Please zoom in or out and select the base layer according to your preference to make the map ready for printing, then press the Print button above.

Sunoco’s Mariner East 2 pipeline in Pennsylvania, United States


The United States has about 200 million miles of natural gas transmission pipelines, many of which are buried beneath the ground nearby residential areas, schools and cities. The US has increased its demand for natural gas power generation as prices plummeted due to new exploitation of domestic natural gas in the last decade or so; now gas accounts for 1/3 of US electric power generation [11]. The Federal Energy Regulatory Commission, which approves interstate pipelines has only denied two such proposals in the past 30 years, which demonstrates a relative ease of development of pipelines in the current political context of the United States [11]. This ease should be questioned given that the past decades malfunctions and explosions stemming from natural gas pipelines have killed more than 300 people and injured or caused health problems for many more [1].

The Marcellus and Utica Shale is found throughout the Alleghany Plateau of the northern Appalachian Basin of North America including southern New York, northern and western Pennsylvania, eastern Ohio, through western Maryland, and throughout most of West Virginia. Marcellus Shale was first exploited in 2003; in 2010 the Utica Shale was explored in the deeper formations beneath the Marcellus Shale [6]. The United States Geological Survey estimated in 2012 that Utica Shale contains approximately 38 trillion cubic feet of natural gas, about 940 million barrels of oil, and 208 million barrels of natural gas liquids [7], but this latter formation is lesser explored. The exploitation of the Marcellus Shale, considered to have the world’s largest gas reserves has accounted for numerous cases of water, land, and air disruptions within human populations [6]. Environmental justice organizations have catalogued over 20,000 complaints of chemical exposures and related health disorders [9]. 

The Pennsylvania (PA) Pipeline Project (PPP)/Mariner East II aims to provide an outlet for both export and domestic use of the abundance of natural gas and natural gas liquids stemming from both the Marcellus and the Utica shale formations. The $5.1 billion PA Pipeline Project or Mariner East Project has nearly completed the first of two pipelines (Mariner East II) despite numerous interruptions due to regulatory and legal complaints from multiple advocacy groups [1, 2]. The two pipelines follow the right-of-way established for the Mariner I East and carry natural-gas liquids such as propane, ethane, and butane, which can transform into a heavier than air vapor upon leaking and collect near the ground [1]. According to Fractracker, these vapors could potentially harm the 105,491 people living in the vicinity of the pipeline project, as well as the children and teachers at the 23 public schools and 17 private schools located within the Mariner East 2’s best-case impact zone [17]. Many of the schools near the pipeline zone serve families in marginalized communities [17]. While these new pipelines have displaced people and caused public outcry, the Pennsylvania Public Utility Commission (PUC) affirmed in a 2014 litigation that Sunoco may continue to act as a public utility, allowing eminent domain [1]. Anxious communities living near the pipeline construction have vehemently protested and more than six community groups or individuals have litigated to rescind the Sunoco company’s right-of-way across the land, stating losses to property values, contamination, and fear of losses or personal harm, but the 2014 decision has not been overturned [16], each time the court has affirmed Sunoco’s right-of-way, upholding the 2014 decision.

In 2015, a pipeline transporting similar gas-liquids exploded in West Virginia, scorching a house about 700 feet away from the blast [1]. Much contestation has highlighted the dangers associated with the natural gas liquids being transported by the pipelines. The highly combustible, odorless liquid gases are difficult to detect in the case of a leak. Also, sink holes have formed in 2017 and 2018 around the Mariner East I pipeline, causing a PUC judge to shut the pipeline Mariner East I down twice and requiring independent investigation. PUC investigators said the sink holes “could have catastrophic results” if not repaired. Activists have cited the West Virginia explosion, noting that sinkhole appeared just prior to the rupture that caused the 2015 explosion of the ATEX Pipeline, which transports similar liquids to the Mariner East system [4]. “They just do what they want, they are Sunoco and they do whatever they want…I don’t want to move, but I’m terrified that we’re going to get blown up,” says one resident who spotted sinkholes on her property [3]. In the second ruling on sinkholes, the judge cited safety concerns and requested to halt work on the Mariner East II and 2X pipelines as well as operations on Mariner I so that additional studies can be carried out on the geology in West Whiteland Township, which is located about 30 miles (50 km) west of Philadelphia [3]. As stated by one resident, “The order is a resounding affirmation of everything we’ve been saying  the Mariner East pipeline project has potentially endangered our neighborhoods, schools, environment, property rights, water resources, infrastructure, and the health, safety, well-being, and very way of life of our communities” [3]. However, upon completion of geological studies, the Pennsylvania PUC has permitted continuation of the pipelines, with the most recently reopening taking place in June 2018 [8]. Fed up with what they call a lack of progress from their local political leaders, residents and community activists in Chester and Delaware Counties have banded together to commission a study of the risks presented by the Mariner East 2 pipeline [5], which will examine the hazards to the community’s safety and be completed by September 2018.

Basic Data

Name of conflict:Sunoco’s Mariner East 2 pipeline in Pennsylvania, United States
Country:United States of America
State or province:Pipeline from Western to Eastern Pennsylvania
Location of conflict:Marcus Hook, PA
Accuracy of locationMEDIUM (Regional level)

Source of Conflict

Type of conflict. 1st level:Fossil Fuels and Climate Justice/Energy
Type of conflict. 2nd level:Oil and gas exploration and extraction
Transport infrastructure networks (roads, railways, hydroways, canals and pipelines)
Shale gas fracking
Specific commodities:Natural Gas
Liquid natural gases: propane, ethane, and butane

Project Details and Actors

Project details

The Mariner East Project is a 300-mile long pipeline that will be built primarily upon the existing pipeline infrastructure (50-foot easements) of the Sunoco pipeline, across the state of Pennsylvania. The original pipeline was established in the 1930s by Sunoco for the transport of refined petroleum from the refinery in Marcus Hook to western locations in Pennsylvania and other states. Pipeline was defined it as a utility, giving it eminent domain upon construction.

In 2012, Sunoco was purchased by Energy Transfer Partners L.P. and the 80-year-old pipeline was refurbished to ship natural gas liquids (a byproduct of fracking) to the eastern seaboard. This original refurbished pipeline transports approximately 70,000 barrels a day of natural gas liquids such as ethane, propane, and butane from Pennsylvania, Ohio, West Virginia, and other states to delivery points within PA, culminating at the Marcus Hook Industrial Complex for exportation to Europe, primarily Scotland and Norway.

On October 2, 2014, the Pennsylvania Public Utility Commission (POC) voted to continue the Sunoco Pipeline’s status as a public utility corporation for the transport of liquid petroleum products within the state [8]. Just prior to the POC’s decision, the Sunoco Pipeline announced plans to add two more pipelines, called Mariner II and Mariner 2X, which will be situated primarily alongside the older Mariner I pipeline and bring the capacity of transport to 345,000 barrels per day and 250,000 bpd, respectively [8]. The pipeline will traverse 17 counties in the southern tier of Pennsylvania. When the Mariner East 2 is completed, Sunoco plans to begin work on its parallel expansion pipeline, called the Mariner East 2X. The company has not announced an expected completion date for the ME2X [1].

Project area:1,300
Level of Investment:5,100,000,000
Type of populationSemi-urban
Affected Population:105,500
Start of the conflict:11/05/2017
Company names or state enterprises:Energy Transfer Partners (formerly Sunoco Logistics). (ETF) from United States of America
Relevant government actors:Pennsylvania Public Utility Commission (PUC)
Pennsylvania Department of Environmental Protection (DEP)
Commonwealth of Pennsylvania
Environmental justice organizations (and other supporters) and their websites, if available:Del-Chesco United for Pipeline Safety;
East Goshen Safety and Environmental Advocates (;
Pennsylvania Alliance for Clean Water and Air;
Clean Air Council (CAC);
Mountain Watershed Association (MWA);
Delaware Riverkeeper Network (DRN)

Conflict & Mobilization

IntensityMEDIUM (street protests, visible mobilization)
Reaction stageIn REACTION to the implementation (during construction or operation)
Groups mobilizing:International ejos
Local ejos
Local government/political parties
Recreational users
Local scientists/professionals
Forms of mobilization:Community-based participative research (popular epidemiology studies, etc..)
Creation of alternative reports/knowledge
Development of a network/collective action
Involvement of national and international NGOs
Land occupation
Lawsuits, court cases, judicial activism
Media based activism/alternative media
Official complaint letters and petitions
Public campaigns
Street protest/marches


Environmental ImpactsVisible: Air pollution, Global warming, Loss of landscape/aesthetic degradation, Noise pollution, Soil contamination, Waste overflow, Oil spills, Deforestation and loss of vegetation cover, Surface water pollution / Decreasing water (physico-chemical, biological) quality, Groundwater pollution or depletion, Other Environmental impacts
Potential: Biodiversity loss (wildlife, agro-diversity), Fires, Food insecurity (crop damage), Large-scale disturbance of hydro and geological systems
Other Environmental impactsConfirmed risk of gas explosions
Health ImpactsVisible: Accidents, Exposure to unknown or uncertain complex risks (radiation, etc…), Other Health impacts
Potential: Mental problems including stress, depression and suicide, Violence related health impacts (homicides, rape, etc..), Deaths
Other Health impactsCancer
Socio-economical ImpactsVisible: Displacement, Violations of human rights, Land dispossession, Other socio-economic impacts
Potential: Increase in Corruption/Co-optation of different actors, Increase in violence and crime, Militarization and increased police presence, Specific impacts on women


Project StatusUnder construction
Conflict outcome / response:Compensation
Court decision (failure for environmental justice)
Project temporarily suspended
Development of alternatives:One individual proposed a 'safer' pipeline that would require a mile-wide berth along the 300-mile long pipeline, in the case of accidents. Another solution proposed was to convert the liquid gases to something less volatile. Other solutions would be to stop fracking shale gas due to the detrimental impacts of fossil fuel production on the climate and subsidize a transition to renewable energy.
Do you consider this an environmental justice success? Was environmental justice served?:No
Briefly explain:Sunoco has a consistently bad record of spills and mismanagement of its infrastructure, and the regulatory agencies have permitted them to proceed with a pipeline carrying highly hazardous hydrocarbons despite the appearance of sink holes, significant litigation, and public outcry. The suspension of activities was only temporary, but later the pipeline was permitted to proceed. The regulators have taken a stance similar to the companies - stall and finish the construction. They believe that once the pipeline is in the ground it will be out of sight and mind. The construction of Mariner II is not a success but a failure for environmental justice.

Sources & Materials

Related laws and legislations - Juridical texts related to the conflict

Feb 2018: proceedings from Clean Air Council, deMarteleire and Bomstein vs. Sunoco Pipeline L.P.

March 7, 2018 PUC Issues Emergency Order Regarding Sunoco Pipeline L.P.; Operations of Mariner 1 East Pipeline Suspended Over Safety Concerns

May 3 2018: DEP Levies Additional $355,000 Penalty Against Sunoco for Mariner East 2 Violations

AUg 6, 2018 DEP Assesses $148,000 Penalty Against Sunoco for Mariner East 2 Violations in Berks, Chester and Lebanon Counties

References to published books, academic articles, movies or published documentaries

[15] 2015. Negotiating Pipeline Rights-of-Way in Pennsylvania


(AUGUST 7, 2018)

[7] Assessment of Undiscovered Oil and Gas Resources of the Ordovician Utica Shale of the Appalachian Basin Province, 2012: United States Geological Survey, Fact Sheet 2012-3116, September 2012.

Industry report about impacts on property values for homes co-existing with pipelines

DEP Fact Sheet: Sunoco Pennsylvania Pipeline Project/ Mariner East II

Links to general newspaper articles, blogs or other websites

[2] June 10, 2014 Critics challenge Sunoco Pipeline as public utility

[6] Utica Shale - The Natural Gas Giant Below the Marcellus

[12] June 2017 Pennsylvanians speak out about losing their land to a Sunoco pipeline

[13] 2015. Negotiating Pipeline Rights-of-Way in Pennsylvania

[8] June 2018: Sunoco Pipeline: PUC Confirms Mariner East 1 Operation is Safe; Approves Restart

[9] List of those who have been harmed by fracking from Utica and Marcellus Shale

[3] April 4, 2018: Sunoco, residents at odds over claim of new ‘sinkholes’ near pipeline construction in Edgmont

[11] Your Guide to pipelines

[4] March 7, 2018 PUC orders Sunoco pipeline shutdown after sinkholes expose bare pipe near Exton

[5] July 18, 2018 Desperate for answers, suburban groups bankroll two-county study of Sunoco pipeline

[17] Mariner East 2: At-Risk Schools and Populations

[18] Key Dates in Dragonpipe History

Inventory of news about the pipeline

Letter: What needs to be done to make Mariner East 2 safe

DEP's website on Mariner II Pipeline Project

Coalition fighting pipeline accused of damaging pipeline

The Dragonpipe Blog: Comprehensive blog of all the happenings of the Sunoco Pipeline, Mariner II, The Dragonpipe, the dragon ships, and this blog

[16] July 23, 2018: A fateful 2014 decision confounds foes of Sunoco's Mariner East pipeline

[1] June 1, 2018: How Sunoco’s Mariner East pipeline is affecting real estate prices in Pa.’s Chester and Delaware Counties

Other documents

Utica Shale Gas deposits Location of the oil and gas assessment units (AU) for the Utica Shale in the Appalachian Basin Province. (USGS 2012)

Meta information

Contributor:Julie L. Snorek, Autonomous University of Barcelona, [email protected]
Last update23/08/2018



Utica Shale Gas deposits

Location of the oil and gas assessment units (AU) for the Utica Shale in the Appalachian Basin Province. (USGS 2012)