KENNER, La. — The emergency alarm on the Deepwater Horizon was not fully activated the day the oil rig caught fire and exploded, killing 11 people and setting off the massive spill in the Gulf of Mexico, a rig worker on Friday told a government panel investigating the accident.
The worker, Mike Williams, the rig’s chief electronics technician, said the general safety alarm was habitually set to “inhibited” to avoid waking up the crew with late-night sirens and emergency lights.
“They did not want people woke up at 3 a.m. from false alarms,” Mr. Williams told the federal panel of investigators. Consequently, the alarm did not sound during the emergency, leaving workers to relay information through the loudspeaker system.
While it is not known whether it would have saved the workers who died in the April 20 disaster, the lack of a fully functioning alarm hampered the effort to safely evacuate the rig, Mr. Williams said.
In a statement, Transocean, which leased the rig to BP, said workers were allowed to set the alarm to prevent it “from sounding unnecessarily when one of the hundreds of local alarms activates for what could be a minor issue or a non-emergency.”
“It was not a safety oversight or done as a matter of convenience,” the company said. Transocean also pointed to a separate audit of the rig in early April, in which inspectors testing the fire detection system found no detectors inhibited.
A six-member panel is investigating the disaster that unleashed the largest oil spill in United States history. At hearings this week here, crew members have described repeated failures in the weeks before the disaster, including power losses, computer crashes and leaking emergency equipment.
The rig’s history of mechanical errors was documented in a confidential audit conducted by BP seven months before the explosion and reviewed by The New York Times. According to the September 2009 document, four BP officials discovered that Transocean, the rig’s owner, had left 390 repairs undone, including many that were “high priority,” and would require a total of more than 3,500 hours of labor. It is unclear how many of the problems remained by the day of the catastrophe.
The 60-page audit found that previously reported errors had been ignored by Transocean. “Consequently, a number of the recommendations that Transocean had indicated as closed out had either deteriorated again or not been suitably addressed in the first place,” investigators wrote.
In a statement, BP said it had expected Transocean to take the audit seriously. “The goal is to have the contractor address all safety critical items in a prompt manner,” the statement said. “As we have previously said, the Deepwater Horizon tragedy had multiple potential causes, including equipment failure.”
During Friday’s hearing, witnesses addressed the role that shortcuts and mistakes played in compounding the rig’s troubles.
An engineering expert told investigators that the crew members had incorrectly performed a critical test of emergency equipment and did not detect a dangerous “kick” of gas roughly an hour before the explosion.
John R. Smith, a petroleum engineering professor at Louisiana State University, told investigators that rig data showed crew members had failed to correctly test the pressure in the well.
“The reality is it’s not a test at all, in my opinion,” Mr. Smith testified, after reviewing records of the crew’s actions. For months, survivors and Transocean officials have maintained that the well pressure test had been properly conducted.
Mr. Williams, who filed a lawsuit against Transocean in federal court in New Orleans on April 29, added several new details about the equipment on the rig, testifying that another Transocean official had turned a critical system for removing dangerous gas from the drilling shack to “bypass mode.”
When Mr. Williams questioned that decision, he said he was reprimanded.
“No, the damn thing’s been in bypass for five years,” he recalled being told by Mark Hay, the subsea supervisor. “Why’d you even mess with it?”
Mr. Williams recalled that Mr. Hay added, “The entire fleet runs them in ‘bypass.’ ”
Problems existed from the beginning of drilling the well, Mr. Williams said. For months, the computer system had been locking up, producing what the crew called the “blue screen of death.”
“It would just turn blue,” he said. “You’d have no data coming through.”
Replacement hardware had been ordered but not yet installed by the time of the disaster, Mr. Williams said.
In the final weeks of drilling, supervisors were under intense financial pressure to complete the ill-fated well, several witness have testified. BP was 43 days behind schedule when the rig exploded, costing the company about $1 million a day in rig rental rates, company officials say.
The confidential BP audit has been referred to by lawyers and investigators but not detailed publicly. The inspection, conducted Sept. 13 to 17, paints a grim picture of Transocean’s upkeep of the rig.
Of BP’s previous safety orders to Transocean, the audit states, some “findings were simply rejected, with no formal risk mitigation demonstrated.”
“While it is appreciated that a good number of findings had been addressed by hard work and effort, there were too many that had not,” it states.
Unsafe working conditions include rig areas covered in a “thick film of drilling mud,” supposedly watertight equipment that actually leaked and safety equipment that was past its inspection date. The recording of maintenance issues was “substandard with missing information and poor quality reports that lacked sufficient detail to convince the reader that the task had actually been performed in accordance with the procedure.”
The findings reinforced those in two separate audits, obtained by The Times, that were performed in March and April by Lloyd’s Register Group, a maritime and risk-management organization. In an audit conducted April 1 to 12, investigators identified 26 components and systems on the rig that were in “bad” or “poor” condition.
A month earlier, an audit on the rig’s “safety culture” by a separate division of Lloyd’s found some workers were dismayed about safety practices and feared reprisals if they reported mistakes.