SemGroup Energy Partners, L.P. ("SGLP") (Pink Sheets: SGLP) today filed its Quarterly Report on Form 10-Q for the quarter ended June 30, 2008 and provided an update on certain recent developments outlined below.

Settlement with the Private Company

As previously disclosed, SemGroup, L.P. (the "Private Company") and certain of its subsidiaries filed voluntary petitions for reorganization under Chapter 11 of the Bankruptcy Code in the United States Bankruptcy Court for the District of Delaware (the "Bankruptcy Court") on July 22, 2008. On March 12, 2009, the Bankruptcy Court held a hearing and approved the transactions contemplated by a term sheet relating to the settlement of certain matters between the Private Company and SGLP (the "Settlement Agreement"). The Bankruptcy Court entered an order approving the Settlement Agreement on March 20, 2009.

The Settlement Agreement provides for the following, among other things:

• SGLP will transfer certain crude oil storage assets located in Kansas to the Private Company. These crude oil storage assets are part of the Private Company's proprietary Kansas crude oil transportation pipeline;
• the Private Company will transfer ownership of 355,000 barrels of crude oil tank bottoms and line fill to SGLP. These barrels of crude oil are necessary for SGLP to operate its crude oil tank storage and the Oklahoma and Texas crude oil pipeline systems;
• the Private Company will reject the existing Throughput Agreement with SGLP pursuant to which SGLP provides crude oil gathering, transportation, terminalling and storage services for the Private Company at certain minimum levels;
• SGLP and the Private Company will enter into a new throughput agreement pursuant to which SGLP will provide certain crude oil gathering, transportation, terminalling and storage services to the Private Company based on actual volumes transported at market rates;
• SGLP and the Private Company will enter into a shared services agreement pursuant to which the Private Company will provide certain crude oil operational services to SGLP;
• SGLP and its affiliates will have a $20 million allowed unsecured claim against the Private Company relating to rejection of the Throughput Agreement;
• SGLP will offer employment to certain crude oil operational employees primarily located in Oklahoma, Kansas, and Texas;
• the Private Company will transfer its asphalt assets that are connected to SGLP's existing 46 asphalt terminals to SGLP or one of its affiliates;
• the Private Company will reject the existing Terminalling and Storage Agreement with SGLP pursuant to which SGLP provides asphalt terminalling and storage services for the Private Company at certain minimum levels;
• SGLP and the Private Company will enter into a new terminalling agreement pursuant to which SGLP will provide asphalt terminalling and storage services for the Private Company's remaining asphalt inventory which will be removed from SGLP's asphalt storage facilities no later than October 31, 2009;
• a subsidiary of SGLP will have a $35 million allowed unsecured claim against the Private Company relating to rejection of the Terminalling Agreement;
• the Private Company will be entitled to receive 20% of the proceeds of any sale by SGLP of any of the asphalt assets transferred to SGLP in connection with the Settlement Agreement that occurs within nine months of the transfer of such assets to SGLP;
• the Private Company will reject the Amended and Restated Omnibus Agreement pursuant to which the Private Company provided certain general and administrative and operational services for SGLP. SGLP is in the process of replacing these general and administrative services and hiring employees to perform certain of these operational services;
• other than as provided above, SGLP and the Private Company entered into mutual releases of claims relating to the rejection of the Terminalling and Storage Agreement, Throughput Agreement and Amended and Restated Omnibus Agreement;
• certain pre-petition claims by the Private Company and SGLP will be netted and waived;
• the Private Company and SGLP will resolve certain remaining issues related to the contribution of certain crude oil assets to SGLP in connection with SGLP's initial public offering, SGLP's acquisition of certain asphalt assets from the Private Company, SGLP's acquisition of the Eagle North pipeline from the Private Company and SGLP's acquisition of certain Cushing crude oil storage assets from the Private Company, including the release of claims relating to such acquisitions; and
• SGLP and the Private Company will enter into a license agreement providing SGLP with a non-exclusive, worldwide license to use certain trade names, including the name "SemGroup", and the corresponding mark until December 31, 2009, and the Private Company will waive claims for infringement relating to such trade names and mark prior to the date of such license agreement.

The Private Company and SGLP have agreed to and are in the process of negotiating and executing definitive documentation with respect to the items contained in the Settlement Agreement, which will supersede the Settlement Agreement when so executed.

The Settlement Agreement is subject to SGLP obtaining a consent from its lenders to the transactions and a waiver of the existing defaults or events of default under SGLP's credit agreement. There can be no assurance that SGLP's lenders will provide the required consent to the transactions or waiver of existing defaults or events of default under SGLP's credit agreement or that the transactions contemplated by the Settlement Agreement will be consummated.

"We believe the proposed settlement with the Private Company is in the mutual best interests of the Private Company and SGLP. The agreement will reunite the Private Company's asphalt assets with our assets and will allow us to provide asphalt and terminalling services at some or all of our 46 owned asphalt terminalling and storage facilities. We do not currently intend to operate an asphalt marketing business, but instead will operate an asphalt terminalling and storage business as we evaluate longer term opportunities for the business. Regarding our crude oil assets, the settlement will result in us receiving crude oil line fill and tank bottoms that are necessary to operate our Oklahoma, West Texas and Longview, Texas storage and pipeline systems. We will continue to pursue additional third party crude oil transportation and storage customers which currently account for approximately 88% of our crude oil revenues. The settlement agreement also resolves numerous other issues between the parties," stated Kevin Foxx, Chief Executive Officer and President of SGLP's general partner.

Realignment of Executive Management Team

On March 18, 2009, the Board of Directors of SGLP's general partner realigned the officers of SGLP's general partner, appointing Michael J. Brochetti as Executive Vice President—Corporate Development and Treasurer, Alex G. Stallings as Chief Financial Officer and Secretary, and James R. Griffin as Chief Accounting Officer. Mr. Brochetti had previously served as Chief Financial Officer and Mr. Stallings had previously served as Chief Accounting Officer and Secretary. Mr. Griffin had previously served as controller of our general partner.

Duke Ligon, Chairman of the Board of Directors of SGLP's general partner said, "We believe this realignment provides additional depth and expertise to our executive management team and better describes the day-to-day responsibilities of each of the officers. We welcome James to the executive management team and look forward to his input and continued contribution to SGLP."

Extension of Forbearance

As previously disclosed, events of default have occurred and are continuing under SGLP's credit agreement, which prohibit SGLP from borrowing under its credit facility to fund working capital needs or to pay distributions to its unitholders, among other things. Effective September 18, 2008, SGLP and the requisite lenders entered into a Forbearance Agreement and Amendment to Credit Agreement (the "Forbearance Agreement") under which the lenders agreed, subject to specified limitations and conditions, to forbear from exercising their rights and remedies arising from SGLP's defaults or events of default described therein for the period commencing on September 18, 2008 until December 11, 2008. The Forbearance Period was extended until December 18, 2008 pursuant to a First Amendment to Forbearance Agreement and Amendment to Credit Agreement, and the Forbearance Period was further extended until March 18, 2009 pursuant to a Second Amendment to Forbearance Agreement and Amendment to Credit Agreement.

On March 18, 2009, SGLP and the requisite Lenders entered into the Third Amendment to Forbearance Agreement and Amendment to Credit Agreement (the "Third Amendment"), dated as of March 17, 2009. The Third Amendment extends the Forbearance Period until the earliest of (i) April 8, 2009, (ii) the occurrence of any default or event of default under the Credit Agreement other than certain defaults and events of default indicated in the forbearance agreement, as amended, or (iii) the failure of SGLP to comply with any of the terms of the forbearance agreement, as amended.

"The forbearance extension will allow us additional time to negotiate definitive documents and the waiver of existing defaults or events of default under our credit agreement required in connection with the settlement agreement with the Private Company. Further, our current cash balance is in excess of $30 million, and we believe this amount of cash is sufficient to run our day to day operations in the near term," stated Mike Brochetti, Executive Vice President—Corporate Development and Treasurer of SGLP's general partner.

Filing of Form 10-Q

SGLP today filed its Quarterly Report on Form 10-Q for the quarter ended June 30, 2008. As previously disclosed, SGLP's common units were delisted from the Nasdaq Global Market ("Nasdaq") effective at the opening of business on February 20, 2009 due to SGLP's failure to timely file its Quarterly Reports on Form 10-Q for the quarters ended June 30, 2008 and September 30, 2008. SGLP's common units are currently traded on the Pink Sheets, which is an over-the-counter securities market, under the symbol SGLP.PK. SGLP continues to work to become compliant with its SEC reporting obligations and intends to promptly seek the relisting of its common units on Nasdaq as soon as practicable after it has become compliant with such reporting obligations. However, there can be no assurances that SGLP will be able to relist its common units on Nasdaq or any other national securities exchange and SGLP may face a lengthy process to relist its common units if it is able to relist them at all.

"Today's filing of our second quarter 2008 Form 10-Q is a significant accomplishment and the result of much time and effort put forth by numerous individuals given the events and circumstances of the past eight months since the Private Company's bankruptcy filing. We intend to continue to work diligently to become fully compliant with our SEC reporting obligations," stated Alex Stallings, Chief Financial Officer of SGLP's general partner.

About SemGroup Energy Partners, L.P.

SemGroup Energy Partners owns and operates a diversified portfolio of complementary midstream energy assets. SemGroup Energy Partners provides crude oil and liquid asphalt cement terminalling and storage services and crude oil gathering and transportation services. SemGroup Energy Partners is based in Tulsa, Oklahoma. SGLP's common units are currently traded on the Pink Sheets, which is an over-the-counter securities market, under the symbol SGLP.PK. The general partner of SemGroup Energy Partners is a subsidiary of SemGroup, L.P. For more information, visit SemGroup Energy Partners' web site www.SGLP.com.

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Forward-Looking Statements

This news release includes forward-looking statements. Statements included in this press release that are not historical facts (including any statements concerning the benefits of the Settlement Agreement and our ability to meet the conditions to effect such agreement and any statements concerning plans and objectives of management for future operations or economic performance, or assumptions related thereto) are forward-looking statements. Such forward-looking statements are subject to various risks and uncertainties. These risks and uncertainties include, among other things, uncertainties relating to the Private Company's bankruptcy filings, uncertainties relating to the consummation of the settlement with the Private Company, uncertainties relating to pursuing strategic alternatives for SGLP's business, insufficient cash from operations, market conditions, governmental regulations and factors discussed in SemGroup Energy Partners' filings with the Securities and Exchange Commission. If any of these risks or uncertainties materialize, or should underlying assumptions prove incorrect, actual results or outcomes may vary materially from those expected. SemGroup Energy Partners undertakes no obligation to publicly update or revise any forward-looking statement, whether as a result of new information, future events or otherwise.

SGLP Investor Relations
Brian Cropper, 918-524-SGLP (7457)
Toll Free Phone: 866-490-SGLP (7457)
investor@semgroupenergypartners.com