A new report from The National Transportation Safety Board says poor planning and risk assessment by Shell Oil led to the wreck of the Kulluk oil rig off the coast of Alaska in December 2012.
The NTSB report comes out as Shell gears up to hunt for oil again this summer in the Arctic Ocean.
The report says it wasn't a single error or equipment failure that caused the wreck: It was the company's failure to leave a margin of safety when planning a risky midwinter trip across the Gulf of Alaska.
The ice-breaker tug Aiviq was towing the Kulluk to Everett, Washington, when its engines failed in heavy seas. Five tense days later, after a U.S. Coast Guard helicopter evacuated the Kulluk's 18-person crew, the rig ran aground off Alaska's Kodiak Island.
The NTSB is the third federal agency to condemn Shell's risk-taking leading up to the wreck. The Coast Guard faulted the energy giant for "complacency" and its failure to understand and respect the risks of towing across the Gulf of Alaska in winter.
After an Interior Department inquiry found "serious deficiencies" in Shell's management of contractors, Interior Secretary Ken Salazar told reporters, “Shell screwed up in 2012, and we're not going to let them screw up, whenever."
The grounding of the Kulluk capped a year-long series of mishaps in Shell's effort to drill off Alaska's north coast.
Shell spokesman Curtis Smith said the company is reviewing the latest federal report.
He said Shell has improved its planning and its supervision of contractors since the grounding.
"This [year's drilling] program places more emphasis on integrated planning and marine protocols – with a great deal of attention focused on contractor management and organizational alignment. To operate exceptionally well, it’s critical that our employees and contractors are looking through the same safety and operational lens," Smith said in an email.
The Kulluk was scrapped last year. It's been replaced by the Polar Pioneer.
That rig is currently docked at the Port of Seattle's Terminal 5 before heading to the Arctic this summer.
City and port officials have said that the Polar Pioneer lacks a permit to moor at Terminal 5, while state officials have said long-term mooring there violates the state constitution.
The Aiviq tug is currently in Everett, along with Shell's second Arctic drill rig, the Noble Discoverer. Shell's oil-spill containment barge, the Arctic Challenger, is parked at the Port of Bellingham.
While the Obama administration has given conditional approval to Shell's plans to drill in the Arctic Ocean this summer, protesters in Seattle and other Puget Sound ports hope to block Shell from doing any more drilling at the top of the world.