What does “reasonably practicable” mean?


What does “Reasonably practicable” mean? (WHS Act section 18)

“Reasonably practicable” is used in the WHS Act to qualify the duties owed by persons in control of the business or undertaking – s 19 to  s 26

This qualification is a change for NSW employers  who previously had to deal with the OHS Act 2000 which required the employer to ensure the health, safety and welfare at work of employees. “Ensure” was interpreted by the courts as meaning to "guarantee, secure, make certain". 

Similarly other groups had a duty “to ensure”, self-employed persons, controllers of work premises, plant or substances; and designers, manufacturers and suppliers of plant and substances for use at work.

The prosecution is now required to prove what “reasonably practical” steps a defendant could have taken to avoid breaching their duty to ensure safety.

The WHS Act sets out what is required to establish what is “reasonably practical” for persons in control of a business or undertaking. It sets the following standard:



S18 What is “reasonably practicable” in ensuring health and safety

In this Act, reasonably practicable, in relation to a duty to ensure health and safety, means that which is, or was at a particular time, reasonably able to be done in relation to ensuring health and safety, taking into account and weighing up all relevant matters including:

(a) the likelihood of the hazard or the risk concerned occurring, and

(b) the degree of harm that might result from the hazard or the risk, and

(c) what the person concerned knows, or ought reasonably to know, about:
 (i) the hazard or the risk, and
 (ii) ways of eliminating or minimising the risk, and

(d) the availability and suitability of ways to eliminate or minimise the risk, and

(e) after assessing the extent of the risk and the available ways of eliminating or minimising the risk, the cost associated with available ways of eliminating or minimising the risk, including whether the cost is grossly disproportionate to the risk.

Notable in this definition is that the cost of measures is only to be taken into account once the likelihood and gravity of the foreseeable risk are weighed up against the feasibility of measures to eliminate or minimise the risk. In the regulators' view measures are only not reasonably practicable if the cost is grossly disproportionate to the risk.

NOTE:  The s18 definition  of “reasonably practicable” only applies to the health and safety duties in sections 19-26; ie the duties of the PCBUs.

However it can be used as reference point for other requirements which are qualified by “so far as reasonably practicable” For example, the requirement to consult with workers.

Determining what is reasonably practicable

The guiding principle of the WHS Act is that all people are given the highest level of health and safety protection from hazards arising from work, so far as is reasonably practicable.

This will depend on the circumstances but will require an assessment of the level of risk, what can be done and what is reasonable to do. In all cases, regulators will expect the highest level of protection in the circumstances.

In determining what is reasonably practicable, there is a requirement to weigh up all relevant matters including:

· the likelihood of a hazard or risk occurring (ie the probability of a person being exposed to harm)
· the degree of harm that would result if the hazard or risk occurred (ie the potential seriousness of injury or harm)
· what the person concerned knows, or ought to reasonably know, about the hazard or risk and ways of eliminating or minimising it
· the availability of suitable ways to eliminate or minimise the hazard or risk
· the cost of eliminating or minimising the hazard or risk.

From the regulator’s perspective, cost will not be the key factor in determining what it is reasonable for a duty holder to do unless it can be shown to be ‘grossly disproportionate’ to the risk. There is a clear presumption in favour of safety over cost.

If the risk is particularly severe, a PCBU will need to demonstrate that costly safety measures are not reasonably practicable due to their expense and that other less costly measures could also effectively minimise the risk.

From the duty holder’s perspective there are two elements that they must consider:

· What is possible to be done
· What is reasonable to be done

In weighing up these considerations, duty holders are expected to consider all the facts and everything relevant to the hazards, risks and their elimination/ minimisation.

Must have knowledge to decide what is reasonably practicable

To do this, duty holders (and in particular officers) will be expected to have knowledge about the hazard or risk and what can be done about it.

WHS Act requires duty holders to utilise the information and current knowledge that exists about a particular hazard and on the controls currently and reasonably available. This requires the person with the primary duty of care to be familiar with the hazards and risks in the workplace and source current information on potential ways to eliminate (e.g. use of micro fibre cloths instead of chemicals for cleaning) or minimise those risks (e.g. more efficient manual handling aids for lifting). 

Duty holders are expected to be aware of the available state of knowledge about how harm could occur, how likely this is, and what can be done to prevent its occurrence.

This means

· Undertaking risk assessments
· Learning from previous incidents
· Checking what regulators and inspectors have said
· Knowing what the regulations and codes require
· Consulting with workers and others in the industry
· Checking OHS publications and websites

Duty holders are expected to be proactive - particularly in assessing hazards and risks from

· Human error and misuse of plant and equipment
· Plant or equipment failure or malfunction
· Multiple hazards interacting

The cost of eliminating risk

The Safe Work Australia Interpretative Guideline states:

Cheaper, available and suitable options may be used instead of a costlier option that may further minimise the risk or severity of harm, where the cost of the costlier option is grossly disproportionate to the risk. This will only apply where the cost is high and the likelihood or degree of harm is low (e.g. a slight chance of minor cuts or strains and the cost of replacing plant would be very high).

Choosing a low-cost option that provides less protection simply because it is cheaper is unlikely to be considered a reasonably practicable means of eliminating or minimising risk.

If the degree of harm is significant (e.g. death or serious injury is at least moderately likely) then it is unlikely that the cost of implementing available and suitable safety measures to eliminate or minimise the risk would ever be so disproportionate to the risk to justify a decision not to do so.

It may be reasonable to expect (and require) a duty-holder to eliminate the risk by ceasing the relevant activity if, after all ‘affordable’ control measures have been considered, there remains a significant risk of serious injury or illness.

Where the cost of implementing risk controls is grossly disproportionate to the risk – e.g. the cost of engineering changes to plant will be high and there is only a slight risk of minor sprains - then this may mean the use of those controls is not reasonable and not required. This does not, however, mean that the duty-holder is excused from doing anything to minimise the risk so far as is reasonably practicable. It may simply mean that a less expensive way of minimising the likelihood or degree of harm may instead be used.

So cost may only be looked at as a last option (after assessing the extent of the risk and what’s available to eliminate or minimise the risk) but this provision does provide for some practicality in instances where the cost of minimising a risk marginally, far outweighs/exceeds the benefits.

What the courts have said about “reasonably practicable”

In almost all prosecutions, the NSW IRC  found it was reasonably practicable for the defendant to eliminate or minimise the risk. This continued until 2010 when a brave and determined employer challenged WorkCover NSW ( as it then was) in the High Court. The High Court's decision led to the eventual dismantling of prosecutions in the NSW IRC with proceedings now held in the ordinary court system.

Since then, decisions make it clear that employers need to have a comprehensive understanding of significant safety risks in their operations and must eliminate or reduce the risk. Key factors are the level of awareness of risk and the likelihood of serious injury.