By Houston Business Journal

Federal testimony on the Gulf of Mexico oil spill Friday revealed that an alarm system on the Deepwater Horizon rig had been ⿿inhibited⿝ for about a year before the rig exploded and sank in April.

Sensors that detect combustible or toxic gases were still active, relaying the message to the computer system, but the trigger for an audible or visual alarm was disabled.

According to numerous media reports, the platformâ¿¿s chief electronics technician Mike Williams told the six-member federal inquiry panel that he had asked about the alarm being partially disabled about a year before the accident and was told by supervisors that it was done to prevent false alarms waking crews up at all hours of the night.

Williams told the committee that no audio or visual alarms were activated the night of the April 20 fire.

The joint hearing, held by the U.S. Coast Guard and the Bureau of Ocean Energy Management, Regulation and Enforcement, was held near New Orleans Friday.

Transocean Ltd. (NYSE: RIG), the operator of the rig, issued a statement on Friday noting that 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."

The company insists that the decision was not a safety oversight or done as a matter of convenience but instead was an attempt to prevent repeated false alarms, which it says can increase risk and decrease rig safety.

The Houston Business Journal is providing continuous coverage of the Gulf oil spill.

Copyright 2010 American City Business Journals
Copyright 2010