Buncefield fire

The explosions seen from a different angle.

The smoke plume from Dunsmore, Bucks (about twenty miles away).

The 2005 Hertfordshire Oil Storage Terminal fire began after a series of explosions early on the morning of 11 December 2005. The terminal, known locally as the Buncefield Depot, is an oil storage facility located near Hemel Hempstead in Hertfordshire in the United Kingdom. These were some of the largest explosions ever to occur in the country and the incident has been described as the biggest of its kind in peacetime Europe. The tank fires were extinguished by the afternoon of 13 December 2005.

Explosions, fire and smoke cloud

The first and largest explosion occurred at 06:03 UTC. An inversion layer permitted people to hear it from a hundred miles (160 km) away; there are reports it was heard as far away as France and the Netherlands^[1]. The British Geological Survey monitored the event, which measured 2.4 on the Richter scale [2]. Subsequent explosions occurred at 06:27 and 06:28. Witnesses observed flames hundreds of feet high from many miles away, with the smoke cloud visible from space, and as far north as Lincolnshire.

Damage from the blasts, including broken windows and blown-in or warped front doors, occurred more than half a mile (800 m) away. Reports also indicated that cars in nearby streets caught fire. The roof of at least one house was blown off. Buildings in the vicinity were evacuated by police.

There were 43 reported injuries; two were deemed serious enough to be kept in hospital, one in Watford General Hospital, with breathing difficulties, and another in Hemel Hempstead Hospital; they were not in a life-threatening condition. Some early media reports spoke of eight fatalities, but these may have been persons missing. All members of staff from the terminal were accounted for.

Hertfordshire police and fire services and the MP for the area, Mike Penning, have made clear that there were seven fuel tanks on the site which, as of 14:00 on 12 December, had not been affected; these tanks could explode if the fire were to spread.

Around 150 firefighters began to tackle the blaze at 08:20 on the morning of 12 December, putting in containment measures before applying a large quantity of foam. Plans had been in place to start using foam at midnight on 11 December, but were delayed by last-minute concerns over possible pollution of local rivers and underlying water sources from contaminated water used to fight the fires. Six high pressure pumps were in use to deliver 32,000 litres of foam and water against the fire per minute. Half the 20 individual fires were reported extinguished by midday. By 16:30 it was reported that a further two tank fires had been extinguished, but that one of the earlier extinguished tanks had ruptured and re-ignited, and was now threatening to cause the explosion of an adjacent tank. This led to the M1 motorway being closed again, the public exclusion area being widened and firefighters being temporarily withdrawn until the risk from the threatened tank could be determined.

Firefighting operations were resumed at about 20:00 and it was still anticipated that all fires could be extinguished during the night. Further damage occurred to one of the storage tanks in the early hours of the morning, causing another halt to operations, but firefighting resumed at 08:30. By midday on the 13 December all but three fires had been extinguished although the largest tank was still burning. The smoke plume had been considerably reduced and was more grey, indicating the amount of vapourised water now joining the smoke. Firefighters were confident that the remaining fires could be extinguished during the day. It was reported at 16.45 that all tank fires were now extinguished, although some smaller fires remained. 75% of firefighters for Hertfordshire were involved in fighting the fire, together with support from 16 other brigades.

Some chemical components of firefighting foams may present considerable risks to water resources and various ecosystems, particularly those in riverine environments.

Smoke cloud

The black smoke cloud, which is clearly visible from satellite photographs, is drifting at high altitude (around 9,000 feet, 2750 m) towards Reading and Swindon, and can be seen across much of South East England. The Met Office reported that it could reach Southampton ^[3] and issued warnings that the smoke in the atmosphere could come down in rainfall during the night of 11 December.

The small particles in the smoke, which contains hydrocarbons, can be an irritant but have low toxicity and should not cause any long-term harm.

By 12 December, it was reported that the smoke cloud had reached northern France; it was expected to arrive in northern Spain by the weekend.^[4]

For the first two days of the fire, the high thermal energy has made the plume highly buoyant; this, together with settled weather conditions, has allowed the plume to rise to a great height with little cross-mixing. When the fire is reduced in intensity it is possible that the plume will be less buoyant and that ground-level smoke concentrations may then rise significantly.

Reactions and responses

Around 2,000 people from the Hemel Hempstead area have been evacuated from their homes, and emergency services have asked residents of the smoke-affected areas to close their windows and doors and stay inside. Hertfordshire Constabulary advised people who have houses with smashed windows to seek refuge with friends or family nearby if possible. Some people whose homes have been damaged by the blast were placed in hotels, while others are staying in a nearby shopping centre. Total, the operator of the Buncefield depot, set up a helpline for people whose properties had been badly damaged by the explosion, and called in local authorities and the Salvation Army to provide accommodation or other help for those affected by the explosion.

The incident occurred close to junction 8 of the M1 motorway. The motorway was shut between junctions 12 and 6a (about eighteen miles or 29 km) shortly after the incident. Other roads in the vicinity, including the short M10 motorway, were also closed. Some local petrol stations reported long queues as people started panic buying. A spokesman for the Department for Trade and Industry gave assurances that no petrol shortage was likely to result from the incident.

About 227 schools across Hertfordshire and Buckinghamshire as well as libraries and other public buildings have announced they will be closed on December 12 and December 13 for public safety^[5]. The "Hertfordshire Direct" website ^[6] includes up-to-date information. The University of Hertfordshire campus located further afield in Hatfield remains open. Firefighters commenced a huge operation to douse the blaze on the morning of Monday 12 December.

Criticisms were expressed by local citizens and the local MP that originally the depot had been constructed away from other buildings, but that developmental pressures had led to both houses and commercial premises being built near to the depot. A number of national companies have been affected by the inability to reach premises used for distribution, even where the premises themselves have been largely unaffected by the blast.

The terminal

The Hertfordshire Oil Storage Terminal (HOSL - Hertfordshire Oil Storage Ltd), known locally as the Buncefield complex, was the fifth largest oil-products storage depot in the country, with a capacity of approximately 60 million Imperial gallons (273 million litres) of fuel, although it was not always filled. This was approximately 5% of UK oil storage capacity. It is a major hub on the UK's oil pipeline network (UKOP) with pipelines to Humberside and Merseyside and is an important fuel source to the British aerospace industry, providing aircraft fuel for local airports including London Gatwick, London Heathrow and Luton airports. Approximately half of the complex is dedicated to the storage of aviation fuel. The remainder of the complex stores petrol and diesel fuel for petrol stations across much of the south-east of England. The terminal is owned by TOTAL UK Limited (60%) and Texaco 40%.

The seat of the fire, and the worst damaged section, is "HOSL West", used by Total and Texaco to store a variety of fuels, and the neighbouring British Pipeline Agency area.

Causes

The police issued a statement saying that they are treating the incident as an accident as opposed to a terrorist attack. Rumours of a deliberate attack, in the form of an aeroplane deliberately crashed into the site, spread in the initial aftermath of the explosion may have been given some credence because of the proximity of Luton airport to the site of the incident, but are unsubstantiated.

Italian television stations early on the morning of the fire described the event as a possible terrorist attack and went to the extent of showing features on the July 2005 terrorist bombings. Speculation about the possible terrorist nature of the blasts was fuelled by the fact that a videotape allegedly released by al-Qaeda four days previously had called for attacks on fuel depots and refineries containing oil "stolen" from Muslim countries [7]. However, the cause of the blasts will likely not be known until a full investigation is completed.

An oil industry specialist speculated on BBC News that a vapour leak could have built up to explosive concentrations because of the ground frost in the area keeping vapour concentration at ground level. This would have resulted in a fuel-air explosion. It is industry practice for detection systems to be in place to reveal leakages. In order for this scenario to be fulfilled there must have been a leakage and the detection system must have failed.

A BBC News 24 interview with a petrol tanker driver, who was about to load his tanker at 06:00, reported a cloud of mist rolling in from the tank farm area behind the loading bay. All electric lights were turned off and they were ordered to leave the site on foot. As he was doing so the blast blew him off his feet. In another interview a security guard in a nearby office building reported an unusual smell of petrol inside his building before the explosion.

Other safety experts spoke of a known "Weekend effect" in industry in which weekend maintenance is carried out on plant which is then reinstated in an unsafe condition.