NEW ORLEANS — Disasters like the explosion of the Deepwater Horizon rig could happen again without significant reform, according to the conclusions of a presidential panel that has the companies involved in the nation’s largest offshore oil spill pointing fingers at each other again.

In a 48-page excerpt of its final report obtained Wednesday by The Associated Press, the commission described systemic problems within the offshore oil and gas industry and government regulators who oversee it. It also said such a disaster could happen again without significant reforms.

The full report is due to the president Jan. 11. But key questions will remain, namely: Why didn’t a hulking piece of equipment that sat at the wellhead and was supposed to choke off the flow of oil in the event of a blowout do its job? Federal investigators analyzing the blowout preventer at a NASA facility in New Orleans aren’t expected to finish until February.

The Justice Department continues its own investigation, as does a joint U.S. Coast Guard-Bureau of Ocean Energy Management, Regulation and Enforcement panel.

The oil spill commission said poor decisions led to technical problems that contributed to the April 20 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. Inquiries by BP and Congress have found the same.

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 blowout 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.

In one example cited by the commission, a BP request to set an "unusually deep cement plug" was approved by the then-Minerals Management Service in 90 minutes. That decision is one of the nine technical and engineering calls the commission says increased the risk of a blowout.

"The blowout 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.

Interior Department spokeswoman Kendra Barkoff said the report focused on areas in which the agency in charge of offshore drilling has 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," Barkoff said in a statement.

BP PLC in a statement issued Wednesday 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."

Transocean Ltd., which owned the rig being leased by BP to perform the drilling, said in response to the commission’s findings that "the procedures being conducted in the final hours were crafted and directed by BP engineers and approved in advance by federal regulators."

Halliburton Co., the cement contractor on the well, also said it acted at the direction of BP and was "fully indemnified by BP."

The commission underscores its central conclusion with a quote from an e-mail written by BP engineer Brett Cocales on April 16, just days before the disaster. The e-mail was first unearthed in an investigation conducted by Rep. Henry Waxman, D-Calif., who at the time led the House Energy and Commerce Committee.

"But, who cares, it’s done, end of story, will probably be fine and we’ll get a good cement job," Cocales wrote, after he disagreed with BP’s decision to use fewer centralizers than recommended. Centralizers are used to center 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.

The suggestion that the BP disaster may not be an isolated incident runs counter to assurances by the oil industry, which has worked hard to portray the accident as a rare occurrence.

"This clearly was a rare incident," the president of the American Petroleum Institute, Jack Gerard, said Tuesday when his organization published a new report urging Congress and the Obama administration to open more areas to oil and gas drilling.

Outside experts in technological disasters were split by the report’s excerpt. They lauded the commission’s focus on organizational and managerial failures instead of blaming the rig workers. But they were divided whether the panel went far enough in criticizing the companies for taking time- and money-saving shortcuts.

University of California at Berkeley engineering professor Bob Bea, who has studied and worked on offshore oil rigs for decades and is an international expert on technological disasters, lauded the panel for "articulating the hows and whys."

"This was a preventable disaster," said Bea, who ran a Berkeley investigation into the accident. "We failed to manage and we were managed."

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Cappiello reported from Washington. AP Science Writer Seth Borenstein contributed to this report.