Abu Dhabi Oil Co., Ltd. Maruzen Oil Co., Ltd. Castrol  Mitsui Oil And Gas Co., Ltd. Corning  Mobilsekiyu Kabushiki Kaisha Cosmo Oil Co., Ltd. Nichigo Engineering Esso Sekiyu K. K. Nippon Mitsubishi Oil Corporation Exxonmobil Okinawa Sekiyu Seisei Company, Ltd. Fuji Kosan Co., Ltd. Seibu Oil Co., Ltd. General Sekiyu K. K. Showa Shell Sekiyu K.K. Idemitsu Kosan Co., Ltd. Showa Yokkaichi Co. Inpex Corporation Taiyo Oil Co., Ltd. Japan Drilling Co., Ltd. Teikoku Oil Co., Ltd. Japan Energy Co., Ltd. Toa Oil Co., Ltd. Japan Oil Development Co., Ltd. Tonen Corporation Koa Oil Co., Ltd. UNOCAL(加州石油) Kyushu Oil Company Limited Yushiro Chemical Industry Co., Ltd.