Halliburton and Transocean on Wednesday rejected BP's characterization.
"This is a self-serving report that attempts to conceal the critical factor that set the stage for the Macondo incident: BP's fatally flawed well design. In both its design and construction, BP made a series of cost-saving decisions that increased risk – in some cases, severely," Transocean said in a statement.
Among BP's cost-saving moves that Transocean said compromised safety are the following:
1) BP opted for a single long run of pipe rather than an alternative approach that would have increased the barriers to gas flow.
2) BP failed to conduct a "cement bond log" test to evaluate the integrity of the cement at the bottom of the well, which was what blocked gas and oil from emerging up the production pipe.
3) BP installed fewer than one-third of the recommended number of centralizer devices, which Transocean said had the effect of "dramatically increasing the risk of cement channeling and gas flow."
Halliburton, for its part, said BP officials were in charge and signed off on every step of its work as it pumped concrete to the bottom of the well to block the emergence of oil and gas.