- CONOCO – Germany
- FRONTIER – El Dorado, U.S.A.
- CONOCO – Ponca City, U.S.A.
- SAMREF – Saudi Arabia
- SHELL – England
- PDVSA – Venezuela
- PETROBRAS, Brazil
- GIANT REFINING – Gallop, U.S.A.
- PETROLSZOLG LTD – Hungary
- FORTUM – Finland
- CITGO – Illinois, U.S.A.
- BP LAVERA – France
