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 May 28, 2004 which appears on page 3 of the Quarterly Report on Form 10-Q/A for the quarter ended April 30, 2004. /s/ BURTON MCCUMBER & CORTEZ, L.L.P. Brownsville, Texas July 23, 2004