I gonna explain the cause of the accident. This is what I heard about the accident.
During the dicharge of a container with rockets, one of the boxes slipped of the hands of one of the workers and felt to the ground.
The box exploded. The result you saw on the video.
The rockets was not made how it has to be. In China they made an error. They used components who can cause a chemical reaction.
This is what i heard about it.
Sorry of my English. I hope you understand what i wrote.