Offshore drilling group Transocean on Wednesday charged Wednesday that British energy giant BP had neglected drilling risks, leading to the giant 2010 oil disaster off the US coast.
It said that an internal "report concludes that the Macondo incident was the result of a succession of interrelated well design, construction, and temporary abandonment decisions that compromised the integrity of the well and compounded the likelihood of its failure," said Transocean, which owned the rig leased by BP.
"The decisions, many made by the operator, BP, in the two weeks leading up to the incident, were driven by BP's knowledge that the geological window for safe drilling was becoming increasingly narrow," it charged.
The Deepwater Horizon rig exploded on April 20, 2010, killing 11 workers and causing millions of gallons of oil to pour into the Gulf of Mexico.
The group said its investigation team found "evidence ... that BP failed to properly assess, manage and communicate risk to its contractors."
Among the elements that the company failed to communicate to the drill crew was the inadequacy of testing on the cement used in the well construction, Transocean said.
In addition, BP neglected to carry out certain risk assessments at the Macondo well, claimed Transocean.
Contacted by AFP, BP declined comment on the Transocean charges.
BP has sued Transocean for damages of $40 billion (27 billion euros) over the disaster and Transocean in turn, has counter-sued.
In April, the US Coast Guard slammed Transocean's "poor safety culture" in a report.