Five companies responsible for the Buncefield oil depot explosion were sentenced to pay a total of more than £9 million today.
Total were fined £3,600,000 plus £2,600,000 costs, Hertfordshire Oil Storage Limited £1,450,000 plus £1,000,000 costs, British Pipeline Agency Ltd £300,000 plus £480,000 costs, and Motherwell Control Systems 2003 Ltd and TAV Engineering Ltd were both fined £1,000 and each ordered to pay £500 in costs.
Sentencing the firms at St Albans Crown Court, Judge Sir David Calvert-Smith said: "Had the explosion happened during a working day, the loss of life may have been measured in tens or even hundreds."
The explosion, on Sunday December 11 2005, is widely thought to be the largest in peacetime Europe. It measured 2.4 on the Richter scale and could be heard 125 miles away.
Jurors heard earlier that the environmental damage from the blast was still not known and could last for decades.
The judge said: "The failures which led in particular to the explosion were failures which could have combined to produce these consequences at almost any hour of any day.
"The fact that they did so at 6.01 on a Sunday morning was little short of miraculous.
"So too was the fact that not one of the few people on the site or in the surrounding area on that Sunday morning lost their lives."
The hushed and packed courtroom was told that the name Buncefield would be forever linked to the explosion.
The destruction at the Hertfordshire depot came after a massive vapour cloud ignited when 250,000 litres of petrol leaked from one of its tanks.
The court heard that people living nearby suffered significant damage to their homes, with windows blown in and doors blown off their hinges.
Residents described the impact as being "like an earthquake" and lawyers said it was "miraculous" that nobody was killed.
Many businesses were affected, some so badly that they were forced out of business.
Judge Calvert Smith explained that the after-effects of the blast had taken a huge toll on the local community.
He explained: "Apart from the short or medium-term physical injuries and the much longer term emotional and psychological injuries suffered by those close to the explosion, families have had to cope with disruption to education, to employment and, so far as home owners are concerned, to a dramatic drop in the value of their homes, even when repaired.
"The name Buncefield is now inextricably linked to the explosion."
TAV Engineering Ltd, of Guildford, Surrey, and Motherwell Control Systems 2003 Ltd, which is in voluntary liquidation, were both found guilty last month of failing to protect workers and members of the public, contrary to the Health and Safety at Work Act.
Hertfordshire Oil Storage Limited (HOSL) was found guilty of failing to prevent major accidents and limit their effects.
It also pleaded guilty to causing pollution to enter controlled waters underlying the vicinity around Buncefield, contrary to the Water Resources Act.
The verdicts followed a joint prosecution by the HSE and the Environment Agency (EA) which the bodies described as the "biggest and most complex criminal inquiry" they worked on together.
Total UK had already pleaded guilty to three charges - of failing to ensure the safety of workers and members of the public and of causing pollution to enter controlled waters.
British Pipeline Ltd also admitted two charges in connection with the explosion - failing to prevent major accidents and limit their effects, and causing pollution to enter controlled waters.Reuse content