The US Coast Guard slammed drilling rig operator Transocean's "poor safety culture" in a report Friday on the massive explosion and fire that unleashed the biggest maritime oil spill in history.
Poor maintenance, inadequate training and the bypassing of alarms and automatic shutdown systems prevented the crew from shutting down the runaway well after it blew and led to a chaotic abandonment of the blazing Deepwater Horizon rig.
"The investigation revealed that Deepwater Horizon and its owner, Transocean, had serious safety management system failures and a poor safety culture," the Coast Guard concluded in a 288-page report.
"The company leaders' failure to commit to compliance with the International Safety Management Code created a safety culture throughout its fleet that could be described as: 'running it until it breaks,' 'only if it's convenient,' and 'going through the motions.'"
The report -- released on the one-year anniversary of the rig's sinking -- is just the first volume in the Coast Guard's investigation and does not touch upon the failures that led to the blowout or the effectiveness of the spill response.
It will, however, provide fodder for the legal battle over financial responsibility for the disaster that killed 11 workers and unleashed 4.9 million barrels (206 million gallons) of oil into the Gulf of Mexico.
Well owner BP filed a $40 billion lawsuit Wednesday against Transocean, which subsequently filed a counter-suit.
BP has also sued oil services giant Halliburton, which was responsible for the well's flawed cement job, and parts manufacturer Cameron, supplier of the faulty blowout preventer.
Explore further: Huge tract of Australia in 'biggest ever drought'