The main objective of this study is to investigate the feasibility of clean gaseous fuels made from plastics, automobile tire rubber, municipal solid waste (MSW), and woody biomass feedstock using a high-temperature pure-steam gasification process. Super-high-temperature steam at 1000 degrees C was used as the gasifying agent to generate the syngas which mainly contains hydrogen and carbon monoxide and can be used as a gaseous fuel. Since the process does not involve air, the syngas is free of nitrogen and its oxides which usually dilutes the syngas and lowers its heating value in the case of an air-blown partial-oxidation/partial gasification process. A lab-scale experimental apparatus was used to produce the high-quality syngas, and the gas was analyzed using a gas chromatography. The results showed that the syngas contained very high H-2 concentrations, and the heating values of the syngas for all four types of feedstock reached 8-10 MJ/m(3) which were approximately 2.5 times higher by weight and 1.6 times by volume as compared to those from the previous air-blown gasification system. In addition, a thermodynamic equilibrium model was developed and successfully verified by the experimental results.