In brief
The hierarchy of controls shows the order to follow when choosing measures against a risk: elimination, substitution, engineering controls, administrative controls and, last of all, PPE. Art. 5 of Law No. 6331 and Art. 10 of the Risk Assessment Regulation explicitly require this order; collective protection comes before personal protection. After the measure, the risk is scored again, and if it has not fallen to an acceptable level, the steps are repeated.
What is the hierarchy of controls?
In risk assessment, finding the hazard is half the job; the real decision is which measure to take. The hierarchy of controls (also called the risk control hierarchy) is a five-step decision tool that ranks measures by effectiveness: it first tries to eliminate the hazard, then to replace it with something less hazardous, then to limit the hazard at source through engineering, and then to organise the working method. Personal protective equipment (PPE) is at the bottom.
The logic of the order is simple: the upper steps depend less on human behaviour. When you remove the hazard, there is no room for anyone to make a mistake; with PPE, protection depends on the employee putting the equipment on correctly every time, and on the equipment being suitably selected and maintained.
How do the principles in Art. 5 of Law No. 6331 link to the hierarchy?
Art. 5 of Law No. 6331 lists the principles of protection from risks that the employer must observe when fulfilling its obligations. The expression "hierarchy of controls" does not appear in the Law; however, the principles describe the same order:
| Step | What does it do? | Equivalent in Art. 5 of Law No. 6331 |
|---|---|---|
| 1. Elimination | Removes the hazard from the work entirely | (a) Avoiding risks; (ç) care in workplace design and choice of production methods |
| 2. Substitution | Replaces the hazardous with the less hazardous | (e) Replacing the dangerous with the non-dangerous or less dangerous; (d) adapting to technical progress |
| 3. Engineering controls | Isolates or limits the hazard at source | (c) Combating risks at source |
| 4. Administrative controls | Organises working method, time, permits and instructions | (f) A coherent prevention policy; (ğ) appropriate instructions to employees |
| 5. PPE | Protects the employee against the remaining risk | (g) Giving collective protective measures priority over individual protective measures |
Reading the five steps through examples
1. Elimination: remove the hazard from the work
This is the strongest measure and is often possible at the design stage. Examples:
- If work at height is needed every month to maintain a fan on the roof, moving the fan to ground level eliminates work at height.
- Placing a conveyor between two stations where parts are carried by hand eliminates the manual handling hazard.
- Removing an intermediate stock area and reorganising the production flow eliminates forklift-pedestrian encounters in that area.
2. Substitution: choose the less hazardous option
The work continues, but the size of the hazard is reduced. This is exactly the answer to the question what is substitution in workplace safety:
- Using an aqueous washing system instead of a volatile solvent for degreasing parts.
- Buying a powdered additive in granule or paste form.
- Switching from an open disc to a machine with an enclosed body for cutting.
The point to watch in substitution is that the new substance or equipment does not introduce another hazard. Review the safety data sheet of the new chemical; do not replace an old risk with a new one.
3. Engineering controls: isolate the hazard at source
The hazard remains in place, but a physical barrier is placed between it and the employee. Engineering controls do not rely on the employee behaving correctly every time:
- Fixed or interlocked guards on the moving parts of machinery; details in our machine guards guide.
- Local exhaust close to the weld for welding fumes.
- Moving a noisy compressor into a separate room or placing it in a sound-insulated enclosure.
- Separating forklift and pedestrian routes with physical barriers.
4. Administrative controls: organise the working method
In OHS practice, administrative controls are procedures, permits to work, rotation, warning signs, instructions and training. They are necessary but weak on their own, because their application depends on supervision and human behaviour. Examples: a hot work permit, a lockout-tagout procedure, rotation that shortens exposure time in a noisy section, and organising pedestrian crossing times.
5. PPE: the last layer for the remaining risk
Hearing protectors, gloves, glasses, respiratory protection and safety harnesses are used only against the risk remaining after the steps above. Art. 5 of the Regulation on the Use of PPE also states that PPE is to be used where risks cannot be prevented or adequately limited by technical measures providing collective protection or by work organisation.
Why is PPE the last resort?
We are not saying PPE is worthless; in most jobs it is indispensable. But when it is written as the only measure in a risk assessment, these weaknesses appear:
- It only protects the wearer. If you enclose the noise source, the whole section is protected; earmuffs protect only the person wearing them correctly.
- Its effectiveness is invisible. A wrong-size mask or a dirty filter cannot be noticed from outside.
- It depends on behaviour. PPE comes off in the heat, in rushed work or for short "one-minute" jobs.
- It can itself create risk. A glove caught in a rotating machine is an example; Art. 6 of the Regulation on the Use of PPE requires equipment to protect without itself creating an additional risk.
- It requires ongoing cost and follow-up. Selection, training, issue, replacement and maintenance never end.
To choose a suitable product, see our PPE selection guide.
Sample decisions: same risk, different steps
Let us think through the steps together for three situations we frequently encounter in metal and plastics businesses in Bursa and neighbouring provinces:
| Risk | PPE-only approach | Decision using the hierarchy |
|---|---|---|
| Noise at a workbench next to the compressor room | Handing out earplugs | Moving the compressor into an insulated room (engineering), hearing protectors for the remaining exposure (PPE) |
| Solvent vapour in paint preparation | Issuing a half-face mask | Switching to a lower-volatility product (substitution), local exhaust at the mixing point (engineering), using the mask only during filling (PPE) |
| Manual handling of 25 kg parts during die changes | Back support and training | Die trolley or lifting equipment (engineering), two-person lifting instruction (administrative) |
No decision ends at a single step. A good action plan usually combines a higher-step measure with supporting administrative and personal measures.
The effect of a measure on the score: an example
Suppose there is an exposed belt and pulley assembly on a workbench. A sample scoring with the Fine-Kinney method shows how the choice of step changes the result:
| Scenario | Probability | Frequency | Severity | Risk score |
|---|---|---|---|---|
| Current situation: no guard | 3 (possible) | 6 (several times a day) | 15 (permanent harm) | 270 |
| Gloves and instruction only | 3 | 6 | 15 | 270 |
| Fixed guard fitted | 0.5 (unexpected but possible) | 6 | 15 | 45 |
Gloves and an instruction do not actually change the probability; they may even increase the risk of a glove being caught on a rotating part. A fixed guard, on the other hand, physically keeps the hand away from the danger zone and lowers the score significantly. The scores are examples given to explain the method; the values for your workplace are set by the team together.
Five questions to ask when choosing measures
In the risk assessment meeting, ask these questions in order as a team for each high-scoring row. Every question answered "no" is the justification for moving down a step, and this justification must be written into the document:
- Can we eliminate this work or this hazard entirely? Has a process change, design change or outsourcing the work been considered?
- Is there a less hazardous substance, equipment or method? Has the supplier been asked for an alternative product?
- Can we physically isolate the hazard at source? Is a guard, enclosure, extraction, barrier or interlock possible?
- What method, permit, time limit or instruction is needed for the remaining risk? Who will supervise them?
- What PPE is needed for the remaining risk and how will it be tracked? Are selection, training, issue and replacement periods defined?
Having the employee representative and the employee who actually does the job present at this meeting ensures that unworkable measures are ruled out from the start.
Common mistakes in risk assessment
- Writing PPE as the only measure. If the measure column says only "gloves will be used", why the upper steps cannot be applied must also be written down.
- Scoring training like an engineering control. Training is an administrative measure; do not assume it reduces risk as much as an engineering control.
- Not rescoring after the measure. Art. 10 of the regulation requires the remaining risk to be determined again and the steps to be repeated if it is at an unacceptable level.
- Overlooking the new hazard of substitution. Carry out hazard identification for the new substance or equipment too.
- Not assigning a deadline and owner to the measure. The implementation plan contains the work steps, the person responsible, and start and end dates.
For scoring methods, see our Fine-Kinney guide; for basic concepts, our article on the difference between hazard and risk; and for the whole process, our guide on how to carry out a risk assessment. In our risk assessment service, we justify every measure according to this order and rescore the remaining risk.
Frequently Asked Questions
Is the hierarchy of controls mandatory under the legislation?
Its name does not appear in the legislation, but its content is mandatory. Art. 5 of Law No. 6331 and Art. 10 of the Risk Assessment Regulation explicitly require the order of eliminating the hazard, replacing it with something less hazardous, combating it at source and giving priority to collective protection.
What is substitution? Can you give an example?
Substitution means replacing a hazardous substance, piece of equipment or method with a less hazardous one while continuing to do the work. An aqueous cleaner instead of solvent, granular instead of powdered raw material and an enclosed cutting machine instead of an open disc are typical examples.
What is the difference between engineering and administrative controls?
An engineering control places a physical barrier between the hazard and the employee and does not depend on the employee's behaviour. An administrative control organises the way work is done through procedures, permits, rotation or instructions, and its application depends on supervision.
Is the risk considered acceptable once we issue PPE?
Not on its own. First, why the upper steps cannot be applied must be assessed, and the risk remaining after PPE must be rescored. If it has not fallen to an acceptable level, new measures are planned.
A risk assessment that identifies and scores hazards on site, links each measure to an owner and a date, and has a clear renewal schedule.
Bursa SİSTEMER OSGB Technical Team — written from the field experience of our OHS specialists and workplace physicians. Legal information is valid as of the publication/update date; contact us for an assessment specific to your business.