Airco Cryoplants, Inc.
Algonquin Gas Transmission Co.
Alliance Pipeline L.P.
Alyeska Pipe Line Service Company
A.N.R. Pipeline Company
Aramco
Arco Pipe Line Company
Arkansas Louisiana Pipe Line Company
Arkla Energy Resources, Inc.
Ashland Pipe Line Company
Boardwalk Pipeline Partners
CenterPoint Energy Gas Transmission
Central Valley Gas Storage
Centurion Pipeline
Chandeleur Pipe Line Company
Cheniere Energy
Chevron Pipe Line Company
Cities Service Oil Company
CMS Energy
Coastal States Gas Corporation
Columbia Pipeline Group
Colonial Pipe Line Company
Columbia Gas Transmission Corporation
Columbia Gulf Transmission Co.
Dixie Pipe Line Company
Dow Chemical Company
Duke Energy Corporation
El Paso Natural Gas Company
Energy Transfer Fuel
Enterprise Products
Explorer Pipe Line Company
Express Pipeline Partnership
Exxon Pipe Line Company
Florida Gas Transmission Company
Great Lakes Gas Transmission Company
Gulf Refining Company
Gulf South Pipeline Company
Intratex Gas Company
Kern River Gas Transmission Company
Kinder Morgan, Inc.
Liberty Gas Storage, LLC
Louisiana Offshore Oil Port
Louisiana Power & Light Company
Louisiana State Gas Corporation
MAPCO, Inc.
Marathon Pipeline Company
MarkWest
Michigan Consolidated Gas Company
MichiganWisconsin Pipe Line Company
Mobil Pipeline Company
Nato Germany
Natural Gas Pipeline Company of America
NikiskiAlaska Pipeline Company
NiSource Transmission & Storage
NiSource Midstream LLC
Northern Border Pipeline Company
Northwest Pipeline Corporation
Occidental Petroleum Corporation Libya
Pan American Argentina Oil Company Argentina
Pennsylvania Power & Light
Petroleos Mexicanos – Mexico
Fluor Engineering
Phillips Pipe Line Company
Plantation Pipe Line Company
Puget Sound Energy, Inc.
Republic of Turkey Turkey
Rockies Express Pipeline / Entrega
Rotterdam Rijn Pipeline Company – Germany
Seadrift Pipeline Company
Sea Robin Pipe Line Company
Sempra Pipelines & Storage, LLC
Shell Pipe Line Corporation
Southern Natural Gas Co.
Standard Oil of Indiana
Stauffer Chemical Company
TC Energy (TransCanada)
Tennessee Gas Pipeline Company
Texas Eastern Gas Pipeline Company
Texas Gas Transmission Company
Texas Pipeline Company
Texoma Pipeline Co.
TransColorado Gas Transmission Company
Transcontinental Gas Pipe Line Corporation
Trunkline Gas Company
Union Carbide Corporation
United Gas Pipe Line Company
USA Environment, LP
Williams Companies