Hierarchy of Controls: A Guide to Managing Workplace Hazards
The hierarchy of controls is a widely accepted system used to manage workplace hazards and reduce the risk of injury or ill health.
Rather than relying on a single safety measure, the hierarchy provides a step-by-step approach for selecting the most effective control measures. It ranks different control methods according to how effectively they protect workers from exposure to a hazard.
The five levels of the hierarchy of controls are:
- Elimination
- Substitution
- Engineering controls
- Administrative controls
- Personal protective equipment (PPE)
Elimination sits at the top because removing a hazard completely is generally the most effective form of hazard control. Personal protective equipment sits at the bottom because the hazard remains present and protection depends more heavily on correct equipment selection and human behaviour.
Understanding this hierarchy can help organisations make better decisions during the risk assessment process and determine whether existing control measures adequately reduce risk.
What is the hierarchy of controls?
The hierarchy of controls is a framework used in occupational health and safety to determine how workplace hazards should be controlled.
It encourages organisations to consider controls in order of effectiveness rather than immediately relying on PPE, warning signs or employee training.
The hierarchy is most commonly represented as a triangle or inverted pyramid containing five levels. The most effective hazard control measures appear at the top, while measures that generally provide less reliable protection appear towards the bottom.
The principle is straightforward:
Control the hazard as close to its source as reasonably possible before relying on workers to avoid exposure.
For example, removing a hazardous chemical from a work process is generally preferable to requiring employees to wear protective equipment whenever they handle i
The hierarchy does not mean that only one control can be used. In many workplaces, the preferred solution will involve a combination of different controls.
Organisations can use risk assessment software to document hazards, associated risks, existing controls and further actions required as part of a structured risk management process.
What are the five levels of the hierarchy of controls?
The five levels move from eliminating the hazard entirely to protecting individual workers when exposure cannot otherwise be sufficiently controlled.
1. Elimination
Elimination means completely removing the hazard from the workplace or hazardous task.
Because the hazard no longer exists, elimination prevents exposure rather than attempting to minimise exposure after the hazard has been introduced.
This makes elimination the most effective hazard control in the hierarchy.
Examples include:
- Removing an unnecessary toxic chemical from a process
- Designing a task so heavy objects no longer need to be manually lifted
- Completing work at ground level rather than working at height
- Removing a sharp tool that is no longer required
- Redesigning a process to eliminate exposure to airborne dust
Elimination is often easiest to implement when a workplace, process or piece of new equipment is still being designed.
Once equipment and working practices have become established, completely removing hazards can become more difficult or expensive.
This is why health and safety considerations should ideally form part of planning and procurement rather than only being considered after an incident has occured.
2. Substitution
Where elimination is not reasonably achievable, the next level is substitution.
Substitution involves replacing something hazardous with a safer alternative.
For example, an organisation could replace a toxic chemical with a substance that creates fewer harmful effects. Plant-based printing inks may sometimes be used instead of solvent-based alternatives, while safer materials may replace substances that present more serious occupational health risks.
However, substitution should not simply replace one hazard with another.
Before introducing a substitute material, process or piece of equipment, organisations should assess the new risks it could create.
Factors might include:
- Toxicity
- Flammability
- Worker exposure
- Manual handling requirements
- Environmental effects
- Compatibility with other materials
- New equipment requirements
The objective is to reduce the overall associated risks rather than moving the problem elsewhere.
3. Engineering controls
Engineering controls reduce exposure by physically separating workers from a hazard or controlling hazards at their source.
Unlike administrative controls, engineering controls do not primarily depend on employees remembering to follow a particular procedure.
Examples include:
- Local exhaust ventilation
- Machine guards
- Protective barriers
- Enclosures
- Fume extraction systems
- Mechanical lifting devices
- Remotely controlled equipment
- Noise isolation
- Physical separation from hazardous processes
A fume hood, for example, can capture airborne contaminants before they enter the wider working environment.
Similarly, local exhaust ventilation can help control airborne dust, fumes, vapours and other contaminants close to the point at which they are generated.
Engineering controls tend to involve greater capital costs initially because they may require modifying equipment, installing mechanical devices or redesigning a workplace.
However, effective engineering controls can provide consistent protection and may reduce future costs associated with incidents, exposure and repeated administrative intervention.
They also require inspection and maintenance. A ventilation system provides little protection if it is damaged, poorly maintained or no longer performing as intended.
Routine workplace inspections can help organisations identify deteriorating or ineffective controls before they contribute to an incident.
4. Administrative controls
Administrative controls change the way people work to reduce their exposure to hazards.
Rather than removing the hazard, these measures attempt to control exposure through procedures, organisation, information and training.
Common examples include:
- Safe systems of work
- Employee training
- Warning labels
- Safety signs
- Job rotation
- Permit-to-work systems
- Limiting exposure time
- Adequate rest breaks
- Restricting access to hazardous areas
- Changing work procedures
- Scheduling hazardous tasks when fewer people are present
Administrative controls can be an important part of workplace safety, but they depend heavily on people following the required process.
Training, for example, can ensure workers understand a hazardous task and the protective measures they are expected to follow. It does not remove the underlying hazard.
The effectiveness of administrative controls should therefore be evaluated regularly.
Workplaces change. Equipment changes, employees join or leave and work practices evolve. A control that was effective when a risk assessment was originally completed may no longer provide adequate protection.
This is one reason risk assessments should be reviewed when there are significant changes or evidence that existing controls are no longer effective.
5. Personal protective equipment
Personal protective equipment (PPE) is the final level in the hierarchy.
PPE is the equipment worn by an individual to reduce their exposure to workplace hazards.
Examples include:
- Safety glasses
- Gloves
- Safety footwear
- Hearing protection
- Hard hats
- Respiratory protective equipment
- Protective clothing
PPE can be essential, particularly where hazards cannot be completely eliminated or adequately controlled using other methods.
However, PPE is generally considered the least effective control method within the hierarchy because it does not remove or isolate the hazard itself.
Its effectiveness can depend on several factors.
The correct equipment must be selected for the hazard. It must fit the individual worker, remain in good condition and be worn correctly.
Where multiple items are required, PPE should also be compatible. Eye protection, hearing protection and respiratory equipment, for example, should not interfere with one another in a way that reduces protection.
Employee training is also important so workers understand when PPE is required, how to use it and any limitations it has.
PPE should therefore form part of a wider system of controls rather than automatically becoming the first response to every workplace hazard.
Why is PPE at the bottom of the hierarchy of controls?
PPE is placed at the bottom because the hazard remains present.
Consider a worker exposed to hazardous airborne contaminants.
Providing respiratory protection may reduce the worker’s exposure, but the contaminant is still being released into the workplace.
An engineering control that captures the contaminant at source reduces the opportunity for exposure in the first place.
Eliminating the hazardous substance entirely would provide stronger protection again.
This demonstrates why the hierarchy encourages organisations to work from the top down.
PPE remains an important protective measure, but higher-level controls should be considered before relying solely on equipment worn by individual workers.
How does the hierarchy of controls fit into a risk assessment?
The hierarchy of controls and risk assessments are closely connected.
A risk assessment identifies hazards, considers who could be harmed and evaluates whether existing control measures adequately manage the risk.
Once a hazard has been identified, the hierarchy can help determine what additional controls should be considered.
A typical process might be:
- Identify the hazard
- Assess who could be harmed and how
- Review existing control measures
- Consider whether the hazard can be eliminated
- Consider substitution where elimination is not possible
- Evaluate suitable engineering controls
- Introduce administrative controls where necessary
- Provide appropriate PPE for remaining risks
- Record and review the controls
This does not mean employers must introduce every possible control.
The appropriate measures will depend on the hazard, level of risk, working environment and relevant safety legislation and guidance.
The UK Health and Safety Executive provides further guidance on managing risks and risk assessment at work.
The hierarchy of controls is also promoted internationally by organisations, including the National Institute for Occupational Safety and Health (NIOSH) in the USA.
Using multiple control measures
Real workplace risks are rarely controlled by a single measure.
A combination of elimination, engineering controls, administrative controls and PPE may provide more effective control than relying on one measure alone.
Consider airborne dust generated by a manufacturing process.
The organisation might first investigate whether the dusty process can be eliminated or replaced.
Where that is not practical, an engineering control such as extraction could remove airborne contaminants at source.
Administrative controls could restrict access and establish cleaning procedures.
Suitable respiratory protective equipment might then provide additional protection where residual exposure remains.
This layered approach can reduce the chance that failure of one control immediately exposes workers to unacceptable risk.
Reviewing whether controls are effective
Introducing control measures is not the end of the risk assessment process.
Controls should be monitored and reviewed to ensure they continue to work as intended.
Review may be necessary following:
- An accident or near miss
- Changes to equipment
- New substances or materials
- Changes in working practices
- New safety information
- Employee concerns
- Inspection findings
- Changes to relevant legislation
- Evidence that a control is ineffective
An incident investigation can reveal that an existing control failed, was missing or was not appropriate for the hazard.
The findings can then lead to corrective actions designed to address the underlying issue and prevent recurrence.
Where possible, organisations should again consider the hierarchy rather than simply adding another administrative rule or item of PPE.
Applying the hierarchy of controls in practice
Imagine employees regularly moving heavy materials between different areas of a workplace.
An organisation could approach the risk in several ways.
At the elimination level, the process could be redesigned so the materials no longer need to be moved manually.
If that is not possible, lighter materials could potentially be substituted.
Engineering controls might include mechanical lifting or handling equipment.
Administrative controls could include training, revised work procedures, limits on loads or job rotation.
PPE such as safety footwear could provide additional protection against specific remaining hazards.
The important point is that the organisation has considered the most effective control measures first rather than immediately relying on training and PPE.
Managing risk with Velappity
Applying the hierarchy of controls effectively requires organisations to understand their hazards, document existing controls and keep risk information up to date.
Velappity helps organisations manage risk assessments digitally, providing a structured way to record hazards, evaluate risk and maintain information relating to workplace controls.
Teams can use Velappity to create and manage assessments, record findings and maintain a clearer digital record of risk information across their organisation.
When inspections or incidents identify weaknesses in existing controls, actions can also be recorded and followed through rather than becoming disconnected from the wider health and safety process.
This helps connect hazard identification, risk assessment, inspections, incidents and corrective actions within a more consistent approach to health and safety management.
Learn more about Velappity’s risk assessment software.
Hierarchy of controls FAQs
What are the five levels of the hierarchy of controls?
The five levels are elimination, substitution, engineering controls, administrative controls and personal protective equipment. They are ranked from the most effective approach to the least effective.
What is the most effective control in the hierarchy?
Elimination is generally the most effective because it removes the hazard and therefore prevents exposure to it.
What is the least effective hazard control?
PPE is generally considered the least effective level because the original hazard remains present and protection depends on the correct selection, use and maintenance of the equipment.
What are examples of engineering controls?
Engineering controls include local exhaust ventilation, machine guarding, protective barriers, enclosures, mechanical lifting equipment and systems that isolate workers from hazards.
How is the hierarchy of controls used in risk assessment?
After hazards have been identified and risks assessed, the hierarchy helps determine which control measures should be considered. Higher-level controls such as elimination and substitution should generally be considered before relying on administrative controls or PPE.
