By Glenn Dobson, CEO, The Drug Detection Agency

With the rise in cocaine detections in workplaces, here is what infrastructure businesses need to know.

In infrastructure, even a small lapse in concentration can lead to serious issues. The latest workplace drug data from The Drug Detection Agency (TDDA) suggests that employers should be paying close attention to emerging risks. That’s why we recently launched our Q4 Imperans Report, a quarterly workplace drug trends report. The report empowers New Zealand infrastructure businesses to engage in proactive workplace risk management.

Cannabis remains the most prevalent substance detected in workplace drug testing, although detections eased in many regions following a third quarter peak.

Detection of amphetamine-type substances (ATSs), including methamphetamine, were up nationwide in the fourth quarter of 2025, representing a modest quarter-on-quarter increase. Cocaine detections jumped 148 per cent from the previous quarter.

Among all positive TDDA results in the fourth quarter:

• cocaine detections rose sharply by 148 per cent quarter-on-quarter, now present in 3.7 per cent of positive tests (up from 1.5 per cent in the third quarter)
• cannabis remains the most prevalent substance, present in 67.5 per cent of positive tests, easing 3.6 per cent from its third quarter peak
• ATSs were present in 24.5 per cent of positive tests (up 1.2 per cent from the third quarter).

The data, collected through our Imperans management platform, comes from 27 sterile clinic locations and more than 60 mobile clinics throughout New Zealand. It points to three broad shifts in substance use patterns nationwide: increasing regional divergence in ATSs, cannabis remains on top in testing, and a concerning rise in cocaine detections, significantly in Bay of Plenty, Auckland West and Waikato.

TDDA warned employers in previous quarters that cocaine use was increasing across the nation, and fourth quarter data shows that this trend nearly doubled over the festive season. Businesses in the Bay of Plenty area need to take action immediately as cocaine detections, which barely registered previously, rose to nine per cent of positive tests. Cocaine causes overconfidence, reduces focus and concentration, correlates with bad judgement, and causes erratic behaviour. For infrastructure businesses operating heavy machinery and working in hazardous environments, these side effects greatly increase workplace risk.

Our fourth quarter data also shows that drug use is changing from region to region, rather than moving in a single national direction. ATSs recorded sharp increases, particularly in Auckland West, Gisborne, Hawke’s Bay, Northland, Southland and Wellington, while easing in some areas such as Canterbury, Manawatū-Whanganui and Taranaki. At the same time, cannabis detections declined in many regions after peaking in the third quarter, although some areas experienced a bounce back.

Use of opioids, which are a real threat to infrastructure workforces, increased across multiple regions, reinforcing the need for closer monitoring. Prescribed or otherwise, these drugs cause loss of focus and drowsiness, significantly degrade a worker’s ability to operate heavy machinery and respond to hazards, and impact a person’s ability to make sound judgments under pressure.

What all this data reinforces is the need to stay proactive. As businesses recruit, onboard new staff or adjust workforce needs, clear expectations become critical. Fit-for-purpose substance use policies, supported by pre-employment testing, regular testing programmes, and ongoing training and education, help organisations manage risk early and prevent issues from arising on the job.

When growth in detection continues across successive quarters, or when drug trends change significantly, it is a signal that employers should not ignore. The priority is stopping trends from becoming established behaviours in your workplace.

For infrastructure employers managing dynamic worksites and regional operations, reviewing policies, embedding pre-employment testing into recruitment processes, maintaining regular and random testing programmes, and investing in education can help reduce risk and maintain safe, productive projects throughout the year.

For more information, visit https://tdda.com/.