The light gas oil (LGO) sidedraw from a crude distillation unit (CDU) experienced a catastrophic pipe rupture, releasing a large volume of hot LGO to grade. The hot LGO partially vapourised and formed a large vapour cloud which engulfed 19 company employees. Approximately 2 minutes after the rupture occurred, the fluid ignited. Eighteen employees managed to escape from the vapour cloud before it ignited; the other was engulfed in the fireball but was wearing full-body firefighting protective equipment and managed to make his way to safety. Six employees suffered minor injuries during the incident and subsequent emergency response activity. A large plume of vapour, particulates and black smoke travelled across the surrounding area and approximately 15,000 people from neighbouring communities sought medical treatment over the next few weeks for a range of ailments such as breathing problems, chest pains, sore throats and headaches. Twenty of these were admitted to local hospitals for treatment as inpatients.

Basic Cause:
Rupture of the LGO sidedraw piping caused by wall thinning due to high temperature sulphidation corrosion (HTSC).