Keiyo Konbinat (Keiyo petrochemical complex) is the most greatest industrial complex in Japan. There are many of oil refineries, chemical factories, ironworks, and thermal power plants. 20% of oil used in Japan, 30% of ethylene, and 10% of steel are produced at there, and are generated electricity electric almost none of used in Tokyo metropolitan area. Natural gas is used for the fuel of the thermal power plants and exhausts only water and carbon dioxide, and soot and waste fluid are proccesed in other factories and are considered environment.