Burning oil depot. Ick
I used to live in Hemel Hempstead. Like any sane person, I got out, but not until after a big chunk of it had been improved by the biggest non-nuclear explosion in history. If you're expecting a hair-raising tale of how I was millimetres away from being atomised, I must disappoint, my home at the time (11th Dec 2005) was just about exactly 1km from the Buncefield oil depot as it exploded, so I got a pretty comprehensive awakening but no damage

We were, however, downwind of it. Over the next hour we were choked by a series of clouds of various sorts of vapours (sometimes diesel-ish, sometimes more like paraffin, some of them seemed as much to be vapourised petrol products as smoke from the burning of them). Briefly, it rained fire,which although damaging the paint on my car a bit, caused no real issues as it was a cold and thankfully damp morning

The smells were rank. Everyone in our street had sore throats for days afterwards and felt like we'd tried to top ourselves through the old car-and-hosepipe method but failed. Ever since, I find walking along roads with heavy traffic to be more acutely unpleasant than I ever did before

Oh, and all the trees in our street died. Never figured out exactly why.
(Carpe Cyprinidae, Fri 17 Jan 2014, 17:20, Reply)