Colorado Interstate Gas Company Announces Pricing and Early Tender Results of Pending Cash Tender Offer for up to $100 Million Aggregate Principal Amount of Certain of Its Outstanding Notes

Market Wire, June, 2008

Colorado Interstate Gas Company (CIG), a majority owned subsidiary of El Paso Corporation (NYSE: EP), announced today that it has determined the consideration to be paid in connection with its pending cash tender offer to purchase up to $100 million aggregate principal amount (as it may be increased, the Tender Cap) of its 5.95% Senior Notes due March 15, 2015 (CUSIP No. 193522AH9) (the 5.95% Notes), and its 6.80% Senior Notes due November 15, 2015 (CUSIP No. 196522AK2) (the 6.80% Notes). The tender offer is subject to the terms and conditions set forth in CIG's Offer to Purchase dated May 23, 2008 (the Offer to Purchase).

Holders who validly tendered (and did not validly withdraw) notes in the tender offer at or prior to 5 p.m. Eastern Time on June 6, 2008, which is the early tender date, will receive $1,001.38 per $1,000 principal amount of 5.95% Notes accepted for purchase and $1,051.82 per $1,000 principal amount of 6.80% Notes accepted for purchase, which is referred to in the Offer to Purchase as the Full Tender Offer Consideration. In addition to the applicable Full Tender Offer Consideration stated above, holders whose notes are accepted for purchase will also receive any accrued and unpaid interest from the last interest payment date for the notes to, but not including, the applicable settlement date.

As of 5 p.m. Eastern Time on June 6, 2008, $40,007,000 principal amount of 5.95% Notes and $201,758,000 principal amount of 6.80% Notes had been validly tendered and not validly withdrawn. CIG expects to purchase all of the 5.95% Notes tendered at or prior to the early tender date on June 9, 2008, the initial settlement date for the 5.95% Notes. Any 5.95% Notes tendered after the early tender date and accepted for purchase, and any 6.80% Notes accepted for purchase, will be purchased on the final settlement date, which CIG expects will occur on June 23, 2008.

Holders who validly tender notes in the tender offer after 5 p.m. Eastern Time on June 6, 2008, and at or prior to 12 midnight Eastern time on June 20, 2008, which is the expiration date of the tender offer, will receive the applicable Full Tender Offer Consideration identified above minus the early tender premium of $30.00 per $1,000 principal amount, which is referred to in the Offer to Purchase as the Late Tender Offer Consideration, plus any accrued and unpaid interest from the last interest payment date for the notes to, but not including, the applicable settlement date.

The consideration to be paid in connection with the tender offer was determined by Merrill Lynch & Co. and J.P. Morgan Securities Inc., the dealer managers for the tender offer, as of 2 p.m. Eastern Time on June 6, 2008, as set forth in the Offer to Purchase.

As set forth in the Offer to Purchase, the amount of a series of notes that is purchased in the tender offer will be based on the acceptance priority level for such series and may be prorated. The 5.95% Notes, which are in the first acceptance priority level, will be purchased before the 6.80% Notes, which are in the second acceptance priority level. CIG may increase the Tender Cap, subject to and in accordance with applicable law, without extending withdrawal rights. If the aggregate principal amount of 6.80% Notes tendered exceeds the amount of the Tender Cap remaining available for application to such series, then, if CIG accepts notes of such series for purchase, CIG will accept such notes on a pro rata basis.

CIG has retained Merrill Lynch & Co. and J.P. Morgan Securities Inc. to serve as the dealer managers for the tender offer and has retained Global Bondholder Services Corporation to serve as the depositary and information agent for the tender offer.

Requests for documents may be directed to Global Bondholder Services Corporation by telephone at (866) 952-2200 or (212) 430-3774, or in writing at 65 Broadway--Suite 723, New York, NY 10006. Questions regarding the tender offer may be directed to Merrill Lynch & Co. at (888) 654-8637 or (212) 449-4914, or J.P. Morgan Securities Inc. at (866) 834-4666 or (212) 834-4802.

This press release is neither an offer to purchase nor a solicitation of an offer to sell the notes or any other securities. The tender offer is made only by and pursuant to the terms of the Offer to Purchase and the related letter of transmittal. None of CIG, the dealer managers or the depositary and information agent makes any recommendations as to whether holders should tender their notes pursuant to the tender offer. Holders must make their own decisions as to whether to tender notes, and, if so, the principal amount of notes to tender.

CIG is a Delaware general partnership, originally formed as a corporation in 1927. CIG is owned 90 percent by a wholly owned subsidiary of El Paso Corporation (El Paso) and 10 percent by a wholly owned subsidiary of El Paso Pipeline Partners, L.P. (NYSE: EPB). CIG's primary business consists of the interstate transportation, storage and processing of natural gas. CIG conducts its business activities through its Colorado Interstate gas system, its 50% equity interest in WYCO Development LLC, and gas storage and processing facilities.