Houston, Texas, September 27, 1999-Tennessee Gas Pipeline Company, a business unit of El Paso Energy Corporation (NYSE:EPG), announced today the completion of construction and initial commercial gas flows on a new interconnect between Tennessee's Donna Lateral and the existing facilities of Pemex Gas y Petroquimica Basica (Pemex-Gas) in Reynosa, Mexico.

The 9.5 mile, 24-inch bi-directional pipeline will flow up to 220,000 dekatherms per day (Dth/d). Pemex has entered into a 10-year firm commitment for 185,000 Dth/d of capacity on the new facilities and on Tennessee's system. Customers will benefit from new supply and market opportunities in both countries.

Construction of the lateral took five months and included 24 irrigation canal and road crossings, as well as a 1,600 foot directional drill under the Rio Grande from Pemex-Gas' Reynosa metering station into the Lower Rio Grande Valley Wildlife Refuge.

"The Tennessee interconnect with Pemex-Gas is the third pipeline to link El Paso's pipeline systems with those of Pemex-Gas," said John W. Somerhalder II, president of Tennessee Gas Pipeline Company. "El Paso and Pemex-Gas have been partnering on projects such as this since the 1930s, and we expect to continue building on our strong relationship in the future. Our goal is to provide customers on both sides of the border with the best supply and market opportunities in the industry."

With over $10 billion in assets, El Paso Energy Corporation provides energy solutions through its strategic business units: Tennessee Gas Pipeline Company, El Paso Natural Gas Company, El Paso Field Services Company, El Paso Power Services Company, El Paso Merchant Energy Company, and El Paso Energy International Company. The company owns the nation's only integrated coast-to-coast natural gas pipeline system and has operations in natural gas transmission, gas gathering and processing, power generation, energy marketing, and international energy infrastructure development. On June 10, the stockholders of both El Paso Energy and Sonat Inc. overwhelmingly voted in favor of merging the two organizations. The merger is expected to close in the fourth quarter of this year, concurrent with the completion of regulatory reviews. Visit El Paso Energy's web site at www.epenergy.com.

This release includes forward-looking statements and projections, made in reliance on the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. The companies have made every reasonable effort to ensure that the information and assumptions on which these statements and projections are based are current, reasonable, and complete. However, a variety of factors could cause actual results to differ materially from the projections, anticipated results or other expectations expressed in this release. While the companies make these statements and projections in good faith, neither the companies nor their managements can guarantee that the anticipated future results will be achieved. Reference should be made to the companies' (and their affiliates') Securities and Exchange Commission filings for additional important factors that may affect actual results.