BP blames American company for Gulf oil spill

Thousands of barrels of oil a day began gushing out of a blown-out well on April 20 causing an environmental disaster. BP was forced to set aside £20 billion for compensation claims and clean-up costs.

The 193-page report makes clear that the disastrous chain of events was triggered by the failure of a cement barrier installed by engineers Halliburton to contain oil and gas.

BP chief executive Tony Hayward, who has lost his job as a result of the storm of criticism that followed, said: "To put it simply, there was a bad cement job."

BP's conclusion will be seen by some as an attempt to spread the blame for the catastrophic spillage. Although "multiple companies and work teams" contributed to the blast, which killed 11 workers, Halliburton and Swiss based rig owner Transocean must shoulder much of the blame, according to the report.

It found that the cement slurry barrier installed by Halliburton did not work, while BP and Transocean engineers disastrously misinterpreted the results of a "critical" safety test of the well, which should have flagged up risks of a blowout.

Once gas and oil had begun rising uncontrollably "over a 40-minute period the Transocean rig crew failed to recognise and act on the influx of hydrocarbons into the well".

As the gas had reached the rig it was not routed overboard, allowing the highly combustible cloud to flood through ventilation systems to the engine room.

Even after the explosion, the Transocean-operated blow-out preventer on the ocean floor should have sealed the well but failed.

In a key passage in the report it found hat "improved engineering rigour, cement testing and communication of risk by Halliburton could have identified the low probablility of the cement achieving zonal isolation".

The inquiry into the accident was carried out over four months by a team led by BP's safety head Mark Bly.

Mr Hayward added: "It would appear unlikely that the well design contributed to the incident, as the investigation found that the hydrocarbons flowed up the production casing through the bottom of the well."

The explosion released an estimated 4.9 million barrels of oil to gush into the Gulf in what was described as America's worst environmental disaster. In his criticism President Obama called BP "reckless".

He added: "We will make BP pay for the damage their company has caused and we will do whatever is necessary to help the Gulf Coast and its people recover from this tragedy."

Environmental groups today said the report amounted to a "sorry catalogue" of failures but said the real blame lay with governments for allowing drilling in areas where accidents were inevitable.

Jim Footner, head of energy at Greenpeace UK, said: "Worryingly, they're just weeks away from drilling at similar depths in UK waters.

"The Government must step in right now and stop this by introducing a moratorium on deep water drilling.

"The real problem is our addiction to oil, which is pushing companies like BP to put lives and the environment at risk.

"Governments around the world must now stop the industry recklessly squeezing the last drops of oil from places like the Gulf of Mexico, the Arctic and the tar sands of Canada."