MarkWest Energy Partners Announces Tender Offers and Consent Solicitations for Its 6.875% Senior Notes due 2014

MarkWest Energy Partners, L.P. (NYSE: MWE) announced today that it has commenced cash tender offers (the "Offers”) for any and all of the outstanding $225,000,000 aggregate principal amount of its 6.875% senior notes due 2014 (CUSIP No. 570506AC9) (the "Series A Notes”) and $150,000,000 aggregate principal amount of its 6.875% senior notes due 2014 (CUSIP No. 570506AL9) (the "Series B Notes” and collectively with the Series A Notes, the "Notes”) and a solicitation of consents to certain proposed amendments to the indenture governing the Series A Notes and the indenture governing the Series B Notes (collectively, the "Indentures”).

Each Offer is scheduled to expire at 11:59 p.m., New York City time, on November 16, 2010, unless extended or earlier terminated (the "Expiration Time”). Holders who validly tender their Notes and provide their consents to the amendments to the related Indenture before 5:00 p.m., New York City time, on November 1, 2010, unless extended (the "Consent Expiration”), will be eligible to receive the Total Consideration (as defined below). The Offers contemplate an early settlement option, so that holders whose Notes are validly tendered prior to the Consent Expiration and accepted for purchase could receive payment as early as November 2, 2010. Tenders of Notes may be validly withdrawn and consents may be validly revoked until the Withdrawal Time (defined below).

The "Total Consideration” for each $1,000 principal amount of Notes validly tendered and not validly withdrawn prior to the Consent Expiration is $1,025.42, which includes a consent payment of $30.00 per $1,000 principal amount of Notes. Holders tendering after the Consent Expiration will be eligible to receive only the ‘Tender Offer Consideration,” which is $995.42 for each $1,000 principal amount of Notes, and does not include a consent payment. Holders whose Notes are purchased in the Offers will also receive accrued and unpaid interest from the most recent interest payment date for the Notes to, but not including, the applicable payment date. Holders who validly tender their Notes before the Consent Expiration will be eligible to receive payment on the initial payment date, which is expected to be on or about November 2, 2010, and holders tendering after the Consent Expiration and prior to the Expiration Time will be eligible to receive payment on the final payment date which is expected to be November 17, 2010.

In connection with the Offers, MarkWest is soliciting consents to certain proposed amendments to each Indenture. Holders may not tender their Notes without delivering consents or deliver consents without tendering their Notes. No consent payments will be made in respect of Notes tendered after the Consent Expiration. Following receipt of the consent of holders of at least a majority in aggregate principal amount of a series of Notes, MarkWest will execute a supplemental indenture to amend the related Indenture to eliminate substantially all of the restrictive covenants and certain events of default in that Indenture.

Tendered Notes may be withdrawn and consents may be revoked before 5:00 p.m., New York City time, on November 1, 2010, unless extended (the "Withdrawal Time”), but generally not afterwards. Any extension, termination or amendment of either Offer will be followed as promptly as practicable by a public announcement thereof.

Each Offer is subject to the satisfaction of certain conditions including: (1) receipt of consents to the amendments to the related Indenture from holders of a majority in principal amount of the outstanding respective Notes governed by such Indenture, (2) execution of a supplemental indenture effecting the amendments, (3) consummation of a new capital markets debt financing raising proceeds in an amount sufficient to fund the Offer and (4) certain other customary conditions.

The complete terms and conditions of the Offers are described in the Offers to Purchase and Consent Solicitations Statement dated October 18, 2010, copies of which may be obtained from D.F. King & Co., Inc., the depositary and information agent for the Offers, at (800) 431-9643 (US toll free) or, for banks and brokers, (212) 269-5550.

MarkWest has engaged Wells Fargo Securities to act as the exclusive dealer manager and solicitation agent in connection with the Offers. Questions regarding the terms of the Offers may be directed to Wells Fargo Securities, Liability Management Group, at (866) 309-6316 (US toll-free) and (704) 715-8341 (collect).

This announcement is not an offer to purchase, a solicitation of an offer to purchase or a solicitation of consents with respect to any securities. The Offers are being made solely by the Offers to Purchase and Consent Solicitations Statement dated October 18, 2010. The Offers are not being made to holders of Notes in any jurisdiction in which the making or acceptance thereof would not be in compliance with the securities, blue sky or other laws of such jurisdiction.

MarkWest Energy Partners, L.P. is a master limited partnership engaged in the gathering, transportation, and processing of natural gas; the transportation, fractionation, marketing, and storage of natural gas liquids; and the gathering and transportation of crude oil. MarkWest has extensive natural gas gathering, processing, and transmission operations in the southwest, Gulf Coast, and northeast regions of the United States, including the Marcellus Shale, and is the largest natural gas processor in the Appalachian region.

This press release includes "forward-looking statements.” All statements other than statements of historical facts included or incorporated herein may constitute forward-looking statements. Actual results could vary significantly from those expressed or implied in such statements and are subject to a number of risks and uncertainties. Although we believe that the expectations reflected in the forward-looking statements are reasonable, we can give no assurance that such expectations will prove to be correct. The forward-looking statements involve risks and uncertainties that affect our operations, financial performance, and other factors as discussed in our filings with the Securities and Exchange Commission. Among the factors that could cause results to differ materially are those risks discussed in the periodic reports we file with the SEC, including our Annual Report on Form 10-K for the year ended December 31, 2009, and our Quarterly Report on Form 10-Q for the quarter ended June 30, 2010. You are urged to carefully review and consider the cautionary statements and other disclosures made in those filings, specifically those under the heading "Risk Factors.” We do not undertake any duty to update any forward-looking statement except as required by law.