Listed below is a partial listing of past and present companies served:

• Audubon Engineering
• Basic Systems, Inc.
• Consumers Energy
• DTE Energy
• El Paso Group:
• Bear Creek Storage Company
• Cheyenne Plains Gas Pipeline Company, LLC
• Colorado Interstate Gas Company
• ELBA Express Co., LLC
• El Paso Natural Gas Company
• Mojave Pipeline Operating Company
• Southern Natural Gas Company
• Southern LNG., Inc.
• Tennessee Gas Pipeline Company
• Wyoming Interstate Co., Ltd.
• Young Gas Storage Co., LLC
• Enbridge Energy Company, Inc.
• Great Lakes Gas Transmission Company
• Koch Pipeline Company, L.P.
• Major Pipeline Company
• PACE Consulting, LLC
• Petrologistics
• Plains All American Pipeline
• Plains Marketing, L.P.
• Patrick Energy
• Quicksilver Resources, Inc.
• Select Engineering
• SRW, Inc.
• TransCanada USA Services, Inc
• ANR Pipeline Company
• ANR Storage Company
• Blue Lake Gas Storage Co., GP
• Eaton Rapids Gas Storage System
• Mid Michigan Gas Storage Company