Decisions intended to save time and money created an unreasonable risk that triggered the largest offshore oil spill in US history, which could happen again without significant reforms, the top-level panel probing the BP blow-out has said.
The commission findings - the result of a probe requested by US President Barack Obama after the April 20 Deepwater Horizon rig explosion - described systemic problems within the offshore energy industry and government regulators who oversaw it.
Poor decisions led to technical problems that the commission, and inquiries by BP and the US Congress, have identified as contributing to the accident that killed 11 people and led to more than 200 million gallons of oil spewing from BP's well a mile beneath the Gulf of Mexico.
BP, Halliburton and Transocean, the three key companies involved with the well and the rig that exploded, each made individual decisions that increased risks of a blow-out, but saved significant time or money. But ultimately, the Deepwater Horizon disaster came down to a single failure, the panel says - management. When decisions were made, no-one was considering the risk they were taking.
"The blow-out was not the product of a series of abberational decisions made by a rogue industry or government officials that could not have been anticipated or expected to occur again. Rather, the root causes are systemic, and absent significant reform in both industry practices and government policies, might well recur," the commission concluded in a 48-page excerpt of its final report. The final report is due to be given to Mr Obama by January 11.
Interior department spokeswoman Kendra Barkoff said the report focused on areas in which the agency in charge of offshore drilling had already made improvements.
"The agency has taken unprecedented steps and will continue to make the changes necessary to restore the American people's confidence in the safety and environmental soundness of oil and gas drilling and production on the Outer Continental Shelf, while balancing our nation's important energy needs," she said.
The panel underscores its central conclusion with a quote from an email written by BP engineer Brett Cocales on April 16, just days before the disaster. "But, who cares, it's done, end of story, will probably be fine and we'll get a good cement job," he wrote, after he disagreed with BP's decision to use fewer centralisers than recommended.
Centralisers are used to centre the pipe to ensure a good cement job. The cement failed at the bottom of the Macondo well, allowing oil and gas to enter it, according to investigations.
BP said the report, like its own investigation, found the accident was the result of multiple causes, involving multiple companies, but the company was working with regulators "to ensure the lessons learned from Macondo lead to improvements in operations and contractor services in deepwater drilling".