The three companies involved in the Deepwater Horizon disaster violated a number of federal safety regulations, leading to the massive explosion and oil spill of April 2010, according to a report released Wednesday by the federal agency responsible for drilling permitting and safety.
Eleven oil rig workers died in the April 20, 2010, explosion and 5 million barrels of oil spilled into the Gulf of Mexico.
A panel of investigators working for the Bureau of Ocean Management, Regulation and Enforcement concluded that a central cause of the blowout was failure of a cement barrier to prevent hydrocarbons from flowing up the wellbore, through the riser and onto the rig, resulting in the blowout. The report said a series of risky decisions by BP may have contributed to the ultimate failure of the cement job.
"The blowout at the Macondo well on April 20, 2010, was the result of a series of decisions that increased risk and a number of actions that failed to fully consider or mitigate those risks. While it is not possible to discern which precise combination of these decisions and actions set the blowout in motion, it is clear that increased vigilance and awareness by BP, Transocean and Halliburton personnel at critical junctures during operations at the Macondo well would have reduced the likelihood of the blowout occurring," reads the report.
According to the report, BP, which owned the well, "set the casing in a location that created additional risks" for the influx of fluids to mix into the piping. After that, BP and Transocean failed to test accurately the integrity of the production casing. As a result, the report concludes, the crew, unaware of the growing problem beneath them, failed to accurately read tests and missed the signs of the coming explosion.
The details were contained in the final report from an investigation team of the U.S. Coast Guard and the agency that regulates offshore drilling. The panel held hearings in the year following the April 20, 2010, Deepwater Horizon tragedy. The Coast Guard-Bureau of Ocean Energy Management Regulation and Enforcement investigation was among the most exhaustive.
Other investigations spread around the blame rather evenly, faulting misreadings of key data, the failure of the blowout preventer to stop the flow of oil to the sea and other shortcomings by executives, engineers and rig crew members. The joint investigation team laid considerable blame on BP's shoulders.
The report said the decisions included using only one cement barrier and BP's choice to set the production casing in a location in the Macondo well that created additional risk of influx of oil or gas. The casing is a steel pipe placed in a well to maintain its integrity.
The panel said BP failed to communicate these decisions and the increasing operational risks to rig owner Transocean.
"BP, as the designated operator under BOEMRE regulations, was ultimately responsible for conducting operations at Macondo in a way that ensured the safety and protection of personnel, equipment, natural resources, and the environment," the panel concluded.
In addition to the rig worker deaths, the resulting oil spill off Louisiana spewed more than 200 million gallons of crude from an undersea well owned by BP. The disaster caused billions of dollars in damages to hundreds of miles of coastline and wreaked havoc on the Gulf economy.
The report pins the causes for the disaster on many of the same faulty decisions as previous probes, including those by the president's independent oil spill commission, Congressional committees and the companies themselves. But it is likely to carry more weight in Congress, where Republican lawmakers in particular have said they are unwilling to adopt reforms until the federal investigation was complete.
The Associated Press contributed to this report.