MarkWest Energy Partners Home Careers Media Relations Operations Customer Portal Contact Us About Us MarkWest, a wholly owned subsidiary of MPLX LP (NYSE: MPLX), is engaged in the gathering, processing, and transportation of natural gas; the transportation, fractionation, storage and marketing of NGLs; and the gathering and transportation of crude oil. Learn More > Operations FERC Pipelines » © 2021 Copyright. MarkWest Energy Partners, L.P. All Rights Reserved. Privacy Policy Terms of Use Sitemap

MarkWest Energy Partners Home Careers Media Relations Operations Customer Portal Contact Us FERC Pipelines Pipeline Safety Safety Data Sheets Safety Data Sheets MarkWest Safety Data Sheets (SDS) – formerly known as Material Safety Data Sheets (MSDS) – provide critical information about our products including the chemical compositions, potential health or environmental hazards, and safe handling instructions. Appalachia Produced Fluids Butane Gasoline Mix Carbon Dioxide Crude Oil Ethane Ethylene High RVP Condensate Hydrogen Isobutane Low RVP Condensate Natural Gas Liquids Natural Gas Natural Gasoline Normal Butane Propane Propylene Wellhead Natural Gas © 2021 Copyright. MarkWest Energy Partners, L.P. All Rights Reserved. Privacy Policy Terms of Use Sitemap

MarkWest Energy Partners Home Careers Media Relations Operations Customer Portal Contact Us Contact Us MarkWest Energy Partners, L.P. welcomes inquiries from investors, news media, business associations, and others interested in the operations of the company. To assist us in responding as quickly as possible, please direct your inquiry to the appropriate contact. General Inquiries MarkWest Energy Partners, L.P. 1515 Arapahoe Street Tower 1, Suite 1600 Denver, CO 80202 Toll Free: (800) 730-8388 Office: (303) 925-9200 Fax: (303) 290-8769 Investor Relations Please refer to the MPLX Investor Relations website. Media Inquiries Please direct all media inquiries to MPLX Public Affairs. © 2021 Copyright. MarkWest Energy Partners, L.P. All Rights Reserved. Privacy Policy Terms of Use Sitemap