At 09:05 am., an explosion occurred in the distillation column of the air separation unit (ASU) of an ethylene complex. The explosion caused the death of 4 employees, injured 4 severely and 27 slightly. Extensive material damage were reported.

The ASU plant capacity was 200 t/d of oxygen at 99.8% purity; it was put in service in 1991. The lower section of the low pressure column consisted of aluminium structured packing fitted in an internal shell.

The accident resulted from an exceptional pollution peak due to venting of ethylene during a shut-down of the ethylene oxyde plant 6 h prior, together with a temporarily low liquid level in the main vaporiser of the air separation unit at reduced load. The hydrocarbon pollutant acted as an igniter and the fuel was aluminium in liquid oxygen.A similar explosion occurred in 1997 in Malaisia (ARIA 23132).