A high-pressure heating pipe (Pressure 12.4 bar, Temperature 185°C) is pierced under a pavement when the road collapses due to violent thunderstorms. Vapour leaks occur and the pipe explodes one hour later during an intervention by the employees of the heating company assisted by firemen and policemen. The explosion created a crater 10 m long and 4 m wide, throwing several people out, breaking windows and damaging nearby vehicles. Two firefighters were seriously injured, one of whom died shortly afterwards, and 21 other people were injured. Major emergency resources were deployed (150 firemen from 19 fire stations, teams with dogs, etc.). A security perimeter is set up and a nearby crèche is evacuated.
The origin of the pipe rupture is attributed to a combination of several factors: lack of penetration of the assembly welds, the accidental presence of water in the gutter where the pipes are placed. The welding defect is probably the result of the lack of preparation of the edges to be welded (non execution of the chamfers) and was highlighted during the examination of several other assemblies from the same subcontractor of the district heating company.