worker safety

The hierarchy of controls: How to control the hazards faced by lone workers

Understand the hierarchy of controls and find out how it can be used to control the hazards and risks faced by lone workers.



The Hierarchy of Controls

The level of risk of an event is established by assessing the likelihood of the event happening and the potential consequences of the event.

Planning and implementing controls to reduce the likelihood or severity of an event is something we do every day.  We wear lifejackets when we are on boats in case of an accident or fall into the water. We put baby gates at the top of the stairs to keep our children from falling downstairs. We put barriers around construction zones to keep unauthorized civilians out of high-risk areas. The list could go on; these are just a few examples of how we do this daily.  

All hazards are not created equal. It's not logical to approach them all the same way. You wouldn't apply the same level of rigor to address the risk of a paper cut as you would a vehicle collision. We use the hierarchy of controls as a method to control hazards and reduce or eliminate risk. The image below, for most safety professionals, is one that is emblazoned on their cerebral cortex. Let's take a look at the image and break it down.

 hierarchy of controls in lone working

Hierarchy of Controls: Everyday Examples

Let's take the example of driving a car. We all know that the risk of an accident has a fairly high likelihood compared to other modes of transportation and can have major consequences. It's one of the most common high-risk activities we take on daily.

Let's examine the hierarchy of controls as a method for controlling hazards associated with driving a car, and evaluate the most effective control methods.


That's an easy one… just don't drive. Eliminate the need to be in the vehicle altogether and problem solved. Unfortunately, our livelihoods depend on driving and while we can minimize the likelihood of an accident by eliminating this hazard in some cases (working from home has helped here), it's not practical to eliminate it altogether.

Because we cannot eliminate all occurrences of driving, we have to look at other control measures to reduce the residual risk. Remember that each subsequent control will have diminished effectiveness in eliminating the hazard.


There are many substitutes for driving that we use every day. Riding a bike, subway, train, bus, walking, or airplane are all other ways of getting us from point A to point B. None of these eliminate the risk, they just substitute the hazard for a less risky hazard.  

Engineering Controls

A plethora of engineering controls in our vehicles attempt to reduce the risk associated with driving; after all, the automobile is a modern engineering marvel that continues to evolve. These controls include anti-lock brakes, traction control, blind-spot detectors, automatic transmissions, all-wheel drive, hazard blinkers, turn signals, brake lights, and so on. But still, after all of that, there is a lot of residual risk to driving.  

Administrative Controls

Administrative Controls are the most noticeable controls we use for reducing the hazard identification of driving.  These seek to change or control the behavior of drivers on the road. Speed limits, lane markers, curve warnings, traffic lights, stop signs, and driver's license requirements are just a few of the many controls we use to reduce the risk of driving on the road.


We cannot control other people's behavior.  We can't control the schedule of mass transportation or its availability.  Sometimes we need to get somewhere that is too far to walk or ride a bike. For these reasons, we have a residual risk that leads us to needing Personal Protective Equipment (PPE) to protect drivers and passengers. PPE protects us from consequences should an event happen. Seatbelts and airbags are just some that come to mind.

Hierarchy of Controls: Examples at Work

Now when we think about the risk associated with how we work, we can start to see why certain things exist. A great example of elimination is using an extension pole to change a light bulb, eliminating the need to work from heights. We can substitute toxic cleaning chemicals and adhesives with non-toxic ones to achieve the same results. We can engineer a ventilation system to reduce hazardous indoor air conditions. One of the most common administrative controls we see every day is the lock-out/tag-out system, which controls different types of energy to ensure energy is isolated while work is being conducted. And of course, our last line of defense, PPE – like hard hats – are used because you cannot eliminate the risk of objects falling on a construction site or accidentally being struck by an elevated load. At large manufacturing facilities and warehouses, we are seeing an increasing substitution of heavy, human-operated forklifts with lighter-weight, intelligent driverless forklifts.

Lone Worker Risk

The Canadian Centre for Occupational Health and Safety (CCOHS) defines a lone worker as a person that is on their own, meaning they cannot be seen or heard by another person.  There are many important factors in determining the level of risk (remember, likelihood, and severity) of a lone worker situation.  For example, a security guard for a warehouse will have different risk levels during the day than at night.  And that security guard, regardless of the shift, will have a different risk profile than a maintenance technician entering a confined space elevator service pit.

You can imagine that working alone, depending on the job, has many similar job hazards to those working in teams; working from heights, inhalation hazards, confined spaces, slips trips and falls, risk of head injury, electrocution, etc. It's when we combine these workplace hazards with being alone that the risk really begins to elevate. Working from heights and entering a confined space become more dangerous without a spotter and social risk and risk of violence increase without the benefit of a colleague or team. In fact, all high-risk activities become even more so when they are done alone, outside of earshot and sight of another person.

While this is by no means meant to be exhaustive, here are a few classic lone worker situations across a multitude of industries for lone workers:

  • Field service technicians spend hours traveling between job sites to work on equipment. Often, they are alone for long stretches outside of cellular coverage.
  • Equipment technicians dispatched for maintenance work could be overcome by toxic inhalation hazards and no one is around to hear the gas detector alarm.
  • Gas plant operators must put in long hours and night shifts - usually in groups of two where they may not be in constant contact - resulting in increased fatigue and impairment.
  • Pipeline operators, responsible for long distances of complex piping systems, are dispatched regularly to investigate issues along the pipe network, often being exposed to dangerous topography, often off-shift hours with little natural light, and driving long distances. 
  • Homecare nurses, home health aides, paramedics, and technicians must constantly mobilize and expose themselves not only to unknown locations and social risks but also to hazardous equipment and substances.
  • Residential service technicians provide services to homes and multi-tenant dwellings with unpredictable conditions and potential for social risk and violence.  
  • Substation and wastewater treatment operators work alone to ensure the facility runs smoothly, often operating on long, 12-hour shifts and rotating days and nights.

Lone Worker Hierarchy of Controls

It can be useful to put the hazards associated with working alone into the context of the hierarchy of controls. Here we will follow the same structure as before: 

Elimination or Substitution

The first step is to eliminate or substitute the hazard or risk the lone worker is exposed to. For example, if the lone worker is required to perform a task that involves working with hazardous chemicals, a safer alternative chemical could be substituted.

Engineering Controls

If elimination or substitution is impossible, then engineering controls should be implemented. For example, installing barriers, guards, or ventilation systems to reduce the risk of exposure to the hazard.

Administrative Controls

If engineering controls are not feasible or practical, administrative controls can be used. An example of administrative control is developing and implementing standard operating procedures for the task to eliminate variability in how a task is performed and to guide the work safely. In addition, implementing a system for regular check-ins with the worker that includes communication with the supervisor and escalation procedures is a great control against the hazard of working alone.

Personal Protective Equipment (PPE)

Personal protective equipment (PPE) can be used as a last resort to protect the lone worker. For example, providing the worker with protective clothing, eye protection, hearing protection, or respirators.

One can see from this analysis that Elimination, Substitution, and Engineering Controls are not specific to lone workers. In fact, they are inherent to any worker's job, working in a group or alone. The reality of working alone is that the hazards of the job are exacerbated by the fact that if something happens, no one is there to see it, hear it, or otherwise help the worker.

Assuming that the proper care has been taken on a job site to protect workers from hazards, the best way to control the hazard of working alone is to invest in administrative controls

Best Practices for Administrative Controls:

  1. Create a Lone Worker Safety Program
  2. Create detailed procedures for check-ins between lone workers and supervisors. Ensure these procedures align with risk assessment for specific jobs such that check-ins are more frequent as required for the work process, travel outside of cell coverage, etc.
  3. Create a hazard check-in process to establish communication with a supervisor when hazardous events are likely to occur.  Example: a procedure that your lone workers must provide a notification that they will be climbing a tower for the next hour or entering a confined space for 30 minutes.
  4. Ensure escalation procedures are in place for emergencies. For work locations where the local response is not possible, ensure that this includes the ability to respond with emergency services.
  5. Ensure that your workers stay connected at all points in their work journey (home, workshop, travel route, worksite). Consider investing in communication technology to ensure this is possible.
  6. Limit the burden on your organization by digitizing this into a Lone Worker Safety System.

Mitigating the risk of lone working

Every day, lone workers face the unique hazards associated with their jobs. The hazards of their work don’t change, but they are intensified because of the addition of a new hazard - the hazard of working Alone. When we look at working alone as its own hazard, we can then effectively seek to control the hazard through the hierarchy of controls - leading to some great best practices for administrative controls. Putting a lone worker safety program in place and deploying it digitally is a great way to mitigate the hazard of working alone.

Aware360 provides solutions that prioritize the safety of lone workers by employing real-time monitoring and communication. These solutions ensure that workers receive assistance whenever required, regardless of location. Get in touch with our experts and explore the latest safety technologies that can make a life-saving difference.

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