1 EXHIBIT 21 SOUTHEASTERN MICHIGAN GAS ENTERPRISES, INC. List of Subsidiaries Exhibit 21 to Form 10-K (1993) The subsidiaries of Southeastern Michigan Gas Enterprises, Inc. (the Registrant) are: Southeastern Michigan Gas Company Michigan Gas Company MI-GAS PROPANE COMPANY (a subsidiary of Michigan Gas Company) Battle Creek Gas Company Southeastern Financial Services, Inc. Southeastern Development Company SEMCO Energy Services, Inc. SEMCO Pipeline Company (a subsidiary of SEMCO Energy Services, Inc.) SEMCO Gas Storage Company (a subsidiary of SEMCO Energy Services, Inc.) SEMCO Arkansas Pipeline Company (a subsidiary of SEMCO Energy Services, Inc.) SEMCO Gathering Company (a subsidiary of SEMCO Energy Services, Inc.) Each is incorporated in the State of Michigan and each does business only under its respective corporate name indicated above.