Could be military related , though – possibly rocket fuel . A friend worked at Thiokol several decades ago , and fortunately was off duty when there was an accidental explosion of rocket fuel components in a concrete bunker . All that was found was a portion of a worker’s spine , close to a mile away . The quantity of highly volatile material was estimated as being only about one barrel .
I find it interesting that there is no description of the material by the official Chinese news outlets , other than ‘dangerous’ .
I would not rule out sabotage … a warning shot across the bow ? The invisible rich and powerful are capable of just about anything to retain power and control globally .