The FracTracker Alliance ( recently produced a set of maps showing the population density along the route of the Dragonpipe (Mariner East 2 pipeline), and what they show is a route that runs through many centers of dense population while ignoring nearby areas where few people live. The maps are based on local population figures from the US Census. The lesson of these maps: Sunoco has put the Dragonpipe in a very bad location.

Here, for example, is a map of the route through Berks, Chester, and Delaware County.

population overview (fractracker) 6-29-18
Population density in southeastern Pennsylvania. Map courtesy of FracTracker Alliance. Location annotations added.

The dark brown areas are the areas of dense population. The lighter the color, the lower the population density.  The black line is the pipeline route.

In the upper left-hand part of the map, you can see that the route passes through the suburbs of Reading, in Berks County. In the lower part, it passes directly through population centers in Chester and Delaware County. We will take a closer look at those below.

Why this route? Sunoco’s convenience, that’s all. At a glance, you can see that the pipeline route is a very bad one. In many areas, it is actually the worst possible route that Sunoco could have chosen: it puts more people at risk than any other path they might have chosen with the same endpoints. Why in the world did they choose it?

The answer is: Sunoco’s corporate convenience. The Dragonpipe, for most of its length, runs side-by-side with Mariner East 1, an existing 80-year-old pipeline designed to carry gasoline and heating oil to customers in the central and western parts of the state. Of course the old pipeline had to go near areas of population: that’s where the customers for gasoline and heating oil were located back in the 1930s.

It was convenient for Sunoco to reverse the flow of the old pipe and to change its content to highly explosive “natural gas liquids” (NGLs). No public notification or review was required for those steps. It was also convenient to use the same right-of-way for its new Mariner East 2 and 2x pipelines.

But Sunoco’s convenience means unnecessary risks for tens of thousands of Pennsylvania residents.

Not only did the old pipeline connect the centers of population from the 1930s (which are much more populous now); in the southeastern part of Pennsylvania, the character of the area has changed dramatically. In the 1930s, when the original pipeline was built, the area it ran through in Delaware and Chester County was mostly farms. Now, that area is densely-settled suburbs, with homes, schools, businesses, hospitals, and shopping centers right next to the right-of-way.

The Exton area is a prime example of how these changes have led to a potentially disastrous pipeline route. Here is a more detailed map of the population density near Exton.


population near Exton (fractracker) 6-29-18
Population density in Exton area. Map courtesy of FracTracker Alliance. Location annotations added.

As you can see, the pipeline route sticks to high-density areas (brown) the entire way, even though low-density options (orange, yellow) exist nearby.

Sunoco (like any corporation) has a moral obligation to conduct its business in a safe manner, and that includes choosing a safe route for a pipeline it knows is dangerous. It did not do so. But more than that, it also had a legal obligation: in the settlement Sunoco reached last August with Clean Air Council, Delaware Riverkeeper Network, and Mountain Watershed Association, Sunoco agreed to consider alternative routing for the pipeline in this area. It simply ignored that part of the agreement. Instead, it dismissed the alternatives as “not practicable” because they did not involve the right-of-way it was already using for Mariner East 1.

Sunoco’s position seems to be: the only factor that matters in considering a pipeline route is whether Sunoco has an existing pipeline there. A better route would reduce by hundreds the number of people who could be killed if there were a leak and explosion, but that is not a factor that matters to Sunoco.

But pipelines do leak. Mariner East 1, in its short career as a pipeline carrying NGLs, has already leaked three times. It is just good luck that the leaks were stopped before the gas ignited. The Atex pipeline, a pipeline of similar size and content that runs down to the Gulf coast, ruptured and exploded near Follansbee, WV, in just its second year of operation.  That’s what could happen with the Dragonpipe.

Sunoco has an obligation to do what it can to minimize the death and destruction caused by an event like the Follansbee one. That explosion was in a forested area. It took out several acres of trees but didn’t kill anyone. The result would have been far different if it had been in a densely populated area.

Just as the maps above show how the Philadelphia suburbs and those of Reading are threatened, other FracTracker Alliance maps will be available that show the threats to suburbs of Pittsburgh and Harrisburg.

Indeed, across the state, the Dragonpipe route seems to go out of its way to approach population centers. That may be convenient for Sunoco, but it is an unacceptable risk for Pennsylvania’s citizens to bear.