EXPLAINER | Mariner East: A pipeline project plagued by mishaps and delays
220 stories

Mariner East: A pipeline project plagued by mishaps and delays

Jon Hurdle / StateImpact PA

A Mariner East 2 construction site in rural Pennsylvania. The Public Utility Commission lifted a ban on construction of a valve, removing one obstacle to completion of the troubled project.

Sunoco Logistics Mariner East pipeline project includes three lines — the Mariner East 1, the Mariner East 2, and the Mariner East 2X, all of which carry or will soon carry natural gas liquids (NGLs) from the Marcellus and Utica Shale plays in eastern Ohio and western Pennsylvania across the state to a processing and export terminal in Marcus Hook, Delaware County.

In 2014, Sunoco completed its conversion of a gasoline pipeline originally built in the 1930’s to ship gas from Philadelphia area refineries to rural Pennsylvania. Reversing the flow of the 8-inch line, Sunoco’s Mariner East 1 now carries NGLs across Pennsylvania to its suburban Philadelphia facility where it is shipped overseas to manufacture plastics.

The Mariner East 2 would expand capacity to 345,000 barrels of NGLs a day. The 20-inch diameter high pressure pipeline tunnels beneath 17 counties, cuts through 2,700 properties with a 50-foot right-of-way, and crosses more than 1,200 streams or wetlands. The company used eminent domain procedings to secure right-of-ways from reluctant landowners, including one family in Huntingdon County that sat in their trees to protest the pipeline construction. Dozens of landowners are still tied up in litigation with the company and the state Supreme Court could decide to hear the cases.

Construction on the $2.5 billion project began in February 2017, after the Department of Environmental Protection identified hundreds of deficiencies in its water-crossing and earth-moving permits. Since then the DEP has issued more than 60 violations to the company for polluting wetlands, waterways, and destroying about a dozen private water wells. In the summer of 2017, DEP, along with several environmental groups, agreed to a consent decree with Sunoco after dozens of drilling mud spills led to the pollution of high value wetlands and trout streams, and the loss of drinking water for residents of a Chester County community.

In April, 2017 Sunoco Logistics merged with Energy Transfer Partners, the builder of the controversial Dakota Access line. Completion of the line is now about 18 months behind its original schedule. The Mariner East 2X is a 16-inch NGL line that will run parallel to the ME2.

In March 2018 Pennsylvania’s Public Utility Commission ordered a temporary shutdown of the Mariner East 1, saying it could have a “catastrophic” effect on public safety if it leaks. The commission said the pipeline had been exposed by the appearance of sinkholes near the construction of the two other Mariner pipelines. On May 3, 2018 the PUC allowed NGL’s to flow through the pipeline after their inspectors reported the sink holes did not pose a threat to public safety.

Latest stories


Crews worked on Monday Jan. 21 to stabilize a new sinkhole that opened up at Lisa Drive, a suburban development in West Whiteland Township, Chester County where Sunoco operates its Mariner East pipelines.
Updated: February 13, 2019 | 12:29 pm

Wolf’s support for pipeline-safety bills boosts bipartisan advocates

Continued problems with Sunoco’s Mariner East project, and the company’s failure to fix problems related to a line in western Pennsylvania, have raised the profile of legislation that has stalled in the past.

By Jon Hurdle

The site of the Revolution Pipeline explosion that occurred in September 2018.
Updated: February 8, 2019 | 4:13 pm

PA DEP halts new pipeline permits for Mariner East, cites ongoing violations with Revolution pipeline

The DEP says Energy Transfer, which is the parent company of Sunoco, failed to fix problems after an explosion rocked Beaver County in September.

By Susan Phillips

A new sinkhole that opened up on Sunday was surrounded by orange plastic fencing outside a suburban home at Lisa Drive in West Whiteland Township, Chester County.

To help deal with Chester County sinkhole, Sunoco removes product from 44 miles of pipeline

No natural gas liquids are flowing in Mariner East 1 anywhere in Pennsylvania, PUC says
By Jon Hurdle

Crews worked on Monday Jan. 21 to stabilize a new sinkhole that opened up at Lisa Drive, a suburban development in West Whiteland Township, Chester County where Sunoco operates its Mariner East pipelines.
Updated: January 22, 2019 | 10:12 am

Sunoco to ‘purge’ part of Mariner East 1 after new sinkhole opens at Lisa Drive

Sinkholes in early 2018 exposed a section of Mariner East 1, prompting a Public Utility Commission administrative law judge to shut down the pipe and halt construction of two new lines, citing an “imminent risk” to the public. 

By Jon Hurdle

This photo taken on July 11, 2012, shows the Marcus Hook Refinery in Marcus Hook, Pa. The facility, which is owned and operated by Sunoco Logistics, is an international hub for natural gas liquids–propane, ethane, and butane–from the Marcellus Shale region of Western Pennsylvania. Sunoco Logistics is spending roughly $2.5 billion on the Mariner East projects, which will connect the western part of the state to the port at Marcus Hook.
Updated: January 10, 2019 | 5:18 pm

Judges say DEP unlawfully issued air-quality permits to Sunoco at Marcus Hook

Agency must review the permits, but ruling has 'no immediate effect' otherwise, environmental group says
By Jon Hurdle

In this May 2018 photo, workers and contractors for Sunoco Pipeline investigate sink holes behind homes at Lisa Drive, West Whiteland Township, Chester County where the company has been drilling for construction of the Mariner East 2 and 2X pipelines. The company offered to relocate residents of the five homes whose yards are crossed by the pipeline right of way.

Chester County DA names former federal prosecutor to beef up pipeline probe

Tom Hogan says investigation will proceed even if there are talks with Sunoco
By Jon Hurdle

The Andover estate in Thornbury Township, Delaware County, along the route of the Mariner East 2 pipeline which began operating on Dec. 29. A valve site for the pipeline is in the center of the picture.

Mariner East startup renews safety fears for some residents in Delaware County

Many who live in the densely-populated southeastern Pennsylvania area have opposed the pipeline project. Now that natural gas liquids are running through the line, one resident says she doesn’t know how she’ll sleep at night.

By Jon Hurdle

Energy Transfer, the parent company of Mariner East 2 pipeline builder, Sunoco, works at Snitz Creek in West Cornwall Township, Lebanon County after a drilling mud spill during the summer.

Mariner East 2 pipeline is up and running, Sunoco says

The project faced multiple regulatory setbacks and was already 18 months behind schedule when it missed a September start-up target. It still faces a hearing before the PUC and a criminal investigation by the Chester County district attorney.

By Scott Blanchard

Mariner East 2 pipeline construction crews work in the backyards of homes on Lisa Drive in West Whiteland Township, Chester County, on May 2, after sinkholes opened in the area. That caused one of the ME2 project's many delays.

Spills, shutdowns and legal challenges: a tumultuous year for Mariner East 2

After multiple delays, Sunoco has said it is on target to start operations of the controversial pipeline by end of 2018.

By Jon Hurdle

Crews work to stabilize sinkholes in a West Whiteland Township, Chester County neighborhood on March 3. The sinkholes appeared  near a construction site for the Mariner East 2 pipeline.
Updated: December 19, 2018 | 5:37 pm

Chester County district attorney opens criminal investigation into Mariner East pipeline project

The district attorney said a recent pipeline explosion in Beaver County, and a visit to see where sinkholes opened last year at a pipeline construction site, prompted him to act.

By Jon Hurdle
LOAD MORE