Sunoco Pipeline LP plans to begin work Tuesday to resume shipping natural gas liquids across southern Pennsylvania through its Mariner East 1 pipeline after a three-month shutdown.
The 88-year-old repurposed pipeline has been out of service since Jan. 20, when a sinkhole exposed several feet of the line in Chester County.
The 8-inch diameter Mariner East 1 — and the larger twin Mariner East 2 pipelines being built alongside it — have been forced to stop and restart operations or construction work several times in the past two years as regulators responded to spills, ground subsidence and water supply disruptions.
Sunoco, a division of Texas-based Energy Transfer LP, gave regulators notice on Friday of its plans to restart the pipeline. Pennsylvania Public Utility Commission spokesman Nils Hagen-Frederiksen said engineers with the commission’s pipeline safety division will be on site Tuesday morning to monitor Sunoco’s restart activities.
The company reached an agreement with the PUC’s investigation bureau to take additional safety steps at the site in West Whiteland Township, where a series of sinkholes on the same street shut down Mariner East 1 for nearly two months in March 2018.
The agreement includes plans for Sunoco to remediate the site and inspect it daily during grouting, perform geophysical tests there every six months for two years, and maintain the existing elevation surveys and strain gauges used to monitor for any movement on the pipeline.
Strain gauges have been in place at the site since 2018 and have not indicated any movement of Mariner East 1 before, during or after the sinkhole appeared, the PUC said.
The pipeline was originally designed to carry gasoline from the Philadelphia area to Western Pennsylvania, but it was reversed in 2014 to deliver natural gas liquids from the Marcellus and Utica shales to East Coast processing facilities and ports for export.
The Mariner East pipelines’ mounting errors have raised alarms with the pipelines’ neighbors, especially in densely populated residential areas in southeastern Pennsylvania.
Mariner East 1 leaked 840 gallons of ethane and propane in Berks County in 2017 at a spot where the pipeline was later found to be corroded. A proposed settlement with regulators would require Sunoco to perform a novel study on the pipeline’s remaining safety life.
Pennsylvania Public Utility Commissioners have not yet voted on whether to adopt the settlement.
Laura Legere: llegere@post-gazette.com.
Updated at 5:41 p.m. April 22, 2019
First Published: April 22, 2019, 3:53 p.m.
