Drug and alcohol policies remain an important work health and safety tool for employers, particularly in safety-critical industries such as construction, transport, mining, ports, logistics, and manufacturing. Where workers perform high-risk duties, one person affected by alcohol, illicit drugs, or prescription medication can create serious risks for themselves, their co-workers, the public, and the business.
Employers now need to manage those risks in a more complex environment. Medicinal cannabis, prescription medication, and changing community attitudes mean that workplace drug and alcohol issues are not always straightforward. A worker may have used a lawfully prescribed medication, consumed alcohol or drugs outside work hours, and attended work believing they could safely perform their duties because they did not feel affected.
WHS obligations start with risk
Employers have a duty to provide a safe workplace, eliminate or minimise health and safety risks so far as reasonably practicable, ensure workers are fit for work, and implement reasonable policies and procedures to manage foreseeable risks.
A drug and alcohol policy helps employers meet those obligations by setting out how the business manages alcohol, illicit drugs, prescription medication, and medicinal cannabis in the workplace.
A clear policy should explain when testing may occur, how testing will be conducted, what happens after a non-negative or positive result, what disciplinary outcomes may follow, and what support options are available to workers.
The relevant issue is not always whether a worker consumed a substance at some point, but whether that worker creates a risk at work. That risk may arise because:
- the worker is impaired;
- there is a possibility of impairment; or
- the worker has breached a clear and reasonable policy designed to manage workplace safety.
Employers should clearly define the conduct their policy regulates. A policy directed at impairment should focus on whether a worker can safely perform their duties, while a presence-based policy should expressly prohibit alcohol, drugs, or metabolites above the relevant cut-off level.
Presence and impairment measure different risks
Employers often ask whether their drug and alcohol policy should test for and prohibit impairment by drugs or alcohol, the mere presence of drugs or alcohol, or both. The distinction is significant because it affects not only workplace safety, but also whether disciplinary action following a positive test is likely to withstand legal scrutiny.
Testing for impairment focuses on whether alcohol or drugs have impaired a worker to the point they cannot safely perform their duties at the relevant time. Testing for presence focuses on whether alcohol, drugs, or metabolites are present within a worker’s body. This will generally be by reference to defined cut-off levels within the drug and alcohol policy.
That distinction matters because consumption does not always equal impairment. A worker may consume a substance outside work hours and attend work unimpaired. Equally, they may feel unaffected but still return a positive result because their body contains detectable metabolites.
Metabolites are produced when the body breaks down food, chemicals, and medicines, including illicit drugs and prescription medication. If an employer intends to test for active and non-active metabolites, the policy needs to say so expressly and explain what that means in practice. Without that explanation, workers may believe they are fit for work once the active effects of a substance have passed, even though the policy treats the ongoing presence of metabolites as a breach.
Cut-off levels provide a practical testing standard
Cut-off levels give employers a practical basis for interpreting test results. They set the threshold for treating a result as negative, non-negative, or positive, and help reduce the risk of false positives, false negatives, and inconsistent decision-making.
Because testing equipment cannot always reliably detect or interpret very small amounts of a drug or metabolite, cut-off levels help determine whether a result should trigger action under the policy.
Australian Standards 4308 and 4760 set out procedures for collecting and testing urine and saliva for drugs and metabolites, and include cut-off levels for screening tests and confirmatory tests across a range of substances.
Employers who align their testing procedures and cut-off levels with the Australian Standards will generally be better placed to show that their testing regime is fair and reasonable.
A positive result should still be considered in context. Employers need to assess the policy wording, the worker’s role, the safety risk, the worker’s understanding of the policy, and the disciplinary options available before deciding what action to take.
Why the distinction matters
The distinction between impairment and presence affects both safety management and fairness. If a policy only prohibits impairment, the employer may need to show that the worker was affected at work, or that there was a real risk they were affected. If a policy prohibits presence above a defined threshold, the employer may not need to prove actual impairment, provided the prohibition is clearly worded, lawful and reasonable.
A breach of a clear, lawful, and reasonable drug and alcohol policy may provide a valid reason for disciplinary action, including dismissal, even where there is no evidence that the worker was impaired.
A positive test result does not automatically justify dismissal. Employers still need to consider:
- the worker’s role
- the nature of the workplace
- the seriousness of the safety risk
- the worker’s length of service
- their disciplinary history
- their explanation
- whether they understood the policy
- whether the policy allows outcomes other than dismissal
A “zero tolerance” approach also does not always require dismissal as the default response. If the policy allows counselling, warnings, rehabilitation, or other disciplinary options, the employer should genuinely consider those options before making a final decision.
The recent decision in Lee Witherden v DP World Sydney Limited [2025] FWC 294 demonstrates how these issues can arise in practice.
Mr Witherden worked as a stevedore at Port Botany. During his days off, he used cocaine heavily over three days, with his last use occurring at 7:00 am on the day before his next shift. When he attended work the following day, he underwent random drug testing and tested positive for cocaine metabolites.
Mr Witherden said he did not feel impaired, but his employer dismissed him.
The Fair Work Commission considered the absence of evidence that Mr Witherden was impaired at work, the fact that the policy did not expressly state that it tested for non-active metabolites, and the employer’s inability to show that it had provided specific training about the drug and alcohol policy. The Commission concluded that the employer failed to communicate that its policy prohibited inactive metabolites and therefore could not rely upon the test result as a reason for dismissal. Mr Witherden was reinstated with continuity of employment.
The case highlights the risk of relying on a positive test result without a policy that clearly identifies what the employer is testing for and how the result will be treated. If an employer intends to test for presence, including inactive metabolites, the policy must say so and explain what that means for workers who may feel fit for duty but still return a positive result.
Medicinal cannabis requires careful policy drafting
Medicinal cannabis can complicate drug and alcohol management because a worker may lawfully use it to manage a health condition. However, lawful use does not necessarily mean the worker can safely perform all duties, particularly in high-risk roles. It also does not automatically give an employer grounds to treat the issue as misconduct.
Employers need to balance their safety obligations with the reality that workers may need prescription medication. They should also consider discrimination risks where the medication relates to a disability or medical condition. Employers should avoid assuming that every worker prescribed medicinal cannabis presents the same level of risk, as the assessment will depend upon the nature of the medication, dosage, timing of use and the inherent requirements of the role.
A practical policy should require workers to disclose prescription medication that may affect their ability to work safely. This allows the employer to assess the risk and consider appropriate controls, including medical clearance, temporary changes to duties, restrictions on high-risk tasks, or other safety measures.
Further considerations for your policy
A strong policy should define key terms, including “drug”, “alcohol”, “metabolite”, “non-negative test”, “positive test”, “confirmatory test”, and “cut-off level”. It should also state whether the business tests for active metabolites, non-active metabolites, or both, and make clear that it tests for the presence of drug, alcohol and metabolites, rather than impairment.
The policy should identify when testing may occur, such as:
- pre-employment testing
- random testing
- incident-based testing
- concern-based testing
- return-to-work testing
- follow-up testing
Employers should explain the policy before an issue arises. This can include:
- covering it at induction
- providing refresher training
- communicating updates
- using toolbox talks where appropriate
- making the policy easy to access
Key takeaway
Drug and alcohol policies work best when they clearly connect the testing regime to the risk being managed.
A strong policy should define the testing standard, explain cut-off levels, address active and non-active metabolites, manage prescription and medicinal drugs, identify testing triggers, provide support options, and guide decision-makers through a fair disciplinary process.
This helps employers respond to safety risks consistently, fairly, and with less scope for dispute.
If your workplace drug and alcohol policies need updating, our Employment team is available to assist.
