The chairman of the company that operated the rig, Transocean, said the real trigger of the blast was faulty cement work by Halliburton. BP America's president, meanwhile, pointed to Transocean as responsible for maintaining the blowout preventer, as did a top Halliburton official.
Lamar McKay, the president of BP America, acknowledged the issues with the device and said they "could have raised concerns about well control." He pledged to investigate fully.
"We'll have to tear that apart piece by piece," McKay told the committee.
Recently unearthed studies commissioned by federal regulators and at times by the oil companies themselves, have for some time raised questions about possible shortcomings with the devices.
In 2004, a review conducted at Texas A&M as part of a student's master's thesis found that blowouts were becoming a special concern as the industry was pushing its drilling operations into deeper and deeper water.
"Unfortunately," the study overseen by Prof. Jerome J. Shubert and written by Samuel F. Noynaert said, "while drilling as a whole may be advancing to keep up with these [deep water] environments, some segments lag behind. Blowout control is one of these areas developed as an afterthought."
"This lax attitude towards blowouts does not mean they are not a major concern," the paper continues. "Obviously, up-to-date technology and techniques for the prevention and control of ultradeep water blowouts would be an invaluable part of any oil and gas company's exploration planning."