Report says Halliburton knew cement being used at Deepwater Horizon was unstable.
Federal investigators say they've uncovered evidence that both Halliburton and BP knew there were critical problems on the Deepwater Horizon rig months before the disaster that killed 11 crew members and led to the worst oil spill in U.S. history.
A presidential commission investigating the explosion and collapse of the well has uncovered documents that show two separate tests by cement contractor Halliburton conducted two months before the accident indicated the mixture being used on the rig was "unstable."
"The cement is the very first line of defense against flow of oil and gas to the surface," says the University of Houston's Professor Don Van Nieuwenhuise.
Halliburton alerted BP about results of one of those failed tests but no action was taken.
Another test just a week before the explosion showed a slightly different cement mixture was still unstable.
Halliburton never shared that information with BP.
Instead the company apparently changed the testing protocol and got one good test.
That's the data Halliburton reported to BP immediately after the explosion.
Cement tests were requested by the commission and carried out by independent engineers from Chevron.
After nine attempts those engineers weren't able to produce any stable cement.
Halliburton questions the materials used in those Chevron tests and in a written statement points out the early tests they conducted were pilot or preliminary tests.
It goes on to say BP knew there were problems and that "the results of those tests were misinterpreted by its own and Transocean's employees on the rig. Had they accurately interpreted the negative tests, remedial action, if necessary, would have been possible."
There's been no response from BP and so far CEO Bob Dudley has declined an invitation to testify before the Congressional committee investigating the disaster.