Hierarchy of Control

The definition of hazard and risk: 

  • A hazard is a situation or thing that has the potential to harm a person. 
  • A risk is the possibility that harm (death, injury or illness) might occur when exposed to a hazard. 

 

What is the Hierarchy of Control 

The Hierarchy of Control is a step-by-step system for controlling and managing risk in the workplace. When it is not possible to eliminate the hazard, it helps to consider different control measures and choose the most effective and practicable ones to reduce the risks. 

Note that under s.35 of the OHS Act Employers have a duty to consult with HSRs and employees in identifying hazards, assessing risks, deciding on controls and monitoring their effectiveness. More about consultation obligations can be found here.

  • Elimination 

Physically remove the hazard and eliminate the risks that come with it

E.g. Eliminate the risk of falling from a height by doing the work at ground level

  • Substitution

Substitute the hazard with a safer alternative 

E.g. using plant-based printing inks as a substitute for solvent-based inks

  • Isolation

Physically isolate the hazard from people 

E.g.  use remote controls for machines 

  • Engineering 

An engineering control is a control measure that is physical in nature 

E.g. installing guards or devices that prevent physical access to the hazard 

  • Administrative

Administrative controls are work methods or procedures designed to minimise exposure to a hazard

E.g. designing policies and safety procedures, signs, time-limiting exposure to the hazard

  • Personal Prtective Equipment (PPE)

PPE is anything employees use or wear to minimise risks to their health and safety 

E.g. safety boots, glasses, harnesses, high visibility clothing 

 

We can divide these controls into two broad groups: 

Higher Order Controls are implemented at a systems level to change the work environment and integrated into the work in a way that does not rely upon employees to change their behavior or follow extra steps. E.g. Substitution, Isolation, Engineering 

Lower Order Controls are less effective control measures. They do not eliminate the source of the risk and rely more on worker behaviour, maintenance programs and supervision. They can be compromised by workplace pressures such as striving for greater productivity or an attitude of just getting the work done. E.g. Administrative, PPE 

 

Employer Duties 

Under s.20(a) and (b) of the Occupational Health and Safety Act 2004 (the OHS Act) employer has a duty to eliminate risks to health and safety so far as is reasonably practicable; and to reduce those risks so far as is reasonably practicable if it is not possible to eliminate them.  

The OHS Act does not impose a duty to rigidly apply the hierarchy to every hazard, even if this is an effective practice and good way to ensure s.21 duties are properly met. In situations where lower order controls are being imposed, as part of the consultation employers should be able to explain why higher order controls are not reasonably practicable giving consideration to the likelihood of harm, degree of harm, what is known about the risk, the availability of controls and the cost. 

However, the Occupational Health and Safety Regulations 2017 do require the application of a hierarchy process when managing certain high-risk work, including: 

  • plant, electrical or construction work; 
  • hazardous atmospheres or chemicals; 
  • Remote or isolated work; 
  • Noise; 
  • Asbestos; 
  • confined spaces; 
  • falls or falling objects; 
  • hazardous manual tasks; 
  • diving work.

As a rule, if elimination is not possible employers must first try to implement higher order controls and only if these are not reasonably practicable should administrative controls and PPE be considered. The precise duty changes for each type of hazard and so the Regulations need to be consulted if you face risks associated with these hazards in the workplace. 

Resources 

WorkSafe Victoria web page about Hierarchy of Control 

Safe Work Australia Code of Practice –How to manage work health and safety risks 

Updated May 2024