Total, the French oil giant, and four other companies are facing criminal prosecution over Britain's biggest peacetime explosion, the Environment Agency said today.

The agency has commenced proceedings with the Health and Safety Executive over the blast at the Buncefield oil storage depot in Hertfordshire in December 2005, which injured 43 people.

Five companies will make an initial appearance at the West Hertfordshire Magistrate's Court in Watford on January 23, including Total's UK arm and Hertfordshire Oil Storage Limited (HOSL), the operator of the Buncefield depot, which Total co-owns with Chevron, the US oil company.

The Environment Agency said it had commenced proceedings after a "thorough and complex criminal investigation" but declined to comment further.

The two agencies, which are jointly responsible for regulating major non-nuclear hazardous industrial sites in the UK, established a committee to investigate the incident, headed by Lord Newton of Braintree, the Conservative peer.

Today the agencies announced that Total is facing three charges — failing to ensure the health, safety and welfare of its employees; failing to protect persons not in their employment; and causing pollution to ground water in the vicinity of the plant.

HOSL is facing two charges: failing to protect a major accident and limiting its consequences to persons and the environment; and polluting ground water.

In a statement, Total said: “We are taking legal advice in relation to these proceedings. Once all the relevant papers have been served, we will consider our position further.”

British Pipeline Agency, an engineering services provider, TAV Engineering, which manufactured an allegedly defective safety switch, and Motherwell Control Systems, which manufactuers monitoring systems, are also facing charges.

The companies face unlimited fines if they deny the charges and are subsequently found guilty at trial. If they plead guilty early on, the fines could be as low as £5,000.

Total and HOSL are also facing a separate civil lawsuit over the Buncefield explosion in which hundreds of businesses, insurance companies and local residents are claiming around £700 million in damages.

That case, which began in October, is ongoing although the claimants moved a significant step closer to receiving compensation when Total admitted early on in the trial that the fire was the result of negligence.

A substantial chunk of the trial has been devoted to a dispute between Total and Chevron over who should compensate the Buncefield victims. Although the two oil giants were joint owners of HOSL, Buncefield’s operating company, Chevron claims it was a silent partner and should not be liable for damages.

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