Notation 8486: On March 11, 2013, the US Chemical Safety and Hazard Investigation Board (CSB) published a request for public comment on a document released on its website titled “Draft Recommendations Evaluation for Public Comment: Fatigue Risk Management Systems (FRMS)” (CSB Evaluation). Subsequently, CSB staff invited the National Transportation Safety Board (NTSB) to share its experiences in investigating transportation accidents in which human fatigue was identified as a safety issue, and related NTSB safety recommendations.
The NTSB is an independent federal agency charged with determining the probable cause of transportation accidents and issuing safety recommendations aimed at preventing future accidents. The NTSB has a long history of making recommendations to reduce fatigue and fatigue-related transportation accidents and, since its inception, has issued over 200 recommendations addressing fatigue in the aviation, highway, marine, railroad, and pipeline modes. We are pleased to share our experiences with the CSB.
The CSB Evaluation comments on actions taken by the American Petroleum Institute (API) and the United Steelworkers International Union (USW) in response to Recommendation No. 2005-04-I-TX-7, issued by the CSB in 2005 to those organizations. The CSB recommendation was issued as a result of the March 23, 2005, Texas City, Texas, refinery explosion and fire. The portion of the CSB recommendation pertinent to this letter reads as follows:
[D]evelop fatigue prevention guidelines for the refining and petrochemical industries that, at a minimum, limit hours and days of work and address shift work….
In April 2010, the API issued an American National Standards Institute-approved Recommended Practice titled Fatigue Risk Management Systems for Personnel in the Refining and Petrochemical Industries, First Edition (RP-755), and an accompanying technical report titled Fatigue Risk Management Systems for Personnel in the Refining and Petrochemical Industries, Scientific and Technical Guide to RP 755. The CSB Evaluation presents the results of a CSB staff review in which the CSB staff determined that RP-755 does not meet the intent of the CSB recommendation in several areas.
The NTSB has reviewed RP-755 as well as the CSB Evaluation. With respect to human fatigue, the NTSB has specific experience with the following issues that are discussed in the CSB Evaluation:
• The hours-of-service limits described in RP-755, which are more permissive than what is indicated by current scientific knowledge, and the suggestion that voluntary FRMS programs will compensate for the risk from excessive hours and days at work, and
• The emphasis of RP-755 on voluntary efforts by industry and its lack of explicit requirements, especially with respect to elements of an effective fatigue management system.
With respect to the hours-of-service limits, RP-755 describes “work sets” during normative conditions, which may include 12-hour day shifts or night shifts for 7 consecutive days, with the possibility of an additional “holdover period” beyond the duty day for training or safety meetings. The RP states that the “holdover period should not exceed 2 hours and, where possible, occur at the end of the day shift.” However, the use of the language “should” is not a requirement but is defined by the document as a “recommendation or that which is advised but not required in order to conform to the RP.” Therefore, a worker could, during a normal work set, work shifts of 14 hours or greater in a 24-hour period for several days.
RP-755 also states that during planned or unplanned outages, workers may be called on to work 12-hour shifts for up to 14 consecutive days, with as little as 36 hours between 14-day, 12-hour work sets. Holdover periods of up to 2 hours are also allowed during outages. The RP also has provisions for extending work shifts up to 18 hours.
In several of its accident investigations, the NTSB has recognized the relationship between long duty days and fatigue, both directly and through their effects on reduced sleep lengths during off-duty periods. For example, in the investigation of the October 2004 Corporate Airlines accident in Kirksville, Missouri, the NTSB determined that the probable cause of the accident was the pilots’ failure to follow established procedures and properly conduct an instrument approach at night, and that fatigue was one factor that contributed to the pilots’ degraded performance. The length of the pilots’ duty day (at the time of the accident, they had been on duty for 14 1/2 hours) was cited along with less-than-optimal overnight rest time, early reporting time for duty, the number of flight legs, and demanding flight conditions, as factors that resulted in the pilots’ fatigue. In the Kirksville report, the NTSB cited research showing that pilots who worked schedules that involved 13 or more hours of duty time had an accident rate that was several times higher than that of pilots working shorter schedules, and that airplane captains who had been awake for more than about 12 hours made significantly more errors than those who had been awake for less than 12 hours. As a result of the Kirksville investigation, the NTSB issued Safety Recommendation A-06-10 to the Federal Aviation Administration (FAA), which stated the following:
Modify and simplify the flight crew hours-of-service regulations to take into consideration factors such as length of duty day, starting time, workload, and other factors shown by recent research, scientific evidence, and current industry experience to affect crew alertness.
The NTSB reiterated Safety Recommendation A-06-10 in 2008 following its investigation of the April 2007 Pinnacle Airlines accident in Traverse City, Michigan. In that accident, the NTSB determined that the probable cause of the accident was the pilots’ poor decision-making as they prepared to land the airplane. The NTSB stated that “This poor decision-making likely reflected the effects of fatigue produced by a long, demanding duty day and, for the captain, the duties associated with check airman functions.” The pilots had been on duty for more than 14 hours at the time of the accident.
The effectiveness of fatigue management is directly related to the availability of work schedules that allow a sufficient period of time between work shifts for the employee to obtain sufficient restorative sleep. The NTSB has investigated several accidents and serious incidents that provided clear and compelling evidence that air traffic controllers were sometimes operating in a state of fatigue because of their work schedules and poorly managed utilization of rest periods between shifts, and that fatigue had contributed to controller errors. Consequently, the NTSB issued Safety Recommendation A-07-30 to the FAA, which stated the following:
Work with the National Air Traffic Controllers Association to reduce the potential for controller fatigue by revising controller work-scheduling policies and practices to provide rest periods that are long enough for controllers to obtain sufficient restorative sleep and by modifying shift rotations to minimize disrupted sleep patterns, accumulation of sleep debt, and decreased cognitive performance.
The NTSB’s consideration of how long duty days affect fatigue and safety has not been limited to the aviation mode. Recently, in our investigation of the September 2010 collision of two freight trains near Two Harbors, Minnesota, the NTSB concluded that crew fatigue was a contributing factor in train crew errors that led to the collision. The train crewmembers who made the errors had been awake between 13 and 14 hours at the time of the accident, and the accident occurred during the final hour of a 12-hour shift. In its report, the NTSB cited a study showing that 12 hour work shifts have been associated with decrements in alertness and performance, compared to 8-hour shifts. Other studies of commercial drivers have found an exponential increase in crash risk with increasing driving times, especially for driving periods that extend beyond 8 or 9 hours.
The NTSB has made numerous recommendations concerning hours of service across the transportation modes. A common theme of those NTSB recommendations has been an emphasis on establishing hours-of-service limits that are scientifically based, that set limits on hours of service, that provide predictable work and rest schedules, and that consider circadian rhythms and human sleep requirements.
The second issue discussed in the CSB Evaluation with which the NTSB has experience concerns the lack of explicit requirements regarding essential elements of a fatigue management program. The CSB Evaluation remarks that
The use of the word ‘should’ for most elements of a Fatigue Risk Management System (FRMS) in the RP means that they are optional, not required. In what is already a voluntary standard to begin with–employers can choose to conform to them, but they are not required by force of law to do so–‘should’ statements have very little force.
The lack of required FRMS elements raises additional concerns because RP-755 states that its hours-of-service limits were “developed in the context of the existence of a comprehensive FRMS” and that “Consistently working at the limits shown is not sustainable and may lead to chronic sleep debt.” Hence, while RP-755 does not require the use of an FRMS, it does ostensibly allow operators to persistently schedule workers at the noted limits.
The NTSB has recommended requiring the implementation of fatigue management programs. For example, as a result of its investigation of a June 2009 multivehicle accident near Miami, Oklahoma, in which a truck driver’s fatigue resulted in his failure to react to and avoid colliding with a slowing traffic queue, the NTSB emphasized the importance of comprehensive fatigue management programs. The report described the North American Fatigue Management Program (NAFMP), which is designed to address scheduling policies and practices, fatigue management training, sleep disorder screening and treatment, and fatigue monitoring technologies. In the report, the NTSB stated that “if the NAFMP guidelines remain voluntary—and are used by some carriers but ignored by others—this important safety tool might have only a limited effect in reducing fatigue-related highway accidents.” As a result of its investigation, the NTSB called on the Federal Motor Carrier Safety Administration to implement the following NTSB safety recommendation:
Require all motor carriers to adopt a fatigue management program based on the North American Fatigue Management Program guidelines for the management of fatigue in a motor carrier operating environment.
The NTSB has also made recommendations in the highway, railroad, and aviation modes to establish ongoing programs to evaluate, report on, and continuously improve fatigue management programs implemented by operators (NTSB Safety Recommendations H-08-14, R 12-007, A-06-11, and A-08-45).
I hope that this information about the NTSB’s history of investigating fatigue-related accidents and the recommendations we have issued will be useful as the CSB moves forward with the evaluation of the API and USW responses to the fatigue-related CSB recommendation resulting from the Texas City investigation.