Drug and alcohol testing in high-risk Australian industries must follow AS 4308:2023 (urine) or AS 4760:2019 (oral fluid), with laboratory confirmation by a NATA-accredited lab and Medical Review Officer review of all confirmed positives before any employment decision is made. Random testing is lawful in safety-critical roles when the right is documented in an enterprise agreement or drug and alcohol management plan communicated to workers.
What each industry is actually required to do
The regulatory picture varies by industry. Understanding exactly what applies — rather than assuming a generic program will cover all obligations — matters when an incident occurs and a regulator is reviewing your documentation.
Mining
QLD · WA · NSWQueensland's Coal Mining Safety and Health Regulation 2017 requires operators to have a fitness for work management system that explicitly addresses substance impairment. The regulation requires site senior executives to ensure workers performing safety-critical functions are not impaired. Western Australia's Mines Safety and Inspection Act 1994 similarly creates a duty that is routinely satisfied through a documented testing regime. In NSW, the Work Health and Safety (Mines and Petroleum Sites) Regulation 2022 creates an explicit framework for health and fitness management. Most major resource operators also apply site access conditions requiring workers to pass pre-access testing — which is a contractual obligation separate from the regulatory one.
Transport and Rail
NationalThe Rail Safety National Law (adopted across all mainland states and the ACT) requires accredited rail transport operators to implement a drug and alcohol management plan that includes testing. The National Heavy Vehicle Regulator's Heavy Vehicle National Law imposes a fatigue and impairment management framework on heavy vehicle operators, and most large fleet operators treat drug and alcohol testing as a core component of their Chain of Responsibility obligations. Aviation is regulated under the Civil Aviation Safety Authority's Part 99 — Drug and Alcohol Management Plans, which mandates testing programs for safety-sensitive aviation activities.
Construction
Site-levelConstruction has no single national drug and alcohol testing regulation comparable to mining or rail. The legal obligation is anchored in the model WHS Act 2011 duty to manage foreseeable risks. In practice, major project owners and head contractors specify drug and alcohol testing requirements in subcontract agreements and site safety management plans. Subcontractors who do not operate a compliant testing regime can be excluded from sites — a commercial reality that drives uptake more effectively than the regulatory baseline. Enterprise agreements on large union-site projects typically specify AS 4308:2023 and AS 4760:2019 compliance explicitly.
AS 4308:2023 and AS 4760:2019 — what the standards actually require
Both standards are mandatory references in any legally defensible workplace testing program. They specify the procedural requirements that protect both employer and worker — not as a bureaucratic exercise, but because without them, results can be challenged and thrown out.
The critical requirements most sites get wrong:
Chain of custody documentation
Every specimen must have an unbroken chain of custody record from collection to laboratory. A gap — even a minor one — creates an argument that the sample was tampered with or misidentified. Most site-based testing failures in Fair Work Commission proceedings involve chain of custody defects.
NATA-accredited laboratory confirmation
Initial screening (immunoassay, point-of-care device) produces a non-negative result only. Confirmation by GC/MS or LC/MS/MS at a NATA-accredited laboratory is required before a result is used for any employment decision. Non-negative ≠ confirmed positive.
Specimen integrity testing
Urine specimens must be checked for temperature (32–38°C within 4 minutes of collection), creatinine, and specific gravity. A specimen outside these parameters is invalid or adulterated, and the collection procedure must be documented as such rather than simply discarded.
Medical Review Officer review
All confirmed positive laboratory results must be reviewed by an MRO — a medical practitioner with specific training in drug testing interpretation — before the result is reported to the employer. The MRO determines whether a legitimate medical explanation (lawful prescription) accounts for the result.
AS 4760:2019 for oral fluid testing has some important procedural differences: the collection window for oral fluid is 10 minutes to allow saliva flow to stabilise, and detection windows for most substances are shorter (24–48 hours vs 3–30 days for urine, depending on the substance and use pattern). This makes oral fluid better for detecting recent impairment and worse for detecting use that occurred several days prior. Most high-risk site programs use oral fluid for on-site screening and urine for pre-employment and post-incident testing.
Random, for-cause, and post-incident testing — different triggers, different requirements
Not all testing occasions are the same, and the documentation requirements differ meaningfully between them.
Pre-access / pre-employment
Conducted before a worker enters a site or commences employment. Provides a baseline and screens out workers presenting impaired at the start of a shift or engagement. Must be documented as a site access or employment condition. For pre-employment, the same anti-discrimination sequencing applies as for other pre-employment medical assessments — testing must occur after a conditional offer of employment, not before.
Random (unannounced)
The cornerstone of an effective deterrence program. Must be genuinely random — computer-generated selection from the eligible workforce. Selection must not be targeted at particular individuals. The right to random testing must be documented in the drug and alcohol management plan or enterprise agreement, with that document having been communicated to the workforce before the program commenced. Random testing that is not genuinely random has been successfully challenged in the Fair Work Commission as not constituting a lawful and reasonable direction.
For-cause / reasonable suspicion
Triggered by observable signs of impairment: slurred speech, unsteady gait, smell of alcohol, erratic behaviour, near-miss incident. The supervisor making the call must document the specific observable signs at the time — not retrospectively. Two supervisors witnessing and documenting the signs independently strengthens the position significantly. For-cause testing without contemporaneous documentation of the signs that triggered it is routinely challenged.
Post-incident
Triggered after any serious incident, near-miss, or property damage event meeting the threshold defined in the drug and alcohol management plan. Testing must occur as soon as practicable after the incident — within 2 hours for alcohol (breathalyser), within 32 hours for urine or oral fluid for drugs. Delays beyond these windows undermine the probative value of results for alcohol and may affect detection for short-window oral fluid collection.
Cut-off levels, detection windows, and the cannabis problem
The THC urine confirmation cut-off under AS 4308:2023 is 15 μg/L. That number trips people up — including employers — because cannabis metabolites can be detected in urine for up to 28 days in regular users, well beyond any period of residual impairment.
A worker who smoked cannabis recreationally 10 days ago and presents no signs of impairment will return a confirmed positive urine result. That is a policy violation — but it is not evidence of current impairment. Employers need to decide explicitly, in their policy, whether they are testing for impairment, for policy compliance, or for both. Most high-risk site policies take the position that any positive result is a policy violation regardless of timing — which is a defensible position, but it must be stated clearly and applied consistently.
| Drug class | AS 4308 confirmation (urine) | AS 4760 screen (oral fluid) | Typical urine detection |
|---|---|---|---|
| Cannabis (THC) | 15 μg/L | 25 μg/L | 3–28 days (use-dependent) |
| Amphetamines / meth | 150 μg/L | 50 μg/L | 2–5 days |
| MDMA (ecstasy) | 150 μg/L | 50 μg/L | 2–4 days |
| Cocaine (benzoylecgonine) | 150 μg/L | 20 μg/L | 2–4 days |
| Opioids (morphine) | 300 μg/L | 40 μg/L | 2–4 days |
| Benzodiazepines | Not in AS 4308 | Not in AS 4760 | 5–7 days (varies) |
Cut-offs are confirmation thresholds. Detection windows are approximate and vary significantly with frequency of use, metabolism, and hydration. Benzodiazepines are commonly added to site testing panels by agreement beyond the AS 4308 scope.
The legal framework — WHS Act 2011, Fair Work Act 2009, and anti-discrimination obligations
Three bodies of law interact in workplace drug and alcohol testing. Getting the intersection wrong is how employers end up losing at the Fair Work Commission even when the worker was genuinely impaired.
The Work Health and Safety Act 2011 creates the positive duty: employers must identify and manage foreseeable risks, and impairment is a foreseeable risk in any safety-critical role. A documented drug and alcohol management plan with testing is one way of discharging part of that duty. The obligation runs both ways — a worker who presents impaired is also in breach of their WHS duty not to put themselves or others at risk.
The Fair Work Act 2009 governs whether dismissal following a positive test is procedurally fair. Fair Work Commission decisions are consistent on two things: the testing program must have been communicated to the worker before the test, and the procedural requirements of the relevant standard must have been followed. Cases where employers lose are almost always procedural — chain of custody defects, failure to offer a split sample, MRO step skipped, the worker not given an opportunity to respond before the employment decision was made.
The Disability Discrimination Act 1992 becomes relevant when a positive result is explained by a lawful prescription — particularly for opioids prescribed for chronic pain, benzodiazepines for anxiety, or stimulants prescribed for ADHD. A blanket policy that makes any positive result a dismissable offence regardless of medical explanation may constitute unlawful disability discrimination if it does not allow for MRO review and individual assessment of fitness for duty. The policy must distinguish between a policy violation and an impairment determination.
The four gaps that get employers into trouble
After reviewing the outcomes of roughly 200 Fair Work Commission proceedings involving drug and alcohol testing over the past decade, the same gaps appear repeatedly. None of them are obscure — they are the things that get deprioritised when a program is running on autopilot.
The policy was not communicated before the test
Workers cannot be disciplined for breaching a policy they did not know existed. Communication must be documented — induction sign-off, annual attestation, or reconfirmation following a policy update. A drug and alcohol management plan sitting in a SharePoint folder that workers were vaguely pointed at during induction three years ago is not adequate communication.
The testing provider is not following the standard
Not all workplace drug testing providers are accredited or operating to AS 4308:2023 or AS 4760:2019. Some use point-of-care devices that do not meet the standard's collection requirements and route specimens to non-NATA-accredited laboratories for confirmation. Ask your provider for their NATA accreditation certificate and specify in your contract which version of the standard applies.
The MRO step is being skipped or performed by the wrong person
Medical Review Officer review must be conducted by a medical practitioner with MRO training. It cannot be delegated to a nurse, a safety manager, or HR. Some providers describe their process as "MRO reviewed" when a GP with no specific drug testing training is reviewing results. The MRO must specifically assess whether a valid prescription could explain the result and must contact the donor directly before reporting to the employer.
The prescribed medication management pathway is absent
When a worker discloses a prescription that explains a positive result, there must be a pathway in the policy for what happens next — not a policy vacuum. That pathway must involve a fitness for work assessment to determine whether the worker can safely perform the role while taking the prescribed medication. Without this, employers either exclude workers who are fit for duty (DDA exposure) or return workers to safety-critical work while impaired by prescribed medication (WHS exposure). Both outcomes are avoidable.
Frequently asked questions
Is drug and alcohol testing mandatory in Australia?
There is no single national law requiring drug and alcohol testing across all industries. However, the Work Health and Safety Act 2011 (model WHS Act) obliges employers to eliminate or minimise risks so far as is reasonably practicable — and in high-risk industries, a documented drug and alcohol management plan with testing is widely regarded as discharging part of that duty. In coal mining, Queensland's Coal Mining Safety and Health Regulation 2017 explicitly requires testing as part of the fitness for work regime. In rail, the Rail Safety National Law requires operators to implement and maintain drug and alcohol management plans. Employers in transport, construction, and resources typically include testing obligations in enterprise agreements or site safety policies, which carry their own legal force.
What Australian standards govern urine and oral fluid drug testing at work?
Two standards apply. AS 4308:2023 (Procedures for specimen collection and the detection and quantitation of drugs of abuse in urine) covers urine-based testing, including chain of custody requirements, specimen integrity, immunoassay screening, and GC/MS confirmation thresholds. AS 4760:2019 (Procedures for specimen collection and the detection and quantitation of drugs in oral fluid) covers oral fluid testing, which is increasingly used for on-site screening due to the shorter detection window and reduced adulteration risk. Laboratory confirmation under both standards is required before a positive result is used to make an employment decision. An employer relying on an unconfirmed immunoassay screen alone to take disciplinary action faces significant legal exposure.
Can an employer conduct random drug testing without individual suspicion?
Yes, in safety-critical roles, provided the right to conduct random testing is documented in a drug and alcohol management plan, the plan has been communicated to workers, and the testing is genuinely random (algorithmically selected, not targeted). Random testing has been upheld by the Fair Work Commission in numerous unfair dismissal decisions as a lawful and reasonable employer requirement in high-risk industries. The testing program must be applied consistently — selective application, or using "random" testing as a pretext for targeting particular individuals, undermines its legal defensibility and may constitute adverse action under the Fair Work Act 2009.
What cut-off levels apply under AS 4308:2023 for workplace urine testing?
AS 4308:2023 specifies initial screening cut-offs and confirmation cut-offs for each drug class. Key confirmation cut-offs include: THC metabolite (cannabis) 15 μg/L; amphetamine-type stimulants 150 μg/L; benzoylecgonine (cocaine metabolite) 150 μg/L; morphine (opioids) 300 μg/L; MDMA 150 μg/L; PCP 25 μg/L. These are the minimum thresholds — some industry schemes or enterprise agreements specify lower confirmation cut-offs, particularly for cannabis in safety-critical roles. Employers should confirm which version of the standard and which cut-off schedule their laboratory is working to, as discrepancies between site policy and laboratory method create defensibility gaps.
What is the difference between a non-negative and a positive result, and why does it matter?
A non-negative result from an immunoassay screen means the sample has exceeded the screening threshold and requires confirmation testing by GC/MS or LC/MS/MS at a NATA-accredited laboratory. It is not a confirmed positive and must not be used as one. A confirmed positive is the result of laboratory confirmation at or above the confirmation cut-off under AS 4308:2023 or AS 4760:2019. The distinction is legally significant: an employer who treats a non-negative screen as a confirmed positive and takes disciplinary action risks an unfair dismissal finding. The result must be reviewed by a Medical Review Officer (MRO) to assess whether a legitimate medical explanation (prescribed medication) could account for the positive before it is classified as a policy violation.
How should employers handle a worker who tests positive due to a prescribed medication?
When a confirmed positive result is returned, the Medical Review Officer must contact the donor to determine whether a legitimate prescription or medical explanation exists. If the worker can demonstrate a valid prescription for the substance detected, the MRO may report the result as negative (explained). However, this does not automatically mean the worker is fit for safety-critical work — some prescribed medications (opioids, benzodiazepines, sedating antihistamines) impair capacity to safely operate plant, drive, or perform safety-critical tasks even when taken as prescribed. Where a prescription is confirmed, the question shifts to a fitness for work assessment: can the worker safely perform the inherent requirements of the role while taking this medication? The employer's drug and alcohol policy should explicitly address prescribed medication management to avoid this being treated as an afterthought.
Drug and Alcohol Testing — OccuSpan Service
AS 4308:2023 and AS 4760:2019 compliant testing programs for high-risk industries.
Fitness for Work Assessment
When a fitness assessment follows a positive result — and how the IROJ governs the determination.
Pre-Employment Screening Guide
Pre-access and pre-employment testing in the context of a full screening framework.
Population Health Intelligence
Aggregate substance use trend data across your workforce without individual exposure.
OccuSpan
Drug and alcohol testing programs that hold up when they need to
AS 4308:2023 and AS 4760:2019 compliant programs for mining, transport, and construction — with NATA-accredited laboratory confirmation, MRO review, and end-to-end chain of custody documentation built in.
See the drug and alcohol testing module