What happened at the Buncefield oil storage facility in 2005?

On 11 December 2005 a number of explosions occurred at the Buncefield oil storage facility resulting in a large fire. 43 people were reported injured but fortunately there were no fatalities.

How did the Buncefield fire start?

A shut-off mechanism failed on tank 912 resulting in an overfill. This allowed a flow of material through the breather venting devices, flowing down the vessel and generating fine droplets of spray as it fell. This formed a large flammable vapour cloud in the region of 110,000m2.

The main violent explosion took place at 06:01:32 hrs, followed by a large fire engulfing 23 large storage tanks. 2,000 people were evacuated from surrounding homes and disruption was caused to nearby motorways.

The fire continued to burn for five days with the resulting smoke plume visible for miles.

What can the industry learn from the Buncefield fire?

Lord Newton was appointed to chair the Major Incident Investigation Board. The Board members included three members of the Competent Authority and two independent members; Dr Peter Baxter and Professor Dougal Drysdale.

Investigation into the incident concluded that tank 912 released up to 300 tonnes of petrol - around 10% of which turned to vapour that mixed with the cold air, eventually reaching concentrations capable of supporting combustion.

Ignition is likely to have taken place at the emergency pump house. The flames accelerated due to undergrowth and trees which produced flame velocities of several hundred m/s. This was followed by a transition to detonation near the junction between Cherry Trees Lane and Buncefield Lane with overpressures in excess of 200kPa.

On 11 December 2008 the Buncefield Investigation Board published its final report, presented in two volumes and covering 78 recommendations for improvements.