A British court fined five companies a total of 9.5 million pounds ($14.6 million) Friday for a massive 2005 explosion at a U.K. oil depot that sent a huge smoke plume drifting across the European continent.

Total UK, a subsidiary of French oil company Total SA, was found liable for negligence and ordered to pay most of it — 6.2 million pounds ($9.5 million).

The explosion at the Buncefield oil depot, about 25 miles (40 kilometers) north of London, was triggered when tens of thousands of gallons of gasoline were released in a huge vapor cloud. The blast injured 43 people, caused more than 1 billion pounds in damage and registered a magnitude 2.4 on earthquake monitors.

The explosion was the costliest industrial disaster in British history, Britain's Health and Safety Executive said Friday. Worse casualties were avoided only because the explosion took place early Sunday morning when few people were at work.

Judge David Calvert-Smith said the companies involved — Total UK Ltd., British Pipeline Agency Ltd., Hertfordshire Oil Storage Ltd., TAV Engineering Ltd. and Motherwell Control Systems 2003 Ltd. — had shown "a slackness, inefficiency and a more or less complacent attitude to safety."

He said the problems at the site were so serious that the disaster could have happened "at almost any hour of any day" and said it was just "short of miraculous" that more people were not injured.