From the Railroad Accident Report "Collision of Two Union Pacific Railroad Freight Trains, Hoxie, Arkansas August 17, 2014" published on January 24, 2017, Report Number: RAR-16-03. Adopted December 19, 2016, PB2017-100970: 2.5 Southbound Train Locomotive Engineer’s Medical Issues
The southbound engineer’s postaccident urine toxicology testing identified 94 ng/ml diphenhydramine and citalopram/escitalopram in his urine, but no blood was available for testing. Although diphenhydramine is considered sedating, there is no accepted method for relating postmortem urine drug results for diphenhydramine to cognitive function impairment at the time of the fatal injury.19 Therefore, it cannot be determined if the engineer was impaired by this sedating antihistamine or its hangover effects at the time of the accident. Urine testing did not differentiate between citalopram and escitalopram, antidepressants commonly marketed with the names Celexa and Lexapro. Both are psychoactive medications and carry warnings about the risk of cognitive impairment in the mental and/or physical ability required for the performance of potentially hazardous tasks (such as, driving, operating heavy machinery). However, personal medical records revealed the southbound engineer had been using escitalopram for many years without reported performance problems.
According to his personal medical records, between 2006 and 2014, the southbound engineer repeatedly reported feeling tired to his primary care physician. In 2010, the primary care physician considered the diagnosis of obstructive sleep apnea and obtained a polysomnography, also known as a sleep study, which was performed in a sleep laboratory. The results included an apnea-hypopnea index (AHI) of 19.3 episodes/hour, oxygen saturation ranging from 93-87 percent, and 29 periodic limb movements recorded with an index of 5.3 per hour.20 All of these measurements are considered abnormal. The sleep specialist diagnosed moderate sleep apnea and the possibility of restless leg syndrome.21 The southbound engineer returned to the sleep center for a trial of treatment with continuous positive airway pressure (CPAP). Following that trial, the sleep specialist recommended the “CPAP be placed at 7 cm/H2O. (No apneas, no snoring, no periodic limb movements).”
The NTSB medical officer reviewed records from the sleep laboratory and sleep specialist, as well as the primary care physician, and interviewed the primary care physician. However, no follow-up visits or evidence of treatment initiation, maintenance, or review with the sleep specialist or the primary care physician were discovered. No evidence was found that the southbound engineer ever obtained or used a CPAP machine to treat his sleep disorder. The night before the accident, the southbound engineer’s work schedule required him to sleep away from home. He had checked out of his accommodation and did not have a CPAP device in his possession at the time of the accident. There is also no evidence that he obtained any other treatment for his sleep apnea, such as surgery or a customized mouthpiece. The NTSB concludes the southbound engineer was fatigued and likely asleep due to his diagnosed but inadequately treated moderate sleep apnea and operating the train in the early morning hours when he was predisposed to sleep.
In September 2013, the southbound engineer was noted to be 6 feet, 3 inches tall and weigh 250 pounds. According to the body mass calculator from the National Institutes of Health, National Heart, Lung, and Blood Institute, his body mass index was 31.2 kg/mg2, which is considered obese.22 Although his body mass index was in the obese category, which increased the risk for sleep apnea, the southbound engineer’s weight was not known to directly cause it.
The NTSB has investigated a number of previous railroad accidents where undiagnosed or inadequately treated sleep apnea or other sleep disorders in safety-sensitive employees caused or contributed to the accident. A head-on collision of two Canadian National/Illinois Central Railway trains occurred in Clarkston, Michigan, in 2001 that the NTSB determined was due to “…crewmembers’ fatigue, which was primarily due to the engineer’s untreated and the conductor’s insufficiently treated obstructive sleep apnea.” (NTSB 2002) As a result, the NTSB issued the following safety recommendation to the FRA:
Develop a standard medical examination form that includes questions regarding sleep problems and require that the form be used, pursuant to [Title] 49 Code of Federal Regulations Part 240, to determine the medical fitness of locomotive engineers; the form should also be available for use to determine the medical fitness of other employees in safety-sensitive positions.
In 2006, partly in response to this recommendation, the FRA created a Medical Standards Working Group as part of the Railroad Safety Advisory Committee (RSAC). Although the FRA has mentioned the RSAC and its Medical Standards Working Group in responses to NTSB recommendations on a number of occasions, it was disbanded after 5 years for being unable to reach consensus.23 On March 10, 2016, the FRA and the Federal Motor Carrier Safety Administration jointly published an advance notice of proposed rulemaking in the Federal Register (FR) regarding obstructive sleep apnea. (FR 2016, 12642) However, the notice primarily poses questions and asks for public comments on the topic. It does not provide information regarding any proposed rules. Currently, no public action has been taken by the FRA to develop guidelines or require screening, diagnosis, or treatment of sleep disorders among railroad employees.
Following the investigation of a head-on collision between two UP freight trains in Goodwell, Oklahoma, in June 2012, the NTSB determined the probable cause of the accident was, in part, due to the conductor’s lack of engagement and the engineer’s inability to see and interpret signals due to a chronic illness and deteriorating eyesight. (NTSB 2013) As a result of this, the NTSB reclassified Safety Recommendation R-02-24 to the FRA as Closed?Unacceptable Action and superseded it with the following safety recommendation:
Develop medical certification regulations for employees in safety-sensitive positions that include, at a minimum, (1) a complete medical history that includes specific screening for sleep disorders, a review of current medications, and a thorough physical examination, (2) standardization of testing protocols across the industry, and (3) centralized oversight of certification decisions for employees who fail initial testing; and consider requiring that medical examinations be performed by those with specific training and certification in evaluating medication use and health issues related to occupational safety on railroads.
The FRA reported it had already created a new RSAC working group, the Fatigue Management Working Group, to develop standards for a railroad’s fatigue management plan.24 The NTSB did not view this reply as responsive to this recommendation and has, therefore, classified Safety Recommendation R-13-21 Open—Unacceptable Response. Like the previous medical working group, the fatigue working group has been operating for years without any publicly available output regarding medical conditions and fatigue.
In the investigation of the April 27, 2011, rear-end collision in Red Oak, Iowa, discussed earlier in this report, the NTSB determined the collision occurred due to “the failure of the crew of the striking train to comply with the signal indication requiring them to operate in accordance with restricted speed requirements and stop short of the standing train because they had fallen asleep due to fatigue resulting from their irregular work schedules and their medical conditions.” Among other ailments, the medical conditions included probable sleep apnea, restless leg syndrome, and chronic insomnia. (NTSB 2012) As a result of that investigation, the NTSB made the following safety recommendation to the FRA.
Require railroads to medically screen employees in safety-sensitive positions for sleep apnea and other sleep disorders.
In response to Safety Recommendation R-12-16, the FRA cited the Rail Safety Improvement Act of 2008 (RSIA) which requires, under section 103, that certain railroads develop a risk-reduction program (RRP).25 Section 103(d)(2) of the RSIA requires a railroad to include a fatigue management plan in its RRP. As part of the development of fatigue management plans, railroads will be required to provide opportunities for the identification, diagnosis, and treatment of any medical condition that may affect alertness or fatigue, including sleep disorders. The FRA, in response to Safety Recommendation R-12-16, stated, “Currently, FRA, in conjunction with a working group of members from the Railroad Safety Advisory Committee (RSAC), is developing a fatigue management regulation that will be responsive to the requirements set forth in the RSIA.”26 The recommendation was classified Open—Acceptable Response by the NTSB in October 2012. However, RSIA specified that this be carried out within 4 years of its implementation, which would have been October 16, 2012. However, as of October 2016, such a regulation has not been promulgated.
On May 25, 2013, a UP railroad freight train collided with a BNSF freight train in Chaffee, Missouri, resulting in a total derailment of 24 cars and 2 locomotives, as well as a postimpact diesel fire and severe damage to a highway overpass. The two UP train crewmembers were injured and five occupants of motor vehicles on the bridge were transported to local hospitals.
The NTSB determined that the probable cause of the accident was:
…the failure of the UP train crewmembers to comply with wayside signals leading into the Rockview Interlocking as a result of their disengagement from their task likely because of fatigue-induced performance degradation. Contributing to the accident was the lack of: (1) a positive train control system, (2) medical screening requirements for employees in safety-sensitive positions for sleep apnea and other sleep disorders, and (3) action by the FRA to fully implement the fatigue management components required by the RSIA. Likely contributing to the engineer’s fatigue was undiagnosed obstructive sleep apnea. Also contributing to the accident was inadequate crew resource management.
As a result of this accident investigation, the NTSB changed the classification of Safety Recommendation R-12-16 that was issued to the FRA to Open?Unacceptable Response. (NTSB 2014)
The NTSB concludes that the continued occurrence of railroad accidents attributed to fatigue caused by sleep apnea are due in part to the failure of the FRA since 2002 to respond to the hazards posed by undiagnosed or inadequately treated sleep apnea. Therefore, the NTSB reiterates Safety Recommendations R-12-16 and R-13-21.