Sunoco empties pipeline to deal with Chester County sinkhole

Sunoco is purging natural gas liquids from 44 miles of its Mariner East 1 pipeline to allow inspection of the line following the appearance of a sinkhole Sunday at a construction site in Chester County’s West Whiteland Township, the Public Utility Commission said.

The removal of product was due to be complete by Thursday evening with the purging of the final 3.8 miles of the line to the Marcus Hook Industrial Complex in Delaware County, the PUC said late Thursday.

On Wednesday, Sunoco finished “temporary stabilization work” around the sinkhole, including securing a section of the pipeline that was exposed when the sinkhole – estimated by the county emergency services to be about 10 feet deep – opened up, the PUC said.

The whole of Mariner East 1 has been shut down since Jan. 21 and will not be allowed to restart until Sunoco gets approval from the PUC’s Bureau of Investigation and Enforcement, the statement said. “No product is flowing in this pipeline anywhere in Pennsylvania,” it said.

In response to the sinkhole incident, Sunoco previously said it would purge the pipeline of product but did not specify how much of the line would be affected.

The sinkhole is the latest to appear at Lisa Drive, a suburban development where Sunoco has been building the Mariner East 2 and 2X pipelines along the same right of way as the existing Mariner East 1. The existing pipeline was built in the 1930s and previously carried gasoline, but has been repurposed for natural gas liquids as part of the multi-billion-dollar Mariner East project.

In early 2018, several sinkholes opened up in the same patch of ground behind five Lisa Drive houses, forcing Sunoco to fill the holes, and prompting a judge to order the shutdown of operation and construction at the site because of concerns for public safety.

Critics said the earlier sinkholes showed the geology of the area was too unstable to support the construction of two new pipelines on the same site as the existing one, and that residents were being exposed to the heightened risk of explosion in their backyards.

Although the PUC later lifted an injunction on operation and construction of the pipelines at Lisa Drive, there are two other sites in the township where the ban remains in place because Sunoco has not yet met the PUC’s requirements, said PUC spokesman Nils Hagen-Frederiksen.

During the current shutdown, PUC safety inspectors are working with Sunoco officials and a geotechnical consultant to ensure public safety, the agency said. It said the bureau can take enforcement action or seek emergency orders from the full commission to protect public safety during the investigation into the new sinkhole.

Lisa Dillinger, a spokeswoman for Sunoco’s parent, Energy Transfer, did not respond to questions on how product is purged from the line and how long it might be before ME1 is restarted.

State Sen. Andy Dinniman, a persistent critic of the Mariner East project and the PUC’s oversight of it, said the reappearance of a sinkhole at Lisa Drive shows that the PUC failed to deal with the problem when it first arose.

Dinniman (D-Chester) repeated his call for the project to be shut down until public safety can be assured. He said there should be an independent inquiry that could be conducted by the state Attorney General, the Governor, or by a task force that would be set up by the Legislature.

After many delays, Sunoco began operating Mariner East 2 on Dec. 29 last year, carrying propane, ethane and butane across Pennsylvania to Marcus Hook, where most of it will be exported.