The case of Maxwell Parks v WorkPac Pty Ltd highlights how failing to align workplace drug testing with current standards and policy can result in an unfair dismissal finding – even when a valid reason exists.

Background

Mr. Parks was dismissed after returning not-negative drug test results at work, despite having conducted self-tests using Oral Fluid kits provided by the employer’s client, Batchfire, which indicated a negative result to THC.

The Oral Fluid self-testing kits were aligned  to the AS 4760:2006 standard cut-offs, while workplace testing was aligned to AS/NZS 4760:2019 cut-offs.

Voluntary Self-Testing Policy

Oral Fluid testing units were made available in a private and confidential area for voluntary self-testing by coal mine workers and visitors prior to swiping onto the site access system.

The Oral Fluid kits could be taken off-site and were intended to:

• Help individuals avoid placing themselves or others at risk
• Increase awareness of drug use

Under Batchfire’s policy, if a self-test returned a result at or above the prescribed limit, the individual was instructed not to commence work and to notify their supervisor. Sick leave provisions could be used, but repeat absences were managed under the site’s absenteeism procedures.

The policy referenced AS 4760:2006, which sets the THC detection threshold at 25ng/mL. However, the Oral Fluid kits used on-site were aligned with AS/NZS 4760:2019, which has a lower threshold of 15ng/mL for screening of THC.

This mismatch meant individuals with levels between 15ng/mL to 25ng/mL of THC were left with false confidence. Self-testing at home in line with the workplace policy, but being tested at work to a stricter standard.

Key Issues

• Cut-off Mismatch – Self-tests Oral Fluid kits used a 25ng/mL THC threshold, while onsite Oral Fluid tests detected THC at 15ng/mL.
• Chain of Custody Failures – One test was altered after being signed off as negative; another was already unsealed before the employee arrived.
• Policy Breaches – The employee was denied a retest (which he was entitled to), and the investigation ignored procedural flaws and personal circumstances.
• Dismissal Deemed Harsh – Despite a valid reason, the Commission found the dismissal unfair due to the employer’s failure to consider all relevant factors.

Mr. Parks Had An Unblemished Work History

• Had taken proactive steps to self-test before work
• Been directed to attend work despite prior non-negative results
• Faced financial hardship and was unable to secure new employment

Lessons for Employers

Drug testing is not just about detection – it’s about fairness, accuracy, and consistency.  This includes:

• Using AS/NZS 4760:2019-compliant Oral Fluid kits
• Ensuring drug & alcohol chain of custody protocols are strictly followed
• Aligning drug & alcohol self-testing and workplace testing thresholds
• Training staff on drug & alcohol policy and procedural rights
• Conducting thorough investigations that consider all circumstances
• Ensuring drug & alcohol policy & procedure documents reference current standards and are regularly reviewed

Our solutions at Alcolizer Technology are:

• Compliant with AS/NZS 4760:2019
• Supported by extensive training, support, and policy review services
• Designed to uphold legal integrity and procedural fairness

If you’re unsure whether your current kits or policies are up to date, contact us for a review. Let’s ensure your drug & alcohol workplace testing program protects both your people and your organisation.

Source
Fair Work Commission Maxwell Parks v WorkPac Pty Ltd (U2025/1247)