Nearly five million barrels of oil spilled from the Macondo well [EPA]

The United States government has filed a lawuit against the oil company BP and eight other companies over a massive oil spill in the Gulf of Mexico earlier this year.

The complaint filed by the justice department in New Orleans on Wednesday accuses the companies of violating safety and operating regulations in the period before the April 20 explosion on the Deepwater Horizon rig, which caused nearly five million barrels of oil to pour into the water. 

"We intend to prove that these violations caused or contributed to the massive oil spill and that the defendants are therefore responsible under the Oil Pollution Act for government removal losses, economic losses, as well as environmental damages," Eric Holder, the attorney-general, said.

"We're also seeking civil penalties under the Clean Water Act which prohibits the unauthorised use of oil in the waters."

The defendants named in the suit were BP Exploration and Production Inc; Transocean Deepwater Inc.; Transocean Offshore Deepwater Drilling Inc; Transocean Holdings LLC; Anadarko Exploration and Production LP; Anadarko Petroleum Corporation; MOEX Offshore 2007 LLC; Triton Asset Leasing GMBH; and QBE Underwriting Ltd/Lloyd's syndicate 1036.

The lawsuit did not name Halliburton, which carried out the cementing work for the Macondo Well, which was criticised in a report into the incident, or Cameron International, which provided equipment for the well.

'Investigations continue'

However, the justice department said its investigation was continuing and more defendants and charges could be added.

"While today's civil action marks a critical step forward, it is not a final step," Holder said.

Holder said the complaint had been made to ensure taxpayers do not pay the cost of the disaster  [EPA]

"Both our criminal and civil investigations are continuing, and our work to ensure that the American taxpayers are not forced to bear the costs of restoring the Gulf area - and its economy - goes on."

BP, the world's third largest oil company, has been selling off assets around the world to raise $30bn to cover both the clean-up and compensation costs of the spill. It has estimated its exposure at nearly $40bn.

On Wednesday, it released a statement saying that the lawsuit is "solely a statement of the government's allegations and does not in any manner constitute any finding of liability or any judicial finding that the allegations have merit".

For every barrel of oil spilled into the Gulf of Mexico, there could be a fine of up to $4,300 if gross negligence is found. That would equal a fine of at least $21 billion. If no gross negligence is found, the fine could be up to $1,100 per barrel or almost $5.4 billion.

The complaint lists the losses from the three-month spill as "hundreds of miles of coastal habitats, including salt marshes, sandy beaches, and mangroves; a variety of wildlife, including birds, sea turtles, and marine mammals".

It also says the spill resulted in lost opportunities for "fishing, swimming, beach-going, and viewing of birds and wildlife".

"The full extent of potential injuries, destruction, loss and loss of services is not yet fully known and may not be fully known for many years," the complaint says.