Bangchak Petroleum
Toyo-Thai Corporation Ltd.
CTCI (Thailand) Co.,Ltd.
Thai Rotary Engineering Co.,Ltd.
Kaystone Valve – Supplier
Nalco Chemical Company (Thailand)
National Petrochemical Public Co.,Ltd.
PAE Thailand – Contractor
Siam Nitsui PTA Co,.Ltd.
Star Petroleum Refining Co.,Ltd. – Factory
Thai Asahi & Chemical
Thai Olefins Co.,Ltd.
TPI (Thai Petrochemical Industry)
Thai Plastic and Chemicals Public Co.,Ltd.
Thai – Polyethylene – Factory
Thai Synthetic Rubbers Co.,Ltd.
TPI Oil Co.,Ltd.
TPI Polene Public Co.,Ltd.
Tuntex Petrochemicals (Thailand) Public Co.,Ltd
Unocal Thailand Co.,Ltd.
Foster Wheeler International Co.,Ltd.

CUEL CO.,LTD
Chevron Thailand Exploration & Production Ltd.
Thai Shinryo Limited
Chevron Offshore (Thailand) Ltd.
BJC Heavy Industries Public Company Limited
Italthai Engineering Co.,Ltd.
Thai Paraxylene Co., Ltd.
Worley Parson
Unimit Engineering Public Company Limited
Thysennkrupp Industrial Solution Company Limited
Thai Woo Ree Engineering Company Limited
New Star Engineering Company Limited
Thai Nippon Steel Sumikin & Engineering Company Limited
Clough (Thailand) Limited
Rayong Engineering and Plant Service Co.,Ltd.
NUI PHAO MINING COMPANY LIMITED
PTT MANTENANCE AND ENGINEERING COMPANY LIMITED
Technip Engineering (Thailand) Limited
POSCO Engineering (former Daewoo Engineering)
PTT exploration and Production Public Company Limited