EXHIBIT 99.1 - PRESS RELEASE DATED FEBRUARY 22, 2001


                                 Contact:    John Fox, CEO and President
                                             Brian O'Neill, COO and Sr. VP
                                             Gerry Tywoniuk, CFO and VP Finance
                                             David Wright, Director of
                                             Investor relations
                                 Phone:      (303) 290-8700
                                 E-mail:     dwright@markwest.com
                                 Website:    www.markwest.com


               LAWSUITS CHALLENGE MARKWEST HYDROCARBON POSITION

      DENVER - February 22, 2001 - MarkWest Hydrocarbon, Inc. (AMEX:MWP) ("the
Company") reported today that three complaints have been filed against it in the
Circuit Court of Wayne County, West Virginia by: Columbia Gas Transmission
Corporation and Columbia Natural Resources, Inc.; Equitable Production Company
and Equitable Energy LLC; and Cobra Petroleum Production Company et al. These
complaints each allege breach of contract and seek various forms of relief and
damages.

      "MarkWest will vigorously defend our position which we believe is fair and
reasonable," said John Fox, president and chief executive officer of MarkWest.
"We have offered these companies a win-win solution. A number of other producers
have agreed to the alternative proposal provided by MarkWest."

      As the Company reported in its fourth quarter 2000 earnings release
February 7, 2001, current and futures prices for natural gas have risen
dramatically, and prices for natural gas liquids (propane, butane, etc.)
("NGLs") have stayed essentially flat. A large portion of MarkWest's processing
services for gas producers in Appalachia involves extracting NGLs from inlet gas
streams and replacing the equivalent heat content with dry natural gas purchased
in the spot or forward markets. This part of the Company's operating margin
depends on a positive spread between NGL prices and natural gas costs. When
feasible, the Company has hedged a substantial portion of its natural gas
redelivery obligation. Effective February 1, 2001, the Company provided
producers with an alternative processing contract that provides for additional
compensation when processing margins are low and reduced compensation when these
margins are high. To date, nearly 50 producers (accounting for a minority share
of the volume) out of approximately 325 have agreed to the new contract. If
producers elect to remain with the existing contract, the Company will return
the replacement natural gas at a later date as permitted under the existing
contract such that the Company can earn a reasonable fee for its services; for
example, the Company recently advised producers it would return gas for February
2001 processing no later than May 2001. The complaints allege this procedure for
the existing contracts constitutes a breach.

      These high natural gas price conditions, of course, are not an isolated
situation with MarkWest--nationwide, producers and gas processors are
renegotiating their processing agreements for this reason.

      These arrangements will assure the continued processing of producers'
natural gas and will provide producers the capacity necessary to support their
increasing production. Between 1999 and 2001, MarkWest is investing $35 million
to provide expanded processing services for the producers. These investments
enable the Appalachia gas producing industry to meet the growing demand for
natural gas and NGLs such as propane.





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      MarkWest Hydrocarbon, Inc., provides natural gas processing and related
services through its modern, efficient plant and pipeline systems. Near-record
drilling activity for natural gas in Appalachia and elsewhere and the growing
trend for natural gas producers to outsource the complex task of converting raw
natural gas at the wellhead into marketable natural gas and NGLs (propane,
butanes, natural gasoline) are driving the demand for MarkWest's services.
MarkWest also produces natural gas in the Rocky Mountains and Michigan.

      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, including statements
with respect to the outcome of the pending litigation matters and contract
negotiations. All statements other than statements of historical facts included
or incorporated herein may constitute forward-looking statements. Although the
Company believes that the expectations reflected in the forward-looking
statements are reasonable, it can give no assurance that such expectations will
prove to be correct. The forward-looking statements involve risks and
uncertainties that affect the Company's operations, financial performance and
other factors as discussed in the Company's filings with the Securities and
Exchange Commission. Among the factors that could cause results to differ
materially are those risks discussed in the Company's Form 10-K for the year
ended December 31, 1999, intermediate or final decisions in the pending
litigation, and the relative positions of the parties in the negotiation of new
agreements.