SemGroup Completes Purchase of Koch Pavement Solutions' Asphalt Businesses; Announces Expanded Credit Facility; Names President

Tulsa, OK- SemGroup, L.P. announced today the completion of its acquisition from Koch Materials Company of asphalt operations and assets located in the United States and Mexico. The purchase price was not disclosed. The definitive purchase and sale agreement was previously announced April 15, 2005.

In conjunction with the acquisition’s closing, SemGroup announced the increase of its credit facility to $1.550 billion. Bank of America Securities LLC is bookrunner for the facility.

SemGroup said the U.S. assets will operate as SemMaterials, L.P. while those in Mexico will be named SemMexico Materials HC, S. de R.L. de C.V. The acquisition includes 47 asphalt terminals in 24 states in the U.S. and 13 asphalt terminals in Mexico; five regional technical centers; 65 worldwide patents and 10 pending patents.

Tom Kivisto, SemGroup president and chief executive officer, also announced that Frank Panzer has been named SemMaterials president and chief operating officer. Panzer previously served as SemGroup’s director – commercial development and led the company’s acquisition team. He joined SemGroup in 2001 and has 30 years of energy and business experience.

About SemGroup, L.P.

SemGroup, L.P. is a midstream service company providing North America’s energy industry means to move products from the wellhead to the wholesale marketplace. It is ranked #14 on Forbes magazine’s list of America’s Largest Private Companies. For additional information, visit www.semgrouplp.com.

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