gas leak at the library (wwrps 2-18-20)
Emergency response to gas line break. In the background is the wall of Chester County library. (Photo: West Whiteland Residents for Pipeline Safety)

Yesterday (February 18) there was very nearly a major catastrophe involving the Dragonpipe (Mariner East pipeline system). Shortly after 1 p.m., a Sunoco contractor digging a trench for the pipeline next to the Chester County library hit a 1-inch feeder pipeline that provides the library with natural gas. The line ruptured, spewing gas into the air. A local resident, smelling the gas, came to investigate and heard the hissing noise from the broken pipe. He called 911.

The police and fire department arrived, and they determined that it was a PECO-owned line that was leaking. PECO was summoned and repaired the line within a couple of hours.

There were no other damages or injuries. That’s the good news.

The bad news:

  • Instead of a small 1-inch feeder, Sunoco’s contractor could have hit and damaged either Mariner East 1 or the “Frankenpipe” (the cobbled-together workaround pipeline that Sunoco is referring to as “Mariner East 2”), both of which are active and are running in the same easement. That could have caused a catastrophic release.
  • The natural gas in the small feeder pipe could have caught fire, creating a “blow torch” adjacent to the Mariner East pipelines and potentially triggering the failure of one or both of them.
  • Sunoco (and its contractor) apparently did not call the authorities to report the damage, but instead simply left the site in a hurry. We must assume that is an example of exactly what to expect if they trigger a leak in one of the Mariner East pipelines.
  • Nobody—not Sunoco, not its contractor, and not even Chester County emergency officials—told local residents what was going on. In the event of a more serious release, would anyone learn of it in time to evacuate?
  • The highly volatile liquids flowing through the Mariner East system do not contain odorants, so residents would not even have been aware of the leak if it had been a problem with one of the Mariner East pipes.

The highly volatile liquids carried by Mariner East are both far more dangerous and at far higher pressure than normal natural gas, and once gas is escaping there is no way to stop it until several miles of pipeline have completely emptied out.

If a major leak had been triggered alongside the library, assuming it did not immediately explode, a huge flammable cloud would have immediately formed. Within 5-10 minutes, it would have extended to a distance of a mile or more (depending on weather conditions).  If that had happened, and first responders somehow became aware of it immediately, they would have had to evacuate the library, the Exton mall, the neighboring residential community, and nearby businesses on Route 30. Everyone would have had to be evacuated on foot and without anyone using any vehicles. The first responders would have had to arrive on foot, after carefully leaving their vehicles at a safe distance—otherwise they themselves would have caused the cloud to explode.

In fact, if there had been a major leak, there is no conceivable way that everything outlined in the paragraph above would happen safely. Instead, there would have been an explosion and many deaths. That is what we are tacitly accepting if we allow this work to continue. That is why you must contact your representatives in Harrisburg, including the governor, and insist that this work be stopped until such time as Sunoco can demonstrate a credible safety plan.