On December 4, the Department of Environmental Protection was notified by MarkWest Liberty Midstream & Resources LLC that horizontal drilling operations on the construction of the shale gas-related Chiarelli to Imperial pipeline resulted in a 31,000 gallon loss of drilling fluids into coal mine voids under Mount Pleasant Township, Washington County.

This was the seventh reported incident bringing the total amount of fluids lost into the voids to at least 360,000 gallons.  Read more here.

DEP inspectors from the Oil and Gas Program and the Bureau of Abandoned Mine Reclamation inspected the site on December 8 in response to the notification to look for inadvertent drilling fluid returns on the surface at the construction site and found none.

DEP's Abandoned Mines staff collected water samples at several acid mine drainage discharge points and from other water resources in the area of the pipeline construction.

DEP Oil and Gas staff also took samples of the drilling fluid being used prior to it being pumped into the drill bore.

DEP's inspection report noted "violations may be forthcoming pending further investigation."

DEP also noted the company had staged a vacuum truck at the site used to vacuum up drilling fluids that spill.

Click Here for a copy of DEP’s inspection report with photos.

Report Violations

To report oil and gas violations or any environmental emergency or complaint, visit DEP’s Environmental Complaint webpage.

Text photos and the location of abandoned wells to 717-788-8990.

Check These Resources

Visit DEP’s Compliance Reporting Database and Inspection Reports Viewer webpages to search their compliance records by date and owner.

Sign up for DEP’s eNOTICE service which sends you information on oil and gas and other permits submitted to DEP for review in your community.

Use DEP’s Oil and Gas Mapping Tool to find if there are oil and gas wells near or on your property and to find wells using latitude and longitude on well inspection reports.

(Photos: Row 1- Drilling rig and fluid pit; Pipeline route; Row 2-- Discharge from old mine entrance sampled by DEP; Stakes marking abandoned Primrose Mine where the loss of drilling fluid occurred.)

[Note: If you believe your company was listed in error, contact DEP’s Oil and Gas Program.]

[Note: These may not be all the NOVs issued to oil and gas companies during this time period.  Additional inspection reports may be added to DEP’s Oil and Gas Compliance Database.]

PA Oil & Gas Industry Public Notice Dashboards:

-- PA Oil & Gas Weekly Compliance Dashboard - Dec. 6 to 12 - MarkWest Pipeline Loses Another 31,000 Gallons Into Mine Voids; Abandoned Conventional Well Violations Reach 666 

[PaEN]

     -- DEP Investigating Another 31,000 Gallon Spill Into Mine Voids From MarkWest Liberty Midstream Pipeline Construction In Washington County; 360,000 Gallons Lost So Far  [PaEN]

-- PA Oil & Gas Industrial Facilities: Permit Notices, Opportunities To Comment - December 13 [PaEN]

     -- DEP Invites Comments On Water Quality Permit Approvals For Eastern Gas Transmission & Storage Appalachian Reliability Pipeline Project In Armstrong, Greene, Westmoreland Counties  [PaEN] 

     -- PUC Publishes Updates To Low-Income Natural Gas, Electric Utility Usage Reduction Program Regulations  [PaEN] 

-- DEP Posted 61 Pages Of Permit-Related Notices In December 13 PA Bulletin  [PaEN]

    -- DEP Invites Comments On Permits For 5 Large Electric Transmission, Substation Projects In 14 Counties, Including 150 Mile Piney-Seward and Erie South-Piney Transmission Project Crossing 8 Counties  [PaEN]

Related Articles This Week:

-- Environmental Quality Board Votes To Accept Petition To Study An Increase In Setback Safety Zones From Shale Gas Wells; And 3 Petitions From Oil & Gas Industry To Change Other Requirements  [PaEN]

-- YaleEnvironment360:  Pennsylvania Faces A New Natural Gas Fracking Boom With Soaring Energy Demands Needed To Feed A.I. Data Centers  [PaEN]

-- Capitol Wire: Natural Gas Fracking Activity In Pennsylvania Surges As Power Demand From A.I. Data Centers Increases

-- Sen. Yaw Bill To Subsidize Building Only Natural Gas Power Plants To Help Meet The Energy Demands Of A.I. Data Centers; Continues ‘One Of The Above’ Energy Policy  [PaEN] 

-- In Case You Missed It: A.I./Data Center Articles - NewClips From Last Week - December 15  [PaEN]

-- PaGasSwitch.com: Natural Gas Costs Increased From 9.26% to 57.5% Over The Last Year For Natural Gas Utility Customers Not Shopping For A Fuel Supplier  [PaEN]

-- PUC Highlights Ways Natural Gas Customers Can Manage Winter Energy Use, Costs, Explore Energy Affordability Options  [PaEN]

-- Independent Fiscal Office: 2025 Act 13 Shale Gas Impact Fee Revenue Estimate $239.9 Million, Up $75.3 Million From Last Year  [PaEN]

-- Susquehanna River Basin Low Flow Water Conditions Trigger Water Withdrawal Restrictions On 40 Shale Gas Water Withdrawal Points; 17 Shale Gas Withdrawals Blocked By Ice Conditions  [PaEN]

NewsClips:

-- Post-Gazette - Laura Legere: DEP To Review Proposal To Expand No-Drill Zones Around Homes, Schools, Streams

-- Inside Climate News - Jon Hurdle: PA Will Study Plan To Keep New Natural Gas Drilling Pads Farther From Homes, Schools, Hospitals

-- Post-Gazette - Anya Litvak: PUC Approves Columbia Gas Rate Increase - 13th Since 2008

-- Morning Call - Elizabeth Deornellas: How A.I. Data Centers Are Driving Up The Cost Of Electricity And What Grid Operators Can Do [PDF of Article]

-- Post-Gazette - Anya Litvak: What’s Important In Affordable Energy?  A Conversation With A Carnegie Mellon Energy Justice Professor

-- Penn State Extension Energy Essentials: Guide To Extension Energy Team; Upcoming Learning Opportunities; Biogas; Home Heating Assistance Opens

-- TribLive: Some Defendants In Plum Boro Fatal Natural Gas Explosion Case Ask Judge To Dismiss Negligence Claims

-- The Derrick: Titusville Under DEP Deadline To Take Action On Underground Jet Fuel Leak At Titusville Airport [PDF of Article]

-- Inquirer: Former Philadelphia Refinery To Be Redeveloped Into Site For DrinkPAK Manufacturer

-- KYW: NJ Governor Declares Emergency Over Propane Shortage Due To Nov. 21 Power Outage At Marcus Hook Refinery In Delaware County

-- Bloomberg: EU Offers Easier Path For US LNG Gas Exporters To Meet Methane Rules

-- Reuters: US EIA: US Power Use To Reach Record Highs In 2025, 2026: Natural Gas Generation Slides 2%; Renewables Increase 2%; Nuclear Drops 1%; Coal Same

-- Reuters: US House Passes Bill To Fast-Track Natural Gas Pipeline Permitting

-- Reuters: Big Tech Shifts To ‘All Of The Above’ A.I. Power Strategy [Still Prioritizing Renewables Over Fossil Fuels]

-- Financial Times: Visual Story: The Power Crunch Is Threatening America’s A.I. Ambitions  [PDF of Article]

[Posted: December 13, 2025]

12/15/2025