Gulf Oil Spill: BP Report Spreads the Blame Around

BP's internal investigation of the gulf oil disaster blames "multiple companies and work teams" for the April 20 explosion that triggered the worst environmental catastrophe in U.S history, CNN reports.

Though the report, released Wednesday morning, did not identify "any single action or inaction that caused this accident," it did point a finger at rig owner Transocean, noting:

"Over a 40-minute period, the Transocean rig crew failed to recognize and act on the influx of hydrocarbons into the well until the hydrocarbons were in the riser and rapidly flowing to the surface." Those hydrocarbons caused the explosion of the Deepwater Horizon rig, which killed 11 men and ultimately dumped an estimated 5 million of barrels (205 million gallons) of oil into the Gulf of Mexico over the next three months.

The report cited "a complex and interlinked series of mechanical failures, human judgments, engineering design, operational implementation and team interfaces [that] came together to allow the initiation and escalation of the accident." But BP admitted that it "incorrectly accepted" results of a negative pressure test aboard the rig before the explosion. And investigators noted "weaknesses in the testing regime and maintenance management system" for the blowout preventer that failed to shut down the well after the explosion occurred.