Hierarchy of control

Control Measure Knowledge

This control measure is based on information provided by the Health and Safety Executive about the hierarchy of control.

Risks should be reduced to the lowest reasonably practicable level by taking preventative measures, in order of priority – the hierarchy of control. These measures are in the order that should be followed when planning to reduce the risks that have been identified at the incident. They should be considered in this order, rather than implementing the easiest measure.

  1. Elimination
  2. Substitution
  3. Engineering controls
  4. Administrative controls
  5. Personal protective clothes and equipment


The task or activity should be redesigned so that the hazard is removed or eliminated. This is the most effective measure that can be implemented to control risk, and should always be considered once a hazard has been identified. In an operational environment it may not be possible to completely remove or eliminate a hazard, perhaps due to the environment or the need to take immediate life-saving actions.


Replace the procedure with a less hazardous one.

Engineering controls

Use equipment or other measures to provide protection, for example physical barriers or machine guards.

Administrative controls

Identify and implement the procedures that will provide a safe working environment. This could include reducing the time or frequency that personnel are exposed to hazards, putting appropriate cordon controls in place or implementing hygiene arrangements.

Personal protective clothes and equipment

Only after all the previous measures have been tried and found ineffective in controlling risks to a reasonably practicable level, should personal protective equipment (PPE) be used. Personnel should be trained in the function and limitation of each item of PPE. PPE may also include using items such as fall arrest equipment.

Refer to Personal protective equipment for more information.

Strategic Actions

Tactical Actions