Exhibit 21 SUBSIDIARIES AND AFFILIATES 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 Nordic Village Corporation Colorado C. S. Land, Inc. California Davis Point Pipeline Company California Diablo Service Corporation California Emerald Shipping Corporation Delaware Golden Valley Pipeline Company California International Energy Insurance Limited Bermuda Marcus Hook Refining Company Delaware O. S. Land Services, Inc. Colorado Pacific Northwest Energy Company Washington Royal Triton Company Delaware Seminole Fertilizer Corporation Delaware Ridgewood Chemical Corporation Delaware The Circle K Corporation Delaware Circle K Stores Inc. Texas Charter Marketing (Connecticut) Connecticut Circle K Arizona Limited Partnership Arizona Circle K Enterprises Inc. Delaware TMC Franchise Corporation Arizona Circle K International, Inc. (US) Texas Circle K Money Orders Corp. Texas CKC, Inc. Massachusetts CKST Corporation Texas Spirit Enterprises, Inc. Delaware K-Cal Ventures Inc. Arizona LLC Circle K Licensing Company, Inc. Texas The Oil Shale Corporation Delaware Tosco (C-TI), Inc. Delaware Tosco (C-TLP), Inc. Delaware Tosco (U.K.) Ltd. Delaware Tosco Capital Corp. Delaware Tosco Commercial Inc. Delaware Tosco Europe Limited United Kingdom Tosco Funding Corporation Delaware Tosco Holdings Corp. Delaware Tosco L. P. Delaware L.P. Tosco Marketing, Inc. Delaware Tosco Northwest Properties III, Inc. Delaware Tosco Northwest, Inc. (formerly Western Hemisphere Corporation) Delaware Avon Marine Corp. Delaware Riverhead Marine Corp. Delaware Tosco Operating Company, Inc. (formerly T Northwest Properties II, Inc.) Delaware Tosco Power, Inc. Delaware Tosco Processing & Marketing, Inc. Delaware Bayway Refining Company Delaware Tosco Pipeline Company Delaware Tosco Refining Company, Inc. Delaware Tosco Refining L. P. Delaware L.P. Tosco Terminal Company Delaware Tosco Trading, Transportation and Supply, Inc. Delaware Toscopetro Corporation Delaware TPC Pipe Line Company Delaware Union Pipeline Company (California) (formerly Unocal California Pipeline Company) California Unocal 76 Mexico Mexico Unocal Expresslube, Inc. Illinois Unocal Pacific Blending PTE Ltd. Singapore