On April 7, 1992, an explosion occurred near Brenham, Texas. Before the explosion, a local resident, Jane Meinen, had called 911 to report a strange white mist near the site of an underground NGL storage area. Not long after that, a neighbor, Gloria Diver, drove into the mist, and it exploded. Gloria and her adult daughter were killed. Her 3-year-old grandson survived, with burns over 30% of his body. Jane Meinen’s home was destroyed, as were many others. Jane Meinen survived, but her son, asleep in bed, was killed. 24 people were injured, some very seriously. 75 cattle grazing nearby were killed.
If this had not been rural Texas, the toll would have been far higher.
The Brenham explosion was caused by NGLs leaking from an underground cavern where they were stored as liquids, under pressure. A combination of accidental overfilling of the cavern and a failure of a safety valve led to NGLs escaping into the air.
You can read the final report of the investigation into the Brenham explosion by the National Transportation Safety Board here.
How about the Marcus Hook caverns? I understand that Sunoco plans to store NGLs in caverns under Marcus Hook. These are limestone caverns that were initially dug during the Cold War to shield fuel supplies from enemy attack, then enlarged as storage during the 1973 energy crisis. An article in the Philadelphia Inquirer provides the background on this. Enough pressure will need to be maintained in the cavern to keep the NGLs in a liquid state. They will be pumped in when they arrive (via the Dragonpipe) and pumped out to fill arriving ships. Is this storage system actually safe? No one knows.
In 1978, when the caverns were being used to store butane, a small leak occurred. Five houses burned down and 30 families were temporarily displaced. Fortunately, no one was killed.
The storage capacity of the caverns is reported to be on the order of 2 million barrels, and there are additional ground-level tanks with a capacity of 800,000 barrels that are intended for NGL storage. I have no doubt that Sunoco/ETP thinks they can manage all this storage safely. But so did Sunoco in 1978, and so did the company responsible for the Brenham explosion. It took a disaster to show that they were wrong.
The Brenham explosion destroyed almost everything within a mile of the leak. Some houses as much as 1.5 miles away sustained enough damage that they had to be torn down and rebuilt. Consider what would happen if an explosion like that occurred in Marcus Hook. Everything between I-95 and the Delaware River, including all of Marcus Hook, Trainer, and Linwood would be devastated, as well as parts of many surrounding communities. More than 10,000 people live within that 1-mile radius.
And there are two reasons why an explosion in Marcus Hook could actually be much more powerful than the Brenham explosion. First, within a few hundred feet of the caverns there are two refineries that deal with highly explosive materials, as well as the above-ground NGL storage just mentioned. All of these might lead to secondary explosions. Second, only 5,000 barrels of NGLs (out of a total storage capacity of 300,000+ barrels at that site) escaped in the Brenham event. A problem in Marcus Hook, where far larger quantities are handled, could result in a far bigger cloud of NGL gases.
Who is permitting Sunoco to build a facility with the potential to kill thousands of people? Who has said this is OK? Who is responsible for protecting southern Delaware County from this risk?