Access Midstream
Agave Energy Company
Anadarko Petroleum Corporation
Atlas Pipeline
Boardwalk Pipelines
BP Pipeline North America
BP US Pipelines and Logistics
Belle Fourche Pipeline Company
CenterPoint Energy
Chaparral Energy
Chesapeake Energy
Chevron Pipe Line Company
Colorado Springs Utilities
ConocoPhillips
Crestwood Midstream Partners, LP
Crosstex Energy
DCP Midstream
Eagle Rock Energy
Enbridge Energy
EnCana Oil & Gas (USA) Inc.
Energy Transfer, LTD
Enogex LLC
EOG Resources
EPCO
Equistar Pipeline
Equitable Resources, Inc.
ExxonMobil
Hess Corporation
Hunt Oil
Kinder Morgan
M3 Midstream
MarkWest Energy
Navajo Nation Oil & Gas Company
Nexen, Inc
Noble Energy, Inc.
Northern Natural Gas Company
NW Natural
Plains All American Pipeline
Portland Montreal Pipeline
Public Service Electric & Gas Co.
Questar Gas Management
Quicksilver Resources, Inc
Red Cedar Gathering
Rosewood Resources, Inc.
Shell Pipeline Company LP
Sinclair Transportation
SM Energy
SourceGas
Southern California Gas Company
Southern Star Central Gas Pipeline
Southwestern Energy Company, Inc.
Summit Midstream
Sunoco Logistics
Targa Resources Operating LP
Texas Gas Transmission
UniversalPegasus
Valero Energy
Whiting Oil and Gas Corporation
Williams Gas Pipeline
Williams Midstream
Williston Basin Interstate Pipeline Co.
Xcel Energy
XTO Energy Inc.
Ypfb Transporte S.A.