Frequently asked questions
Q: Whose pipeline is this?
A: The Mariner East 2 Pipeline was initiated by Pennsylvania-based Sunoco Logistics, which has since been merged into a Texas-based company, Energy Transfer Partners (ETP). ETP is basically a pipeline company (they own the controversial Keystone XL pipeline) and is not involved in drilling wells or in the processing of the materials it transports.
Q: What makes this pipeline so dangerous?
A: It does not carry familiar flammables like gasoline or natural gas. It carries the gases propane, ethane, and butane, compressed until they take the form of a liquid. These liquids are far more explosive and difficult to control than natural gas. If there is a leak, the leaking material instantly becomes a gas.
Q: What agency oversees the safety of high-pressure liquefied gas pipelines like this one?
A: Amazingly, there is no government body that has clear authority to regulate this particular type of pipeline. The Pennsylvania PUC is supposed to enforce the guidelines from PHMSA (the federal Pipeline and Hazardous Materials Safety Administration). PHMSA has guidelines for ordinary natural gas (methane) and for flammable liquids, but none that specifically address these highly-compressed liquified gasses, which should require additional protections. That has meant that Sunoco/ETP has only needed to follow the pipeline standards for uncompressed liquids, standards that actually offer far less protection than those for natural gas.
Q: Who approved the pipeline?
A: By proposing to compress the pipeline contents into a liquid, rather than leaving them as a gas, Sunoco was able to bypass most pipeline regulation. There was no federal approval process, and almost none at the state level.
Q: Who approved its route?
A: No one approved it. Pennsylvania has no state body that regulates pipeline routing. The Pennsylvania Public Utility Commission (PUC) has granted Sunoco/ETP permission to act as a public utility, meaning it can take possession of lands through eminent domain if the landowner does not want to sell access rights. (But this is not a “utility” pipeline in the way most of us understand that word. A utility is a monopoly that is regulated by the state for the benefit of its residents. Sunoco/ETP is selling almost all of this flammable material to European customers, not to Pennsylvanians.) And since no one approved the route, Sunoco is basically free to run its pipeline anywhere.
Q: In case of a leak, how will those near the pipeline be warned?
A: There is no realistic plan for warning, and no opportunity in any case. If you are near the pipeline when there is a significant leak, two things can happen. If it ignites, there is a huge fireball. If it doesn’t, an invisible fog of explosive gas spreads quickly along the ground until it encounters a car, cellphone, doorbell, air conditioner, or other source of a spark to ignite it. You are on your own.
Q: How will those in harm’s way be evacuated?
A: There is no realistic evacuation plan, and no realistic opportunity for evacuation. If you are within 1000 feet of a significant leak and it ignites, you will be engulfed in a fireball from which no evacuation is possible. In principle, everyone within a radius of about 3 miles of a leak is supposed to “self-evacuate”. In Delaware and Chester counties, that means tens of thousands of people, including entire towns. The recommended procedure is to walk upwind and away from the pipeline. How well is that likely to work?
Q: If there is an explosion, how will the resulting fire be put out?
A: There is no way to put it out. When Sunoco/ETP detects the falling pressure from the leak, it will shut off valves that control the flow to that section of the pipeline. The valves are several miles apart. The fire will continue to burn until all of the gas from that section has been burned off. That will take many hours, and might take several days.
Q: How will leaks be detected? How will they be corrected?
A: If there is a serious leak, it will register as a loss of pressure and Sunoco will shut down that section of the pipeline. All of the contents will be allowed to leak out, and then Sunoco will send a robotic device through the empty pipe to try to locate the leak. Then, the pipe will have to be dug up and fixed. If the leak is less than 1% of the material flowing through the pipeline, it will probably not be detected until some event (like the explosion of accumulated gas) brings attention to it.
Q: Parts of the pipeline will be put in place by pulling it through tunnels just wide enough to fit the pipe. How does Sunoco know if part of the pipe in a tunnel has been damaged while being pulled through?
A: Sunoco/ETP sends a robotic leak-seeking device through the pipe once it is in place. Large leaks and thin spots would be detected in this way, but I have not been able to confirm whether it could detect smaller cracks. (Readers, please point me to resources that could clarify this.) Likewise, it is unclear whether it is possible to detect areas where the pipe’s anti-corrosion coating has been scraped off in the process of pulling it through the tunnel. Corrosion, if it occurred, would gradually lead to leaks.
Q: Have there been previous instances of leaks in a pipeline like this? If so, what happened?
A: Yes, there have been several such incidents. For example, a pipeline carrying similar materials exploded near Follansbee, WV (south of Pittsburgh) in January, 2016, and burned for 24 hours, wiping out 5 acres of trees. No one was in the area at the time. An analogous accident in a more densely-populated area was the explosion in San Bruno, CA (a suburb south of San Francisco) in 2010. That involved a pipeline carrying natural gas (less explosive than Mariner’s compressed gases and far lower in pressure). It killed 8 people, injured 66, and destroyed 38 homes.
Q: What is Sunoco’s history in terms of pipeline leaks?
An analysis of the record of Sunoco pipeline incidents resulted in an estimate of one leak every 7 months per 300 miles of pipeline (the approximate length of the Dragonpipe) which equates to one leak every 7.5 years along the 25-mile stretch through Delaware and Chester counties. Since the Dragonpipe is a new pipeline, and many of the leaky ones are older, we can hope that the performance of the Dragonpipe will be better than the estimate above, at least in its early years.
For technical details concerning the risks of this pipeline, see the study by Quest Consultants here.