It’s clear that the Dragonpipe (Mariner East 2 pipeline) has serious risks for an explosion. But just how serious are they? Putting those risks into numbers (how far would the damage reach? how many deaths could there be?) is a task that no regulatory body or public entity has taken on. And of course, Sunoco has a vested interest in making sure this information is kept quiet. Until now, only the Middletown Coalition for Community Safety has taken on the challenge and commissioned a risk study from Oklahoma-based Quest Consultants.
A new study by Seth Kovnat, an engineer who has worked with the Middletown Coalition on pipeline risks, has taken the analysis several steps further. He shows how the risks vary up and down the pipeline route and he compares the risks with those of an ordinary natural gas pipeline. Let your elected representatives know that they need to read this. It will provide important new ammunition for the many newly-elected anti-pipeline officials in their bid to get their municipalities to oppose completion of the pipeline. Be sure to bring this study to their attention!
Quest’s results. The Quest study, which provides the basis for much of Kovnat’s work, did an excellent job of quantifying a specific set of risks, based on the possible effects from a rupture and explosion at a single location in Delaware County, either with immediate ignition of the escaping gas or a 3-minute delay before ignition. The study quantified the size of the area where serious burns could occur which provided the basis for figuring out a “blast zone” (formally known as the “PIR” for “primary impact radius”) along the pipeline route.
Expanding the analysis. In a detailed document that lays out his methodology, Kovnat extends Quest’s analysis of a single site to cover the length of pipeline from Derry Township, Dauphin County, to Marcus Hook, a distance of about 100 miles. He then compares his analysis with actual data on damage from an explosion on a comparable pipeline (the 2015 Atex pipeline explosion in Follansbee, WV) and shows that the results are similar. Finally, he takes census data on the populations in each of the communities along the pipeline and shows an approximate count of the number of people who are in the blast zone, as well as the number who would need to be evacuated, for every location.
At various points throughout his analysis, Kovnat compares the effects of an explosion involving ethane (the primary material that will travel through the pipeline) with ordinary natural gas (the contents of many existing pipelines in our area). The difference is dramatic—at many locations, more than 10 times as many people are in harm’s way with ethane rather than natural gas, because of ethane’s greater explosive power.
As I noted in a recent post (see “Sunoco wants to mislead your officials about pipeline risks”), Sunoco has been badmouthing the Quest study because it assumed the use of a Berks County pumping station which was in the plans Sunoco submitted to the DEP. Sunoco now says it will not use that pumping station, and that change would lower the pressure (and hence the blast area) in the downstream section of the pipeline. In Kovnat’s new study, he analyzes the cases with and without the Berks County pumping station. (He was kind enough to share data from that analysis with me for use in my earlier blog post.) His analysis shows that even without the Berks pumping station, an explosion would be a major disaster.
Check out the graphs. For me, at the heart of Kovnat’s analysis are the graphs he presents toward the end of the paper. They are dense with information but well worth your time to try to understand the content. Here’s an example.
There’s a lot going on in this graph, but here’s how to look at it. The horizontal axis is distance from Derry Township in Dauphin County. The vertical axis is the number of people in the blast zone. Chester and Delaware counties are at the right (miles 60-100). The wavy lines show the number of people in the blast zone. The different lines illustrate different conditions: solid lines with the Berks County pump in operation and dotted lines without it, and different colors for immediate vs. delayed ignition.
From the graph, you can see that depending on the conditions (pump in operation or not; immediate ignition or not) the number of people in the blast zone can vary dramatically. For example, at Goshen (around mile 75) the top line (with the pump operating and a 3-minute ignition delay) shows close to 750 people in the blast zone. The orange dotted line near the bottom (pump not operating, immediate ignition) shows about 200 people in the blast zone for Goshen. At the very bottom, the tan-colored dashed line shows the comparison for natural gas. It shows that around 50 people would be in the Goshen blast zone if this pipe carried ordinary natural gas (methane). This line is strictly for purposes of comparison: Sunoco is not planning to use this pipeline for natural gas.
Kovnat has done us a great service by doing this analysis. We need to get our local representatives to study his report. What they will learn is that this pipeline is unlike anything their communities have dealt with in the past. If they allow it to be completed, they will be turning the fate of dozens (or even hundreds) of their residents over to a company that has a history of leaks and of total disregard for the interests of the communities it operates in.