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Entity | State of Incorporation | |
|---|---|---|
| Bright Star Partnership | Texas | |
| Centrahoma Processing LLC | Delaware | |
| MarkWest Blackhawk, L.L.C. | Texas | |
| MarkWest Energy Appalachia, L.L.C. | Delaware | |
| MarkWest Energy East Texas Gas Company, L.L.C. | Delaware | |
| MarkWest Energy Finance Corporation | Delaware | |
| MarkWest Energy GP, L.L.C. | Delaware | |
| MarkWest Energy Operating Company, L.L.C. | Delaware | |
| MarkWest Gas Marketing, L.L.C. | Texas | |
| MarkWest Gas Services, L.L.C. | Texas | |
| MarkWest Hydrocarbon, Inc. | Delaware | |
| MarkWest Javelina Company, L.L.C. | Texas | |
| MarkWest Javelina Pipeline Company, L.L.C. | Texas | |
| MarkWest Liberty Bluestone, L.L.C. | Delaware | |
| MarkWest Liberty Gas Gathering, L.L.C. | Delaware | |
| MarkWest Liberty Midstream & Resources, L.L.C. | Delaware | |
| MarkWest Mariner Pipeline, L.L.C. | Delaware | |
| MarkWest Marketing, L.L.C. | Delaware | |
| MarkWest McAlester, L.L.C. | Oklahoma | |
| MarkWest Michigan Pipeline Company, L.L.C. | Michigan | |
| MarkWest Mountaineer Pipeline Company, L.L.C. | Delaware | |
| MarkWest New Mexico, L.L.C. | Texas | |
| MarkWest Ohio Fractionation Company L.L.C. | Delaware | |
| MarkWest Oklahoma Gas Company, L.L.C. | Oklahoma | |
| MarkWest Pinnacle, L.L.C. | Texas | |
| MarkWest Pioneer, L.L.C. | Delaware | |
| MarkWest Pipeline Company, L.L.C. | Texas | |
| MarkWest PNG Utility, L.L.C. | Texas | |
| MarkWest Power Tex, L.L.C. | Texas | |
| MarkWest Ranger Pipeline Company, L.L.C. | Delaware | |
| MarkWest Texas PNG Utility, L.L.C. | Texas | |
| MarkWest Utica EMG, L.L.C. | Delaware | |
| MarkWest Utica Operating Company, L.L.C. | Delaware | |
| Mason Pipeline Limited Liability Company | Michigan | |
| Matrex, L.L.C. | Michigan | |
| Mule Tracts, L.L.C. | Delaware | |
| Ohio Gathering Company, L.L.C. | Delaware | |
| West Shore Processing Company, L.L.C. | Michigan | |
| Wirth Gathering, a general partnership | Oklahoma |