New sinkhole forms along Mariner East pipeline in Chester County

Susan Phillips

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Susan Phillips tells stories about the consequences of political decisions on people's every day lives. She has worked as a reporter for WHYY since 2004. Susan's coverage of the 2008 Presidential election resulted in a story on the front page of the New York Times. In 2010 she traveled to Haiti to cover the earthquake. That same year she produced an award-winning series on Pennsylvania's natural gas rush called "The Shale Game." She received a 2013 Alfred I. duPont-Columbia University Journalism Award for her work covering natural gas drilling in Pennsylvania. She has also won several Edward R. Murrow awards for her work with StateImpact. In 2013/14 she spent a year at MIT as a Knight Science Journalism Fellow. She has also been a Metcalf Fellow, an MBL Logan Science Journalism Fellow and reported from Marrakech on the 2016 climate talks as an International Reporting Project Fellow. A graduate of Columbia School of Journalism, she earned her Bachelor's degree in International Relations from George Washington University.

Marie Cusick / StateImpact Pennsylvania

In this photo from May 2018, Mariner East 2 pipeline construction crews work in the backyards of homes on Lisa Drive in West Whiteland Township, Chester County. The area has dealt with a number of sinkholes, including one on July 6, 2023. The problem led to Energy Transfer buying at least five homes along Lisa Drive after the aquifer there was damaged.

July 11, 2023 | 6:22 PM

The Pennsylvania Public Utility Commission is investigating a newly formed “earth feature” along the Mariner East natural gas liquids pipeline in Chester County.

More often referred to as land subsidence or a sinkhole, it occurred in the area of Lisa Drive, West Whiteland Township, where multiple sinkholes first appeared during construction of the pipeline in March 2018.

At that time, the PUC ordered a temporary shut down of a parallel natural gas pipeline, citing a “catastrophic” effect if it led to a leak. At least five homes on Lisa Drive were later sold to the Texas-based pipeline builder and operator Energy Transfer after its work damaged the aquifer and left gaping holes in residents’ backyards.

Sinkholes caused by construction continued to appear in Chester County, including near the Chester Valley Trail and the Exton Library. The area sits on limestone, a porous rock that was prone to sinkhole development even before construction of the Mariner East.

In this most recent incident, Energy Transfer notified the Department of Environmental Protection that on July 6, a new sinkhole, 18 inches in diameter and 54 inches deep, opened up near its natural gas liquids lines along the Lisa Drive right-of-way. The company reported it had excavated and backfilled the sinkhole, according to a DEP spokesperson.

In an emailed statement to WHYY, the PUC said its “independent Bureau of Investigation – which includes the Pipeline Safety Division – was notified of, and responded to, an earth feature on the Lisa Drive right-of-way in West Whiteland Township, Chester County. I&E will continue their investigation, as appropriate.”

Ginny Kerslake, a Chester County resident and organizer with Food and Water Watch, visited the site after hearing from a nearby resident. On Tuesday, she said she saw fresh straw on top of what looked to be the site of the newly remediated sinkhole.

Energy Transfer did not respond to a request for comment by Wednesday evening.

In December 2022, the company filed a brief in a case before the Public Utility Commission where Chester and Delaware county residents sought a complete shutdown of the pipeline system for safety reasons. In the brief, one of the company’s experts, Dr. Timothy Bechtel, vouched for the subsequent remediation of the Lisa Drive sinkholes. He referred to the area as “the most intensely geophysically investigated real estate of which I am aware…the most geophysically studied parcel on the planet.”

Alex Bomstein, an attorney with the Clean Air Council, a plaintiff in the case, was surprised when informed of the new sinkhole.

“This was supposed to be put to rest,” Bomstein said. “So why is this extremely analyzed piece of earth shifting once again beneath our feet?”

The Mariner East pipelines carry volatile natural gas liquids from the Marcellus Shale gas fields in Ohio and western Pennsylvania across the state to the Marcus Hook industrial complex in Delaware County. Construction of the three-line project began in February 2017 but became mired in legal challenges and mishaps, and was subject to a number of consent decrees resulting from citizen lawsuits. It was completed in February 2022, several years behind schedule.

The DEP has issued dozens of notices of violations to Energy Transfer, which has paid more than $20 million in fines and assessments since construction began.

In August 2022, the company agreed to pay an additional $10 million while “accepting criminal responsibility” for dozens of charges related to construction of its Mariner East pipeline project and the 2018 explosion of the Revolution pipeline in Beaver County.

The settlement came after the Attorney General released a grand jury presentment in October 2021, which was dozens of pages long and detailed sinkholes, drilling mud spills, and drinking water contamination at 22 sites in 11 counties across Pennsylvania.

Meanwhile, the Chester County Commissioners were scheduled to vote Wednesday on funds to help remediate damage from Mariner East construction, including almost $500,000 to remediate sinkholes at the Exton Library and along the Chester Valley Trail. Also on the agenda is a $720,000 grant from federal pandemic relief funds to create an emergency preparedness plan.