1 Exhibit 21 SUBSIDIARIES OF THE REGISTRANT STATE OF SUBSIDIARY INCORPORATION - ---------- ------------- The Canton Oil & Gas Company Ohio Target Oilfield Pipe & Supply Company Ohio Ward Lake Drilling, Inc. Michigan Peake Energy, Inc. Delaware Engine Power Systems, Inc. Ohio As of December 31, 1996, the other subsidiaries included in the registrant's consolidated financial statements, and all other subsidiaries considered in the aggregate as a single subsidiary, did not constitute a significant subsidiary.