This refinery, which first began operating in 1964, was processing 1.7 million tonnes of crude oil a year. Its LPG storage zone contained 12,850 m³ (theoretical capacity: 13,100 m³) of pressurised hydrocarbons in 10 propane or butane spherical tanks, placed as close as 22.5 m from the A7 motorway. A technician’s assistant was extracting a sample while bleeding one of the 1,200-m³ capacity propane spheres filled to 60%. After several incidents, a strictly-controlled operating procedure had been devised to bleed the spheres (calling for opening the upper valve, then gradually the lower valve without ever opening it entirely). At 6:40 am, the assistant performed these steps in the wrong order, causing the valves to freeze and become locked. A propane leak formed an inflammable cloud that slowly drifted over the motorway. Vehicles drove through the cloud without consequence. But at 7:15 am, a car stopped 100 m from the point of the leak on the CD4 frontage road, led to the cloud’s ignition; the driver sustained severe burns and subsequently died. An intense blowpipe flame appeared beneath the sphere 1 min later. First responders from the refinery as well as the Vienne and Lyon municipal services arrived on the scene between 7 and 8:30 am; they tried to cool the adjoining spheres and extinguish the giant flare that had grown even larger once the safety valves on top of the sphere had been opened. The sphere suddenly exploded around 8:45 am (1st BLEVE explosion), causing 13 fatalities. The fireball rose 400 m high and reached 250 m in diameter. An adjacent propane sphere then exploded at 9:40 am (2nd BLEVE), this time resulting in no victims. The human toll was heavy: 18 deaths, including 11 fire-fighters and 84 injured among the 158 present onsite. Property damage was extensive: ignition of neighbouring tanks and the opening of several storage spheres; projectiles blasted by the two BLEVE recovered more than 700 m away, one weighing 48 tonnes found at 325 m; an immense crater where the 2 spheres once stood; 8,000 m³ (1,500 tonnes) of petroleum products destroyed. The blast from the explosion could be observed as far as Vienne (16 km to the south), and 1,475 dwellings were damaged. Criminal charges were brought against both the technician’s assistant and the safety officer for noncompliance with operating instructions. The Site Director was also indicted. On the civil side of the suit, damages and interest were awarded. This disaster set the stage for major reforms in regulations and in the administrative agency assigned oversight of classified facilities.