HOUSTON -- Federal safety regulators warned Thursday that another disastrous offshore oil well blowout could happen despite regulatory improvements in the four years since a BP well explosion in the Gulf of Mexico killed 11 workers and dumped millions of gallons of oil into the sea.
The warning came with release of a Chemical Safety Board report that put much of the blame for destruction of the Deepwater Horizon, the rig involved in the BP disaster, on a buckled steel drill pipe that interfered with the functioning of an emergency device in sealing the well.
The report was consistent with other government reports that pointed to multiple causes for the disaster. But the new one focused more acutely on malfunctioning of the blowout preventer, the rig's last defense, which was supposed to cut through the drill pipe and seal the Macondo well.
Unlike previous reports, the Chemical Safety Board study concluded that the blowout preventer's blind shear ram, an emergency hydraulic device with two cutting blades, probably activated as intended the night of the accident. But the shear ram did not seal the well drill pipe; instead, it punctured the pipe and sent oil and gas gushing to the surface.
The study found that the drill pipe had buckled under tremendous oil and gas pressure rising in the well in the initial blowout, while prior studies concluded that the pipe buckled days after the initial explosion.
Perhaps most notable in the report was the warning that the problems revealed could cause future accidents -- although the principal government regulatory agency monitoring offshore drilling has been thoroughly revamped, and the oil and gas industry has become more alert.
"Although there have been regulatory improvements since the accident, the effective management of safety-critical elements has yet to be established," board official Cheryl MacKenzie, who led the investigative team, said in a statement. "This results in potential safety gaps in U.S. offshore operations and leaves open the possibility of another similar catastrophic accident."
The report found several problems with the blowout preventer, built by Cameron International and maintained by Transocean, the Deepwater Horizon owner. It said the component meant to shear and seal the well was not suitable for the drilling operation and could not be counted on to shear the drill pipe.
The board concluded that neither Transocean nor BP had performed adequate regular inspections or testing of the blowout preventer's emergency systems.
Geoff Morrell, a BP senior vice president, said the report's core findings were consistent with prior reports in concluding that the accident had multiple causes. But he added that some new Chemical Safety Board conclusions were "based on flawed assumptions."
Transocean spokesman Chris Kettmann said his firm concurred with the board that the buckled drill pipe prevented the blind shear ram from properly functioning. But he added, "We respectfully disagree with other findings in the report, including and especially CSB's assertions regarding Transocean's operational and safety culture."