Can you fail workplace alcohol testing in Western Australia simply by using mouthwash? That’s a question on a lot of people’s lips since a union official in WA’s Pilbara region failed an alcohol test and then blamed his oral hygiene practices.
It’s a story that has gained attention across the mining sector and beyond. It also highlights an important issue for employers and workers alike—how workplace alcohol testing works, and whether everyday products like mouthwash can influence results.
In this blog, we break down what happened, what the science says, and what workplaces in Western Australia should do to maintain safe and fair testing practices.
What happened in the WA incident?
As reported in the Courier Mail, a union official was refused entry to a mining site in the Pilbara, WA, operated by BHP after returning a positive breath alcohol reading at the gate.
The official, representing the Australian Manufacturing Workers’ Union (AMWU), reportedly recorded a breath alcohol (BrAC) of 0.04. A second test taken 10 minutes later returned a lower reading of 0.02.
The union claimed the result was caused by alcohol-based mouthwash used shortly before the test. The company stood by its zero-tolerance policy and denied site access.
While the situation has become part of a broader industrial relations discussion in the Pilbara, it also raises a practical and important question for every workplace in Western Australia.
How workplace alcohol testing works
Most workplaces in safety-critical industries, such as mining, construction, and transport, use breath alcohol testing.
Breathalysers measure alcohol in a person’s breath and estimate their breath alcohol concentration. In industries with strict safety requirements, the acceptable BrAC is often 0.00. This is like rules applied to learner and probationary drivers across Australia.
However, not all positive readings are equal. That’s why proper procedures matter.
Can mouthwash trigger a positive alcohol test?
So, is it possible to fail workplace alcohol testing in WA because of mouthwash?
While it is possible, because many mouthwashes do contain ethanol, any effect is short-lived. In practice, this means that if you gargled with mouthwash that contained alcohol and then had a breathalyser test you could be above 0.0.
However, the effect of the mouthwash wears off quickly. Plus, and this is most important, any professional workplace alcohol testing will require confirmation testing be conducted a short time after the first test. This confirmation test will prove negative if mouthwash was the cause of the first test being above 0.0.
In simple terms, mouthwash can temporarily affect a breath test—but only for a short period.
In the Pilbara case, with the facts presented, it appears the company was correct to refuse entry. A second confirmation test was taken 10 minutes after the initial test and this was still above 0.0.
Why confirmation testing is critical
The Pilbara case highlights the importance of confirmation testing.
A single breath test should never be the final decision in a workplace setting. Best practice includes:
- Waiting a set period (often 10–20 minutes)
- Conducting a second confirmatory test
- Following strict testing protocols
If alcohol is present in the body due to drinking, the test result will remain consistent or may even rise. If the reading was caused by residual alcohol in the mouth (such as mouthwash), the level will return to zero.
This is why professional testing providers always build confirmation testing into their procedures.
What this means for WA workplaces
For employers in Western Australia, especially in high-risk industries, this situation reinforces several key points:
- Clear policies are essential. Your drug and alcohol policy should clearly explain testing procedures, including confirmation testing. And if you have zero tolerance (i.e. 0.0 is your expectation) your policy should state this and state why.
- Education reduces confusion. Workers should understand how alcohol testing works and how products like mouthwash can affect results temporarily.
- Consistency builds trust. Applying the same rules to everyone—employees, contractors, visitors, and union officials—helps maintain fairness and credibility.
- Testing must follow best practice. Using trained professionals and certified equipment ensures accurate and defensible results.
What workers should know before a test
Employees and site visitors also play a role in ensuring accurate testing outcomes.
Simple steps include:
- Avoid using alcohol-based mouthwash immediately before testing
- Be honest and proactive if you think something may affect your result. For example, some over-the-counter and prescription cough medicines can also contain alcohol, or substances that can cause a non-negative drug test.
These small actions can prevent unnecessary complications.
The bigger picture on workplace alcohol testing in WA
Industries like mining operate in high-risk environments. Even small impairments can lead to serious incidents.
That’s why companies like BHP enforce strict alcohol and drug policies. These policies are not about punishment—they are about protecting workers and ensuring everyone goes home safely.
At the same time, fair and accurate testing processes are just as important. Workers must have confidence that results reflect reality, not anomalies.
Which is where Integrity Sampling in WA steps in. Like all our branches, our Western Australia team delivers a complete workplace drug and alcohol management solution. This includes developing clear policies and procedures, carrying out reliable testing, and supporting workforce education on the risks associated with drugs and alcohol.
We use precise, reliable and accurate Dräger drug and alcohol testing equipment for all our workplace testing. In addition, all our technicians are trained, accredited, and qualified, and Integrity Sampling operates under robust, independently recognised quality frameworks.
With ten locations in Western Australia, we’ve got safety-sensitive workplaces covered for all drug and alcohol management needs.
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Gargling mouthwash is certainly good for oral hygiene, but can it lead to a failed workplace alcohol test?
