Many employers assume that a “zero tolerance” drug and alcohol policy gives them a clear path to dismiss any worker who returns a positive test. In a recent decision, the Fair Work Commission (FWC) made it clear that this assumption is wrong. The case involved a long serving supervisor dismissed after a low level positive test for cannabis metabolites, despite no evidence of impairment at work, and it resulted in reinstatement with backpay.​ 

For HR managers, supervisors and advisors, the decision is an important reminder: drug and alcohol policies must be applied proportionately, consistently with their own wording, and in line with the unfair dismissal framework. A positive test may be a valid reason to dismiss, but it is not an automatic justification for termination in every case.​ 

The story: 27 years’ service, one joint, and a low positive 

Mr Glenn Brew had worked for Downer EDI Works Pty Ltd and its predecessors for more than 27 years, most recently as an Area Supervisor in the transport and infrastructure division. He had a strong performance and safety record and no prior disciplinary history.​ 

On a Friday night in August 2025 he shared a cannabis cigarette at a dinner party, taking two inhalations. Concerned about his obligations, he bought a chemist self-test kit and tested himself on the Sunday before travelling for work, returning a negative result. On the Monday, he was subject to workplace urine testing, which produced a non-negative onsite result and a later laboratory confirmatory result of 41 µg/L THC metabolites, above the lab cutoff of 15 µg/L but below the onsite cutoff of 50 µg/L.​ 

Downer treated this as a breach of its Alcohol and Other Drugs Procedure, Cardinal Rule 10 (“never consume or be under the influence of alcohol or non-approved drugs in the workplace”), his contract (fitness for work clause) and its Standards of Business Conduct (no working under the influence). After a show cause process, senior management decided that, in line with a strict “zero tolerance” approach, summary dismissal was the appropriate outcome for serious misconduct.​ 

Mr Brew admitted the Friday cannabis use, explained his self-testing and stressed his long, unblemished service, safety focus and willingness to undertake ongoing testing. He lodged an unfair dismissal application seeking reinstatement.​ 

What the Commission decided – and why 

The Commission accepted expert evidence that the urine test detected THC metabolites, not active THC, and that Mr Brew was neither intoxicated nor impaired at work on the Monday.  

On that basis, it held that he had not breached Cardinal Rule 10, because that rule was about consumption or being under the influence at work and he had neither consumed nor been under the influence on the test day.. 

It also found he was fit for duty and had not breached his contractual obligation to disclose lack of fitness, nor the Standards of Business Conduct focused on working under the influence.​ 

However, the Commission still found there was a valid reason for dismissal based on the positive test and Downer’s Managing Misconduct Standard, which defined a positive drugs test as serious misconduct that may lead to dismissal.  

The show cause process, notification of allegations, and support person arrangements were all adequate and weighed in Downer’s favour.​ 

The real contest was whether dismissal was harsh in all the circumstances. The Commission concluded that it was, for several reasons.  

• Downer treated “zero tolerance” as if it mandated dismissal for every positive test, even though its own Alcohol and Other Drugs Procedure and Managing Misconduct Standard clearly contemplated a spectrum of disciplinary outcomes (counselling, warnings, performance plans, demotion, no further action) and did not prescribe automatic termination.  

• Mitigating factors – 27 years’ service, clean record, safety contributions, low metabolite level, self-testing before work, full cooperation and contrition, and his indication that cannabis use was out of character – were not properly weighed.​ 

• The testing procedure was not followed correctly: the onsite tester failed to offer the mandated second test after a non-negative result, and there was evidence the kit had been opened before use, all against a backdrop of an anomalous cut-off structure (onsite threshold higher than the lab threshold).  

• Internal communications showed an expectation that anything other than dismissal for a “Cardinal Rule breach” had to be specially justified, reflecting a default to dismiss mindset inconsistent with the written policy framework.​ 

Balancing the factors, the Commission held that the unqualified dismissal of a long-serving, otherwise exemplary employee for a single positive test (with no impairment, no safety incident and real mitigating circumstances) was harsh. It ordered reinstatement with continuity of service and backpay.​ 

Why this matters for employers and HR 

This case underscores several key points for HR managers, supervisors and advisors.  

A positive test can be a valid reason – but it is not an automatic “green light” for dismissal, and the Commission will closely examine whether dismissal is proportionate in the circumstances, having regard to s 387 and to the employer’s own policies.  

“Zero tolerance” is not magic wording; if your policy language and associated standards leave room for discretion and alternative sanctions, a rigid practice of always terminating for a positive test will be vulnerable.​ 

The distinction between presence and impairment is increasingly important. Here, the Commission was prepared to say there was no breach of “under the influence” rules where only metabolites were detected and evidence showed no impairment at work.  

Failure to follow your own testing and disciplinary processes (for example, not offering a second test where required) will weigh heavily towards a finding of harshness.​ 

What employers should review and do now 

For organisations with drug and alcohol regimes – particularly in safety critical environments – this decision is a prompt to act. 

1. Audit policy wording 

• Clarify whether “zero tolerance” means zero presence, zero impairment, or both, and ensure consistency between the high level policy, procedures, “Cardinal Rules” and misconduct standards.​ 

• Explicitly map out the range of possible sanctions for a positive test and make clear that dismissal is one option, not the default in all circumstances.​ 

2. Align practice with policy 

• Train managers and HR that they must genuinely consider mitigating and aggravating factors (service length, prior record, level of reading, role, explanations, cooperation, remedial steps) rather than treating dismissal as automatic.​ 

• Review decisionmaking templates and communications to remove language that assumes termination unless someone can “justify” a lesser sanction.​ 

3. Tighten testing procedures 

• Ensure third party testers strictly follow documented processes, including kit integrity, timing and the availability of second tests where procedures require it.​ 

• Revisit cutoff levels and any differences between onsite and lab thresholds and make sure these are clearly explained internally so decisionmakers understand what a result actually shows (presence vs likely impairment).​ 

4. Consider impairment and risk, not just results 

• Build into your assessment a structured analysis of whether there was actual or likely impairment at work, impact on safety, and any related incident or near miss, rather than relying solely on the numerical result.​ 

• For senior or safety critical roles, be explicit about expectations and reinforce education around out of hours substance use and detection windows.​ 

5. Plan for alternative responses 

• Develop and document non-termination responses: targeted education, EAP referral, medical review, ongoing or random testing, redeployment or demotion where appropriate.​ 

• Reserve termination for cases where there is repeat noncompliance, dishonesty, refusal to engage in remedial steps, or clear impairment and risk.​ 

If your organisation relies on a zero-tolerance drug and alcohol policy, now is the time to check whether your policies, procedures and decision-making practices would withstand Fair Work Commission scrutiny. 

Mr Glenn Brew v Downer EDI Works Pty Ltd [2026] FWC 955 (23 March 2026)