At around 12:20 p.m., a welder caused an explosion and ignited a leak while performing a hot tap operation on a buried natural gas line (P 4 bar, DN 200, 1982, polyethylene, cast iron sleeve) that was to be deviated. A deafening noise filled the street and flames measuring 20 m high spread to the facade of an adjacent building.

The emergency services established a 100-metre security perimeter around the area and evacuated 500 people. The hospital near the accident suspended the registration of incoming patients, and 150 patients were moved further inside the premises. The gas utility disconnected the gas supply by closing 3 valves and purged the line at around 1 p.m. The ignited gas leak was extinguished at 10:25 p.m. after a 4th valve was closed.

Four firefighters and two residents were taken to the hospital. At around 3 a.m., while clearing out the debris, the rescue services discovered the welder’s lifeless body under 50 cm of rubble. Six flats were destroyed, and 36 inhabitants had to be relocated. The thermal radiation damaged many vehicles that had been parked on the street. For two days following the accident, 500 customers were deprived of gas.

The subcontractor’s technician, a former gas agent, used a torch on a plastic pipe thinking it was a steel pipe with a plastic coating. The plastic piping had not been marked with a yellow stripe. An inquiry was conducted to determine the causes and circumstances of the accident.