on a Sunday morning, in a ceramic factory, a leak on a 100 m tank containing 370 kg of hydrogen caused an explosion. The generated pressure wave causes significant damage to exterior buildings (broken windows, fire starts); a fragment of the tank was found several hundred meters from the place of the explosion. The human toll shows 23 people from the public who were slightly injured. A fire broke out soon after on the site and threatened storage of acetylene and hydrogen fluoride. A safety perimeter of 500 m is set up, road and rail traffic are stopped, the population evacuated.The tank at the origin of the accident had been put into service in December 1982, after having been modified to notably increase its storage capacity. Its first regulatory check after 5 years of use had revealed nothing abnormal, the second was to take place a few months after the accident. Operating at a maximum operating pressure of 44.1 bar, the storage was replenished as soon as its pressure fell below 15 bar (several times a week). The last loading by an external company had been carried out less than 2 hours before the explosion.Fatigue corrosion was the source of the leak that caused the explosion. The modification work carried out on the tank and in particular the removal of the roof along the weld had caused a deformation of the tank (oval instead of circular section) and induced tension in the material. Frequent filling of the repository only accelerated the weakening process of the tank.