EXHIBIT 15 ACCOUNTANT'S ACKNOWLEDGMENT We acknowledge the incorporation by reference in the Registration Statements on Form S-3 (filed in October 2000 and March 2001) and Form S-8 (filed in November 1997) of Penn Octane Corporation of our report dated December 4, 2003 which appears on page 3 of the Quarterly Report on Form 10-Q/A for the quarter ended October 31, 2003. /s/ BURTON MCCUMBER & CORTEZ, L.L.P. Brownsville, Texas May 21, 2004 39