The hierarchy of control is a ranked list of ways to control a risk, from the most effective to the least effective. The order is: eliminate the hazard, substitute it with something safer, use engineering controls, use administrative controls, and use personal protective equipment (PPE) last. You always start at the top and work down, and you only rely on the lower levels when the higher ones are not enough.
Key takeaways
- The hierarchy of control puts the most effective measures first: eliminate, substitute, engineering controls, administrative controls, then PPE.
- Removing the hazard completely is always better than managing it.
- PPE comes last because it protects only the person wearing it and relies on that person using it correctly.
- Controls that protect everyone at once, such as guardrails, are better than controls that rely on individuals.
- Most real jobs use more than one level together, but the stronger controls should come first.
- Removing the hazard is the strongest control.
What the hierarchy of control means
A hazard is something with the potential to cause harm. A control measure is anything done to remove the hazard or reduce the chance or severity of harm. The hierarchy simply ranks those measures by how reliable they are.
The idea is that the best controls do not depend on people remembering, being careful or wearing something all day. A hazard that has been removed cannot hurt anybody. A hazard that is controlled only by a warning sign can hurt someone who does not read it.
You may see different versions of the hierarchy with slightly different wording, for example with an extra step such as "isolate" or with "reduce" in place of "substitute". The principle is the same in all of them, and this article uses the common five-level version. This five-level order is general practice, not wording taken from the HSE risk page.
The five levels
| Level | Meaning | Construction example |
|---|---|---|
| 1. Eliminate | Remove the hazard completely | Assemble components on the ground so no one has to work at height to fit them |
| 2. Substitute | Replace the hazard with something less hazardous | Use a less harmful product in place of a more harmful one for the same job |
| 3. Engineering controls | Use physical measures to separate people from the hazard or contain it | Guardrails, machine guards, barriers between walkways and moving plant, dust extraction |
| 4. Administrative controls | Change how people work, using procedures and instructions | Safe systems of work, signs, training, exclusion zones, job rotation |
| 5. PPE | Protect the individual with equipment as a last line of defence | Hard hat, safety boots, gloves, eye protection, hearing protection |
Level 1: Eliminate
Eliminating means the hazard no longer exists in the task. If you can design or plan the work so that the dangerous step is not needed, nothing is left to control. Prefabricating off site, or doing a job from the ground instead of from height, are typical ways of thinking about it. It is often the cheapest level to use when it is considered early, at the planning stage, and hardest to use once work has started.
Level 2: Substitute
Substitution replaces something hazardous with something less hazardous. The hazard is reduced rather than removed. A common example is choosing a different material or method that gives off less dust or fume. Always check that the replacement does not create a new problem.
Level 3: Engineering controls
Engineering controls are physical measures that work whether or not people are paying attention. They either keep people away from the hazard or contain it at source. Edge protection, guards on equipment, ventilation and physical barriers all fit here. These are collective measures: they protect everyone in the area at once.
Level 4: Administrative controls
Administrative controls change how work is organised. They depend on people following rules, which makes them less reliable than the levels above. Method statements, permits to work, signage, supervision and training belong here. They are important, but they need checking, because they fail when people are tired, rushed or unaware.
Level 5: PPE
PPE is the last level. Good practice treats PPE as the last line of control, after the hazard has been removed or controlled by other means (general practice). It protects only the wearer, it can fail if it is the wrong type, damaged or badly fitted, and it does nothing to the hazard itself. It is still essential on construction sites, and for many tasks it is needed in addition to other controls. Read PPE explained for what the different types are for.
How the hierarchy fits into risk assessment
HSE's risk page sets out three steps: identify hazards, decide how likely harm is and how serious, and take action to eliminate or control the risk. Regulation 3 of the 1999 Regulations requires a suitable and sufficient assessment, and regulation 3(6) requires the significant findings to be recorded where an employer has five or more employees. The hierarchy is the tool you use at the step where you decide on precautions. You ask: can we remove it? If not, can we replace it? If not, can we guard or separate it? If not, can we organise the work differently? And only then: what PPE is needed for the risk that remains?
Our article on risk assessment on site shows where this step sits in the wider process.
Why PPE is not the first answer
It is tempting to hand out PPE because it is quick, visible and easy to buy. The weakness is that it depends on every wearer, every time. If the equipment is left off, worn wrongly or not suitable, the person has no other protection. Higher levels protect people even when they make a mistake.
Checklist: choosing controls
Work through this list for any task with a significant risk.
- [ ] Can the hazard be removed by changing the design or the method?
- [ ] If not, can a safer material, tool or process replace it?
- [ ] Can a physical measure, such as a guard, barrier or edge protection, protect everyone?
- [ ] Are procedures, signs, training and supervision in place for the risk that remains?
- [ ] Is the right PPE specified for what is left, and do people know how to use it?
- [ ] Is each control checked to make sure it is still working?
- [ ] Has the combination of controls been reviewed if the work or conditions changed?
Worked example: cutting paving slabs
Imagine a team has to cut a large number of paving slabs for a path. Cutting masonry throws off dust, and the dust is the hazard. Here is how the team might work down the hierarchy (a general practice illustration, not a method taken from an HSE page).
- Eliminate. Can the slabs be ordered pre-cut to size, so the cutting is done away from the site? If yes, no dust is made on site at all.
- Substitute. If cutting cannot be avoided, is there a different product or method that makes less dust?
- Engineering. If the cutting stays, use a saw that suppresses or extracts the dust at the point of cutting, and set up the cutting area away from walkways and other trades.
- Administrative. Brief the team on the method, mark an exclusion zone, limit who is in the area and make sure the supervisor checks the controls are being used.
- PPE. Provide the protective equipment that the risk assessment says is needed for the risk left over, and make sure people know how to wear and look after it.
Notice that the team does not stop at the first level that sounds practical. They ask the questions in order, and each answer shapes the next. The lower levels are added to cover what the higher levels could not remove. If the dust extraction fails, the team stops and checks, rather than relying on masks alone.
Linking the hierarchy to the other guides
The hierarchy is one step in a chain of ideas, and it makes more sense when read together with the neighbouring topics.
- The risk assessment on site guide explains how hazards are identified and how the decision about precautions is reached. The hierarchy is the order you use when you reach that decision.
- The PPE explained guide covers the last level in more detail, including why equipment has to be the right type and in good condition.
- A control at the administrative level, such as a method statement, only works if it is followed, so it is worth reading how it fits alongside the higher levels.
When you practise questions about the best way to control a risk, ask which level each option sits at. As a study habit, the option nearest the top is often the strongest, as long as it suits the task described.
Practice check
These two questions are original and written for this site. They are not official CITB questions. Practice is not an official result.
Question 1. Workers are cleaning surfaces with a product that gives off harmful fumes in a poorly ventilated room. Which action is highest in the hierarchy of control?
- A. Issue everyone with a respirator
- B. Put up a sign warning of fumes
- C. Check whether the job can be done with a safer product or without the product at all
- D. Ask workers to take turns so no one is exposed for long
Answer: C. Removing or replacing the hazardous product deals with the problem at source, which is the top of the hierarchy. A is PPE, B and D are administrative controls, and all three leave the fumes in place.
Question 2. Which of the following is an engineering control?
- A. Briefing the team on a method statement
- B. Fitting a guard to a cutting machine
- C. Wearing safety glasses
- D. Putting up a warning sign
Answer: B. A guard is a physical measure that works whether or not people are paying attention. A is an administrative control, C is PPE and D is an administrative control.
For more, try our free practice questions and the CITB HS&E test practice page. This site is independent and not affiliated with CSCS or CITB.
FAQ
What is the order of the hierarchy of control?
The order is eliminate, substitute, engineering controls, administrative controls and PPE. The first is the most effective and the last is the least effective. Some versions use different wording but keep the same principle.
Why is PPE the last control in the hierarchy?
PPE only protects the person wearing it and depends on that person using it correctly. Good practice treats PPE as the last line of control, after the hazard has been removed or controlled by other means (general practice). It does not remove or contain the hazard.
Does the hierarchy mean I should not use PPE?
No. PPE is still needed for many tasks and is often required in addition to other controls. The hierarchy simply says you should not rely on it first. Wear the PPE that your site and risk assessment require.
What is the difference between engineering and administrative controls?
Engineering controls are physical measures such as guardrails or machine guards that work without relying on people. Administrative controls are rules, procedures, signs and training, which depend on people following them. Engineering controls are higher in the hierarchy because they are more reliable.
Sources
- HSE: Risk assessment
- HSE: Personal protective equipment (PPE)
- Legislation.gov.uk: Management of Health and Safety at Work Regulations 1999
Independent guide, not affiliated with, authorised by, approved by or endorsed by CSCS or CITB. Last updated 2026-10-08.