Exhibit 23 CONSENT OF INDEPENDENT ACCOUNTANTS We consent to the incorporation by reference on Form S-3 (File No. 333-20153) and Form S-8 (File No. 33-39303, File No. 33-51243, and File No. 33-54153) of our report dated February 28, 1997, on our audits of the consolidated financial statements and the financial statement schedule of Tosco Corporation and subsidiaries as of December 31, 1996 and 1995, and for the years ended December 31, 1996, 1995, and 1994, which report is included in this Annual Report on Form 10-K. /s/ Coopers & Lybrand L.L.P. Coopers & Lybrand L.L.P. San Francisco, CA March 3, 1997