THC in Drug Test Leads to Lawful Dismissal: Key Lessons from FWC Ruling
In a recent Fair Work Commission (FWC) ruling, the dismissal of a long-serving employee was upheld after he tested positive for THC in a random drug test.
Case Background
Mr G, a stevedore at an Australian airport was dismissed in March 2024 following a failed drug test. The Employer’s Alcohol and Other Drugs Policy prohibits employees from attending work with proscribed substances in their system and required employees to disclose prescription medication that could impact their alertness or safety.
On 5 February 2024, Mr G was randomly selected for a drug test which confirmed the presence of THC in his urine. Following an internal investigation and disciplinary process, Mr G was dismissed for serious misconduct, which he challenged as an unfair dismissal.
Key Issues Considered by the Commission
1. Was there a valid reason for dismissal?
The Commission first considered whether the Employer had a valid reason for terminating Mr G’s employment. The Employer’s policy sets strict requirements for employees in safety-critical roles, including:
A prohibition on attending work with drugs or alcohol in their system above prescribed limits.
A requirement to disclose any prescribed medications that could impair work performance.
Mr G breached both of these policy requirements.
Despite Mr G's claim that he was not impaired at work, the Employer argued that impairment was not the key issue. The Employer’s Policy was based on the presence of a proscribed substance rather than proof of impairment. The Fair Work Commission agreed, stating that because impairment from THC is difficult to measure, workplace policies often take a zero-tolerance approach to avoid potential safety risks.
Medical Evidence on Impairment
During the hearing, two expert witnesses presented medical evidence:
Dr R (for Mr G) argued that THC presence does not necessarily indicate impairment and that, based on Mr G’s reported last use, he was unlikely to be impaired at work.
Dr W (for the Employer) countered that THC consumption at the levels detected in Mr G’s system would likely result in some impairment, and that impairment from cannabis use is not always visually apparent.
While the Commission acknowledged the difficulty in proving impairment, it upheld that the Employer’s zero-tolerance policy was lawful and reasonable, meaning that the mere presence of THC at high levels constituted a valid reason for dismissal.
2. Did Mr G’s failure to disclose his prescription matter?
The second issue was whether Mr G's failure to disclose his medicinal cannabis prescription to the Employer contributed to his dismissal.
The Employer’s policy clearly stated that employees must disclose prescription medication that could impact their ability to safely perform their duties. Mr G argued that he did not believe he was impaired, so he saw no need to report his prescription. However, he had signed a patient consent form acknowledging that he understood he must not operate heavy machinery while taking THC-containing medicinal cannabis.
The Commission found that Mr G:
Was aware of the requirement to disclose his medication.
Had deliberately chosen not to inform the Employer.
Had signed a medical consent form stating he should not operate machinery while taking THC.
The failure to disclose was viewed as serious misconduct, as it prevented the Employer from assessing potential risks and determining whether reasonable adjustments could be made.
3. Was the Employer’s policy lawful and reasonable?
Mr G’s legal team argued that the Employer’s policy was unfair, especially given the increasing legal use of medicinal cannabis in Australia. However, the Commission ruled that:
The policy was lawful and reasonable given the high-risk nature of the work.
The policy was consistently enforced, with all employees subject to the same standards.
Employees were given regular updates and reminders about the policy through emails, toolbox talks, and workplace bulletins.
4. Did the Employer follow a fair process?
Mr G argued that the Employer had a zero-tolerance approach that made his dismissal inevitable, regardless of his response during the disciplinary process.
However, the evidence presented showed that the Employer:
Stood Mr G down on full pay while the investigation was conducted.
Provided him with written notice of the allegations against him.
Allowed him to present medical evidence and seek a response from his treating doctor.
Considered mitigating factors, including his long service and personal struggles.
Provided him with multiple opportunities to respond in writing and in person.
The Commission concluded that while the Employer had a strict drug and alcohol policy, the decision to dismiss Mr G was not predetermined, and due process had been followed.
5. Was the dismissal harsh, unjust, or unreasonable?
Finally, the Commission weighed whether dismissal was a proportionate response.
Mitigating factors included:
Mr G’s 19 years of service.
His personal circumstances, including mental health struggles.
His remorse and willingness to comply in the future.
However, these factors were outweighed by:
The high levels of THC detected.
The safety-critical nature of Mr G’s role.
His failure to disclose his prescription, preventing the Employer from assessing risks.
The Commission ruled that summary dismissal was proportionate, particularly given that the Employer’s policy explicitly allows for dismissal in cases of high-range drug test results.
Key Takeaways from the Decision
This case reinforces several important lessons for both employers and employees in high-risk industries:
For Employers:
Ensure drug and alcohol policies are clear and well-communicated – The Employer successfully defended its decision because employees were regularly informed about the policy, and expectations were clearly documented.
Adopt a zero-tolerance approach for high-risk roles – The FWC has repeatedly upheld strict drug and alcohol policies for safety-critical workplaces, recognising that impairment is difficult to measure.
Follow a fair and transparent disciplinary process – The Employer provided written notices, multiple meetings, and opportunities to respond, which helped demonstrate procedural fairness.