The Black Sea is a unique sea. Its water contains hydrogen sulfide (H2S). The Black Sea is the world's largest water body containing H2S and its hydrogen sulfide layer begins about 200 meters below the surface. H2S potential in the Black Sea is investigated as a source of hydrogen. The total sulfide pool in the Black Sea is believed to be around 4.6 x 10(9) tons. H2S, an acid gas, is generally considered to be an environmental pollutant. As an industrial by-product, it is produced mostly during fuel processing. One-step thermal decomposition methods appear to be more suitable for hydrogen production from H2S. Superadiabatic partial combustion is an encouraging process for the near future. Environmentally, H-2 production based on this H2S-splitting cycle is carbon free.