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.

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].