The unanswered question is what blew up... twice.
Calcium carbide, potassium nitrate, sodium nitrate, and water?!?
It sounds almost like a combination that was planned for sabotage.
If you put wet fire fighting foam on calcium carbide, it will evolve acetylene. The nitrates are great explosives. And then what, was someone talking about cyanide?
That is a key question.
This is almost like a covert act of warfare.
What is going on? I note that the disappearance of MH370 is still a mystery, and that plane was on its way to Beijing, with many Chinese on board.
As far as I can tell, everything blew up Even the stuff that wasn't flammable blew up when they sprayed water on it.
Calcium Carbide and water make Acetylene Gas.
If one reads the whole article, the author states that there were explosions each time the fire men sprayed water on the fire.
Apparently there are still some chemicals there (like Calcium Carbide or sodium) , even after the giant explosion and fire.
Based on the pic in #2 I think the first explosion dispersed a lot of unexploded material into the air which then detonated. The cars being crushed like that suggests a strong downward shock wave.