Gives you some idea of scale if yesterday. The Buncefield oil depot explosion 15 yrs ago had an estimated equivalent explosive force of 29tons. The Tianjin explosion in China a few years ago was estimated at 336tons of TNT, yesterday's Beruit explosion was estimated at 1.1KT or 1136tons of TNT, Fauld was estimated at 2KT of TNT and the Halifax, Nova Scotia explosion in WW1 was 2.9KT. The last one effectively destroyed the whole town and caused a tsunami 60ft high. The other scary thing you notice when you check these things out is how many of these big explosions have occurred and still occur.
No way should that fertiliser have been stored in such close promity to the port, city and residential areas.