( BW)(CO-MARKWEST)(MWE)(MWP) MarkWest Announces Approval of Redemption
and Merger

Business Editors/Energy Editors

DENVER--(BUSINESS WIRE)--Feb. 21, 2008--MarkWest Energy Partners,
L.P. (NYSE: MWE) and MarkWest Hydrocarbon, Inc. (AMEX: MWP) announced
today that their respective equityholders approved and adopted the
previously announced Agreement and Plan of Redemption and Merger (the
"Redemption and Merger Agreement") between the two companies as well
as the transactions contemplated by the Redemption and Merger
Agreement. At separate special meetings of equityholders held in
Denver, Colorado, on February 21, 2008, approximately 21.4 million
units of MarkWest Energy Partners and approximately 9.8 million shares
of MarkWest Hydrocarbon, representing approximately 63 percent and 82
percent, respectively, of the total units and shares outstanding and
entitled to vote at the respective meetings, were voted in favor of
the redemption and merger and related proposals. The number of units
and shares voted in favor of the redemption and merger and related
proposals represent approximately 97 percent and 99 percent,
respectively, of the total units and shares that were voted at the
equityholders meetings.

"The combination of MarkWest Energy Partners and MarkWest
Hydrocarbon is very compelling for our equityholders, and will unlock
substantial long-term value for MarkWest Energy Partners," said Frank
Semple, President and Chief Executive Officer of MarkWest Energy
Partners and MarkWest Hydrocarbon. "We believe the elimination of the
incentive distribution rights will result in MarkWest having one of
the lowest costs of capital in the MLP industry, which will drive
improved financial results from our expansion projects and will
greatly improve our ability to compete for new acquisitions. Looking
ahead, we remain focused on our primary business objective of
providing superior and sustainable returns for our stakeholders,
coupled with a customer-focused growth strategy."

MarkWest Energy Partners, L.P. (NYSE: MWE) is a publicly traded
master limited partnership with a solid core of midstream assets and a
growing core of gas transmission assets. It is one of the largest
processors of natural gas in the Northeast and is the largest gas
gatherer of natural gas in the prolific Carthage field in east Texas.
It also has a growing number of other gas gathering and intrastate gas
transmission assets in the Southwest, primarily in Texas and Oklahoma.

MarkWest Hydrocarbon, Inc. (AMEX: MWP) controls and operates
MarkWest Energy Partners, L.P. (NYSE: MWE), a publicly traded limited
partnership engaged in the gathering, processing and transmission of
natural gas; the transportation, fractionation and storage of natural
gas liquids; and the gathering and transportation of crude oil. We
also market natural gas and NGLs.

This press release includes "forward-looking statements" within
the meaning of Section 27A of the Securities Act of 1933, as amended,
and Section 21E of the Securities Exchange Act of 1934, as amended.
All statements other than statements of historical facts included or
incorporated herein may constitute forward-looking statements.
Although we believe that the expectations reflected in the
forward-looking statements, specifically those including those
referring to future performance, growth, cash flow, operating income,
distributable cash flow (DCF), distributions, or other factors, are
reasonable, these forward-looking statements are not guarantees of
future performance and we can give no assurance that such expectations
will prove to be correct and that projected performance or
distributions may not be achieved. Among the factors that could cause
results to differ materially are those risks discussed in our joint
proxy statement/prospectus, dated January 7, 2008, as filed with the
SEC. You are also urged to carefully review and consider the
cautionary statements and other disclosures, including those under the
heading "Risk Factors," made in the joint proxy statement/prospectus,
which identify and discuss significant risks, uncertainties and
various other factors that could cause actual results to vary
significantly from those expressed or implied in the forward-looking
statements. We do not undertake any duty to update any forward-looking
statement.

Investors and security holders are urged to read the joint proxy
statement/prospectus carefully because it contains important
information regarding MarkWest Energy Partners, MarkWest Hydrocarbon,
and the transaction. Investors and security holders may obtain a free
copy of the joint proxy statement/prospectus and other documents
containing information about MarkWest Energy Partners and MarkWest
Hydrocarbon, without charge, at the SEC's website at www.sec.gov.
Copies of the joint proxy statement/prospectus and the SEC filings
that will be incorporated by reference in the joint proxy
statement/prospectus may also be obtained free of charge by directing
a request to the entities' investor relations department at
866-858-0482, or by accessing the companies' website at
www.markwest.com.

MarkWest Energy Partners, MarkWest Hydrocarbon, the officers and
directors of the general partner of MarkWest Energy Partners, and the
officers and directors of MarkWest Hydrocarbon may be deemed to be
participants in the solicitation of proxies from their security
holders. Information about these persons can be found in the Annual
Report on Form 10-K/A for the year ended December 31, 2006, for each
of MarkWest Energy Partners and MarkWest Hydrocarbon, as filed with
the SEC, and additional information about such persons may be obtained
from the joint proxy statement/prospectus.

This document shall not constitute an offer to sell or the
solicitation of an offer to buy any securities, nor shall there be any
sale of securities in any jurisdiction in which such offer,
solicitation, or sale would be unlawful prior to registration or
qualification under the securities laws of any such jurisdiction. No
offering of securities shall be made except by means of a prospectus
meeting the requirements of the Securities Act of 1933, as amended.

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CONTACT: MarkWest Energy Partners, L.P. and
MarkWest Hydrocarbon, Inc.
Frank Semple, 866-858-0482
President & CEO
or
Nancy Buese, 866-858-0482
Senior VP & CFO
or
Andy Schroeder, 866-858-0482
VP Finance & Treasurer
Fax: 303-925-8709
investorrelations@markwest.com
www.markwest.com

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