BP opted to keep an ineffective test valve rather than replace it with one that might have pinched off the flow of oil and helped avert the Gulf oil spill disaster, the Washington Post reported on Sunday.
The daily wrote that it had obtained a letter showing that BP knew it was risky to keep the test valve on Deepwater Horizon's "blowout preventer," but kept it in place -- possibly in an effort to save time and money during testing -- rather than replacing it with a permanent "variable bore ram."
The blowout preventer is a critically important safety system designed to stop the flow of oil and gas if a driller loses control of the pressure in a well.
The letter, dated October 11, 2004 by rig owner Transocean's senior marketing executive Christopher Young and signed by BP, documented an agreement that Transocean would convert a variable bore ram with a test ram at BP's expense.
Young wrote that by signing the letter, BP would be acknowledging that the conversion would "reduce the built-in redundancy" of the blowout preventer, "thereby potentially increasing contractor's risk profile."
A BP representative signed the letter on October 19, 2004. A company spokesman told The Washington Post on Saturday that Transocean was responsible for any modifications to the rig.
BP told members of Congress at a hearing earlier this month that it was uncertain about whether there had been a reconfiguration of the blowout preventer or what exact changes might have been made.
A variable bore ram can clamp down and seal openings around pipes of different sizes, The Washington Post wrote.
The newspaper reported that the after installing the test valve, two variable bore rams still remained on the blowout preventer.
While the test valve was shown to be utterly ineffective, it remains unclear if a third bore ram might have succeeding in stopping the flow of oil.