Buncefield Explosion

The 2005 Hertfordshire Oil Storage Terminal fire was caused by a series of explosions early on the morning of 11 December 2005. The terminal, generally known as the Buncefield Depot, is an oil storage facility located near the M1 motorway on the edge of Hemel Hempstead in Hertfordshire, England. News reports described the incident as the biggest of its kind in peacetime Europe. The tank fires were extinguished by the afternoon of 13 December 2005. However, one storage tank re-ignited in the evening, and the firefighters left it to burn, rather than attempting to re-extinguish it.

The first and largest explosion occurred at 06:01 UTC near container 912. From all accounts, it seems to have been an unconfined vapour cloud explosion of unusually high strength. Because of an inversion layer, the explosions were heard a hundred miles (160 km) away; there were reports it was audible in France and the Netherlands. The British Geological Survey monitored the event, which measured 2.4 on the Richter scale.

It was reported that people were woken in south London, and as far west as Wokingham, where in its southern suburb, Finchampstead, numerous people felt the shockwave after the initial explosion. Subsequent explosions occurred at 06:27 and 06:28. Witnesses observed flames hundreds of feet high from many miles away, with the smoke cloud visible from space, and as far north as Lincolnshire.