Indeed, more than a year before Pleasant's frantic efforts to stop an inferno, a large study of BOP reliability in the Gulf of Mexico had warned industry experts and federal safety officials that balky control systems were by far the most common cause of BOP failure – and apparently getting worse.Īltogether, 63 percent of blowout preventer test failures cited in that 2009 study, a joint effort by the industry and the regulatory US Minerals Management Service (MMS), involved control systems. But when the Obama administration on Monday issued a revised offshore drilling moratorium in the Gulf, it cited fresh concerns about the reliability of BOP control systems as one reason for its action. That mystery won't be solved unless the BOP is pulled off the sea floor months from now. No one knows yet just why the rig's BOP did not work – or why the device's hydraulic-electric control system gave Pleasant the wrong readings. "I knew it was time to leave," Pleasant testified. So, despite BOP control system lights showing the shear-ram closed, it was not. Another set of gauges just above the BOP control panel showed no hydraulic pressure at all – "no flow," he testified. Valve indicator lights flicked from green (open) to red (closed), he told federal investigators in May in New Orleans. If its massive "shear ram" valve closed, it would slice through the drill pipe and stop the torrent of burning gas.įor one fleeting moment, the control panel lights offered a ray of hope – showing the shear ram and other BOP valves apparently closing. Pleasant – a subsea superviser for Transocean, the rig's owner – pressed two buttons simultaneously to activate a 450-ton blowout preventer sitting 5,300 feet below the sea surface. In those last frantic minutes in the rig's central control room, Mr. Before he leaped into a lifeboat in the middle of the night on April 20, Christopher Pleasant tried to trigger a deep-sea safety device to squelch the oil-well blowout and fire raging aboard the Deepwater Horizon drill rig.