Fatigue and inadequately treated obstructive sleep apnea contributed to an Aug. 17, 2014, collision between two Union Pacific Railroad freight trains in Hoxie, Arkansas, according to a report synopsis presented by the National Transportation Safety Board at a public meeting on Dec. 6, 2016. As a result of the collision, the engineer and the conductor from the southbound train died, and the engineer and the conductor from the northbound train were seriously injured.

The NTSB found that the southbound train conductor was likely asleep at the time of the accident due to the variability of his shift start times. The southbound train locomotive engineer was fatigued and likely asleep due to his diagnosed but inadequately treated moderate sleep apnea.

“The continued occurrence of railroad accidents attributed to fatigue caused by sleep apnea are due in part to the failure of the Federal Railroad Administration since 2002 to respond to the hazards posed by undiagnosed or inadequately treated sleep apnea,” states the NTSB report synopsis.

The synopsis from the NTSB’s report is subject to further review and editing to reflect changes adopted during the public meeting. A final report will be released at a later date.

Aerial photo of Union Pacific freight train collision at collision point (NTSB)