An explosion originating in the hydrogen processing unit occurred in this 75,000 bbl/d refinery. Extensive damage was caused to the hydrocracker, hydrodesulphurization, and hydrogen processing units by the explosion and subsequent fires. The fires were fuelled by hydrocarbons released from the damaged process column and equipment. The explosion, which damaged nearby buildings and shattered windows several miles away, was recorded as a ‘sonic boom’ at the California Institute of Technology in Pasadena, approximately 20 miles from the refinery.

The explosion resulted from the rupture of a the outside radius of a six-inch-diameter carbon steel 90° elbow and the release of a hydrocarbon-hydrogen mixture to the atmosphere. The vapor cloud ignited within seconds of the rupture. There were no out-of-range or warning indications relevant to the incident until after the failure of the pipe elbow. An inspection after the failure found the line at nearly full design thickness a short distance away from the failure. On these facts, it was concluded that the line failure was the result of the thinning of the carbon steel elbow due to long-term erosion/corrosion. The fire-fighting effort was coordinated by the refinery emergency response team, with the Los Angeles City and Los Angeles County Fire Departments utilizing the Joint Incident Command System. The refinery emergency response team placed booms in the Dominguez Channel storm drain to stop oily water run-off generated by the fire fighting effort from reaching the Los Angeles Harbor. The fire was finally extinguished after three days. The refinery’s gasoline production was reduced to 35,000 bbl/d (approximately 70% of rated capacity) until repairs to the damaged process units were completed.

[ Property Damage $78 Million. Estimated Current Value $165 Million ]

Image credit: Tesoro