A 63 kVA transformer fire, followed by a 63 kVA circuit breaker explosion, occurred at approximately 9 a.m. in an industrial gas plant. The alarm, triggered in the control room, caused the site installations to be secured. A significant plume of black smoke (containing soot) emerged. Some of the 9 t of oil (without PCBs) in the transformer overflowed into the retention basin. The facility operator alerted the emergency services at about 9:10 a.m., then activated its internal contingency plan and evacuated the 40 employees. The fire brigade arrived at around 9:20 a.m. while the site was in an electrical blackout. The facility operator informed the town authorities and the customer plants using the air gases produced by its installations. As the fire was naturally decreasing in intensity (owing to a lack of oil) at around 10:45 a.m., the fire brigade waited for the neighbouring transformer to cool down before intervening with foam and CO2 so as to prevent any possible damage. At about 12:00 noon, the firefighters were able to extinguish the flames burning on over 5 m of power cables using 6 powder type extinguishers. The fire brigade left the site at around 12:20 p.m. while the internal contingency plan was being put into place. The 15 t of extinguishing water and oil that had been pumped into the retention basin were disposed of in an approved treatment centre. The transformer had been destroyed, and the one next to it was damaged by the thermal effects of the fire. The operator issued a press release.

The fire started in the transformer tank (built less than 14 years prior), then a portion of the boiling oil spilt over into the retention basin. The oil did not ignite there due to the grating placed above the retention basin which limited the supply of air. It was determined that the origin of the fire was an explosion caused by a rise in pressure or an electric arc following a fault in the transformer’s ground phase (failure of one of the bushings, a surge protector or an internal defect).