Site Background
MarkWest Liberty Midstream & Resources LLC (MarkWest) is currently authorized to operate its Harmon Creek Gas Plant under GP5-63-01011B and Plan Approval 63-01011.
The Harmon Creek Gas Processing Plant is located at 123 Point Pleasant Road in Smith Township, Washington County.
What’s New
On January 19, 2024, DEP received MarkWest’s application for air quality plan approval [PA-63-01011B] to construct and temporarily operate air contamination sources and air cleaning devices associated with the proposed DeEthanizer II and 330 MMscfd Cryo II projects at its Harmon Creek Gas Processing Plant.
On February 8, 2025, DEP published notice of its intent to issue a draft plan approval [PA-63-01011B]. More information on the plan approval application and draft are available in the Permitting/Approvals section.
On March 11, 2025, DEP will hold a public hearing to receive public comments on its intent to issue air quality plan approval [PA-63-01011B]. More information on the hearing is available in the Public Participation section.
Permitting/Approvals
Public Participation
Public Notice and Comment Period
On December 3, 2022, DEP published notice of its intent to issue the air quality plan approval [PA-63-01011] in the Pennsylvania Bulletin. This notice also commences a 30-day public comment period.
- Pennsylvania Bulletin Notice (starts on page 7434)
On February 8, 2025, DEP published notice of its intent to issue the air quality plan approval [PA-63-01011B] in the Pennsylvania Bulletin. This notice also commences public comment period.
- Pennsylvania Bulletin Notice(opens in a new tab) (starts on page 1328)
Public Hearing – March 11, 2025
On March 11, 2025, DEP will hold a public hearing to receive public comments on its intent to issue air quality plan approval [PA-63-01011B].
March 11, 2025 from 6:30 to 8:30 PM
Burgettstown Area Middle/High School Campus
LGI Room
100 Bavington Road
Burgettstown, PA 15021
Members of the public will have the opportunity to present up to three minutes of oral testimony relevant to the draft plan approval.
Those wishing to register for the public hearing must contact Emily Green, Southwest Regional Environmental Justice Coordinator, by email at emgreen@pa.gov or by calling 412-442-4042 at least 24 hours before the hearing. Testimony is limited to three (3) minutes in length. DEP requests that organizations designate one spokesperson to present testimony on their behalf. Individuals should provide a copy of their testimony and exhibits for submission to DEP at the hearing. Submitted materials are not limited in length and must include the name, address, and phone number of the person submitting them and identification of the proposed Plan Approval (PA-63-01011B). DEP will equally consider all comments, whether delivered orally during the hearing or submitted in writing.
Individuals wishing to attend who require an auxiliary aid, service, or other accommodations to participate should contact Emily Green. The Pennsylvania AT&T Relay Service is available by calling 1-800-654-5984 (TTD users) or 1-800-654-5988 (voice users) and request that the call be relayed to Emily Green at 412-442-4042
Compliance/Enforcement
On October 5, 2022, DEP and MarkWest Liberty Midstream & Resources, LLC executed a consent assessment of civil penalty (CACP) to resolve violations 2021 of visible emissions from flaring.
- CACP (10-5-2022) (PDF)
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Southwest Community Information