Residents staged a protest march on their way to the Chester County Commissioners meeting, August 31, 2021.

Exton lies in the center of the Great Valley, a valley formed over the eons by the erosion and collapse of the karst (limestone) that underlies it. That swiss-cheese formation of voids, fissures, and caverns, is still collapsing from time to time as the groundwater eats it away. Those who fix the local highways are well aware of the phenomenon.

If the ground sinks under a highway, it is usually not too big a deal. A lane is closed for a while and the hole is filled and paved over. But if the ground sinks under a pipeline, the pipeline can sag and rupture. The result can be a disaster. It happened in 2018 with the Revolution pipeline in Beaver County and in 2015 near Follansbee, West Virginia with the ATEX pipeline. In both cases, explosions took out several acres of trees and damaged nearby houses. No one was killed, but that was only because no one was close by.

That is the type of accident that could happen at any moment in Exton, where Sunoco’s construction work on Mariner East has triggered over a dozen sinkholes, all of them adjacent to operating pipelines filled with highly volatile, explosive gases. An explosion there would be far more serious than the Beaver County or Follansbee explosions. The work is occurring in a densely populated suburb, next to the library and a major shopping mall. Chester County needs to act now to prevent a catastrophe.

Appeals from residents. On August 31, the Chester County Commissioners held their monthly “Sunshine Meeting”, at which public comments are heard. (You can watch the video of it here. Public comments start around the 46-minute mark.) At that meeting, 15 residents, most of them living right in the potential blast zone, raised their concerns about the Mariner East work. They urged the commissioners to file with the Public Utility Commission (PUC) for “emergency relief”, requesting that the active lines be shut down until the danger could be properly assessed.

Those who spoke reminded the commissioners of the letter they had sent to the PUC on July 19. (For some reason, that letter is not available on the county website, but it can be viewed here and here.) In it, the commissioners write: “We respectfully request you stop operation of Energy Transfer’s Mariner East 1 eight-inch natural gas liquid (NGL) pipeline (ME1) and it’s [sic] 12-inch NGL pipeline (sometimes referred to as the ‘workaround’ pipeline) until further investigation can be conducted into the risks presented to these lines by the sinkholes that are occurring on a regular basis.”

The letter continues: “We ask the [PUC] to investigate and take swift action on this issue.” But failing that, “… we stand ready to take action to ensure our residents’ safety. However, you, the [PUC], are one of the few bodies that can truly ensure our residents’ safety by immediately stopping the operation of the current Mariner East lines, and fully studying the issue before allowing product to move again.”

Now, almost two months after that letter, there has apparently been no response from the PUC.

Ginny Kerslake’s statement. Of the residents who spoke at the August 31 meeting, the one whose statement I found the most compelling was Ginny Kerslake, and I have decided to take the unusual step of reproducing it here in its entirety. Here is what she told the commissioners:  

“Unreasonable, inadequate and unsafe. Those are the words you used to describe Mariner East in your July 19 letter to the PUC. As someone who lives in the blast zone in West Whiteland Township, I could not agree more.

Since February the ground on this 370-foot section underlain by karst has become increasing more unstable as the result of Mariner East construction activities. The extraction of vast quantities of groundwater, on the order of one million gallons per day for months, has rendered a geology inherently prone to sinkholes even more so.

When you wrote to the PUC, we had already documented nine sinkholes there since February. The largest was 23 feet long, parallel to and mere inches from ME1. In the weeks since your letter there have been three more – July 31, August 5 and August 27. Twelve sinkholes in total there, and I have personally witnessed them all.

Friday afternoon’s was particularly alarming and disturbing in how much worse it could have been. I was standing on the little bridge over Valley Creek watching work on the opposite bank near the library. After about twenty minutes of standing there, the creek bed spontaneously collapsed taking the creek with it. The sinkhole expanded as the water rushed into it. Fortunately I was there to alert the workers: No one was monitoring the creek for sinkholes.

In the roughly 10 minutes it took for workers to hurry in and build a sand bag dam, the sink hole grew to about 10 feet in diameter.  What if I hadn’t been there? How large would the sink hole have grown before someone noticed? What if it had occurred late Friday night when the creek was raging from the rain? The sinkhole was directly on ME1 with highly explosive ethane flowing through this 90-year-old pipe.

I was told by the DEP inspector on site that Energy Transfer was being allowed to fill the sinkhole with grout even though it was in violation of the Clean Streams Act — because the PUC determined it was a public safety threat since ME1 is active.

We got lucky again on Friday. The sinkhole did not result in a leak on Mariner East. But when our luck runs out, we will be a facing a catastrophic explosion in West Whiteland Township. One we have no emergency plan for to warn and protect thousands in the blast zone.

When you wrote to the PUC over a month ago asking them to halt operation of Mariner East and conduct a thorough geological investigation you said that if the PUC failed to, you stood ready to take action to ensure the safety of Chester County residents. The PUC has failed to.

We stand before you today to echo the request made in almost 600 emails to you from residents: File a Petition for Emergency Relief with the PUC now to halt Mariner East and conduct an independent and publicly available geological investigation. As County Commissioners you have the standing, the resources and the responsibility to do so. Relying on luck is not enough.”

Attorney Mark Freed wants an analysis of strain data. The commissioners sat silent throughout the public comments. None of them had a response. Instead, they sent Mark Freed, the attorney they have retained for pipeline-related work, to the podium. Freed made the case that the commissioners had already made an “informal complaint” (the letter mentioned above).

Freed pointed out that, in the Dinniman case, Judge Barnes (the PUC Administrative Law Judge hearing the case) wanted to shut down the operating pipelines. But she was overridden by vote of the five PUC commissioners. They wanted more evidence, Freed said, to demonstrate that the sinkholes actually presented a threat of a leak or rupture. So Freed wants to be able to have that evidence in hand before any potential filing with the PUC.

Although Freed did not spell out his current thinking in detail, I interpret his approach as follows. Sunoco contractors have recently been installing strain gauges at the Exton construction site. Freed takes this as evidence that Sunoco wants to monitor strains on the operating pipes in case either geologic changes (such as sinkholes) or construction operations (such as earth movements from hammer drilling) are pushing the pipelines out of position and causing stress. If the stress reaches dangerous levels, the pipelines could fail. (Of course, even if no stress is detected at a given moment, that could change when a sinkhole unexpectedly opens. And strain gauges can’t measure the stress on the pipeline that was already present before they were installed.)

Evidently, Freed’s thinking is that an expert in pipeline stress and failure would be able to assess the data from the strain gauges in order to understand whether the pipelines are approaching dangerous levels of stress. Freed is looking for such an expert, and believes he may have found one or two.

It seems to me that Freed cannot expect to get the data from the gauges, short of either the “discovery” phase of a suit or in-person testimony in a trial. I can’t imagine that Sunoco would provide the data voluntarily. If I am correct about that, then a case would need to be filed as soon as Freed has lined up the appropriate expert(s).

But Freed stopped short of saying whether a formal complaint would ever be filed. He said that possibility would need to be reviewed with experts and “evaluated”.

I am willing to believe Freed’s statement that he is actively seeking experts and that a formal complaint is still a possibility. But the statement he made is similar to what a lawyer might have said if the objective was to postpone action indefinitely, without admitting that was the intention. As it stands, the County Commissioners are left with a serious credibility problem. How confident can we be that they are serious about the safety of this pipeline?

Give us a date. The least the commissioners can do is to specify a date, sometime in the next 30 days, by which they will say whether or not a PUC complaint will be filed. (Even better would be a date by which the filing will be made.) Otherwise, reasonable people will conclude that the commissioners have settled on delay as their best tactic.

If that is their choice, they have evaded their responsibility to keep the residents of Chester County safe. They have plenty of evidence of a situation they know is endangering hundreds (or perhaps thousands) of people. Will they choose to do nothing?

Let the commissioners know what you think. A convenient way to do that is to make use of the comment form that Food & Water Watch has set up here. A generic comment is provided, which you can edit to ask for a date when a decision will be made on filing a PUC complaint.