a process for breaking down rubber polymer materials by selective oxidative decoupling of carbon - carbon , carbon - sulfur and sulfur - sulfur bonds at supercritical or near supercritical conditions for water and wherein supercritical water or water near supercritical conditions is used as a solvent and reforming agent , is used to produce relatively high yields of lower molecular weight hydrocarbons and oxygenated hydrocarbons which are suitable for use as a fuel or which can be separated or further refined to produce various commodity chemicals , specialty chemicals or both . the invention provides an environmentally friendly process for recycling rubber waste materials such as waste tires to generate valuable fuels or chemical feedstocks in a closed oxidation process which is free of hazardous stack emissions . the rubber polymer materials which can be recycled in accordance with the process can include typical amounts of conventional compounding ingredients and other impurities without significantly affecting the overall conversion .