Tulsa, OK— August 12, 2009 —SemGroup, L.P. announced today Kevin Clement has been named President of its SemStream, L.P. subsidiary. He succeeds Larry Payne who has resigned to pursue other opportunities.

Clement was most recently President and Chief Operating Officer of SemMaterials where he was responsible for the overall business, including planning and executing its sale. He previously served as SemMaterials’ Vice President of residual fuel and Vice President of asphalt supply and marketing.

Clement also brings to SemStream more than 20 years of professional leadership experience gained as an officer within several Koch Industries’ market sectors – including natural gas liquids operations and marketing, asphalt processing and marketing, and residual fuels.

Clement graduated from Wichita State University’s W. Frank Barton School of Business with a BBA in marketing.

About SemGroup

Based in Tulsa, Okla., SemGroup, L.P., is a midstream service company providing the energy industry means to move products from the wellhead to the wholesale marketplace. SemGroup provides diversified services for end users and consumers of crude oil, natural gas, natural gas liquids, refined products and asphalt. Services include purchasing, selling, processing, transporting, terminalling and storing energy.

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