At an LPG filling station, around 2:15 pm, a station employee was drilling in the “automation” utility room located in a zone outside of any risk of gas presence: this room provided access to the administrative building via 3 juxtaposed electrical ducts leading into the building’s crawl space. At the time of this drilling task, a flash-arc occurred and burned the employee, who was able to trip the closest emergency shutoff switch. The emergency system secured the site (shutdown of installations and automatic sprinkling of sensitive zones). Site employees quickly controlled this fire breakout. One of them raised a floor board in the room then another board before getting burned by a second flash-arc, which was quickly brought under control using powder extinguishers. Both of the injured employees had to be hospitalised (burns to their faces, hands). The utility room was damaged and the station’s activity shut down for a short while. Following verifications, the safety installations were resupplied under normal conditions around 7 pm.

The accident would have been caused by a leak on the propane pipeline feeding the administrative building’s heating boiler. The copper piping (diameter: 22 mm), laid aboveground from the storage tank (11.6 m³, for heating the administrative building + the filling zone, with direct feeding from the filling zone) and then run underground (diameter: 14 mm) via the crawl space, before reaching the boiler room: a screwed connection in the underground part broke, causing the leak and gas accumulation in the ground along the duct until reaching the crawl space. From this point, the combustible made its way into the electrical ducts, which were not blocked, in the direction of the automation room. The drill provided the flash point for the first flash-arc. The second time around, a hotspot smouldered and raising the floor boards created a draft that reignited the remaining gas. At the suggestion of inspection authorities, a prefectural restraining order requested the periodic verification of all pipelines, along with the monitoring of strength and seal inspections and an update of the internal emergency plan. The operator planned to implement the following measures at this site: placement of a 1.7-m³ tank dedicated to heating the administrative building, and filling of the heating tanks from a lorry. The operator also ordered all sites under his control to reference all underground pipeline segments and then undertake a program of converting these into aboveground segments, in addition to a campaign of blocking all electrical supply ducts in off-zone locations.