A vapor cloud explosion occurred in the gas plant associated with the 29,700 bbl/d FCC unit on a 136,000 bbl/d refinery. The initial vapor cloud explosion and several subsequent lesser explosions could be heard in Marseille, approximately 18 miles from the refinery. An estimated 11,000 pounds of light hydrocarbons were involved in the initial explosion. A gas detection system in the FCC unit sounded an alarm indicating a major gas leak. While the unit operator was contacting the security service to warn of this situation, the initial explosion occurred. The initial gas release is believed to have resulted from a pipe rupture in the gas plant, which was used to recover butane and propane produced in the FCC unit. The explosions and subsequent fires devastated about two hectares of this refinery, which covers an area of about 250 hectares. The gas plant, FCC unit, and associated control building were completely destroyed by this incident. Two new process units, which were under construction and scheduled to come into operation in 1993, were seriously damaged. Outside of the refinery, roofs were damaged in the nearby town of Chateauneuf les Martigues and windows were broken within a radius of 3,000 feet. Some windows were broken up to six miles away.

The refinery fire brigade and more than 250 fire fighters from three neighboring industrial sites and four nearby towns were used for more than six hours to bring this incident under control. Approximately 37,000 US gallons of foam concentrate were used during the fire fighting effort. Some fires were intentionally left burning after the incident was under control to allow safe depressurizing of the process units since the flare system was partially damaged by the explosions.

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[ Property Damage $225 Million. Estimated Current Value $474 Million ]

Image credit: Total