Three employees of a maintenance firm were repairing the floating roof of an empty 30,000-m³ gasoline tank, which prior to these works had been insulated, degassed and washed, when a flash type explosion occurred. The Internal Emergency Plan was activated. The workers were able to escape, but their vehicle was set ablaze. Pieces of the roof were projected some 100 metres. Fire-fighters used water to cool the pipes and adjacent tanks; during their intervention, they noted the poor quality of available emulsifiers. The fire extinction products had remained in the basin. It took roughly 10 min to extinguish the fire. Close monitoring extended throughout the night, and the order was issued to cease all similar works. Total property damage was assessed at 9 million francs.