> Vapor cloud detonation has never been considered particularly likely, and never documented as far as I know

This is an example of a vapor cloud detonation. I'm just pointing out that it's happened, so I'm not sure why you're saying it's never been documented. Unless you just meant in the context of a tanker, but that's not how you phrased it.

As it happened, I lived in the area at the time (about 40 miles away on the back side of Cypress, Texas). I didn't think so much about it being an earthquake, but instead thought a large airplane had crashed nearby. I ran out into the street expecting to see fire and explosions and whatnot within a block or few of my house ... only for there to be _nothing._