In a steel foundry, one of the induction smelters (1-tonne capacity) was punctured. The molten metal made contact with the induction coil cooling water, causing an explosion that blew off the smelter cover. Molten metal was sprayed over a 5-m radius. Steel poured through the puncture into the foundry pit at the base of the smelter and ignited adjacent cablings and machinery in damaging 3 other smelters (capacities: 500 kg and 2 x 100 kg). On-site technicians notified the guard station, which in turn alerted fire-fighters, in accordance with fire response procedures. The entire workforce was evacuated while the maintenance team shut off the building’s power supply. Fire-fighters were called in to close an oxygen supply valve located above the smelter and bring the blaze under control. The 4 damaged smelters were shut down for several weeks. Production was allowed to continue on a 5^th smelter with a 3-tonne capacity after verification it was damage-free. This accident, examined within the scope of a facility hazard study (explosion by water-molten metal contact), caused no impacts (pressure surge, heat flux) outside the building housing the installations. The request to develop an internal emergency plan had been officially addressed in the authorisation order under review at the time.