The chemical factory stores vinyl chloride (chloroethene, chloroethylene) in three tanks. Two tanks were full with the chemical at the time of the incident. Due to leak, pressure in the tank dropped. Instead of finding the cause for pressure drop, operators pumped more chemical into the tank. This lead to bursting of tank and release of chemical. Ignition source from outside the plant caused explosion of the leaked chemical, burning the trucks and cars outside the plant. 23 persons died and 22 were injured in the incident.
http://www.ecns.cn/news/2018-11-30/detail-ifzahqkf0371003.shtml
http://www.ecns.cn/news/2018-11-29/detail-ifzahqkf0369490.shtml)
http://www.ecns.cn/news/society/2018-12-10/detail-ifzanuxq9377375.shtml