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    Southwest Community Information

    Mazzaro - McKees Rocks Landfill HSCA Response

    This page was last updated on February 13, 2025

    Site Facts

    Municipality: 
    Kennedy Township, Allegheny County

    Hazardous Sites Cleanup Act (HSCA) site since: 
    2004

    Primary Contaminants of Concern: 
    landfill gas, including methane

    Background

    Work by DEP and its contractors has demonstrated that landfill gas (LFG), including methane, exists within the site and potentially beyond the boundaries of the site, at levels that exceed standards established in Pennsylvania's Title 25, Chapter 273 regulations for combustible gas monitoring, off-site migration and mitigation at permitted municipal waste landfill sites. DEP has completed a prompt interim response at the site in order to help prevent the potential for offsite LFG migration.

    What’s New

    Since the installation of a passive trench venting system, DEP has performed post-construction performance monitoring to assess the efficacy of the landfill gas remediation system. The monitoring indicates that the system is performing as designed.          

    Prompt Interim Response under HSCA

    DEP has considered the following six alternatives to address the potential for LFG migration from the site: 1) take no action; 2) installation of an enhanced gas venting system; 3) Installation of a passive trench venting system; 4) installation of a semi-active trench venting system; 5) Installation of an active trench system; and 6) installation of impermeable barriers.

    DEP chose alternative number 3, the installation of a passive trench venting system, because it complies with the applicable or relevant and appropriate requirements and is the most cost-effective.

    In spring 2021, DEP’s contractor completed work to help control the off-site migration of landfill gas which consisted of installing a collection trench system to capture and vent the gas. In October 2021, DEP’s contractor submitted a remedial construction completion report.

    Administrative Record

    The administrative record which contains the information that forms the basis and documents the selection of this response action is available for public review and comment. The administrative record is linked below in digital form.

    Public Participation

    Public Notice:

    DEP published notice of its prompt interim response under HSCA at the Mazzaro – McKees Rocks Landfill site in the February 20, 2021 edition of the Pennsylvania Bulletin. This included information on DEP’s hearing and public comment period.

    An identical notice was published in the legal notices section of the Pittsburgh Post-Gazette on February 18, 2021.

    On March 5, 2021, DEP issued a press release announcing the public hearing.

    Public Comment Period on Administrative Record:

    The administrative record was open for comment from February 15, 2021 until May 21, 2021. 

    Public Hearing:

    DEP held a virtual public hearing to receive oral comments for inclusion in the administrative record on Tuesday, April 6, 2021.

    More Information on the Hazardous Sites Cleanup Act (HSCA) Program