Series Of Sinkholes Spurs Action In Chesco To Halt Pipeline Work

CHESTER COUNTY, PA — Sinkholes — one after another along Mariner East 2 construction sites in Chester County — prompted a letter from the Chester County Commissioners today calling for the work to stop.

In a letter to the Pennsylvania Public Utility Commission (PUC), the Chester County Commissioners on Monday requested that two Mariner East pipelines be ordered to cease operations while further investigations examine the impact on public safety from a recent outbreak of construction-induced sinkholes near the lines.

With at least seven sinkhole formations documented this year, the Commissioners urged PUC to take swift action to protect residents' safety.

The lines in question are Energy Transfer’s Mariner East 1 (ME1) 8-inch and 12-inch natural gas liquid (NGL) pipelines. Both pipelines have been in the ground for about 80 years but only began carrying NGLs under high pressure much more recently. A PUC document explained ME1 is used to transport liquid propane, butane, and ethane.

According to the letter from Commissioners’ Chair Marian Moskowitz, and Commissioners Josh Maxwell and Michelle Kichline, at least seven sinkholes have been caused by construction near the lines in 2021 in the fragile, hollow karst geology in West Whiteland Township. The Commissioners asked that work be halted and the cause of the sinkholes be determined.

The Commissioners' letter reported that one recent sinkhole near the lines swallowed a tree, a phenomenon caught on video and provided with the letter to the PUC.

"It seems to us that the significant risk of exposing these pipelines makes the potential for a catastrophic leak that much easier to occur and renders the ME1 and 12-inch pipelines 'unreasonable, unsafe and inadequate,'" wrote the County Commissioners.

"This is why we are asking that you order operations of the ME1 and 12-inch pipelines be ceased until the Commission can better understand the cause of these sinkholes and the risks that they present to the operation of the operating NGL pipelines," the letter said.

The County Commissioners are asking the PUC to investigate and take swift action, noting that the PUC has access to the necessary geological and engineering studies and reports provided by Energy Transfer.

The County Commissioners have engaged their own independent pipeline engineer and geologist to study the issue, but those experts must rely on only publicly available information.

In their letter to PUC Secretary Rosemary Chiavetta, Chester County Commissioners wrote, “You, the (Public Utility) Commission, are one of the few bodies that can truly ensure our residents' safety by immediately stopping the operation of the current Mariner East lines, and fully studying the issue before allowing product to move again. Please help us in our efforts to keep our residents safe."

This isn't the first series of sinkholes in the area. In 2018, according to PUC documents, engineers from the PUC's Pipeline Safety Division investigated reports of the formation of sinkholes near the ME1, located along Lisa Drive in West Whiteland Township. Three sinkholes were reported discovered near, or in the path of, ME1 in March 2018.

A local residents' group that regularly posts photos and videos of the sinkholes and pipeline construction activity, on Sunday called on County Commissioners to ask the PUC to take action.

West Whiteland Residents for Pipeline Safety is urging others to attend Tuesday's 10 a.m. meeting of the Chester County Commissioners to further urge them, with Chester County Department of Emergency Services, to focus on emergency preparedness and response should there be a leak on any of the Mariner East pipelines that span the County.

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