A federal government report says that a bent drill pipe prevented the blowout preventer (BOP) from cutting off the flow of oil, which led to the Deepwater Horizon oil rig explosion last April.
The report was issued by the Joint Investigative Team (JIT) made up of officials from Department of Homeland Security and the Department of the Interior.
The report will serve as a key bit of evidence in the multidistrict litigation (MDL) surrounding the Gulf of Mexico oil spill.
During the loss of well control, blind sheer rams (BSRs) designed to cut the drill pipe in the event of a blowout were unsuccessful because the "drill pipe elastically buckled within the wellbore," the report states.
The buckling occurred due to pressure which built up before the BOP had a chance to operate.
The report also blames the failure on the BOP itself, stating that "the BOP functionality testing indicated some back-up control system components did not perform as intended."
BOP testing also indicated that "not all back-up control systems had built-in redundancy," the report found.
It a statement, Congressman Ed Markey (D-Mass.) said that all BOPs being used in the Gulf of Mexico should be subject to comprehensive testing before they're allowed to be used.
BP agreed with Markey's demands in a statement.
In another statement, Transocean said the BOP "was in proper operating condition" and the accident occurred because the conditions "exceed the scope of BOP's design parameters."
The report states that none of the workers on the Deepwater Horizon initiated the BOP system until after hydrocarbons began to make their way up the well.
A series of recommendations to reexamine and study everything from the redundancy systems to emergency protocols to the use of remotely operated vehicles are also in the report.
The 200-page report includes background on the Deepwater Horizon oil rig, the BOP, which was placed on the Macondo well, and the testing methods used at the NASA-Michoud test facility in New Orleans.
The report was handled by the forensic firm Det Norske Veritas.