BP spreads blame over oil spill

BBC:

An investigation carried out by BP said it was responsible in part for the disaster, but it also blamed other companies working on the well.

BP faces billions of dollars worth of legal claims for compensation over the spill, the worst in recent US history.

An estimated 4.9m barrels of oil leaked into the Gulf after the blast.

The well was capped on 15 July, and an operation to permanently seal it is due to take place in the next few weeks.

In the 193-page internal report released on its website, BP said that decisions made by "multiple companies and work teams" contributed to the accident, which it said arose from "a complex and interlinked series of mechanical failures, human judgements, engineering design, operational implementation and team interfaces".

BP was leasing the Deepwater Horizon rig from Transocean, and its cement contractor was Halliburton. The BP report was critical of the processes and actions of teams from both firms.

However, in a statement issued after the report, Transocean deflected BP's criticism, calling the company's own well design "fatally flawed".

"In both its design and construction, BP made a series of cost-saving decisions that increased risk - in some cases, severely," the Associated Press reported Transocean as saying.

'Bad cement'

The report, conducted by BP's head of safety, Mark Bly, highlighted eight key failures that, in combination, led to the explosion.

BP said that both BP and Transocean staff incorrectly interpreted a safety test which should have flagged up risks of a blowout.

"Over a 40-minute period, the Transocean rig crew failed to recognise and act on the influx of hydrocarbons into the well" which eventually caused the explosion.

BP criticised the cementing of the well - carried out by Halliburton - and repeated previous criticism of the blowout preventer.

Among the other findings, the report said:

• There were "no indications" that Transocean had tested intervention systems at the surface, "as was required by Transocean policy", before they were deployed on the well
• "Improved engineering rigour, cement testing and communication of risk" by Halliburton could have identified flaws in cement design and testing, quality assurance and risk assessment
• A Transocean rig crew and a team described as "mudloggers" working for Halliburton Sperry Sun may have been distracted by what are described as "end-of-well activities" and, as a result, important monitoring was not carried out for more than seven hours
• Crew may have had more time to respond before the explosion if they had diverted escaping fluids overboard.