Exhibit 21 CASTLE ENERGY CORPORATION Listing of Parent and Subsidiaries As of February 29, 1996 Relationship Company's to Ownership Entity Company Business Percentage ------ ------------ -------- ---------- Parent Castle Energy Corporation Parent Holding Company N/A Refining Indian Refining I. L.P. Subsidiary- Refining - Inactive 100% Limited Partnership Indian Refining & Marketing I. Inc. Subsidiary General Partner of IRLP - Inactive 100% Powerine Holding Corp. Subsidiary Holding Company - Inactive 100% Indian Oil Company Subsidiary Refiner - Inactive 100% Natural Gas Marketing Castle Pipeline Company Subsidiary General Partner - Pipeline 100% Partnership Castle Pipeline Resources Company Subsidiary Limited Partner - Pipeline 100% Partnership Castle Texas Pipeline L.P. Subsidiary Natural Gas Transmission 100% Limited Partnership CEC Marketing Company Subsidiary General Partner - Gas Marketing 100% Partnership CEC Marketing Resources Company Subsidiary Limited Partner - Gas Marketing 100% Partnership CEC Gas Marketing L.P. Subsidiary- Gas Marketing 100% Limited Partnership Exploration and Production Castle Exploration Company, Inc. Subsidiary Oil and gas development, drilling 100% and well operations Castle Production Company Subsidiary General Partner - Production 100% Partnership Castle Production Resources Subsidiary Limited Partner - Production 100% Company Partnership Castle Texas Production L.P. Subsidiary- Oil and gas production 100% Limited Partnership Supply Castle Energy Canada Ltd. Subsidiary Supply, Operations and Marketing 100% IP Oil Co., Inc. Subsidiary General Partner 100% Hedging/Future - Inactive Indian Powerine L.P. Subsidiary- Supply/Hedging/Futures - Inactive 100% Limited Partnership Other CEC, Inc. Subsidiary Passive Activities 100% Longview Acquisition Corp. Subsidiary Acquisitions 100%