Under work health and safety (WHS) laws, a duty holder cannot contract out of its WHS responsibility. If your business engages contractors, hosts them on its sites, is a purchaser of materials or plant, or is itself engaged as a contractor or subcontractor, your business is a Person Conducting a Business or Undertaking (PCBU) under WHS laws and it will hold its own WHS duties, despite the duties or actions of any other PCBU.

Recent WHS charges and prosecutions demonstrate how overlapping WHS duties operate in practice and when PCBUs might be able to rely on the expertise of an engaged contractor as a defence or partial defence.

1. Two PCBUs with overlapping safety duties prosecuted for a scaffolding failure

Ausino Group Pty Ltd (Ausino), the principal contractor for rooftop works on a Sydney building site, engaged Secura Scaffold Services Pty Ltd (Secura) in September 2022 to supply and erect two six-metre mobile scaffolds. In high winds, one scaffold blew off the rooftop and fell six storeys onto a neighbouring building’s glass roof. While no one was injured in the incident, the public was exposed to the risk of death or serious injury.

Arising out of this incident:

• Ausino was fined $20,000 for failing to consult with Secura about the scaffolds’ intended use and location, failing to ensure that a site-specific safe work method statement adequately addressed the work being undertaken, and failing to supervise the installation;
• an Ausino director was fined $8,000 for failing to exercise due diligence to ensure that safe systems of work were in place and followed;
• Secura was fined $40,000 for failing to ensure that the scaffolds were safely selected, assessed and installed, including by failing to implement adequate systems requiring a site inspection and assessment of the suitability of the scaffolds for the work being undertaken; and
• a Secura director was fined $8,000 for failing to ensure Secura had effective systems of work in place, with his absence overseas at the time of the incident not reducing his liability.

The Ausino decisions confirm that, while principals can rely on the engagement of a specialist subcontractor, this will not absolve the principal PCBU from providing critical site information to the contractor, consulting with the contractor about the work to be performed or verifying that safety systems are adequate and being implemented.

The Secura decisions confirm to subcontractors that a client’s failure to disclose critical information may reduce, but does not extinguish, a specialist contractor’s legal responsibility, and that directors who delegate site-specific work remain personally exposed where they fail to verify that the systems underpinning that delegation are actually being followed.

2. Three PCBUs charged, but not yet found guilty, after fatal cyanide exposure at a mine site

In August 2024, it is alleged that a truck driver died after delivering caustic soda to a gold mine in Western Australia and that the death was caused by exposure to a cyanide-containing solution while cleaning his truck on site.

WorkSafe WA has charged three PCBUs, including two related entities, as follows:

• the owner of the Thunderbox mine, Northern Star Resources Ltd, with a Category 1 offence under section 31 of the Work Health and Safety Act 2020 (WA) (WHS Act), alleging that its failure to comply with its duty caused the driver’s death;
• the holder of the environmental licences of the Thunderbox mine, Northern Star (Thunderbox) Pty Ltd, with a Category 2 offence, alleging exposure of a worker to a risk of death, injury or serious harm; and
• the truck driver’s employer, Coogee Chemicals Pty Ltd, with a Category 2 offence, alleging exposure of a worker to a risk of death, injury or serious harm.

The charges demonstrate how concurrent duties across three PCBUs in one supply chain may be considered by WHS regulators, with three separate PCBUs facing charges for the same incident. Any contractual risk allocation between them cannot completely displace the statutory duty owed by each and cannot act as a contractual indemnity.

This matter is significant for any PCBU that hosts, supplies to, or transports for another business on a shared site, as it confirms that proximity to the hazard does not determine legal liability, even where PCBUs are related. A PCBU’s duty to identify and control a risk is not reduced, or deferred to another party, simply because that party is more directly involved in the work.

While the allegations are only charges at this stage, and we stress that they remain untested, the prosecution may demonstrate the WHS regulator’s willingness to pursue multiple PCBUs in a contracting chain arising from a single incident, even where PCBUs are related.

3. PCBUs are entitled to rely on manufactured hardware

In March 2023, an employee of IES Stormwater Pty Ltd (IES) was replacing filters on storm drain guards, known as OceanGuards. The guards were affixed inside the storm drains, using four masonry screws. Despite being rated to bear over seven tonnes, all four screws on one drain failed while a worker was on the drain, and the worker fell and suffered serious injuries.

The accident was a one-off, caused by an undetectable manufacturing fault with the screws.

In the initial prosecution, the Queensland Magistrates Court found that it was reasonably foreseeable that the screws could fail, serious injury could ensue and that there were a range of reasonably practicable steps that could have been taken. The Magistrate found that it was not reasonable for IES to have relied on the masonry screws, the reliability of which was unverifiable, and found IES guilty and fined it $70,000.

In the appeal, the District Court considered whether IES was entitled to rely on the masonry screw rating by the manufacturer, finding on appeal that:

• it was not reasonably foreseeable that the screws could fail, which should then impact on what was found to be reasonably practicable for IES to implement as a hazard control; and
• reasonably practicable steps that the employer PCBU could take to ensure health and safety in its workplace did not go so far as to require the PCBU to engage in destructive testing or other extraordinary tests.

Key takeaways for employers

If your business operates in a contracting chain, as principal, host, supplier or subcontractor, key takeaways from these recent charges and prosecutions should shape the management of WHS responsibility:

1. Consultation must be proactive and mutual, not merely available on request.
2. Contractual terms can allocate commercial risk, but this will not necessarily affect statutory liability.
3. A specialist subcontractor cannot assume that a client’s silence eliminates its own obligation to obtain the information necessary to perform the work safely.
4. Courts assess each PCBU’s contribution separately, by reference to its own capacity to influence and control the risk. The existence of overlapping duties does not diminish the obligation of each PCBU to eliminate or minimise risks so far as is reasonably practicable.
5. Duties extend beyond direct employees and PCBUs may owe duties to contractors, subcontractors and labour hire workers affected by the work.
6. Officers must verify, not merely delegate.

This article was written by Danielle Flint, Partner, and Jasmyn Joseph, Solicitor.