Fatigue at Work: What Australian WHS Law Requires (And Why It's Not Just a Transport Issue)
- OHS News
- 11 hours ago
- 7 min read
Staying awake for 17 or 18 hours can impair your performance to roughly the same level as a blood alcohol concentration of 0.05 (the legal limit for driving). Research by Dawson and Reid (1997) found this equivalence in hand-eye coordination testing, showing that 17 to 24 hours of continuous wakefulness can produce performance deficits comparable to a BAC of 0.05 to 0.10. A separate 2000 study by Williamson and Feyer reached a similar conclusion, finding that performance after 17 to 19 hours without sleep was equivalent to or worse than a BAC of 0.05.
A lot of us have hit 17 hours on a long work day with a commute. And unlike a drink, there's no breathalyser catching it at the gate.
Fatigue is one of the most under-documented hazards in Australian workplaces. Not because it's obscure or difficult to understand, but because it doesn't look like a hazard. It looks like hard work. It looks like dedication. And in a lot of small businesses, it's treated as a badge of honour.
That framing is a problem. Not just for the workers carrying it, but for the business under WHS law.
What causes fatigue at work?
Fatigue isn't just about sleeping too little the night before. It's the cumulative effect of multiple contributing factors, and in small businesses those factors tend to stack up:
Long hours and extended shifts. When you're owner-operated, 10 and 12-hour days feel normal. But the cognitive and physical effects of sustained exertion compound over time. By hour ten, reaction times and decision-making quality have measurably declined, regardless of how experienced or fit the person is.
Shift work and early starts. Trades and construction often start at 6am or earlier. Early starts disrupt natural sleep cycles, and workers who commute long distances may be waking at 4:30am. By midday on a build site, some of those workers have been on the go for seven or eight hours already.
Back-to-back jobs with no recovery time. In busy periods, small crews often move directly from one demanding job to the next with no real break in between. This is particularly common in the lead-up to project completion dates or in the summer peak for trades.
High mental demand. Fatigue isn't only physical. Complex problem-solving, sustained attention (think: driving a vehicle for hours, or managing a site with multiple moving parts), and high-stakes decision-making are all mentally draining in ways that accumulate across a day or week.
Poor sleep quality. Even if a worker clocks eight hours, poor sleep quality (disrupted sleep, sleeping at the wrong point in the circadian cycle, or sleep conditions affected by physical discomfort) means they may arrive at work already fatigued.
Any one of these factors is a risk. In combination, they create the kind of fatigue that makes a simple mistake catastrophic.
Why fatigue is a WHS issue for every industry
This is the point where a lot of small businesses switch off: “That's a trucking problem. We do landscaping.” Or construction. Or cleaning. Or professional services.
It isn't.
Under the primary duty of care in section 19 of the Model WHS Act, a Person Conducting a Business or Undertaking (PCBU) must ensure, so far as is reasonably practicable, that workers and other persons are not exposed to risks to their health and safety. Safe Work Australia is explicit that fatigue is a hazard that falls within this duty, and that the obligation to eliminate or minimise fatigue risks applies to every PCBU, regardless of industry.
The Model Code of Practice: Managing the Risk of Fatigue at Work provides practical guidance on how to meet this duty. It's not a transport-specific document. It covers any workplace where fatigue is a plausible risk. When you consider the factors above, that's most of them.
The distinction matters in a very practical way. If a worker is injured and a regulator investigates, they will ask what systems the PCBU had in place to identify and manage fatigue as a hazard. “We didn't think it applied to us” is not a defence.
The alcohol-equivalence research: what it actually means
Research by Dawson and Reid (published in Nature in 1997) used a hand-eye coordination test to compare the effects of extended wakefulness to increasing doses of alcohol. Their finding: around 17 hours of continuous wakefulness produced performance impairment equivalent to a BAC of approximately 0.05, rising to around 0.10 after about 24 hours. A separate 2000 study by Williamson and Feyer reached a similar conclusion, finding that performance after 17 to 19 hours without sleep was equivalent to or worse than a BAC of 0.05.
To be clear about what “research suggests” means here: these are controlled studies with specific testing conditions. The equivalence is an analogy, not a clinical diagnosis. Fatigue affects different people differently, and not every person at hour 17 is impaired to exactly 0.05. What the research does tell us is that the impairment from extended wakefulness is real, measurable, and in the same territory as alcohol-level impairment. Yet most workplaces treat a tired worker very differently from a worker who has been drinking.
That gap in how we treat the two risks is exactly why documented fatigue management matters.
What this looks like for small businesses
Here are three scenarios:
The sole trader running 12-hour days. A sole trader in commercial cleaning is working a 4am hospital contract, then picking up residential jobs through the afternoon. By the time she finishes at 5pm, she's been awake for 14 hours and working for 12. She's driving a vehicle, handling chemicals, and working on client premises. There is no fatigue policy. There is no procedure for when to stop. If something goes wrong, there is also no documentation showing the hazard was identified and managed.
The small crew on back-to-back jobs. A three-person landscaping crew has been on a tight schedule all month: up at 5:30, on-site by 7, working until dark to meet contract milestones. The owner knows the team is tired. But there's nothing written down: no roster limit, no procedure for flagging fatigue, no record that any of this was acknowledged as a risk. The hazard exists. The documentation doesn't.
The office team in crunch. A five-person professional services firm is approaching an end-of-financial-year deadline. The team has been working evenings for two weeks. There's no policy on working hours, no process for workers to flag that their capacity is affected, and no consideration of the psychosocial and cognitive load accumulating across the team. Office-based businesses often assume they're low-risk because no one is operating machinery. But fatigue-related errors in financial work, legal work, or client-facing roles carry their own serious consequences. The WHS obligation is the same.
The most common objection: “That's just hard work, not a hazard”
This one comes up a lot. The idea is that fatigue is just the cost of doing business, that pushing through is part of what it means to run a small operation, and that formalising it with procedures is over-the-top paperwork that doesn't reflect the reality of how small businesses operate.
Here's what actually matters: the law doesn't make an exception for hard-working businesses.
A PCBU's duty is to manage fatigue risks so far as is reasonably practicable. That phrase, “so far as is reasonably practicable,” is a specific legal standard that weighs the severity of the harm, the likelihood of it occurring, and the burden of eliminating or reducing the risk. For most small businesses, a documented fatigue management procedure isn't a heavy burden. It's a few pages of policy covering roster limits, rest break expectations, a process for workers to report when they're fatigued, and a statement in the risk register acknowledging the hazard exists.
That's the minimum. And without it, you have nothing to point to if something goes wrong.
The culture around “just push through” also has a practical safety cost. Workers who feel they can't flag fatigue (because admitting it is seen as weakness, or because the expectation is that everyone just gets on with it) are more likely to keep working when they shouldn't. A documented approach, accompanied by a toolbox talk, signals to workers that fatigue is taken seriously. That changes behaviour.
What a documented fatigue management approach looks like
You don't need a 40-page manual. A solid fatigue management procedure covers:
Hazard identification. Which roles and tasks in your business carry a fatigue risk? Think about hours worked, start times, shift patterns, driving requirements, and mental demand. This goes in your risk register.
Risk controls. What will you do to minimise the risk? This might include maximum shift lengths, mandatory rest breaks, limits on consecutive days worked, and rostering practices that allow for recovery. The controls need to be proportionate to the actual risk in your business.
Worker reporting. How can workers flag that they're fatigued without consequences? This is about creating a process that makes it safe to say “I'm not fit to work right now.”
Management responsibilities. Who in the business is responsible for monitoring fatigue, reviewing rosters, and making decisions when a worker appears impaired?
Review. How often will you review the procedure and update it as the business changes?
Your WHS Management Systems should have a Fatigue Management procedure that covers all of these elements.
Start with the toolbox talk
Before you update your documentation, run a conversation with your workers about fatigue.
Our free Toolbox Talk: Fatigue Management is designed for exactly this: a short, structured team discussion that covers what fatigue is, what causes it, how it affects safety, and what workers should do when they're not fit to continue.
It should only take about 5-10 minutes. It creates a record that you've addressed the topic with your team. And it often surfaces information you didn't have. Workers will sometimes tell you in a toolbox talk that they've been concerned about fatigue on a particular job or roster pattern, when they wouldn't have raised it any other way.
Connect it to your WHS Management System
A fatigue management procedure doesn't sit on its own. It connects to your broader approach to risk management, your induction process (workers need to know your expectations from day one), your incident investigation procedure (fatigue is often a contributing factor in incidents that get recorded as something else), and your consultation obligations (you need to involve workers in identifying and managing fatigue risks).
If you don't have a WHS Management System that ties all of this together, that's worth addressing. A system gives you the framework (the procedures, the forms, the policies) so that fatigue management isn't a standalone document gathering dust, but part of how your business actually operates.
About Everything OHS
Everything OHS has been helping Australian small businesses get their WHS documentation right since 2008. More than 12,000 businesses have used our industry-specific documentation, and we've earned 60+ five-star Google reviews along the way. Our documents are built by WHS specialists and are aligned to Australian regulations.
If you've been putting off your fatigue management procedure, or you're not sure whether your current documentation actually covers this hazard, this is a good week to fix that.