| 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. | |