As an underlying cause of incidents and accidents, fatigue can be a sneaky culprit to monitor and mitigate, says Walter Tharp, manager of environment, health, and safety for Irving Materials, based in Greenfield, Ind. “It can be the result of working long hours or doing tiring tasks, and it also can be the results of personal sleep habits or situations at home. What fatigue affects is our ability to mentally process information. Workers can lose their ability to concentrate, and it dulls their responses to hazards,” he says.
According to Todd Dawson, manager of Fatigue Solutions for Caterpillar, fatigue is often something that’s viewed as being a problem with lazy, unmotivated, or uncaring people. “But we all can experience fatigue,” Dawson says. “Whether we might work on a night shift, and our circadian rhythms are working against us, or we’re operating under stress; life just gets in the way. It’s human nature to experience fatigue at least some of the time.”
For an office employee, fatigue may not present many on-the-job hazards (although it can affect the commute home). For aggregates workers in the plant, fatigue can result in serious incidents and accidents. In fact, fatigue-related incidents can be more severe that non-fatigue-related incidents in that the fatigued worker often will fail to make any corrective actions or maneuvers. And as a precursor to sleep, in the brief span of time before actually falling asleep, a driver is operating similarly to someone who is legally intoxicated.
“Spending 22 hours awake is equivalent to having a 0.08 percent of blood alcohol content,” Dawson says. “Even a distracted or drunk driver will typically attempt to correct if he’s drifting or approaching a traffic stop.”
While it has historically been difficult to monitor fatigue among workers, Jamie Ross, head of safety, risk, and security at Newcrest Mining in Melbourne, Australia, says that there are signs managers can watch for amongst their workers. These include small errors, lapses and slips (dropping tools, picking up the wrong item); poor hand-eye coordination; loss of attention (not hearing things said by others); slow reaction times; bad moods; and yawning or visible drowsiness.
In applying technology to the issue, it makes sense that an available automated system might primarily focus on the worker’s eyes — including the momentary eye closure that often is involved. Dawson says that the Cat Driver Safety System (DSS) is in-cab, camera-based technology for rolling equipment that monitors facial features, especially the driver’s eyes. “The DSS uses algorithms to determine if you’re closing your eyes more than a blink,” he says. “It also looks at head orientation and gaze to monitor distraction. And it can provide an alert — an alarm or seat vibration — to wake the driver.”
Worksite Safety: Mitigating Fatigue
Over the past 20 years, Todd Dawson has become one of the leading experts in developing and implementing comprehensive fatigue risk management systems in large and complex environments. As manager of Fatigue Solutions for Caterpillar, Dawson has assisted companies with fatigue mitigation due to PHMSA regulations. He holds a bachelor’s degree in biological anthropology from Harvard University.
Walter Tharp, P.E., is manager of environment, health, and safety (EHS) for Irving Materials, which is based in Greenfield, Ind. With 25 years in the aggregates industry, Tharp has worked in the safety field for close to 35 years. His first safety-related job was in loss control for an insurance company, which needed a civil engineer to service its construction division.
Jamie Ross, head of safety, risk, and security at Newcrest Mining in Melbourne, Australia, is also the mind and voice behind MiningMan.com, a website devoted to advancing leadership, safety, and productivity in mining. A mining engineer, Ross has spent more than 15 years in operational, technical, and leadership roles in mining operations throughout Australia, the United States, and China.
Voices of Experience
Worker fatigue is a topic not usually dealt with during on-the-job safety behavior observations, says Jamie Ross, head of safety, risk, and security at Melbourne, Australia-based Newcrest Mining. “It is a difficult thing to observe for, and the very fact that someone is being ‘observed’ can tend to ‘wake’ them up and mask any behavioral signs of fatigue,” he notes.
While it can be difficult to observe and recognize signs of fatigue, the causes and consequences of fatigue are certainly something that should be discussed with teams one-on-one — and the best time to do that is during safety toolbox talks. “There are some convenient times and situations that can act as prompts to discussing fatigue,” Ross says. These include:
Last shift of the week or tour;
When people may be about to drive long distances at the end of the shift;
During any night shift or a shift where the person had a particularly early start;
At the end of a very long shift;
On jobs with repetitive work;
Working in hot and humid conditions; and
Following an incident where fatigue was thought or known to be involved.
The following factors are the key contributors to work fatigue:
Poor quality of sleep or inadequate sleep before shifts;
Working irregular hours and night shifts;
Drinking prior to sleeping;
Extended physical or mental exertion at work;
Strenuous or stressful activities outside work; and
General health and fitness.
“The discussion can also cover what controls a person or work team are putting in place to manage fatigue, but, in general, the hazards of fatigue are best managed by prevention rather than managing it once it has set in. Some controls that are possible if a person is feeling fatigued include rest, changing jobs, working in cooler areas, avoiding working alone, and avoiding any high-risk jobs or driving,” Ross says.
Fatigue not only can cause workers to lose their concentration, but in worst-case scenarios, it can actually cause a worker to fall asleep. “Haul truck drivers often experience fatigue due to the fact that their jobs can become boring and repetitive,” says Walter Tharp, environment, health, and safety manager for Greenfield, Ind.-based Irving Materials. “When you begin doing your job by rote, then you can stop actively thinking about what you’re doing. Your mind can wander.”
Outside influences for fatigue include natural circadian rhythms and seasonal changes — with shorter days affecting a worker’s sleep cycles. Longer days in summer can mean longer shifts, however, which also can lead to fatigue.
Tharp says that advancements in mobile equipment have helped to reduce fatigue in operators. “Twenty-five years ago, truck and loader cabs had little insulation for noise and temperature, and there was no air conditioning,” he notes. “Improvements in these areas alone have created better work environments and have made operator and driver jobs less tiring to do. Noise reduction in particular is important, as noise can cause stress, which leads to fatigue.”
Foremen and site managers at Irving Materials are encouraged to actively be involved in their crews’ activities and to get to know crew members well, so that actions that seem out of the ordinary will be noticed and monitored. “The best chances of mitigating fatigue lie in our ability to recognize it and assist our workers,” Tharp says. “Our managers should know their crews well enough that they will recognize if a worker seems fatigued. They can try to identify the cause of the fatigue, and get the worker assistance if necessary.”
Tharp says Irving Materials also works to reduce fatigue among workers by discussing healthy habits during safety meetings. Managers emphasize the need for proper diet and getting enough rest, as well as tips for separating the home environment from the work environment.
“We’re very bad at recognizing how fatigued we are,” says Todd Dawson, manager of Fatigue Solutions for Caterpillar. “We usually can’t tell when we have gone from ‘I’m tired’ to ‘I’m dangerously tired.’ And we can easily slip from there to ‘my eyes closed, and I drifted off the roadway.’”
According to Dawson, the gold technology standard for monitoring fatigue is the EEG. “Unfortunately, it’s a challenge to take that technology into a mobile job because it requires having electrodes hooked to your skull during your shifts. No one wants that,” he says.
To help in monitoring and mitigating fatigue, Cat has looked into other ways to measure a worker’s level of tiredness. “Most sleep studies require another person to interact with the subject,” Dawson explains. “But technologies have come out that require little to no interaction with drivers.”
One such technology, called the Driver Safety System (DSS), is an in-cab, camera-based system that monitors features on the driver’s or operator’s face. The system can determine if the driver has closed his eyes for more than a mere blink or if his gaze has become distracted, and it will provide an alarm or a seat vibration to warn and wake the driver.
Another system available is called the Smart Band. It is a wearable device similar to a FitBit, which the user wears at all times. A 3D accelerometer captures movement of the wearer, and translates it into patterns of waking and sleeping. Together with information about that worker’s shift schedule, the Smart Band can help to build a picture of that worker’s quantity and quality of sleep over 30 days. If it becomes apparent that the worker’s sleep patterns are cause for concern, managers can use this information to help the worker gain better sleep quality.
“Of course, technology is a great help. But workers still should know the signs of fatigue. And it is best for operations to advance a culture where workers feel they can ask for assistance — or even a break,” Dawson says.