EXHIBIT 32.1 CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002 This certification is provided pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, 18 U.S.C. Section 1350, and accompanies the quarterly report on Form 10-Q for the quarter ended June 30, 2003 (the "Form 10-Q") of SEMCO Energy, Inc. (the "Issuer"). I, Marcus Jackson, Chairman of the Board, President and Chief Executive Officer of the Issuer, certify that: (i) The Form 10-Q fully complies with the requirements of Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934 (15 U.S.C. 78m(a) or 78o(d)); and (ii) The information contained in the Form 10-Q fairly presents, in all material respects, the financial condition and results of operations of the Issuer. Dated: August 12, 2003 /s/Marcus Jackson -------------------------------------- Marcus Jackson Chairman of the Board, President and Chief Executive Officer SEMCO Energy, Inc.