when drilling resumed, Williams says there was an accident on the rig that has not been reported before. He says, four weeks before the explosion, the rig's most vital piece of safety equipment was damaged.
Down near the seabed is the blowout preventer, or BOP. It's used to seal the well shut in order to test the pressure and integrity of the well, and, in case of a blowout, it's the crew's only hope. A key component is a rubber gasket at the top called an "annular," which can close tightly around the drill pipe.
Williams says, during a test, they closed the gasket. But while it was shut tight, a crewman on deck accidentally nudged a joystick, applying hundreds of thousands of pounds of force, and moving 15 feet of drill pipe through the closed blowout preventer. Later, a man monitoring drilling fluid rising to the top made a troubling find.
"He discovered chunks of rubber in the drilling fluid. He thought it was important enough to gather this double handful of chunks of rubber and bring them into the driller shack. I recall asking the supervisor if this was out of the ordinary. And he says, 'Oh, it's no big deal.' And I thought, 'How can it be not a big deal? There's chunks of our seal is now missing,'" Williams told Pelley.
And, Williams says, he knew about another problem with the blowout preventer.
The BOP is operated from the surface by wires connected to two control pods; one is a back-up. Williams says one pod lost some of its function weeks before.
Transocean tells us the BOP was tested by remote control after these incidents and passed. But nearly a mile below, there was no way to know how much damage there was or whether the pod was unreliable.
In the hours before the disaster, Deepwater Horizon's work was nearly done. All that was left was to seal the well closed. The oil would be pumped out by another rig later. Williams says, that during a safety meeting, the manager for the rig owner, Transocean, was explaining how they were going to close the well when the manager from BP interrupted.
"I had the BP company man sitting directly beside me. And he literally perked up and said 'Well my process is different. And I think we're gonna do it this way.' And they kind of lined out how he thought it should go that day. So there was short of a chest-bumping kind of deal. The communication seemed to break down as to who was ultimately in charge," Williams said.
On the day of the accident, several BP managers were on the Deepwater Horizon for a ceremony to congratulate the crew for seven years without an injury.