Explosion in a hydrogenation unit of a refinery

The event occurred at a hydrogen processing unit of the refinery. A mixture of hydrocarbon and hydrogen leaked ad the 90-debrees-elbow of a carbon steel pipe. The mixture formed a cloud which exploded.

The investigation concluded that the failure of the line was the result of the thinning of the carbon steel elbow due to long-term erosion/corrosion.
The explosion was followed by fires which caused extensive damage to the hydrocracker, hydrodesulphurisation, and hydrogen processing units.
The explosion is classified by one of the source (Oral et al.) as a Vapour Cloud Explosion (VPE).

INITIATING cause was the failure of a pipe due corrosion.
Inspection was possibly not able to detect the damage, but it is not known if this was due to limitation of the non-destructive equipment , to the absence of the correct inspection schedule or incorrect assessment of the risk and consequences. ICHEME/MHIDS reported a wrong dimension of the failed part, which suggest A ROOT CAUSE related to installation errors, wit ha contribution from an inadequate inspection.

Pipe and valve

The fire was visible from 32 km away. People in a 5 sq. km area were evacuate. Material damage is significant ($ 78.3 million).
Los Angeles Times reproted 14 light injuries, Rigas&Amyotte 16.

The company had to pay a $550,000 penalty to the South Coast Air Quality Management District in a settlement stemming from the 1992 explosion and other violations.
[https://www.latimes.com/archives/la-xpm-1994-08-10-me-25508-story.html, accessed November 2025]

People in a 5 sq. km area were evacuated.
The fire-fighting effort was coordinated by the refinery emergency response team, with the city and County fire departments using the joint incident command system. The refinery emergency response team placed booms to stop oily water run-off generated by the firefighting effort from reaching the city harbour.
The fire was finally extinguished after three days.