The latest report of the ongoing investigation into the explosion at the Buncefield oil depot on 11 December last year has been published by the Buncefield Major Incident Investigation Board. The third progress report indicates that a storage tank was overflowing for over 40 minutes before the explosion in which 43 people were injured. Fuel had in fact been piped into the tank for 11 hours before the blasts and by 5:20am nobody had noticed it was full and the mechanical safeguards had failed. The explosions began at 6:01am and more than 20 tanks caught alight and raged for almost two days. The Health and Safety Executive (HSE) concluded that these mechanical failures and human error were partly to blame and two safety devices designed to prevent such an incident had malfunctioned. The first was a level gauge which got stuck and did not rise and register as the tank continued to fill, and additionally, a high-level alarm should have triggered once the tank reached a certain level. The resulting overflow caused a huge vapour cloud to build up which was then ignited by a spark.
The HSE has welcomed the clarity of the report and aims to respond and act on its findings to ensure the highest standards of safety at oil and fuel storage sites. In addition, the Department for Environment, Food and Rural Affairs (DEFRA) have published their initial "Review of the Air Quality Aspects of the Buncefield Oil Depot Explosion". This states that despite the massive scale of the explosion and fire, ground-level concentrations of a range of pollutants did not deviate from those normally expected at this time of year. It is also unlikely that the pollutants emitted had widespread impacts on air quality at ground level.
