Negative self-tests using work site's kits contradicted positive workplace testing
The Fair Work Commission (FWC) recently examined an unfair dismissal claim involving a mobile plant operator who argued his termination was harsh after returning positive drug tests despite conducting negative self-tests before attending work.
The case arose when the worker was dismissed following two consecutive days of testing that revealed THC in his system, despite his belief that he was fit for work based on negative results from employer-provided self-testing kits.
The worker argued his dismissal was unfair because he had proactively tested himself using self-testing units provided by the mine site and received negative results before attending work on both days in question.
He maintained that conflicting policies between his labour hire employer and the mine client, combined with different testing sensitivities, created an impossible situation where compliance with one policy could lead to breaches of another.
Policy framework creates employee confusion
The employment relationship involved a labour hire worker employed by WorkPac and assigned to operate mobile plant equipment at a mine site operated by Batchfire Resources.
The worker had been employed since May 2021, operating rear dump trucks with payloads above 200 tonnes and was also authorised to operate dozers.
The worker's employment contract required compliance with both WorkPac policies and the mine site's fitness for work policies, creating a complex framework of overlapping requirements.
WorkPac's Employment Guide required employees to "present for work in a fit for work state, defined as being in a physical, mental, and emotional state which enables individuals to perform the requirements of their position in a safe manner," while also stating the company had "zero tolerance to illegal drugs and or alcohol use in the workplace."
However, the mine site's Batchfire policy provided self-testing units for employees to take home, stating these were available "so the person does not place themselves or others at risk" and "to increase the awareness of drug use."
The policy specified that employees could use sick leave provisions if self-tests showed results above prescribed limits, creating an apparent framework for managing drug presence rather than absolute prohibition.
Work site's self-testing protocols
On the evening of 25 January 2025, the worker consumed a small amount of cannabis for what he described as self-medication purposes related to mental health issues stemming from family separation.
Between 5:30 and 6:00 am on 26 January 2025, before his rostered 6:30 am shift, he performed a self-test using a unit provided by Batchfire, which produced a negative result for drug presence.
The worker's evidence was that he "firmly believed that he was fit for work on that day" based on the negative self-test result.
He arrived at work, swiped on at 6:30 am, and received a green light to proceed to work as usual, suggesting the site's entry screening system also indicated fitness for duty.
At approximately 8:00 am, the worker was called by his field supervisor and instructed to participate in a drug and alcohol test "for cause of suspicion."
The stated reason was that another employee sharing accommodation with him had produced a non-negative test result for THC that morning, though this rationale appeared to conflict with the mine's policy requiring specific observable signs or symptoms for cause-based testing.
Testing procedures reveal multiple irregularities
The worker's first test on 26 January produced a non-negative result, but when he was tested again immediately as permitted under policy, the second test was negative.
According to Batchfire's policy, a negative second test should have allowed him to "proceed to work" as normal, but instead, he was sent home despite the policy requirement.
The FWC found significant procedural failures in the testing methodology, noting:
"The reason for the worker being tested did not appear to fit within the meaning of for cause testing within the policy. His first test on 26 January was non-negative, and his second was negative. According to the policy, he should have returned to work under the Batchfire Policy."
On 27 January 2025, the worker again performed a negative self-test before attending his rostered night shift as directed by his supervisor.
However, during on-site testing, he was initially told his test was negative, and both he and his supervisor signed documentation confirming this result.
More than 30 minutes later, he was recalled and informed that the test had changed to non-negative, with the paperwork altered from "negative" to "non-negative" without his knowledge or consent.
Laboratory results conflict with procedural fairness
Despite the numerous procedural irregularities, laboratory analysis of samples from both 26 and 27 January confirmed the presence of THC at levels of 15ng/ml and 17ng/ml, respectively.
The employer relied on these results to issue a show cause notice on 31 January 2025, alleging the worker had attended work under the influence of drugs and breached multiple company policies.
The worker's response acknowledged consuming cannabis on 25 January but maintained he believed he was fit for work based on the negative self-tests and his understanding of the policies.
He stated: "I had no intentions of coming to work with any traces of anything in my system. I take pride in having a safe workplace for me and others in it. That's why if I ever did take that substance that can impair coordination or impair my cognitive thinking I would perform a self test before driving to work."
The FWC found the worker to be "an honest witness who answered questions directly, and did not try to tailor his evidence in a self-serving way."
The Commission accepted his evidence that he "had previously obtained a self-testing kit from Batchfire to test whether he was fit to attend work" and "would not have attempted to work" had the self-tests returned non-negative results.
Policy contradictions create compliance impossibility
A critical issue emerged regarding the different sensitivity levels of various testing methods. The worker discovered that self-testing units provided by Batchfire had different detection thresholds compared to the testing units used for official workplace testing, with Batchfire's policy specifying a 25ng/ml threshold while the actual tests used detected at 15ng/ml levels.
The worker argued: "By implementing testing kits that produce a positive result at a level of 15 ng/ml, these tests are effectively producing false 'non-negative' for anyone with a level under the prescribed limit of 25 ng/ml but has trace levels over 15 ng/ml."
This technical discrepancy meant employees could pass site-provided self-tests but fail official workplace testing for the same substance levels.
The FWC found merit in the worker's argument about policy confusion, stating:
"I have found some support in the evidence for the workers argument that by completing and returning a negative self test on both 26 January and 27 January provided by WorkPac's client... in circumstances where the self tests are calibrated differently to the tests at work, it sets an employee up for failure."
Site manager fails to investigate procedural concerns
The site manager acknowledged during cross-examination that she had not investigated the worker's concerns about procedural failures in the testing process.
She stated she was "more concerned with sticking to Workpac's policies than Batchfire's policies once the testing had been completed," despite the complex interplay between the two policy frameworks.
When asked about potential alternative disciplinary measures, the site manager agreed "there were other options she could have potentially taken," including first and final warnings, but maintained that termination was appropriate because of the test results.
The FWC noted: "[The] investigation into the allegations did not look into the procedural failures that were raised by the [worker] and merely adopted the laboratory results as the reason for termination."
FWC finds dismissal harsh despite valid reason
The FWC concluded that while there was a valid reason for dismissal due to THC presence in the worker's system, the termination was harsh given all the circumstances.
The Commission noted: "the investigation conducted by the [employer] did not take into account all of the circumstances, and I have concluded the decision to terminate the worker was harsh given all of the circumstances."
Key factors weighing in favour of unfairness included the worker's proactive self-testing before attending work, his unblemished four-year employment history, deficiencies in the testing procedures, his personal circumstances involving family separation, and the financial impact of dismissal.
The FWC found: "In circumstances where the worker had recorded both a negative and non-negative result on 26 January 2025... it is completely understandable that the worker... fully expected he was fit to work that day."
The Commission awarded compensation of $37,222.50, representing six months' pay reduced by 50% to reflect the worker's misconduct in attending work with THC in his system.
The FWC determined: "I am satisfied that the worker presenting to work to operate heavy machinery for the Assignment at the Mine two days in a row with THC in his system was a breach of WorkPac policy that was a form of misconduct that contributed to the [employer’s] decision to dismiss him."
