In a polyethylene manufacturing plant, the explosion of a flammable cloud (isobutane, ethylene, hexane and hydrogen) escaped from a reactor during maintenance caused 23 fatalities and 314 injured workers. The explosion is equivalent to that of 2.4 t TNT and comparable to an earthquake of 3.5 on the Richter scale.The main explosion was followed by multiple other explosions (including those of 2 isobutane tanks) and fires which will only be under control after 10 hrs of emergency response.

During the polymerization of ethylene in a 750 liters pressurized reactor, an exothermic runaway decomposition occurred and ethylene and its decomposition products were released through the two reactor vent stacks and via the dump valves on the supply lines. The released gas (cloud) was ignited apparently by the hot carbon particles obtained by the decomposition of the ethylene and an aerial explosion occurred. The following substances were involved in the accident: Ethylene (60 kg). Ethylene (together with the decomposition products about 60 kg).