In a petroleum refinery, during the start-up procedure in the crude distillation unit, an intern corrosion causes the rupture of a pipe at the bottom of naphta stabilizer tower. 5,5 t of hydrocarbons (light naphtha, propane and butane) are released into this atmosphere. The cloud unconfined ignites on the site to 150 m and causes a violent explosion. Inside the establishment 14 people were killed and 22 people were injured by the explosion. Fire requires the intervention of 150 firemen whose one specialised team. The cost of the material losses has been evaluated in about 10 MF.