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Fatigue is one of the leading causes of deadly traffic accidents and railroad crashes. It turns out truck drivers and train operators are more likely than other people to suffer from a common sleep disorder known as obstructive sleep apnea. Federal regulators want to require them to be screened for obstructive sleep apnea. And that's proving to be controversial, as NPR's David Schaper reports.
DAVID SCHAPER, BYLINE: Just before 2:30 in the morning on August 17, 2014, two Union Pacific freight trains were heading toward one another on the same tracks near the small town of Hoxie, Ark. National Transportation Safety Board investigator Jana Price says the southbound train was supposed to stop so the northbound train could bypass it on a side track.
JANA PRICE: In this case, the train went through three signals and then ultimately collided with another train coming in the opposite direction.
SCHAPER: Why didn't the southbound train heed those warning signals?
PRICE: The southbound locomotive engineer was fatigued and likely asleep due to his diagnosed but inadequately treated moderate sleep apnea.
SCHAPER: Obstructive sleep apnea causes people to stop breathing in their sleep. When deprived of oxygen, their brain wakes them up to stay alive.
PRICE: For people with severe obstructive sleep apnea, this pattern can repeat 30 times or more per hour. And so the upshot is that people simply are not getting sleep.
SCHAPER: That can lead to daytime drowsiness and fatigue, even nodding off. At night, the risk for train engineers or truck and bus drivers with sleep apnea falling asleep at the wheel is even greater.
STEFANOS KALES: As many as 20 percent of crashes of large trucks and buses are estimated to be fatigue-related. And obstructive sleep apnea is the most common medical cause of fatigue.
SCHAPER: Dr. Stefanos Kales of the Harvard School of Public Health has studied the link between sleep apnea in truckers and their likelihood of being in a serious accident.
KALES: Drivers with untreated obstructive sleep apnea who were noncompliant with treatment had a five-fold increase in the risk of serious preventable crashes.
SCHAPER: But Kales says when sleep apnea is accurately diagnosed and fully treated...
KALES: The risk is statistically not distinguishable from the risk of people without the disorder.
SCHAPER: Dr. Kales says 10 to 25 percent of Americans may have obstructive sleep apnea. Risk factors include snoring, family history and being overweight. And he says the sleep disorder is much more common in train operators, and especially so in truck drivers, who tend to be middle-aged men with much higher rates of obesity. The federal government requires airline pilots to be screened and treated for sleep apnea, but there's no such requirement for railroad engineers and truck and bus drivers. The Federal Railroad Administration is in the process of developing such a rule. But in the trucking industry, the regulations are murky.
SCOTT GRENERTH: It's kind of like the Wild West out there with the way drivers are being screened for and supposedly diagnosed for sleep apnea.
SCHAPER: Scott Grenerth is director of regulatory affairs for the Owner-Operator Independent Drivers Association. While truckers are not required to be screened for sleep apnea, they are required to be medically certified to drive. So at some driver examination clinics, he says they're often forced into sleep apnea screening and treatment even if they're not at risk.
GRENERTH: We've had far too many members have that experience where they are treated as a cash cow that just walked in their door, and they're going to perform what I so lovingly call a cashectomy (ph) on them and get every bit of money out of them as they can.
SCHAPER: Grenerth says truck drivers want clear guidelines for sleep apnea screening and treatment with greater flexibility to use their own doctors. And he says if there's going to be a new sleep apnea mandate from the government that could be costly, truck drivers don't want it rushed into place. David Schaper, NPR News, Chicago. Transcript provided by NPR, Copyright NPR.