In a distillery, a 5,000-m³ tank containing 1,000 m³ of ethanol at 96% concentration exploded when lightning struck and then ignited. The raised roof fell into the reservoir, which remained intact. However, the tank foot valve cracked upon impact. An emulsifier delivered 2 hours later enabled preventing the fire from spreading to the 1,000-m² retention basin. The blaze was extinguished in 3 hours and the fire-fighters for over 5 hours cooled 3 adjacent 2,500 m³-tanks exposed to the intense heat. Their structural condition would be controlled prior to resuming facility operations. During the emergency response, 23,000 litres of emulsifiers stored onsite and a total of 7,000 m³ of water (including cooling water) were used. An Internal Response Plan drill conducted 2 months earlier and based on a comparable scenario involving one of these tanks served to facilitate the actual intervention. The loss was valued at 30 million francs (including 2.5 million of alcohol destroyed and 3 million of emulsifier). The extinction water (1,500 m³) collected in the retention basins would be diluted in a lagoon. An outside organisation was called to verify the electrical installations of the storage zone. Both the flame arrestors on the vents and the breathing valves on the tanks, which had been recommended 18 months prior at the time of a lightning risk evaluation study, had not been installed. The operator was issued a formal warning to install these devices within one month. Groundwater quality was monitored on a daily basis for 7 days, then weekly for another 3 weeks: no groundwater impact was to be found.

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