Abstract: Scrap rubber chunks from used tires are processed and the monomeric chemicals from which the tire rubber was synthesized are recovered. Rubber chunks reduced to a finely divided size are exposed to gaseous ozone to break down the cross-linked structure of the rubber. Subsequent thermal depolymerization occurs in a reactor chamber. Finely divided silica is introduced within the reactor to prevent agglomeration of rubber particles and to enhance the maintenance of a uniform reactor temperature. Reduced pressure within the reactor permits rapid removal of monomer vapors. Once the monomer vapors are separated, silica and carbon residues are recovered separately for either recycle or disposal.