MWP Markwest Hydrocarbon,

MarkWest Hydrocarbon, Inc. (AMEX: MWP) will announce second quarter 2007 financial results and file its Quarterly Report on Form 10-Q with the Securities and Exchange Commission after market close on Wednesday, August 8, 2007. You are invited to join a conference call and webcast on Tuesday, August 14, 2007, at 5:00 p.m. Eastern Time with Frank Semple, President and Chief Executive Officer; Nancy Buese, Senior Vice President and Chief Financial Officer; Randy Nickerson, Senior Vice President and Chief Commercial Officer; and Andrew Schroeder, Vice President Finance and Treasurer. The conference call can be accessed by dialing 888-324-4145 (passcode �MarkWest�) or via webcast, the link for which is available in the �Investor Relations� section of the MarkWest website at www.markwest.com. A replay of the conference call will be available through Tuesday, August 21, 2007, by dialing 866-393-0878 (no passcode required). Alternatively, the conference call will be archived on the website above. 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 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 our Annual Report on Form 10-K for the year ended December 31, 2006, and our Quarterly Reports on Form 10-Q, as filed with the SEC.