MarkWest Energy Partners, L.P. (NYSE: MWE) (“MarkWest” or “the Partnership”) announced today the resumption of operations at its Houston processing and fractionation complex (“Houston complex”) in Houston, Pennsylvania. As previously announced, the Houston complex was shut down following what appears to be a weather related incident that occurred on the evening of May 28, 2014. The Houston complex consists of three processing plants totaling 355 million cubic feet per day (MMcf/d) and 98,000 barrels per day of ethane and heavier fractionation capacity. An engineering assessment and inspection of the Houston complex’s facilities and equipment has indicated that the incident was isolated to a heat exchanger that is required for the operation of Plant III. Plants I and II and all of the fractionation units have safely been returned to operation. Plant III will remain shut down in order to complete repairs. In order to minimize the disruption to producer customers utilizing the Houston complex, MarkWest is currently routing gas volumes to the Majorsville complex in Marshall County, West Virginia. The Majorsville complex currently consists of 870 MMcf/d of total processing capacity and is connected to the Houston complex through a large, high-pressure, rich-gas header system. MarkWest will continue routing gas to the Majorsville complex for processing until all required repairs to Houston’s Plant III equipment have been completed and the facility can safely return to normal operation. MarkWest Energy Partners, L.P. is a master limited partnership engaged in the gathering, processing and transportation of natural gas; the gathering, transportation, fractionation, storage and marketing of natural gas liquids; and the gathering and transportation of crude oil. MarkWest has a leading presence in many unconventional gas plays including the Marcellus Shale, Utica Shale, Huron/Berea Shale, Haynesville Shale, Woodford Shale and Granite Wash formation. 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 MarkWest believes that the expectations reflected in the forward-looking statements are reasonable, MarkWest can give no assurance that such expectations will prove to be correct. The forward-looking statements involve risks and uncertainties that affect operations, financial performance, and other factors as discussed in filings with the Securities and Exchange Commission (SEC). Among the factors that could cause results to differ materially are those risks discussed in the periodic reports filed with the SEC, including MarkWest’s Annual Report on Form 10-K for the year ended December 31, 2013. 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.” MarkWest does not undertake any duty to update any forward-looking statement except as required by law.