensed into an oil-like liquid which can then be used as a fuel. The larger molecules that cannot be condensed remain as a gas; this gas is used to provide heat for the process.