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    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 Plant is located at 123 Point Pleasant Road in Smith Township, Washington County.

    Permitting/Approvals

    On June 29, 2022, DEP authorized the facility to operate under GP5-63-01011B (AG5-63-00011A).

    On June 29, 2022, DEP received an air quality plan approval application from MarkWest.

    On July 8, 2022, DEP deemed the application to be administratively incomplete and noted technical deficiencies. On July 11, 2022, DEP received a response from MarkWest. On July 13 and 14, 2022, DEP received responses to technical deficiencies. On July 21, 2022, DEP deemed the application to administratively complete.

    On September 1, 2022, DEP requested a more detailed BAT analysis that DEP received on October 17, 2022. DEP received additional revised technical information on the following dates: October 19, October 31, November 1, November 3, November 4, November 10, November 17, and November 21, 2022.

    On November 23, 2022, DEP issued a draft plan approval.

    On December 3, 2022, DEP published notice of its intent to issue the air quality plan approval in the Pennsylvania Bulletin.

    On April 12, 2023, DEP issued the air quality plan approval.

    Public Involvement

    On December 3, 2022, DEP published notice of its intent to issue the air quality plan approval in the Pennsylvania Bulletin. This notice also commences a 30-day public comment period.

    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.