Australia WHS Act: Duty of Care and the PCBU Explained
If you operate in Australia, the language your safety obligations are written in is different from the OSHA or HSE framework you may be used to. The WHS Act does not talk about "employers" as the primary duty holder — it talks about a PCBU, and it asks you to prove you eliminated risk "so far as is reasonably practicable." Get the terminology wrong and you can build an entire compliance program around the wrong duty holder, the wrong standard of care, and the wrong evidence.
This guide explains who a PCBU is, what the primary duty of care under Section 19 actually requires, the 2026 penalty exposure including industrial manslaughter, and how to generate the documented evidence that demonstrates due diligence when a regulator comes asking.
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What the Australia WHS Act Is and Where It Applies
The Work Health and Safety Act is Australia's harmonised model law for workplace safety, developed by Safe Work Australia and adopted — with local variations — across most states and territories. Rather than a single national statute, the WHS framework is a model Act and model Regulations that each jurisdiction enacts into its own law.
As of 2026, the model WHS laws have been adopted in:
| Jurisdiction | WHS law status | Regulator |
|---|---|---|
| Commonwealth | Adopted | Comcare |
| New South Wales | Adopted | SafeWork NSW |
| Queensland | Adopted | Workplace Health and Safety Queensland |
| South Australia | Adopted | SafeWork SA |
| Tasmania | Adopted | WorkSafe Tasmania |
| ACT | Adopted | WorkSafe ACT |
| Northern Territory | Adopted | NT WorkSafe |
| Western Australia | Adopted (WHS Act 2020) | WorkSafe WA |
| Victoria | Not adopted — operates under its own OHS Act 2004 | WorkSafe Victoria |
The practical takeaway is that Victoria runs a separate Occupational Health and Safety regime, so a national operation needs to map its obligations to both the harmonised WHS model and the Victorian OHS Act. Everywhere else, the duties and definitions described below apply with only minor local differences.
Who Is a PCBU: The Person Conducting a Business or Undertaking
A PCBU — a Person Conducting a Business or Undertaking — is the central duty holder under the WHS Act, and it is deliberately broader than the concept of "employer." A PCBU is any person, company, partnership, association, or other entity that conducts a business or undertaking, whether alone or with others and whether or not for profit.
This breadth is the point. The WHS Act replaced the narrower employer-focused language of older legislation specifically so that safety duties would follow the work, not just the employment relationship. In practice, a PCBU includes:
- Companies and corporations running any business activity
- Sole traders and partnerships conducting a business
- Government departments and public authorities
- Not-for-profits and associations with employees or activities (volunteer-only associations are generally excluded)
- Principal contractors and subcontractors on a construction site — each is its own PCBU
A single workplace frequently has multiple overlapping PCBUs. On a construction project, the principal contractor, the labour-hire firm, the scaffolding subcontractor, and the equipment supplier can each be a PCBU with concurrent duties for the same workers and the same hazards. Section 16 of the WHS Act confirms that more than one person can hold the same duty, and Section 46 requires PCBUs to consult, cooperate, and coordinate with each other where their duties overlap.
What a PCBU is not is a substitute for individual officer duties. Officers — directors and senior executives who make or substantially influence decisions — carry a separate due diligence duty under Section 27, discussed below.
The Primary Duty of Care Under Section 19
Section 19 of the WHS Act sets the primary duty of care: a PCBU must ensure, so far as is reasonably practicable, the health and safety of workers and of other persons who may be affected by the business or undertaking. "Health" here expressly includes psychological health, not just physical safety.
The duty runs to two groups: workers (employees, contractors, subcontractors, labour-hire staff, apprentices, work experience students, and volunteers) while they are at work in the business; and other persons — visitors, members of the public, and anyone else whose health and safety could be put at risk by the work.
Section 19(3) spells out specific measures a PCBU must take so far as is reasonably practicable:
| Section 19(3) obligation | What it means in practice |
|---|---|
| Safe work environment | Eliminate or control physical and psychosocial hazards in the workplace |
| Safe plant and structures | Maintain machinery, equipment, and buildings without risk |
| Safe systems of work | Documented procedures, safe work method statements, permits |
| Safe use, handling, storage of substances | Hazardous chemical and dangerous goods controls |
| Adequate facilities | Amenities such as washrooms, drinking water, rest areas |
| Information, training, instruction, supervision | Competence for the task and the hazards |
| Monitoring of health and conditions | Health surveillance and workplace exposure monitoring |
The duty is non-delegable. A PCBU cannot transfer the obligation by outsourcing, by contract, or by relying on a subcontractor — it can engage others to help discharge the duty, but it remains accountable for the outcome.
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What "So Far As Is Reasonably Practicable" Actually Requires
"Reasonably practicable" is the standard against which every WHS duty is measured, and it is defined in Section 18 of the Act. It means doing what is reasonably able to be done to ensure health and safety, weighing up all relevant matters at the time the duty applies.
The Section 18 test requires you to consider:
- The likelihood of the hazard or risk occurring
- The degree of harm that might result
- What you know, or ought reasonably to know, about the hazard and the ways to eliminate or minimise it
- The availability and suitability of ways to eliminate or minimise the risk
- Cost — but only after the first four factors, and a high cost is relevant only where it is grossly disproportionate to the risk
The sequence matters. Cost is the last consideration, and it cannot be used to justify leaving a serious, foreseeable risk uncontrolled. This is materially different from a pure cost-benefit test. The duty starts from elimination of the risk and only moves to minimisation through the hierarchy of controls where elimination is not reasonably practicable.
The hierarchy of controls under the WHS Regulations follows the familiar order: eliminate the hazard first; then substitute, isolate, or apply engineering controls; then administrative controls; and personal protective equipment only as the last and least reliable layer. A control program that leans on PPE and "be careful" signage where engineering controls were reasonably available will not satisfy the reasonably practicable standard.
For an investigation team, the implication is concrete. After an incident, you are not only documenting what happened — you are documenting whether the controls in place represented what was reasonably practicable before the event, given what the business knew or ought to have known.
Officer Due Diligence Under Section 27
Section 27 of the WHS Act imposes a personal duty on officers — separate from the PCBU's duty — to exercise due diligence to ensure the PCBU complies with its WHS obligations. An officer is someone who makes, or participates in making, decisions that affect the whole or a substantial part of the business, typically directors and senior executives.
Due diligence under Section 27 is defined as taking reasonable steps to:
- Acquire and keep up-to-date knowledge of WHS matters
- Understand the operations of the business and the hazards and risks involved
- Ensure resources and processes to eliminate or minimise risks are available and used
- Ensure processes for receiving and responding to information about incidents, hazards, and risks, and responding in a timely way
- Ensure processes for complying with WHS duties are implemented
- Verify that those resources and processes are in place and being used
This is why incident data flow to leadership is a legal matter, not just good practice. An officer cannot demonstrate Section 27 due diligence if there is no system that surfaces incidents, hazards, and the status of corrective actions to the decision-makers. Officers can be prosecuted individually even where the PCBU is not, and the due diligence steps are exactly the kind of activity a documented incident and corrective-action system is built to evidence.
WHS Penalties in 2026: Categories and Industrial Manslaughter
The WHS Act sets a tiered penalty structure, and several jurisdictions have added industrial manslaughter offences with substantial individual and corporate exposure. The figures below reflect the model WHS laws and key state variations as of 2026.
The model WHS Act offence categories:
| Offence category | Conduct | Indicative maximum (body corporate) |
|---|---|---|
| Category 1 | Reckless or grossly negligent conduct exposing a person to risk of death or serious injury | Highest tier; individuals also face imprisonment |
| Category 2 | Failure to comply with a duty exposing a person to risk of death or serious injury | Mid tier |
| Category 3 | Failure to comply with a duty (no exposure to death/serious injury required) | Lowest tier |
According to Safe Work Australia, the model WHS laws set a maximum monetary penalty of $20,441,000 for a body corporate for the most serious offences, with industrial manslaughter under the model law carrying up to 20 years' imprisonment for an individual.
Industrial manslaughter penalties vary by jurisdiction. As of 2026:
| Jurisdiction | Body corporate (max) | Individual (max imprisonment) |
|---|---|---|
| Model WHS Act | $20,441,000 | 20 years |
| New South Wales | $20 million | 25 years |
| Queensland | $10 million | 20 years |
| South Australia | $18 million | 20 years |
Industrial manslaughter applies where a PCBU's or senior officer's gross negligence causes the death of a worker. The trend across Australian jurisdictions has been to introduce or strengthen these offences, which raises the stakes for the officer due diligence duty under Section 27 considerably.
The penalty figures matter for one practical reason: the difference between a Category 1 charge and a defensible position often comes down to whether the business can show it understood the foreseeable risk and took reasonably practicable steps. That evidence is built before the incident, not after.
Frequently Asked Questions
Q. Is a PCBU the same as an employer?
No. A PCBU (Person Conducting a Business or Undertaking) is broader than an employer. It captures companies, sole traders, partnerships, government bodies, and not-for-profits whether or not they have employees, and it includes principal contractors and subcontractors. An employer is usually a PCBU, but many PCBUs have duties to workers who are not their direct employees, such as labour-hire staff and subcontractors.
Q. Can a PCBU transfer its duty of care to a contractor?
No. The primary duty of care under Section 19 is non-delegable. A PCBU can engage contractors and others to help discharge the duty, but it remains accountable for ensuring health and safety so far as is reasonably practicable. Where multiple PCBUs share a workplace, Section 46 requires them to consult, cooperate, and coordinate — duties overlap, they do not transfer.
Q. What does "so far as is reasonably practicable" mean?
It is the standard defined in Section 18 of the WHS Act. You weigh the likelihood of harm, the degree of harm, what you know or ought to know about the risk and its controls, and the availability of controls — then cost, but only last and only where it is grossly disproportionate to the risk. It is not a simple cost-benefit test; serious foreseeable risks must be controlled even at meaningful cost.
Q. Does the WHS Act cover psychological health?
Yes. Section 19 expressly includes psychological health within the primary duty of care. The WHS Regulations require PCBUs to manage psychosocial hazards — such as excessive workload, low control, poor support, and harassment — using the same risk-management process applied to physical hazards.
Q. How do officers prove due diligence under Section 27?
By taking documented, reasonable steps: keeping WHS knowledge current, understanding operational hazards, ensuring resources and processes to control risk exist, and verifying they are used. A system that reliably surfaces incidents, hazards, and corrective-action status to decision-makers is direct evidence that an officer maintained the processes Section 27 requires.
Key Takeaways
- The Australia WHS Act is a harmonised model law adopted across most jurisdictions; Victoria operates a separate OHS Act, so national operators must map duties to both regimes.
- A PCBU is broader than an employer and captures companies, contractors, government bodies, and not-for-profits — and a single workplace often has multiple concurrent PCBUs with overlapping, non-transferable duties.
- Section 19 sets the primary duty of care covering physical and psychological health, measured against the Section 18 "so far as is reasonably practicable" standard where cost is the last factor considered.
- Officers carry a personal due diligence duty under Section 27, which makes incident and corrective-action visibility to leadership a legal obligation, not just good practice.
- WHS penalties in 2026 include model maximums of $20,441,000 for bodies corporate and industrial manslaughter offences carrying up to 20–25 years' imprisonment depending on jurisdiction.
Related Resources
| Resource | Description | Best For |
|---|---|---|
| ISO 45001 Incident Investigation: Requirements and Best Practices | How to structure investigations and effectiveness verification under ISO 45001 Clause 10.2 | WHS teams aligning investigation practice with an international standard |
| Corrective Action Management: Stop Losing Track of Your CAPA Items | Building a closed-loop corrective action system that proves actions were effective | PCBUs evidencing reasonably practicable controls after an incident |
| Safety Management Trends 2026: AI, IoT, and Regulatory Changes | The technology and regulatory shifts reshaping EHS, including psychosocial risk mandates | Officers keeping WHS knowledge current under Section 27 |
A WHS investigation that demonstrates due diligence is one that links the incident to its root cause, the controls that were reasonably practicable, and corrective actions verified as effective. Start building that evidence trail with WhyTrace Plus →
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