Fire boat response crews battle the blazing remnants of the off shore oil rig Deepwater Horizon, off Louisiana, in this handout photograph taken on April 21, 2010 and obtained on April 22. 
 
 HOUSTON | 
 
 HOUSTON (Reuters) - An emergency alarm that could have warned workers aboard the doomed Deepwater Horizon Gulf of Mexico drilling rig was intentionally disabled, a rig engineer told U.S. investigators on Friday. 
 
 Mike Williams, chief engineer technician aboard Swiss-based Transocean Ltd's rig, said the general alarm that could have detected the cloud of flammable methane gas that enveloped the rig's deck on April 20 was "inhibited." 
 
 "They (rig managers) did not want people woke up at three o'clock in the morning from false alarms," Williams told a six-member federal board in the New Orleans suburb of Kenner, Louisiana. 
 
 Williams' appearance capped a week of testimony from company officials involved in the rig, which exploded on April 20 and sank two days later, killing 11 crewmen and sparking the worst oil spill in U.S. history. 
 
 The Transocean-owned rig was drilling a well a mile beneath the Gulf under contract for London-based BP Plc.. 
 
 However, written statements from several rig personnel taken by U.S. investigators and obtained by Reuters refer to alarms sounding on the rig. 
 
 "At time of incident, I was in engine control room working on nightly log," wrote Douglas Brown, the rig's chief mechanic. "At which (sic) multiple gas alarms went off." 
 
 "The general alarm configuration on the Deepwater Horizon was intentional and conforms to accepted maritime practices," Transocean said in a statement. The rig "had hundreds of individual fire and gas alarms, all of which were tested, in good condition, not bypassed and monitored from the bridge." 
 
 Four Transocean witnesses declined to appear voluntarily on Wednesday at the hearings before a joint U.S. panel convened by the U.S. Coast Guard and the Interior Department's Bureau of Ocean Energy Management, Regulation, and Enforcement. 
 
 The board on Thursday declared two BP officials "parties of interest" in the investigation, after they declined to appear. 
 
 The panel will convene for another week of hearings in Houston from August 23 to 27, where high-level managers from BP and Transocean are scheduled to testify. 
 
 At this week's hearings, Transocean officials recited a litany of mechanical problems that plagued the rig, which was 43 days behind schedule in drilling the Macondo well -- called the "well from hell" by rig workers. 
 
 Williams, who has filed a lawsuit against Transocean, said a computer system that monitored well-drilling operations, known as the "A chair," was often offline due to technical issues. 
 
 "We called it the blue screen of death," Williams said. "It would turn blue and you would have no data coming through." 
 
 (Reporting by Chris Baltimore; Editing by Peter Cooney and Philip Barbara) 

 Critical fire and gas leak alarm systems had been disabled for at least a year aboard the Deepwater Horizon because the rig’s leaders didn’t want to wake up to false alarms, a rig chief engineer tech told federal investigators. 
 
 “I discovered it was ‘inhibited’ about a year ago,” said Mike Williams, the chief engineer tech who worked for rig owner Transocean aboard the Deepwater Horizon, which erupted in flames April 20, killing 11 men and starting the worst offshore oil spill in U.S. history. 
 
 “I inquired," Williams told an investigative panel from the U.S. Coast Guard and the Interior Department in suburban New Orleans. "The explanation I got was that from the [offshore installation manager] down, they did not want people to wake up at 3 a.m. due to false alarm,” Williams said. Williams later said the rig’s captain had also agreed that the alarms were to be disabled. 
 
 Williams said he complained repeatedly about disabling the systems, from six months to three days prior to the rig’s explosion. He said he told supervisors it was unsatisfactory for the alarms to be disabled, but was rebuffed. 
 
 The alarm systems could have been helpful to alert crew members of catastrophe and initiate an emergency shutdown system that could have shut down the engines -- a dangerous ignition source -- as soon as a surge of flammable natural gas surged up the oil well onto the rig. 
 
 Williams testified that prior to the explosions, he heard a hissing sound and heard an engine over-rev. Alarms in “inhibited” mode means that a control panel that would detect the alarm would indicate the alert, but general alarms that would sound loudly across the rig would not go off. 
 
 The emergency shutdown system also had previous problems. Williams said another employee, at some point before the April 20 disaster, inadvertently triggered an emergency shutdown system to an engine that was running. Down came fire doors intended to deprive the engine of oxygen, which would have put out a fire in the engines had there been one. 
 
 But the doors weren’t built strongly. Once the doors came down, the force of the engines ripped the fire doors off their hinges. 
 
 
 
 “The engine was running. The fire dampers closed, and it sucked the fire doors off the engines,” Williams said. “The function of them was to shut down the engine. If it can’t get air, it can’t run.” 
 
 
 
 Williams said that as a result of that previous problem, the crew did not test the automatic function of the emergency shutdown system for the engine. 
 
 The testimony was given at a hearing probing the cause of the oil spill. 
 
 [Update, 2:35 p.m.: Transocean officials issued the following statement in response to the testimony: 
 
 The general alarm configuration on the Deepwater Horizon was intentional and conforms to accepted maritime practices, including those on some Navy and Coast Guard vessels. It was not a safety oversight or done as a matter of convenience. 
 
 
 
 The alarm system on every large maritime vessel, including the Deepwater Horizon, is zone based. The Deepwater Horizon had hundreds of individual fire and gas alarms, all of which were tested, in good condition, not bypassed and monitored from the bridge. 
 
 
 
 The general alarm is controlled by a person on the bridge and sounded from there, only when conditions require. This is an option on each individual vessel designed to prevent the general alarm from sounding unnecessarily when one of the hundreds of local alarms activates for what could be a minor issues or a non-emergency. 
 
 
 
 Repeated false alarms increase risk and decrease rig safety.] 
 
 -- Rong-Gong Lin II in Kenner, La.
– As deadly pockets of oil and gas raced up the Deepwater Horizon's pipes on April 20, a key emergency alarm sat intentionally disabled and silent—giving workers no warning of the impending disaster until the oil rig blew sky high, according to testimony by an engineer. When he discovered the alarm's "inhibited" status a year earlier, managers told him they "did not want people woke up at three o'clock in the morning from false alarms," Mike Williams told a federal review board yesterday. Williams also detailed previous failures of the rig's emergency shut-down system, reports the Los Angeles Times, including one case where doors intended to stop an engine fire simply blew off when activated. Williams' testimony doesn't entirely jibe with other accounts, notes Reuters, including the chief mechanic's testimony that "several gas alarms" went off. TransOcean countered the claims in a statement: The Deepwater Horizon "had hundreds of individual fire and gas alarms, all of which were tested, in good condition, not bypassed and monitored from the bridge."