On November 28, 2018, the Delaware County Council released the risk assessment report that it had commissioned from G2 Integrated Solutions. Upon reading it, I must say I was dismayed. If it is accurate, the potential for a catastrophe is far worse than I had thought—and I had already concluded it was completely unacceptable, based on previous information.

The Delaware County report (G2 ME2-Adelphia Risk Assessment v2.1) describes the consequences of a possible leak or rupture of either the proposed 20-inch Mariner East 2 pipeline or the Adelphia natural gas pipeline. It is the Mariner East 2 pipeline (the Dragonpipe) that concerns me most.

Two things immediately struck me about this report’s Mariner East 2 analysis.

A huge cloud of flammable vapor. First, in the event of a Dragonpipe rupture, the software used for the Delaware County report (called “Phast”) calculated a far larger combustible vapor cloud than the “Canary” software that was used by Quest for the Citizens’ Risk Analysis (Citizens Risk Assessment Final Report 10-19-18). In the Delaware County report, the flammable cloud from a rupture of the 20-inch pipeline stretched about three times farther downwind and was about 8 times larger overall than the maximum size in the previous risk assessment. If it then ignited, it would burn completely in a few seconds, resulting in a far larger flash fire than I had even thought possible. When a pipeline carrying NGLs ruptures, the vapor cloud and resulting flash fire are responsible for the majority of the fatalities.

The diagram below shows how much bigger the vapor cloud in the Delaware County report would be.

flammable cloud size (G2 vs quest) 12-3-18
This diagram shows the relative size of the flammable vapor cloud calculated by Quest for the Citizens’ Risk Assessment, compared with the corresponding cloud calculated by G2 for the Delaware County risk assessment. In both cases, approximately the same assumptions were used concerning the rupture of a 20-inch pipeline carrying propane, under light wind conditions, with delayed ignition.

The consequences of such a cloud igniting would be almost unimaginable. The cloud would be up to 6,800 feet long and over 4000 feet wide, which means that a rupture near Glenwood Elementary School, for example, could envelope not just the school, but everything from there to the far side of Granite Run Mall in a lethal cloud, as shown in the image below. When it reached an ignition source, the entire cloud would burn in a few seconds, killing everyone outdoors as well as many who were indoors at the time.

vapor cloud from rupture at Glenwood (G2) 12-4-18
The red line in this image is the Dragonpipe right-of-way. The light-colored oval shows the potential size of a flammable vapor cloud from a rupture at Glenwood Elementary School (based on the Delaware County risk assessment). Depending on the wind and the length of time before ignition, the cloud could envelope the school, the center of Lima, Riddle Hospital, the Riddle Village senior living facility, and most of the Granite Run mall complex.

An immense shock wave. In addition to the vapor cloud, the Delaware County report includes an analysis of “overpressure” (the shock wave from the exploding gas) which the Citizens’ Risk Assessment did not. In areas where the overpressure reaches a level of 0.3 bar (or 1.3 times the normal atmospheric pressure of 14.7 pounds/square inch), it will be lethal regardless of whether the person is indoors or out. The lethal shock wave extends about 2,130 feet in every direction from the center of the flammable cloud. In practice, this means that many people would be killed by the shock wave in addition to those who are killed by the flash fire from the vapor cloud. Injuries and structural damage would extend much farther still.

Taken together, these two aspects of the Delaware County risk assessment suggest that the rupture of a 20-inch NGL pipeline has the potential for about ten times as many deaths as would be expected based on the Citizens’ Risk Assessment. We are a densely populated county, and a pipeline like this does not belong here. Anywhere in the county that a rupture occurred, there would be many deaths. Based on this new study, it is clear that in some locations, in the worst case, thousands would die.

Contact your representatives. This potential for catastrophe, as unlikely as it may be, is completely unacceptable. Let your elected representatives, from your county council and school board on up, know that they must take action. Each of them needs to file a petition for emergency intervention by the PUC (or at the very least, join as an intervenor in a petition filed by someone else) to stop this pipeline project now. Make sure Governor Wolf hears from you: he can stop this immediately, but has been totally silent about it for months.