The Pennsylvania Public Utility Commission (PUC) late Wednesday suspended operations on Energy Transfer Partners LP’s Mariner East (ME) 1 pipeline after the state’s Bureau of Investigation and Enforcement (I&E) sounded the alarm about sinkholes formed near it.
The emergency order came only hours after the I&E petitioned state commissioners to suspend natural gas liquids (NGL) transportation over concerns about pipeline integrity and the potential threat posed to infrastructure, including nearby homes and an Amtrak line. Three sinkholes, one of which the I&E said was within 10 feet of a house’s foundation, formed in West Whiteland Township near the area where horizontal directional drilling for the ME 2X pipeline is underway.
Within 24 hours of the order, state regulators said Energy Transfer subsidiary Sunoco Pipeline LP is required to run an in-line inspection tool through ME1 from points at least one mile upstream and one mile downstream of the sinkhole locations, which all formed within a 550-foot area. Twelve hours after the inspection tool run, Sunoco is required to suspend NGL service for a “study period” that could last up to 14 days.
During the study period, Sunoco has been ordered to conduct geophysical testing and analyses in the construction area near ME 1 and then share the findings with the I&E and the PUC’s Pipeline Safety Division. Sunoco may maintain sufficient pressure in the pipeline to avoid gasification of the NGLs, but it may not flow volumes during the study period.
Sunoco won’t be able to resume operations on the system until regulators are satisfied with the test results and any corrective actions necessary.
“This period should allow us to share what our professional geologist has established to date -- that the ME1 pipeline is stable, is located in suitably safe geology and will continue to operate safely as it has done for decades,” said Sunoco spokesman Jeffrey Shields. “The safe operation of our pipelines is of critical importance to us, and we believe the study period will reaffirm the safety of the pipeline.”
ME1, a former oil pipeline, was converted to move 70,000 b/d of ethane and propane from Western Pennsylvania to the Marcus Hook Industrial Complex near Philadelphia. After it was repurposed, it entered full service in 2016. The ME2 and ME 2X projects, which are under construction in the ME1 right-of-way, would run parallel for about 350 miles to move ethane, propane and butane from processing facilities in Ohio, Pennsylvania and West Virginia to Marcus Hook.
The Mariner East projects, particularly ME2, have had several regulatory snags. Shields stressed that Wednesday’s order does not affect construction of the other two pipelines.