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PUC orders Sunoco to suspend operations of Mariner East pipeline after sinkholes are found near it in Chester County

HARRISBURG — The Pennsylvania Public Utility Commission issued an emergency order requiring Sunoco Pipeline L.P., a.k.a. Energy Transfer Partners (Sunoco), to suspend operations of the Mariner East 1 Pipeline in response to safety concerns about the pipeline’s integrity caused by sinkholes near the pipeline in Chester County, the commission announced Thursday.

The order also requires Sunoco to run additional testing and analysis of the pipeline, the PUC says.

The PUC’s Bureau of Investigation and Enforcement says it has investigated reports of sinkholes forming at or near the path of the pipeline, located along Lisa Drive in West Whiteland Township. Three sinkholes were discovered near or in the path of ME1, an eight-inch diameter pipeline used to transport liquid propane, butane and ethane. The sinkholes are near an area where construction, including horizontal directional drilling, is underway for a new pipeline, known as Mariner East 2.

The order issued by the PUC requires the following actions:


  • Within 24 hours of the entry of this Order, Sunoco shall run at least one in line inspection tool through the Mariner East 1 Pipeline, inspecting the pipeline from a point at least 1 mile upstream from the Lisa Drive location to a point at least 1 mile downstream from Lisa Drive.
  • Within 12 hours of completing the inspection tool run Sunoco will suspend hazardous liquids transportation service on its Mariner East 1 pipeline for a period of time, presently estimated by BIE and Sunoco to be of 10-14 days duration (the “Study Period”), in order for Sunoco to perform the following:
    • Conduct geophysical testing and analyses (including at least the following: resistivity, seismic and gravity) in the HDD area described in the BIE Petition; and
    • Share all findings of the inspection tool run and geophysical testing with BIE/Pipeline Safety staff; and,
    • Meet and discuss the findings with BIE/Pipeline Safety staff, such discussions shall include, but not be limited to Sunoco’s addition of strain gauges to Mariner East 1 in the study area.
    • During the Study Period, Sunoco shall maintain sufficient minimum pressure in Mariner East 1 to avoid gasification of NGLs.  However, the NGLs shall not be flowing during such period.
  • Sunoco will not reinstate hazardous liquids transportation service on Mariner East 1 until the earlier of the following:
    • Completion of the inspections and testing specified in the Commission’s Order, with any corrective actions taken, or planned to be taken, to the satisfaction of BIE/Pipeline Safety coupled with BIE/Pipeline Safety’s concurrence with reinstatement of transportation service on Mariner East 1, subject to Commission review and approval.
    • If BIE/Pipeline Safety does not concur with Sunoco’s request to resume service on ME1, Sunoco may file an Answer to the BIE Petition within 3 business days following notice of BIE’s noncurrence.
    • The Petition and Answer will be assigned for expedited hearing(s) before the Office of Administrative Law Judge;
    • Sunoco may not resume hazardous liquids transportation service on Mariner East 1 without prior Commission approval.

The Pennsylvania Public Utility Commission balances the needs of consumers and utilities; ensures safe and reliable utility service at reasonable rates; protects the public interest; educates consumers to make independent and informed utility choices; furthers economic development; and fosters new technologies and competitive markets in an environmentally sound manner.