1 EXHIBIT 21 QUAKER STATE CORPORATION Subsidiaries All of the following subsidiaries are 100% owned by Quaker State Corporation unless otherwise indicated: Jurisdiction of Name of Subsidiary Incorporation - ------------------ -------------- Fort William Coal Dock Company, Ltd. Ontario Green Shield, Inc. Delaware Lubricants, Inc. Arkansas Myatt-Brooks, Inc. (1) Arkansas QS/Brooks Distribution Company (2) Tennessee QS Holding Company Delaware Quaker Oil Corporation Texas Quaker State, Inc. Canada Quaker State Investment Corporation Delaware Freedom Freightways, Inc. (3) Missouri QSE&P, Inc. (3) Delaware Q Lube, Inc. (3) Delaware Quaker State Minit-Lube Canada, Inc. (4) Ontario Minit-Lube Ontario, Inc. (5) Ontario Lubeco, Inc. (4) Delaware Quaker State Resources L.L.C. (4) Utah The Valley Camp Coal Company (3) Delaware Donaldson Mine Company (6) West Virginia Kelley's Creek and Northwestern Railroad Company (6) West Virginia Valley Camp Investment Company (6) Delaware Elm Grove Coal Company (7) West Virginia Valley Camp Coal Sales Company (7) Ohio The Helen Mining Company (7) Pennsylvania Kanawha and Hocking Coal and Coke Company (7) West Virginia Shrewsbury Coal Company (7) West Virginia Valley Camp of Utah, Inc. (7) Utah Truck-Lite Co., Inc. (3) New York T-L Automotive Industries, Inc. (8) Delaware Truck-Lite International, Inc. (8) Delaware Valley Camp, Inc. (3) Canada Quaker State Japan Co., Ltd. Japan Quaker State Oil Refining Corporation, B.V. Holland Quaker State - Slick 50, Inc. Delaware 2 Jurisdiction of Name of Subsidiary Incorporation - ------------------ -------------- Petrolon UK Ltd. (9) United Kingdom Sutherwell Ltd. (14) United Kingdom Petrolon British Isles Ltd. (15) United Kingdom Petrolon Deutschland GMBH (10) Germany Petrolon Australia Pty. Ltd. (11) Australia Petrolon International Management Monaco SAM (10) Petrolon International Limited (10) Isle of Man Petrolon Overseas Ltd. (12) United Kingdom Petrolon Europe Ltd. (13) Isle of Man Slick 50 Management, Inc. (10) Delaware Slick 50 Products Corporation (16) Delaware Slick 50 Corporation (16) Delaware Specialty Oil Company, Inc. Delaware Westland Oil Company, Inc. Louisiana - -------------------------------------------------------------------------------- (1) 50% owned by Lubricants, Inc. and 50% owned by Specialty Oil Company, Inc. (2) 50% owned by Myatt-Brooks, Inc. (3) 100% owned by Quaker State Investment Corporation (4) 100% owned by Q Lube, Inc. (5) 50% owned by Quaker State Minit-Lube Canada, Inc. (6) 100% owned by The Valley Camp Coal Company (7) 100% owned by Valley Camp Investment Company (8) 100% owned by Truck-Lite Co., Inc. (9) 5% owned by Quaker State - Slick 50, Inc.; 95% owned by Petrolon Europe Ltd. (10) 100% owned by Quaker State - Slick 50, Inc. (11) 5% owned by Quaker State - Slick 50, Inc.; 95% owned by Petrolon Europe, Ltd. (12) 100% owned by Petrolon International Ltd. (13) 99% owned by Petrolon International Ltd.; 1% owned by third party. (14) 100% owned by Petrolon UK Ltd. (15) 100% owned by Sutherwell Ltd. (16) 100% owned by Slick 50 Management, Inc.