In a refinery, 10 to 20 t of gaseous and liquid hydrocarbons were released in 5 minutes starting at 4.46 pm by 3 of the 5 valves of the atmospheric distillation unit during restart operations.At 6 pm, the firemen notified the Classified Installations Inspectorate which observed a deviation from the prefectoral order governing the site: The valves were not connected to the site’s flare-stack network.The accident was caused by a series of errors relative to the restart procedures and in the transmission of information between and within the shift crews: column normally full, numerous alarms ignored… underscoring violations and organisational deficiencies.Partly owing to the strong mistral winds, part of the release fell on the vegetation, homes and the beach of the neighbouring community of Sausset-les-Pins; the traces left allowed the zone to be evaluated at 1 km wide by 8 km long. The 70 children at a holiday camp were restricted indoors, and 7 were examined by doctors. One person was effected by the product and subsequently hospitalised.The Prefecture requested that samples and analyses be conducted on the fallout. The municipal authorities informed the population concerned by the fallout. The regional management of the group operating the refinery received 661 claims: 320 people were mobilised to clean 132 swimming pools, 563 homes and 726 vehicles. The consequences of this accident could have been much more serious if the cloud had ignited on one of the site’s 2 flare-stacks or if the liquid part had fallen on the distillation unit.The operator analysed the accident and the initial measures were taken: installation of a pressure sensor on the tower head to shut down the furnaces in case a high pressure threshold is met, shut-down of heating and closure of furnace supply line valves (shutting down the tower supply line) the pressure drop threshold in the column is exceeded (upper threshold difference between the pressure at the base and at the head of the tower). Costs of cleaning and compensations raised 1.7 million euros. Due to the numerous complaints, Police Court fined the operator 10,250 € on June 8th.

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