UPDATED 13.11pm, Eye Witness Report: Seven hours after three explosions ripped apart the Buncefield fuel depot outside Hemel Hempstead, the emergency services have the blaze contained.
But as the fire is fought with thousands of gallons of foam and water, the smoke becomes ever thicker.
The east side of the town lies shrouded in a choking brown fog, and the skyline resembles an erupting volcano.
Mercifully, however, the casualty count of 39 injured, two seriously, seems relatively stable.
Numerous houses near the plant have been damaged, and as the towering smoke drifts south towards London thick fresh filth continues to belch skywards.
The fuel capacity of the depot is believed to be in the region of 60.0m gallons stored in at least 20 colossal tanks.
Holding primarily petrol and kerosene, highly flammable jet engine fuel, Buncefield is a major supplier of Luton and Heathrow airports.
Further explosions have not been ruled out, but are now looking increasingly unlikely.
"It's a brilliant day but the sun is just like a 40 watt light bulb through the smoke."
Eye Witness
The initial explosions, which were felt as far afield as Surrey and Oxfordshire, shook the entire town of Hemel between 06.03am and six-thirty, smashing windows, cracking walls and bringing people running from their homes.
Local hospitals began receiving the walking wounded before 7.00am, mostly those cut by flying glass.
Police are treating the explosions as a major industrial accident, though Total Oil which operates the depot (alongside Texaco) has accounted for all its people on site.
The M1 motorway which runs close by the depot has been closed both ways between junctions 6a and 12, and people are being advised to keep indoors and stay away from the scene.
The M10 is also now closed, as are several main routes into and out of Hemel Hempstead. A thick fog of light brown pollution is drifting through the streets on the east side of town.
Those Hemel residents determined to go out stand and stare. People are wandering around with cameras and phones taking pictures of a solid wall of smoke.
Others have started panic buying at the petrol pumps.
My own apartment building, which lies just three miles from the Buncefield plant, shook me awake shortly after 6.00am, and my first thought was that a train had crashed near Apsley station.
Within moments, however, a colossal tower of smoke was visible from my windows over the Grand Union Canal and it was clear that disaster had struck Buncefield.
"It's a brilliant day but the sun is just like a 40 watt light bulb through the smoke," said one eye witness.
Though the fumes are not believed to be toxic, the air over the town tastes acrid and police are advising people to close doors and windows.
Luton Airport, ten miles away, remains open with no disruption to flights thus far.
