The Work Health and Safety Act 2011 qualifies the requirement of safety duty-holders to manage risk by taking 'reasonably practicable' steps to eliminate or minimise risks.
The Act goes on to outline the meaning of 'reasonably practicable':
Resonably practicable, in relation to a duty to ensure health and safety, means that which is, or was at a particular time, resonably 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 occuring;
(b) the degree of harm that might result from the hazzard or the risk;
(c) what the person cencerned knows, or ought resonably to know, about-
(i) the hazard or the risk;
(ii) ways of eliminating or minimising the risk;
(d) the availability and suitability of ways to eliminate or minimise the risk;
(e) after assessing the extent of the risk and the available ways of eliminatin 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.
Also, a regulation may prescribe what are, or are not, reasonably practicable steps to eliminate or minimise a risk.
‘Reasonably practicable’ is enshrined in the ILO’s Occupational Safety and Health Convention No.155. Article 4. Clause 2 of this convention provides that the aim of national policy on occupational safety, occupational health and the working environment "shall be to prevent accidents and injury to health arising out of, linked with or occurring in the course of work, by minimising, so far as is reasonably practicable, the causes of hazards inherent in the working environment.”
OHS legislation in Australian and in the UK, Singapore and other common law countries, provide for duties of care to be subject to, or subject to a defence relating to, the duty holder meeting the duty so far as is ‘reasonably practicable’. The inclusion of the test of reasonably practicable is often expressed as the standard of conduct or a limitation on the otherwise unlimited nature of the duty to ensure health and safety.
Reasonably practicable will often involve having regard to:
All these factors should be taken into account in determining whether a safety duty has been met.
The following opinion given by Lord Asquith in 1949 is often offered as the cleanest and simplest definition of a duty to do things in so far as is reasonably practicable. If we base our decisions on the following definition then we will have a strong argument to suggest we have discharged our duty.
'Reasonably practicable' is a narrower term than 'physically possible' and it seems to me to imply that a computation must be made by the owner, in which the quantum of risk is placed on one scale and the sacrifice involved in the measures necessary for averting the risk (whether in money, time or trouble) is placed in the other; and that if it be shown that there is a gross disproportion between them - the risk being insignificant in relation to the sacrifice - the defendants discharge the onus on them. Moreover, this computation falls to be made by the owner at a point of time anterior to the accident.
Source: Edwards v National Coal Board (1949) 1 KB 704 at 712, CA, per Asquith LJ
For more information on what is Reasonably Practicable click here