The AZF plant exploded [0], blasting windows on thousand meters radius, killing directly 17 persons and wounded thousands.
I was at the other side of the town (not as big as Houston) and wall trembled. A friend of mine who lived about 50 miles away had her windows vibrate.
It was a terrible thing. But less than half a miles were the SNPE (National Powder and Explosive Company) and it could have turned in a major blast with thousand of death by the explosion and leak of mustard gas that were also stocked there.
The question was, and still is in my opinion : why on earth do you build chemicals plant that have a risk to explode near habitations ?!! (Or in reverse why authorize building habitations near Seveso 2 plant ?)
[0] http://edition.cnn.com/2001/WORLD/europe/09/21/france.explos...