It seems that BP were not alone in their culpability, as they said from the start. At least they faced up to theirs.
"Halliburton, a major contractor on BP's doomed Deepwater Horizon oil rig, where a fatal explosion led to the worst-ever offshore oil spill, knew that cement used in the project was unstable but went ahead anyway, a US presidential commission on the disaster has found. The report strengthened BP's case that it shares blame for the Gulf of Mexico disaster with its business partners, and shares in Halliburton fell 16 per cent after the findings.
Halliburton conducted four tests on cement used to seal the bottom of the well, two just days before the well was activated. Only one of the tests suggested the cement was stable. BP was told by Halliburton about the findings of one failed test, but it was buried deep in a report... "
Halliburton linked to BP oil spill - Americas, World - The Independent