Huge UK depot fire probe report

Investigators probing last year's huge explosion at the Buncefield oil depot north of London said yesterday the blast was probably caused by the ignition of a vapour cloud after a storage tank overflowed.

An automatic safety system should have prevented the overflow but had failed to cut off the fuel supply, they added.

A series of explosions at the depot in Hemel Hempstead, Hertfordshire, early on December 11 spawned a three-day inferno which became one of Britain's biggest-ever peacetime blazes.

The Buncefield Major Investigation Board said in a report that the tank - number 912 - had been overflowing for more than 40 minutes before the blast.

But the extensive damage from the blast meant it had not been possible to identify what sparked the cloud of fuel vapour that would have formed.

Possible candidates were a nearby emergency generator, a fire pump-house or even a spark from a passing car.

Unleaded fuel was being piped into the tank for 11 hours before the blast and it would have been full by 5.20 a.m, some 41 minutes before the explosion, the report said.