Safety investigators have sent government agencies a wake-up call about sleep apnea, a disorder that's showing up in a wide range of transportation accidents.

The National Transportation Safety Board said Tuesday that commercial truck and bus drivers and merchant ship pilots should be screened for sleep apnea. The board made similar recommendations for airline pilots and train operators earlier this year.

In letters to the Coast Guard and the Federal Motor Carrier Safety Administration, the board recommended requiring medical examiners to question drivers and ship pilots about the disorder — which involves disruptions in breathing during sleep — and to develop programs to identify the problem.

Sleep apnea denies people the rest they need, and it has been found to be a factor in incidents involving every transportation mode, NTSB Chairman Deborah Hersman said in the letters.

The board has sent similar recommendations to the Federal Aviation Administration and to local transit agencies across the country.

Among the incidents cited in the letters:

— In January 2008, a motorcoach carrying passengers returning from a weekend ski trip went too fast around a curve on a rural Utah highway. The bus went careening down a mountainside, killing nine people and injuring 43 others. The driver suffered from sleep apnea and had trouble using a device to regulate his breathing while sleeping in the days before the accident.

— The same month, two go! airlines pilots conked out for at least 18 minutes during a midmorning flight from Honolulu to Hilo, Hawaii, as their plane continued to cruise past its destination and out to sea. Air traffic controllers were finally able to raise the pilots, who turned the plane around with its 40 passengers and landed it safely. The captain was later diagnosed with sleep apnea.

— A trolley train crashed into another train in May 2008 in Newton, Mass. Investigators said the driver probably fell asleep because she suffered from sleep apnea, but it could not be proved because she died.

— In November 2001, a train engineer drove through a stop warning in Clarkston, Mich., striking another train and killing two crew members. He was found to be a very high risk for sleep apnea, but he had not been diagnosed or treated.

— In June 1995, a cruise ship maneuvering through Alaska's Inside Passage was grounded on a submerged but charted and marked rock by a pilot later diagnosed with sleep apnea. The ship was carrying about 2,200 people.

A 2002 study that found 7 percent of adults have at least a moderate form of the disorder, but people often don't know they have it.

The motor carrier administration is already considering a rule to tighten its standards for medical certification of commercial drivers, Transportation Department spokeswoman Sasha Johnson said.

The FAA is also in the process of drafting new rules to broadly address pilot fatigue and will consider the board's recommendations, spokeswoman Laura Brown said.

The letters noted the Federal Railroad Administration is also working on drafting new regulations to address the problem.

Mark Rosenker, a former NTSB acting chairman, said the issue has long been a concern of the board, but the go! airlines incident jarred board members.

"Obviously when two pilots fall asleep in the cockpit and they miss their stop, that triggers a lot of interest at NTSB," Rosenker said.


On the Net:

National Transportation Safety Board: www.ntsb.gov