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

Mariner East: A pipeline project plagued by mishaps and delays

Marie Cusick / StateImpact Pennsylvania

Mariner East 2 pipeline construction in Delaware County

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 continues to sit in 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 30 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.

Latest stories


The Delaware River basin: Officials say proposed new rules would strengthen protections against contamination from fracking waste water brought into the basin.

Pull the Mariner East permit, environmental group urges Delaware River Basin Commission

Delaware Riverkeeper Network says “severe and ongoing” permit violations are causing “significant harm” to the river basin. It wants the commission to suspend Mariner East 2 construction.

By Jon Hurdle

Workers and contractors for Sunoco Pipeline have been investigating 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.

Suit accuses Sunoco of violating federal Clean Water Act

Even though the oil and gas industry is exempt from obtaining the permits – unlike other kinds of industrial construction such as powerlines — that exemption disappears when a water violation occurs, argued Aaron Stemplewicz, senior attorney for DRN.

By Jon Hurdle

About 150 people showed up at a rally in West Chester on Jun 9 to urge the state's Public Utility Commission to shut down Sunoco's Mariner East pipeline project.

As PUC decision nears, Mariner East foes rally to call for total shutdown 

Sunoco has said the project is nearly finished. Demonstrators said the project’s violations — and the fact that the line was recently struck by a contractor — are reasons to shut it down.

By Jon Hurdle

Mariner East 2 pipeline construction in Delaware County

Officials: Water main contractor struck Mariner East 2 in Delaware County

Damage was minor, but critics say incident highlights public safety risks
By Jon Hurdle

Mariner East 2 pipeline construction in Chester County
Updated: June 6, 2018 | 11:24 am

Chester County commissioners slam Sunoco for ‘appalling’ lack of pipeline information

In a letter to the PUC, the commissioners said local officials haven’t seen some key emergency information, and are learning about “the majority of issues” regarding the Mariner East project from media and residents.

By Jon Hurdle

Mariner East 2 pipeline construction crews work in the backyards of homes on Lisa Drive in West Whiteland Township, Chester County, on May 2. Sinkholes that opened in the area prompted the state's Public Utility Commission to order that an existing pipeline nearby, the Mariner East 1, be shut down until it could be determined that the sinkholes didn't threaten its safety. PUC on May 3 approved a re-start of Mariner East 1.

Sunoco urges PUC to overturn judge’s order halting pipeline construction in Chester County 

The company said that the judge’s decision means a utility would have to prove a project is safe even if no “credible evidence or properly-supported expert testimony” has been offered to show a project threatens public safety.

By Jon Hurdle

Mariner East 2 pipeline construction in Chester County
Updated: May 24, 2018 | 5:05 pm

Mariner East construction, operation halted again in Chester County

An administrative law judge said the project poses “an imminent risk to the public,” and more study is needed before construction can resume. Sunoco’s parent company ripped the decision as “a significant departure from the law.”

By Jon Hurdle

Mariner East 2 pipeline construction crews work in the backyards of homes on Lisa Drive in West Whiteland Township, Chester County, on May 2. Sinkholes that opened in the area prompted the state's Public Utility Commission to order that an existing pipeline nearby, the Mariner East 1, be shut down until it could be determined that the sinkholes didn't threaten its safety. PUC on May 3 approved a re-start of Mariner East 1.

Tree clearing for construction of the Mariner East 2 natural gas liquids pipeline at  site in Delaware County.

Mariner East 2 pipeline construction crews work in the backyards of homes on Lisa Drive in West Whiteland Township, Chester County, on May 2. Sinkholes that opened in the area prompted the state's Public Utility Commission to order that an existing pipeline nearby, the Mariner East 1, be shut down until it could be determined that the sinkholes didn't threaten its safety. PUC on May 3 approved a re-start of Mariner East 1.
LOAD MORE