Make safer decisions with the hierarchy of controls

How to apply the hierarchy of controls to manage hazards at your workplace.

Every workplace has its hazards. Identifying them is the first step to reducing their risks.

No matter if you’re at the start of a project or in the thick of the job, the task is the same: look closely at the work environment and the work being done to spot conditions or actions that could lead to harm. Early recognition of hazards allows employers and workers to take the right steps to control risks and most effectively prevent incidents.

But once a hazard is identified, what is the best way to deal with it? Using the hierarchy of controls provides an answer.

The hierarchy of controls is a standardized framework that ranks hazard control measures from most effective to least effective. It is widely used in the construction sector, industrial work, and as part of workplace health and safety programs.

The hierarchy arranges controls in five levels, with the principle that workplaces should always try to apply the most effective controls first. Typically, those “best” controls deal with hazards at the source or along the path, while less effective measures control hazards at the worker.

To see how this applies in practice, it’s helpful to examine the hierarchy of controls and understand how each of its five levels reduces risk.

Use the five levels of controls to build safer work conditions

Elimination

The most effective control, elimination means removing the hazard from the workplace completely. When you eliminate the hazard, it cannot cause harm to workers because it no longer exists in the work process.

Examples: Using prefabricated building components— which are brought to the jobsite, assembled on the ground, and hoisted into place—to remove (or significantly reduce) workers’ exposure to fall hazards.

Substitution

If elimination of hazards isn’t possible, the next control level is substitution, which involves replacing a hazard with an alternative that performs the same function (or produces the same result) but with less risk to the worker. Depending on the hazard, you can substitute materials or chemicals, alternate equipment, and even modified work processes.

Examples: Swapping out an oil-based product in favour of a water-based product. Replacing building materials that contain silica with safer options. Using electric rather than gas-powered generators or equipment.

Engineering controls

These controls reduce risk by separating workers from the hazard or isolating the hazard itself. This often means making changes to the work environment or equipment.

Examples: Installing guardrails around openings, fencing around hazardous areas, or barricades to separate pedestrian and vehicle/machinery traffic. Using wet-cutting methods to reduce airborne silica dust.

Administrative controls

Unlike the higher-level controls, above, administrative controls do not affect the hazard. They focus on policies and practices that help workers understand how to work safely around the hazard—that is, what actions to take (or avoid) to protect themselves and others. Because they rely on consistent worker behaviour, administrative controls are most effective when combined with higher-level controls and proper supervision.

Examples: Documented workplace health and safety procedures. Competent supervision and job planning. Job rotation or rest schedules. Providing training and instruction on specific tasks or hazards.

Personal protective equipment (PPE)

PPE can protect workers from injury, but it doesn’t remove or reduce exposure to hazards. It’s the least effective control in the hierarchy—and is dependent on proper use, fit, and maintenance. PPE is commonly used in tandem with other controls. It should not replace more useful measures.

Examples: Respirators. Hard hats. Safety glasses. Hearing protective devices such as earplugs. Fall protection systems—which can stop workers from hitting the ground due to a fall, but do not prevent falls from happening.

Put the hierarchy of controls to practice

Applying the hierarchy of controls during job planning and through risk assessments helps ensure that hazards are addressed systematically, before work begins or when conditions change. Working through the hierarchy step by step ensures the strongest possible controls are always considered and applied first.

When planning a job, ask these questions to guide your decision-making on how to control each identified hazard:

• Can the hazard be eliminated completely?
• If not, can it be substituted with a safer material, tool, process, or method?
• Can engineering controls be introduced to isolate workers from the hazard or reduce exposure?
• What administrative controls—such as procedures, training, job rotation, or supervision—can support safe work practices?
• If exposure can’t be prevented, what PPE is required?

In many situations, more than one control measure will be needed. For example, a construction jobsite might have barricades to separate vehicle traffic from workers (engineering control), supported by a traffic management program (administrative control) and workers wearing high-visibility clothing (PPE). Using multiple controls together provides multiple layers of protection.

Identifying hazards and applying the most appropriate controls are key to preventing incidents on any jobsite. Using the hierarchy of controls ensures the most effective measures are considered first, to minimize risk and keep workers safe.

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