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.