Buncefield probe tracks fuel leak

London -- Investigators have established many of circumstances leading up to the massive explosions and fire at the Buncefield Oil Storage Depot on 11 Dec, last year. However, “much more needs to be done before the root causes of the incident can be identified,” the Health & Safety Executive said in a progress report on the investigation.

The report cites eyewitness evidence of a thickening vapour mist of around one metre high rolling from bund A on the site toward a tanker loading gantry. CCTV cameras also detected a mist flowing westward from inside bund A, at 5.38am – 23 minutes before the first explosion.

The source of the vapour release is not yet known, though CCTV records indicate that it was in the area of bund A, according to the report on the joint investigation by HSE and the Environment Agency.

“It is therefore vital to continue work on the examination of pipework and storage tanks to ascertain the precise source of the release and the mechanism of formation of the flammable mixture and why preventative control measures were inadequate,” the report stated.

The most plausible scenarios involve large-scale loss of containment of vessels or pipework within bund, the report also noted.