Buncefield Oil Storage Depot, 2005: A Massive Explosion and a Tank-Overfill Lesson
Explosions and a large fire destroyed most of the Buncefield depot in England. The UK investigation led to major changes in fuel-storage safety standards and to convictions against five companies.
Chemical & Process · Last reviewed
What happened
In the early hours of Sunday, December 11, 2005, explosions occurred at the Buncefield Oil Storage Depot at Hemel Hempstead, Hertfordshire. At least one of the initial explosions was of massive proportions, and a large fire engulfed a high proportion of the site. More than 40 people were injured, and there were no fatalities. There was significant damage to commercial and residential property nearby, and a large area was evacuated. The fire burned for several days and destroyed most of the site.
What the investigations produced
- The UK Health and Safety Executive (HSE) and the Environment Agency investigated the incident and secured convictions against five companies, who were ordered to pay almost £10 million in combined fines and costs.
- The Major Incident Investigation Board and the Process Safety Leadership Group published reports and recommendations, including "Safety and environmental standards for fuel storage sites", and the HSE lists them with its follow-up research.
- The HSE research reports that followed cover overfill of fuel storage tanks and the layers of protection used against it, vapour cloud formation, the explosion mechanism, the integrity management of bulk storage tanks, and instrumented level detection systems.
Apply the lesson
- For a tank or vessel that must not overfill, how many independent protections stop it (level gauge, high-level alarm, independent high-high shutdown)? Are they independent of one another?
- Is the high-level protection tested on a schedule, and does the test cover the whole chain from sensor to valve?
- Where could a released vapor cloud drift, and what is nearby that people occupy?
Engineering lesson: preventing a loss of containment depends on independent layers of protection that are tested, and on knowing what lies beyond the fence if they fail.
Facts at a glance
| Item | What the HSE page states |
|---|---|
| Date and place | Early hours of Sunday, December 11, 2005, Buncefield Oil Storage Depot, Hemel Hempstead, Hertfordshire |
| Explosions and fire | At least one initial explosion of massive proportions; a large fire engulfed a high proportion of the site and burned for several days |
| Injuries and deaths | More than 40 people injured; no fatalities |
| Off-site effects | Significant damage to commercial and residential property nearby; a large area evacuated on emergency-service advice |
| Legal outcome | HSE and the Environment Agency secured convictions against five companies, ordered to pay almost £10 million in fines and costs |
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Questions
Where are the official reports?
The HSE Buncefield page, linked below, lists the investigation board reports, the safety standards report and the research papers.
Does this apply outside the fuel industry?
The overfill-protection and layers-of-protection ideas apply to any process where a vessel or tank can be overfilled with hazardous liquid.
Was anyone killed?
The HSE page says that more than 40 people were injured and that there were no fatalities.
Who investigated?
The Health and Safety Executive and the Environment Agency investigated, and a Major Incident Investigation Board and a Process Safety Leadership Group published reports and recommendations.
Educational material. Examples use simplified, hypothetical inputs and are not a design, a construction document or professional engineering advice. Confirm requirements with the codes and standards adopted where the work is built and with a licensed engineer.