Major Petrochemical and Oil & Gas Companies
- BASF
- BP Petronas Acetyls Sdn Bhd
- Carigali – HESS Operating Company Sdn Bhd
- Carigali-PTTEPI Operating Co. Sdn Bhd (CPOC)
- Esso Refinery (now Petron Refinery)
- Ethylene (M) Sdn Bhd
- Exxonmobil Exploration Production Malaysia Inc. (EMEPMI)
- Malaysia LNG (MLNG)
- MTBE Chemical
- Murphy Oil
- Nippon Oil Exploration
- Petrofac (Malaysia) Ltd
- Petronas Carigali Sdn Bhd (PCSB)
- Petronas Gas Berhad – GPPA & GPPB (PGB)
- Petronas Penapisan (Melaka Refinery)
- Sabah Shell Petroleum Co. Ltd
- Sarawak Shell Bhd (SSB)
- Shell Refinery (now Hengyuan Refining Company Bhd)
- Talisman Malaysia Ltd (now Repsol)
Major EPC Contractors and System Integrators
- Aker Solutions
- Brooks Dockyard
- Emerson Process Management
- Honeywell Automation & Control
- Malaysia Marine & Heavy Engineering (MMHE)
- Malaysian Mining Corporation (MMC)
- Ranhill Worley
- RNZ Integrated (Malaysia)
- SapuraKencana Petroleum Bhd (now Sapura Energy Bhd)
- SBM Malaysia Sdn Bhd
- Siemens Malaysia
- Technip (now TechnipFMC)
- Yokogawa Industrial Safety Systems Sdn Bhd (YISS)
