China Petroleum and Formosa Plastics Petroleum.
Others are:
China Oil and Gas Company Limited
Changchun Petrochemical Company Limited
Taiwan Province Petroleum Co., Ltd.
Guoqiao petrochemical co., ltd.
Panshi hydraumatic industry co., ltd
Huihong petrochemical co., ltd
Yitian petroleum co., ltd
Cai Zhen ltd.
Taiwan Province United Global Oil Company
And dozens of other petrochemical or product trading companies.