Nothing should gloss over that BP is a company with an abysmal record for safety and other concerns.
IIRC, BP managers overrode the concerns the drilling team had and they also insisted that heavy drilling mud is replaced by sea water.
I hope that Haliburton's error's do not diminish BP's culpability in this disaster in any way but that Haliburton is just one more stinking fish caught in the net.