WASHINGTON, D.C. — A Michigan train wreck that killed two men last year was caused because both crew members of the oncoming train were suffering from severe sleep apnea and dozed off, the National Transportation Safety Board said in a report approved Tuesday.
Engineer Allen Yash and conductor Jesse Enriquez, who were operating a Canadian National freight train southbound toward Detroit, were diagnosed before the accident with obstructive sleep apnea by their private physicians. Neither had been successfully treated and their conditions were not listed in company medical reports, NTSB’s investigation found.
The two men fell asleep while traveling in a wooded area near Clarkston, Mich., just before 6 a.m. on Nov. 15, 2001, and did not see a stop signal or the lights of an oncoming train, the report said. Their train struck another Canadian National train northbound for Flint, killing its 49-year-old engineer, Thomas Landris, and 58-year-old conductor, Gary Chase. Yash and Enriquez were hospitalized with serious injuries.
Obstructive sleep apnea, or OSA, causes a person to periodically stop breathing while asleep. Dr. Mitch Garber, a physician on the NTSB’s investigation team, said people with the condition will feel extremely sleepy during the day and they can drift off after a few minutes in a quiet or monotonous environment.
Garber estimated that 1 percent to 2 percent of the population has the severe form of OSA.
“It seems odd to have both members of a two-man crew with a similar condition,” said board member John Hammerschmidt.
Steve Jenner, another investigator, said Yash had been diagnosed with the condition about a year before the wreck. Despite his doctor’s warning that it could cause him to fall asleep on the job, he never followed the physician’s instructions to attend a sleep clinic.
Enriquez had been diagnosed several years earlier and was treated at a sleep clinic and given an air-pumping mask to wear at night, but he still suffered from sleeplessness and snoring, so Jenner said it may not have been set at the right pressure.
The NTSB recommended that Canadian National requires “fatigue awareness training” for its employees. It also recommended that the federal government develop a standard medical form for railroad companies that would inquire whether operators suffered from sleep conditions and require that employees with incapacitating medical conditions report them to the company and stop working in safety-sensitive positions until they are successfully treated.