Fires were raging last night after a series of explosions ripped through an oil storage depot at Hemel Hempstead near London yesterday morning in what is thought to be the largest incident of its kind in peacetime Europe.
Incredibly, only two people were seriously injured among 43 casualties after flames shot hundreds of feet into the sky following the blasts at the Buncefield depot, in Hertfordshire. The explosions forced the evacuation of some 2,000 people living near the 100-acre site.
With the first blast just after 6am heard some 100 miles away, there were initial fears of a terrorist attack as Britons awoke to find vast plumes of black smoke spreading across southern England.
Anti-terrorist officers will now join the police investigation now under way despite Hertfordshire chief constable Frank Whiteley's confidence that there was "nothing to suggest anything other than an accident".
One survivor described a scene from hell yesterday after the explosions ripped through the fuel depot.Part-time security guard Raheel Ashraf escaped with just a few scratches after jumping 15 feet from blown-out windows to find an adjacent building devastated as the inferno triggered what experts believe may be the largest incident of its kind in peacetime Europe.
The depot is Britain's fifth-largest fuel distribution depot.
One man who was standing 200 yards from the blast site was being treated at Watford General Hospital for injuries to his lungs, while a second was kept at Hemel Hempstead Hospital for observation.
People told of being blown out of their beds by the force of the explosions, which blew out and buckled doors and cracked walls in properties at least a quarter of a mile away. Britain's deputy prime minister John Prescott visited the scene last night as firefighters assembled the resources necessary to launch their attack on the fire which could rage for some days.
With the worst case scenario that they could be forced to wait for daybreak, Hertfordshire's chief fire officer Roy Wilsher said they were just "hours away from launching an attack on the fire".
Experts had advised this was "possibly the largest incident of its kind in peacetime Europe", said Mr Wilsher. But with investigators standing by, and some experts suggesting the precise cause of the suspected accident might never be fully identified, the chief warned: "The damage a fire of this intensity will cause may, or may not, leave clues for the fire investigation team."
With more than 100 firefighters at the scene, Mr Wilsher said a quarter of a million litres of foam concentrate was on its way to Hertfordshire from various parts of the country.
When mixed with water this would generate the millions of tonnes of foam necessary to allow his men to begin tackling the blaze. Fire officers were also consulting oil industry experts about how to tackle the flames at the site which houses some 26 storage tanks, some of them said to hold three million gallons of fuel.
As the vast plumes of smoke spread across southern England, police advised people living nearby to keep their doors and windows shut. Hertfordshire's director of public health Jane Halpin said the smoke was most likely to affect those who already suffered from respiratory problems.
The smoke was made up of hydrocarbons which in the short term were likely only to affect people with illnesses such as asthma and chronic pulmonary disease, while the people most at risk were those who had inhaled it.
Dr Halpin added that samples of the smoke had been taken to determine its exact composition and the long-term implications of exposure to it, if any.
The Environment Agency was monitoring the potential environmental effect of the explosions, and was also working with the Health Protection Agency to establish the potential effects of the smoke plume.
Schools in and around Hemel Hempstead are expected to be closed today, as again are sections of the MI. Some flights were disrupted at Heathrow yesterday although Luton airport was operating as normal.