EXHIBIT 21 MATERIAL SUBSIDIARIES 1. Trunkline Gas Company, LLC, a Delaware limited liability company 2. Pan Gas Storage Company, LLC, a Delaware limited liability company 3. Panhandle Partner, LLC, a Delaware limited liability company 4. Panhandle Holdings, LLC, a Delaware limited liability company 5. Trunkline LNG Holdings, LLC, a Delaware limited liability company 6. Trunkline LNG Company, LLC, a Delaware limited liability company