CenterPoint EnergyElectric Transmission and Distribution
CenterPoint Energy closes on gathering and processing assets in northeast Texas

HOUSTON – July 31, 2012 – CenterPoint Energy Field Services, LLC (CEFS), an indirect, wholly-owned natural gas gathering, processing and treating subsidiary of CenterPoint Energy, Inc. (NYSE: CNP), announced today that it has closed on an acquisition of gathering and processing assets for approximately $275 million from Prism Gas Systems I, L.P. (Prism), a wholly-owned subsidiary of Martin Midstream Partners L.P. (NASDAQ: MMLP). The assets acquired include Prism’s 50 percent interest in Waskom Gas Processing Company (Waskom). A subsidiary of CEFS currently owns the other 50 percent interest in Waskom. CEFS also acquired certain other gathering and processing assets from MMLP’s Natural Gas Services segment.

CEFS owns and operates approximately 3,900 miles of gathering pipelines and processing plants that gather, treat and process approximately 2.6 billion cubic feet per day of natural gas from approximately 150 separate systems located in major producing fields in Arkansas, Louisiana, Oklahoma and Texas.

CenterPoint Energy, Inc., headquartered in Houston, Texas, is a domestic energy delivery company that includes electric transmission & distribution, natural gas distribution, competitive natural gas sales and services, interstate pipelines, and field services operations. The company serves more than five million metered customers primarily in Arkansas, Louisiana, Minnesota, Mississippi, Oklahoma, and Texas. Assets total more than $22 billion. With about 8,800 employees, CenterPoint Energy and its predecessor companies have been in business for more than 135 years. For more information, visit the Web site at www.CenterPointEnergy.com.

This news release includes forward-looking statements. Actual events and results may differ materially from those projected. The statements in this news release regarding the anticipated benefits of the Prism acquisition and other statements that are not historical facts are forward-looking statements. Factors that could affect actual results include the timing and extent of changes in commodity prices, and other factors discussed in CenterPoint Energy’s and its subsidiaries’ Form 10-Ks for the fiscal year ended December 31, 2011, and form 10-Qs for the quarterly period ended March 31, 2012, and other filings with the SEC.