Toulouse chemical factory explosion

On 21 September 2001, an explosion occurred at the AZF (French initialism for AZote Fertilisant, i.e. nitrogen fertiliser) fertiliser factory in Toulouse, France, belonging to Grande Paroisse, a subsidiary of Total. Three hundred tonnes of ammonium nitrate was stored (the maximum capacity was 2,000 tonnes) in hangar 221 222. The entire factory was destroyed, making a crater with a depth of about 7 metres (23 ft) and a diameter of 40 metres (130 ft). Steel girders were found 3 kilometres (1.9 mi) away from the explosion site. The blast measured 3.4 on the Richter scale, with an estimated power equivalent to 20-40 tons of TNT. The explosion was heard up to 100 km (62 mi) away, with the sound of the explosion audible as far away as in Canejan, Spain 90 km (56 mi) south of Toulouse. Due to the acoustics of the hills and the loud sound, the explosion was reported as occurring in multiple places. Police at first believed that at least five bombs had simultaneously gone off.