1 EXHIBIT 21 SUBSIDIARIES OF THE COLUMBIA GAS SYSTEM, INC. as of December 31, 1993 State of Segment / Subsidiary Organization - --------------------------------------------------- ------------------- Oil and Gas Operations - ---------------------- Columbia Gas Development Corporation Delaware Columbia Natural Resources, Inc. Texas Transmission Operations - ----------------------- Columbia Gas Transmission Corporation Delaware Columbia Gulf Transmission Company Delaware Columbia LNG Corporation Delaware Distribution Operations - ----------------------- Columbia Gas of Kentucky, Inc. Kentucky Columbia Gas of Maryland, Inc. Delaware Columbia Gas of Ohio, Inc. Ohio Columbia Gas of Pennsylvania, Inc. Pennsylvania Commonwealth Gas Services, Inc. Virginia Other Energy Operations - ----------------------- Columbia Atlantic Trading Corporation Delaware Columbia Coal Gasification Corporation Delaware Columbia Energy Services Corporation Delaware Columbia Gas System Service Corporation Delaware Columbia Propane Corporation Delaware Commonwealth Propane, Inc. Virginia TriStar Ventures Corporation Delaware TriStar Capital Corporation Delaware TriStar Trading, Inc. Delaware