ANR Pipeline Company
Cimarex Energy Company
Consumers Energy
Dominion East Ohio
DTE Energy/MichCon
DTE Biomass
El Paso Corporation
Enbridge Energy
Exxon/Mobil
GE Energy
Great Lakes Gas Corporation
Kinder Morgan
LHB, Inc. 
Marysville Hydrocarbons
Midwest Grain Processors LLC
Panhandle Eastern Pipeline Company
Progress Energy
Samson Resources
Tennessee Gas Pipeline
TransCanada
Wolverine Pipeline Company
Zeeland Farm Services