The combustion of cereal dust released a heavy smoke plume on a Saturday afternoon in the upper gallery of a vertical concrete silo containing 15,000 tonnes of wheat and rapeseed. Notified by eyewitnesses, first responders set up a 350-m safety perimeter in recognition of the explosion risks. Some 100 locals (neighbours and supermarket customers/employees) were evacuated; rail traffic on the Amiens/Rouen line and road traffic on national highway RN 29 were halted. Forty fire-fighters and 10 emergency vehicles were deployed. Fire-fighting teams equipped with self-breathing apparatuses brought the blaze under control by sprinkling with 2 water spray nozzles, one from the outside (on a tall ladder) the other from inside the handling tower (dry riser). The safety perimeter was removed at the beginning of the evening. The emergency intervention was extended until the next day to extinguish all residual hotspots. An electrical malfunction on the neon lighting system was the most likely cause of this incident. The Inspection authorities for classified facilities performed an investigation during the same day and subsequent days revealing 53 electrical compliance failures that had already been identified in a July 2004 installation inspection report and not remedied since (insufficient or nonexistent equipment protection indices, indication of missing surface temperatures). Excessive dust accumulation on the installations was also observed; the most recent deep cleaning had been performed back in April 2002. This investigation also revealed a lack of rapid personnel evacuation measures (i.e. one single escape), the absence of an emergency plan in the event of an accident, and an out-of-date safety report. The Inspection authorities for classified facilities noted all of these points. An emergency prefectural order issued on 20th May, 2005 imposed drainage of the damaged silo, given the self-heating risks still present (thermometry out of order, and the cereal contained in 2 cells sprinkled with fire extinction water), and suspended facility operations until full compliance with guidelines. Moreover, the following measures were prescribed: renovation of silo components weakened by the fire, modernisation of all zones containing explosive atmospheres, remediation of electrical installations, thorough silo cleaning, and permanent onsite availability of all necessary equipment. A judicial investigation was also opened.