Williams Partners L.P. (NYSE: WPZ) announced today that it is initiating a non-binding open season from May 30 to June 28, 2012, for an expansion of its Transco interstate pipeline to provide incremental firm natural gas transportation capacity to markets in northern Georgia and Alabama by 2016. Williams (NYSE: WMB) owns approximately 68 percent of Williams Partners, including the general-partner interest. The Dalton Expansion Project is being designed to provide up to 600,000 dekatherms per day of incremental firm transportation service on Williams Partners’ Transco pipeline from interconnections accessing Marcellus natural gas production at its Zone 6 Station 210 pooling point to delivery points in northern Georgia and Alabama. “The Transco pipeline is uniquely positioned to provide power generators and local distribution companies located in the southeastern United States with direct access to substantial Marcellus natural gas supplies,” said Randy Barnard, president of Williams Partners’ natural gas pipeline business. The capacity, scope and cost of the project will be determined by the results of the open season. The proposed project will be subject to approval by the Federal Energy Regulatory Commission and other agencies. For customer inquiries, contact Toi Anderson at (713) 215-4540. The Transco pipeline is an approximately 10,000-mile transmission pipeline system which transports natural gas to markets throughout the northeastern and southeastern United States. The current system capacity is approximately 9.6 million dekatherms per day. About Williams Partners L.P. (NYSE: WPZ) Williams Partners L.P. is a leading diversified master limited partnership focused on natural gas transportation; gathering, treating, and processing; storage; natural gas liquid (NGL) fractionation; and oil transportation. The partnership owns interests in three major interstate natural gas pipelines that, combined, deliver 14 percent of the natural gas consumed in the United States. The partnership’s gathering and processing assets include large-scale operations in the U.S. Rocky Mountains and both onshore and offshore along the Gulf of Mexico. Williams (NYSE: WMB) owns approximately 68 percent of Williams Partners, including the general-partner interest. More information is available at www.williamslp.com. Portions of this document may constitute “forward-looking statements” as defined by federal law. Although the partnership believes any such statements are based on reasonable assumptions, there is no assurance that actual outcomes will not be materially different. Any such statements are made in reliance on the “safe harbor” protections provided under the Private Securities Reform Act of 1995. Additional information about issues that could lead to material changes in performance is contained in the partnership’s annual reports filed with the Securities and Exchange Commission.