BP report shifts blame for Gulf of Mexico oil spill to American contractors-'There was a bad cement job':

BP triggered a further backlash last night as it tried to shift the blame for the Gulf of Mexico oil disaster.

In a report released yesterday into the cause of the spill, the beleaguered British oil giant claims two other multinational companies were largely at fault.

The 193-page internal investigation plays down BP's culpability for America's worst ever oil leak, which took 87 days to plug and strained relations between the U.S. and Britain.


* BP highlights roles of Transocean and Halliburton
* 'Shoddy' cement caused gas & oil to enter well
* Oil rig workers took 40minutes to realise fault
* Explosion caused 5m barrels of oil to leak into Gulf

Findings: BP has admitted failures among its staff which led to the Deepwater Horizon oil spill

The Macondo well in the Gulf of Mexico. A blow-out caused the biggest ever off-shore oil spill

But it provoked an angry response last night from U.S. politicians, environmentalists and the firms it singled out for blame.

BP insisted that a 'sequence of failures involving a number of different parties' led to the April 20 rig explosion that killed 11 rig workers and spilled almost five million barrels of oil into the ocean.

According to the four-month probe, 'multiple companies and work teams' contributed to the accident. BP denied the design of its deepwater well triggered the catastrophe.

Distancing itself further from blame, BP castigated Transocean, the U.S. owners of the rig, for failing to prevent the blast and U.S. contractors Halliburton for a botched cement job that allowed highly explosive natural gas, or hydrocarbons, to seep into the well.

Investigators also claimed the blowout preventer – a key piece of safety equipment operated by Transocean – should have sealed off the well immediately after the explosion.

'To put it simply, there was a bad cement job and a failure of the ... barrier at the bottom of the well,' BPs departing chief executive Tony Hayward said last night.

'It would appear unlikely that the well design contributed to the incident.'

However, critics said BP drew its conclusions without examining the broken blowout preventer, which was only hauled to the surface last week and is currently being probed by government experts.

The report brought a sharp rebuke from U.S. Congressman Edward Markey, a member of the investigating political committee.

'This report is not BP's mea culpa,' he said last night. 'Of their own key findings, they only explicitly take responsibility for half of one.BP is happy to slice up blame, as long as they get the smallest piece.'

Environmental groups in the U.S. claimed BP was 'bending over backwards' to avoid the blame to combat multi-billion pound lawsuits and possible charges of criminal negligence.

Transocean also hit back at the report, drawn up by BP safety chief Mark Bly and team of 50 employees.

This is a self-serving report that attempts to conceal the critical factor that set the stage for the incident: BP's fatally flawed well design,' the company said in a statement.

'In both its design and construction, BP made a series of cost-saving decisions that increased risk – in some cases, severely.'

Halliburton said it had carried out its work at the well 'in accordance with BP's specifications' and that the report contained 'a number of substantial omissions and inaccuracies'.

The report is far from the last word in determining culpability.

The U.S. Coast Guard and Department of Justice are carrying out their own inquiries, which could result in criminal charges.

Blame game: Outgoing BP CEO Tony Hayward supervises recovery operations in the Gulf of Mexico in may