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News Releases from Region 03

EPA settlement with MarkWest addresses Clean Air Act violations at Evans City, Pa. plant

Contact Information: 
EPA Region 3 Press Office (

PHILADELPHIA (September 25, 2020) – The U.S. Environmental Protection Agency announced today a settlement with MarkWest Liberty Bluestone, L.L.C. to settle alleged Clean Air Act violations at its natural gas processing plant in Evans City, Pennsylvania.

EPA cited MarkWest for violations that included:

  • Failure to timely conduct a third-party leak detection and repair audit,
  • Failure to timely comply with requirements for monitoring leaks at connectors, and
  • Failure to timely apply to incorporate these leak detection requirements into a federally enforceable state operating permit. 

These alleged violations increased the risk of excess fugitive volatile organic compound emissions from the facility.

EPA identified the alleged violations while reviewing the company’s compliance with a previous administrative compliance order from March 2017 related to prior violations.

As part of the settlement, MarkWest did not admit liability for the alleged violations, but has agreed to pay a penalty of $150,000 and has certified that it is now in compliance with applicable Clean Air Act requirements.

For more information on the Clean Air Act, visit: