Exhibit 21 SUBSIDIARIES OF TOSCO CORPORATION (A Nevada Corporation) Jurisdiction of Incorporation AZL Resources, Inc. Arizona Arizona-Florida Land & Cattle Company Florida AZCO Properties, Inc. Colorado AZL Engineering, Inc. Arizona Breckenridge North Village Corporation Coloardo Diablo Service Corporation California International Energy Insurance Limited Bermuda Marcus Hook Refining Company Delaware Seminole Fertilizer Corporation Delaware Ridgewood Chemical Corporation Delaware T Northwest Properties I, Inc. Delaware T Northwest Properties II, Inc. Delaware The Circle K Corporation Delaware Circle K Stores, Inc. Texas CKC, Inc. Massachusetts Charter Marketing (Connecticut) Connecticut Circle K Money Orders Corp. Texas Circle K International, Inc. (US) Texas Circle K Properties, Inc. Delaware Circle K Franchise Corporation Arizona CKST Corporation Texas Circle K Arizona Limited Partnership Arizona The Oil Shale Corporation Delaware Tosco (C-TI), Inc. Delaware Tosco (C-TLP), Inc. Delaware Tosco Capital Corp. Delaware Tosco Corporation (a subsidiary) Delaware Tosco Europe Limited United Kingdom Tosco Marketing, Inc. Delaware Tosco Northwest, Inc. (formerly Western Hemisphere Corporation) Delaware Avon Marine Corp. Delaware Riverhead Marine Corp. Delaware Tosco Power, Inc. Delaware Tosco Processing & Marketing, Inc. Delaware Bayway Refining Company Delaware Tosco Pipeline Company Delaware Tosco Refining Company, Inc. Delaware Tosco Terminal Company Delaware Tosco Trading, Transportation and Supply, Inc. Delaware Tosco (U.K.) Ltd. Delaware Toscopetro Corporation Delaware TPC Pipe Line Company Delaware Emerald Shipping Corporation Delaware Soundview Fitness Center, Inc. Delaware