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 February 2, 2005 which appears on page 3 of the Transition Report on Form 10-Q for the transition period from August 1, 2004 to December 31, 2004. /s/ BURTON MCCUMBER & CORTEZ, L.L.P. Brownsville, Texas February 22, 2005 45