Explosions and Sinkholes: The Sordid History of Sunoco’s Pipelines in Pennsylvania

A leading pipeline operator is accused of using a “frankenpipe” to transport highly volatile liquids.
Sections of steel pipe lie in a staging area before being inserted underground as part of the ETP-Sunoco Mariner East 2 pipeline in the Marchwood neighborhood of Exton, Pennsylvania on June 5, 2019. Image: Robert Nickelsberg/Getty Images

On paper, it might appear that Sunoco Logistics Partners is having a difficult time figuring out the logistics of pipelines, even though that’s its core business. In September 2018, for instance, Sunoco began operating a new, 100-mile natural gas pipeline in Pennsylvania called the Revolution. One week into service, a segment of the Revolution was hit by a landslide and subsequently exploded, leveling a house and forcing an evacuation about 30 miles outside Pittsburgh.


As state regulators began investigating the Revolution explosion, Sunoco moved ahead with construction on a different group of pipelines in Pennsylvania known as the Mariner East project, despite concerns from locals that this project could be even more explosive.

Unlike a regular natural gas pipeline, the Mariner East pipelines are intended to carry particularly volatile chemicals known as natural gas liquids, containing ethane, propane, and butane left over from shale drilling operations in the eastern United States. The Mariner East pipelines would ship the liquids from shale fields in Pennsylvania and Ohio to a refinery in Marcus Hook, about 25 miles away from Philadelphia. From there, the chemicals would then be exported to Scotland for the manufacturing of plastics, the point of this all being to “wring as much revenue as they could from their Northeast wells,” as one industry trade publication explains.

Sunoco’s parent company, the pipeline giant Energy Transfer Partners, has anticipated that the operation will generate billions of dollars and thousands of construction jobs and says that Mariner East provides “needed infrastructure” to Pennsylvania.

The company says that American consumers may still use the plastics that are produced overseas. "The ethane that is exported overseas is mainly used for ethylene production, which is converted to polyethylene to make many types of plastics and synthetic fibers, such as nylon, polyester and spandex, which again, are in products used by Americans every day,” Energy Transfer Partners spokesperson Lisa Coleman told Motherboard.


Mariner East makes use of the same path, and some of the same pipe, that was originally constructed in the 1930s to provide heating oil to residential buildings and towns. Opponents thus nicknamed the project “franken-pipe” and argued that the combination of factors—the natural gas liquids, the old pipe, and the densely populated routes the pipelines follow—was a recipe for a horrible disaster.

“Ethane, propane, and butane, these are all gases that are heavier than air,” George Alexander, a retired technical journalist who has been covering Mariner East for his popular local blog the Dragonpipe Diary, told Motherboard. In the event of a leak, “it means you get these massive clouds going which are entirely flammable as soon as they reach an ignition source of some kind…They behave like a fog.” (A pipeline safety consultant has similarly described natural gas liquids as “hugging the ground” in the event of a leak; Natural gas liquids are considered to be “highly volatile” by the United States Pipeline and Hazardous Materials Safety Administration),

According to recent testimony from the director of emergency services for Delaware County, PA any leak from the Mariner East pipeline would affect “a large amount of people” and have devastating consequences.

"Safety has been and will always be our first priority—the safety of the environment, the safety of the communities through which we pass, and the safety of our employees," Coleman said. "We regularly inspect, maintain and update on our pipelines to ensure they will operate safely for decades to come."


For the fossil fuel industry, the Mariner East project marks an important milestone for natural gas production in Appalachia, with its high production capacity in a relatively new business sector. The United States Department of Energy, in a 2017 report that is supportive of the industry, optimistically predicted that natural gas production in Appalachia would increase 350 percent by 2040. Until recently, the agency said, production of natural gas liquids in the United States remained relatively flat, but because shale fields in the eastern United States tend to have more natural gas liquids, that sector is also poised for growth. The DoE predicts that between 2013 and 2023, production of natural gas liquids in Appalachia would increase 700 percent. Anticipating this growth, Royal Dutch Shell is currently constructing a massive petrochemical complex along the Ohio river; the project will be the first and biggest ethane production plant in the Appalachian region.

“The opportunity to take advantage of the full economic value of NGLs produced in Appalachia has been identified by regional leaders,” the Department of Energy report explains.

The Mariner East II and IIx pipelines would have capacity to carry a respective 275,000 and 250,000 barrels per day, according to the Department of Energy. The next-highest capacity natural gas liquid pipeline in the region, operated by Enterprise Product Partners, went into service in 2014 and has capacity of 125,000 barrels a day. Opponents note that a portion of that company’s pipeline exploded on a landowner’s pasture in 2015. There were no injuries, but a local fire chief recalled, in an interview with the Philadelphia Inquirer, that "I've never been involved with anything of that magnitude before…it sounded like a damn jet engine, and the flame was huge."


Opponents also note that Sunoco’s track record is relatively poor compared to other oil and gas pipeline operators. According to data submitted to the Pipeline and Hazardous Materials Safety Administration, and analyzed by NPR, Sunoco has the oil and gas pipeline industry’s second-highest number of self-reported incidents to federal regulators over the past 12 years.

In Sunoco’s defense, none of its Mariner East pipelines have exploded, and a consulting firm the company hired has claimed that the risk of civilians getting injured by these pipelines is less than getting hurt in a car crash. But the ongoing construction process hasn’t exactly been building confidence from locals; sinkholes have repeatedly appeared around construction of the pipeline. State regulators also found that thousands of gallons of drilling fluid had been improperly discharged into creeks. In total, Energy Transfer Partners has amassed hundreds of environmental violations in the course of construction, just for this project. Both Republicans and Democrats in the state legislature, even those friendly to the oil and gas industry, have described Sunoco as a “rogue company” that makes business more difficult for other pipeline operators in the state.

In 2017, environmental groups suing to stop Mariner East found that Pennsylvania’s Department of Environmental Protection had identified hundreds of “deficiencies” in Sunoco’s permitting application, but approved it anyway. In November 2019, the Associated Press reported that the FBI had opened a corruption investigation into the role that Pennsylvania Governor Tom Wolf’s office may have played in the permitting of the project. Some recent lawsuits against Energy Transfer Partners, pointing to the FBI investigation as evidence, allege that the state environmental permits had been obtained through “bribery” or “other illicit means.”


Energy Transfer Partners spokesperson Lisa Coleman told Motherboard that the company has not has not been contacted by the FBI. “We believe our project was properly permitted by all agencies,” Coleman said.

Landowners who live along the route of Mariner East have repeatedly risked arrest to protest the project, most recently in December 2019. They’ve claimed that the arrests were improper. In one of the most prominent cases, retired school teacher Ellen Gerhart was sentenced to six months in prison for allegedly setting fires and placing food in construction areas in an effort to lure bears to the site where people would be working. Gerhart has argued in court that her protest was nonviolent. A state court disagreed and sided with Sunoco in the matter, upholding the charges against her.

But not all local officials are sympathetic to Sunoco in the criminal protest cases. In December 2019, the Chester County District Attorney’s office said that Energy Transfer Partners had illegally recruited state constables to act as private security guards for the construction sites. The councy brought bribery and conspiracy charges against three constables.

Despite all of the above, the Mariner East pipelines are still going forward. In January 2020, Energy Transfer Partners agreed to pay a $30 million fine to Pennsylvania’s Department of Environmental Protection over the Revolution explosion. In exchange, the state agreed to lift a company-wide permitting moratorium, which had been in place for a year, and allow Sunoco/Energy Transfer Partners to continue working in the state.


Pennsylvania regulators said, with the announcement of the $30 million settlement agreement, that the company has “demonstrated its intention to correct its unlawful conduct.” Energy Transfer Partners said in a recent public statement that it is “pleased” that the state “will allow us to safely complete the construction projects we have underway in Pennsylvania.”

Citizens groups remain unconvinced, and they’re hoping that lawsuits and public pressure may eventually change the outcome.

“It’s really slipshod work that they have done,” adds Alexander, the Dragon Pipe Diary journalist. “They have been fined and fined and fined, but it's been a mouse that doesn’t make a difference in the context of a $2.5 billion pipeline project.”

Energy Transfer Partners insisted that the project will be safe.

"Specifically, Mariner East 1 underwent integrity testing and major upgrades when it was repurposed for NGL service in 2014, including new valves and pump stations," Coleman said. "Additionally, the 12-inch pipeline being used in a section of Mariner East 2 pipeline went through a $30 million upgrade in 2016 as part of our ongoing Integrity Management Program."

She added that the upgraded section of the pipe exceeds the requirements of the Pennsylvania Public Utility Commission and Pipeline and Hazardous Materials Safety Administration.

Correction: This story previously said that state regulators found that Sunco discharged natural gas liquids into creeks. State regulators found that Sunco discharged drilling fluid into creeks, not natural gas liquids. Motherboard regrets the error.