BUNCEFIELD The catastrophic failures in Tank 912 First of all the fuel level gauge broke
Then the overflow alarm failed to shut off petrol supplies
To top that the tank  design then helped
create a lethal cloud
40 minutes later the country was rocked by the Buncefield Blast


THE failure of two key safety mechanisms at the Buncefield oil depot led to the huge fuel spill that caused the disaster.

For 40 minutes before the blast 300 tonnes of petrol - enough to fill 8,500 cars - overflowed from Tank 912, leading to the formation of a massive cloud of fuel vapour.

Fuel was still being pumped into the tank at the time of the explosion because a level gauge failed and showed the tank two thirds full.

A final failsafe switch, designed to sound an alarm and shut off the fuel supply into the tank, also did not work.
Investigators believe the vapour cloud was then ignited by a spark in either, or both, a power generator at Northgate Information Solutions and a pump house on the oil storage site, part of the depot's automatic firefighting system.

The failures have come to light in the third progress report of The Buncefield Investigation into Europe's largest peacetime fire, in which 43 people were hurt.
The blaze was started by an explosion at just after 6am on

December 11 and took four days to bring under control, leaving Hemel Hempstead under a huge smoke plume.

Investigation manager Taf Powell said: “The filling detection equipment recorded an unchanged reading – we know filling did continue.

“The tank would have been full by about 5.20am. From that time it would have begun to overflow. From page 1 “The fuel could easily have generated a large vapour cloud very rapidly.
“Whether or not an alarm sounded, and we don't know that one did, there was no shutdown of the system because filling did continue.”

The investigation board, chaired by Lord Tony Newton, refused to be drawn on whether it was technical or human error behind the disaster.

Lord Newton said aspects of the report 'take us straight into questions of culpability and blame which can only be decided by the courts and not this board'.

Mr Powell referred to the inquiry as a 'criminal investigation' but said: “We are focusing on physical processes and plain facts – we don't address any shortcomings in the design and operation of the site.”

The board's report reveals the disaster started in Tank 912, which was taking delivery of unleaded fuel from the Lindsey oil refinery in Lincolnshire.

From 3am the tank's level gauge gave an unchanged reading, but filling continued, and it has been calculated the tank would have been full at 5.20am.

Fuel spilled out of air vents in the roof and cascaded down the sides of the tank.

The design of the tank, with a high lip around the roof and a band around the sides, meant the liquid splattered to the ground and mixed more easily with the air to form the vapour cloud.

The failsafe switch, which was relatively new, was supposed to sound an alarm in the control room, where two people were on duty that night, but investigators do not know whether this happened.

The switch also had an override function to prevent the system automatically shutting off the inlet valves into Tank 912 in the event of an alarm, but investigators refused to say whether or not this had been turned on.

Investigators have considered the possibility that the leak tripped an alarm, causing a spark in the fire pump house, which then ignited the vapour cloud.

“The pumps might have been activated and solenoid valves within them would have released quite a high energy spark which would have been capable of igniting vapour in that pump house,” Mr Powell said.

The next stage of the investigation will focus on why the failures occurred, including any underlying causes, and why the explosion was so violent.

A number of residents are still unable to return to their homes following the disaster while many jobs have been lost with companies moving out of the area.

Lawyers say  report will benefit claimants

LAWYERS acting for around 200 people hit by the Buncefield disaster say they will be returning to the courts in light of the latest investigation progress report.

Des Collins, of Collins Solicitors, says the report gives them enough ammunition to get a fresh hearing on a group compensation claim.

A High Court hearing in March into various claims against Hertfordshire Oil Storage Limited (HOSL), which runs the oil depot, was adjourned until October.
But in this week's report investigators point to failings in the safety systems at the depot as factors in the disaster.

Mr Collins said: “Clearly we have to wait for the response from HOSL. If that is positive in terms of claimants' concerns we can be in a position to move forward quickly.
“We think the latest developments are sufficiently important to go back to the court.”

Mr Collins said he would be making an application to the judge to reopen the hearing 'as quickly as possible'.
One victim in the group action is Ford Shackcloth, whose home in Cherry Tree Lane was badly damaged in the explosion.
He said: “I think this report's quite good because it keeps the pressure on the oil companies.

“It puts it back in the public domain and begins to point the finger at the oil companies.”

Mr Shackcloth's home, just 300m from the depot, had its front door blown in, ceilings collapsed and parts had to be completely rebuilt, including the conservatory. Oil bosses say they are starting to agree pay-outs PAY-OUTS to those in severe hardship following the Buncefield disaster are in the process of being agreed with Hertfordshire Oil Storage Limited (HOSL).

Claims specialists working for HOSL have collected hundreds of questionnaires from claimants, so that the most severe cases can be dealt with. A spokesman for HOSL, a joint venture between Total and Texaco, said: “Any cases of severe hardship that are identified through these questionnaires are being considered on a without prejudice basis and if a claim has been agreed, payment will be made. The process remains ongoing.”
HOSL has refused to reveal how many claims have been settled.

People experiencing psychological or physical injuries are also being offered rehabilitation treatment if considered appropriate following a medical assessment.

In response to the third progress report published by the Buncefield Investigation Board yesterday (Tuesday, May 9), a HOSL spokesman, said: “This report goes a long way in explaining what happened at the Buncefield terminal. HOSL will continue to work closely with the HSE in its investigation so we can now understand why the incident happened.
“Until we know why the incident at Buncefield happened, it is
not possible to determine legal
liability.”

COUNTDOWN TO EXPLOSION

Midnight – terminal closed.
1.30am – stock check completed. No abnormalities found.
3am – level gauge for Tank 912 shows unchanged reading.
5.20am – Tank 912 completely full and starting to overflow.
5.38am – CCTV footage shows vapour 1m deep flowing from bund A.
5.46am – vapour 2m deep flowing in all directions.
5.50am – pumping rate into Tank 912 increases and vapour cloud reaches Northgate and Fuji buildings.
6.01am – first and largest explosion occurs.

Rules changed to allow harmful PFOS into water

WATER bosses cannot guarantee that a highly toxic chemical, used in foam to extinguish flames during the Buncefield inferno, will not be leaked into drinking water.

New safety levels to allow perfluorooctane sulfonate (PFOS) into drinking water have been set by the Drinking Water Inspectorate in the wake of the depot disaster.

The controversial decision has been made because fire water mixed with the toxic fire-fighting foam escaped from the Buncefield Oil Depot and leaked into a deep borehole running into the chalk aquifer in Cherry Tree Lane.

A lagoon on-site at the depot, which was designed to capture water, was damaged by the explosions and also leaked contaminated water into the ground.

Three Valleys Water cannot promise that PFOS will not eventually get into local drinking water, but pledged to keep levels of the chemical below the safety limit set by the Drinking Water Inspectorate of three micrograms of PFOS per litre of water.

Spokesman for Three Valleys Water, Jonathan Baggott, said: “We can guarantee that we won't exceed the safety limit, but to say we won't ever see levels of PFOS - we can't say that.”
Since the blast at Buncefield in December, Bowbridge water pumping station, used by Three Valleys to supply some of its drinking water, has been closed to help prevent contamination reaching homes and businesses. It is about three kilometres away from the oil depot.

Before the fire at Buncefield PFOS levels were not monitored in water supplies as it was not thought necessary by health bosses. In 2004 a consultation was launched to ban the chemical from being used in the UK following work by Defra that concluded the presence and persistence of PFOS in the environment, together with its potential for accumulating within the body, made it a priority for action. The then Environment Secretary Margaret Beckett had drawn up legislation banning the import of fire-fighting foams that include PFOS.

The nearest water source to Buncefield that Three Valleys is currently using is about nine kilometres from the site.
Levels of PFOS higher than the amount deemed safe to drink have been detected in boreholes in Cherry Tree Lane by the Environment Agency, but these are not used for water extraction.

Other samples tested further away from the site have found traces of the chemical, but not above the safety level.
Colin Chiverton, environment manager for the Environment Agency said: “Everything we have been told and all of our results from testing say there isn't a problem with drinking water in Hemel Hempstead and I am quite happy to drink it.”

The Environment Agency is tracking the movements of contaminated water underground.
Sue Pennison, an inspector from the Drinking Water Inspectorate, said: “If anything is picked up from a monitoring borehole we will have to make a decision about how to protect the public through discussions with water companies.”

Hemel Hempstead MP Mike Penning said: “The clear implication is that the rules have been changed because there is a clear possibility that PFOS may find its way into our drinking water. This is not how health and safety decisions should be made.

“The Government should set safety standards first and then determine whether we drink the water, not the other way round.

“Here we have: pre-Buncefield the stuff is so dangerous we don't want any in the country, post-Buncefield it's not so bad after all.”

‘No evidence of lasting health risks'

ANXIETY over health risks from Buncefield hit about half the local population immediately after the explosion says a report released yesterday.

But the report by health chiefs said that a survey taken seven weeks after the disaster showed that the numbers still worried had fallen to just 13 per cent.

Preliminary findings in the investigation carried out by The Health Protection Agency working with Primary Care Trusts are that there is currently no evidence of a lasting public health risk from exposure to the black plume which rose from the oil depot.

The fire did result in 244 people attending accident and emergency departments, mainly on December 11 2005, the first day of the fire and in the few days following it.

Of those 117 had symptoms attributable to the incident. Thirty eight of these were members of the public. The majority of those visiting hospital were from the rescue services and attended for precautionary check ups. Most had no symptoms but 63 emergency workers suffered respiratory complaints, of which half were sore throats.

Injuries treated included cuts and sprains as well as respiratory symptoms such as shortness of breath, coughs and asthma attacks.

The findings of this week's report indicate that there were no serious public health effects from the accident and that there is currently no evidence of a lasting public health risk from exposure to the plume.

It said that there was no significant exposure to hazardous chemicals for the public living near the site or under the smoke plume and the air quality data at the time showed that it was unlikely that there would be any impact at ground level.

To confirm this, 72 samples from 33 locations were taken from soils and grass downwind of the fire and the samples did not show any contamination due to the fire.

The health chiefs said that given the unprecedented scale of the explosion and fire there was understandable public concern about the health effects. By the end of January when 5,000 local people were asked to take part in the survey on health concerns it was revealed that those under the plume, primarily south of Buncefield, had most concerns.

They were worried about breathing toxic fumes and whether there would be any long-term health effects.

Chief executive of the HPA Dr Pat Troop said: “This is an important study to see what actually happened and to assess the public health effects of this incident. It was very fortunate that no-one was seriously injured or killed by such an enormous explosion and fire. Furthermore our preliminary findings indicate there were no other serious public health effects from the accident.” Giant smoke plume ‘had little impact on air quality' It is unlikely that pollutants emitted after the Buncefield Oil Depot explosion had widespread impacts on air quality at ground level, a report published yesterday confirmed.

The interim review - authored for Defra by consultants Netcen, the Met Office and the Health Protection Agency - summarised the wide range of air pollution monitoring during and after the fires, and assessed the impacts of the incident on air quality.

This monitoring showed that:

• Despite the unprecedented 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 over local, regional and national scales
  
• The plume buoyancy and favourable weather conditions resulted in the plume being trapped aloft, with minimal transport to ground-level
  
• There was no widespread public exposure to the plume
  

The wide range of pollutants measured and reported includes particulate matter, nitrogen oxides, carbon monoxide, volatile organic compounds, dioxins, furans, hydrocarbons and polycyclic aromatic hydrocarbons.

Measurements taken from within the plume by a research aircraft showed that the plume was mainly black carbon-soot. Concentrations of chemical contaminants, such as polycyclic aromatic compounds and hydrocarbons which would be expected from a fire of this nature, were low.