File under things I did not know until the past week: the largest refinery on the East Coast sits smack in the middle of South Philadelphia, and uses hydrofluoric acid as a catalyst.

It had a[nother] major fire last week. We almost had a disaster that would have easily bumped Union Carbide Bhopal off the top of the "worst industrial disaster" list.

Cool, cool.


In the Bhopal accident, 600,000 people were exposed to the gas, in approximately 40 square kilometers, mostly south of the Union Carbide plant.

Using the 1 PSI radius as a instrument to determine population living with a radius, and centering the detonation in the tank farms in eastern South Philadelphia, it takes 129 square kilometers to encompass the same 600000 people (


@seachanged I'm not sure what metrics they use, but the risk-management plan they filed with the federal/state/city governments has a worst-case exposure of 1.1 million, most within ten minutes.

And the whole shelter-in-place notification system wasn't activated for about twelve hours (plus it came on top of about a week of near-continuous emergency alerts so I dunno about Philly but South Jersey all would have gone "meh, another flood, that's not us).

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Finishing up, that's 1/3 the population density, 1/10 the chemical release, and 1.5 times the toxicity, so all other things being equal, that's about 5% of a Bhopal, in terms of human lives lost.

There are many other important factors: weather, temporal dispersion of agent, medical care, emergency response, housing differences regarding shelter-in-place.

It wouldn't be as bad here, I think.

@seachanged I do wonder if that assumes "business hours so all the downtown buildings are fully occupied" which of course wasn't the case... though they certainly didn't prevent everyone from *coming* to work an hour or two after the initial fire. 🀷


1.1 million in ten minutes? Wow! Sounds like an explosive release of the entire stock of HF in a gale-force wind blowing the optimum direction. I've done some more calcs, but I think I've become tiresome πŸ™‚

I wonder if I could lay my hands on that planning document. I'd love to see their models.

Petroleum refineries are not good neighbors, and in Richmond refinery there are windsocks everywhere: it's important to know which way the wind is blowing when you hear the sirens.

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