Cannabis is the most commonly used illegal drug in New Zealand. If cannabis is legalised following the referendum, it will become regulated and more widely accessible.
Studies have proven that both short-term and long-term use of cannabis can impair staff performance and impact on health and safety.
"Cannabis particularly affects people operating machinery and tools and driving vehicles," said Kirk Hardy, CEO of The Drug Detection Agency (TDDA).
"Drug-impaired employees tend to cause more accidents and have slower reaction times. Cannabis use can reduce mood, memory, motor-coordination, and decision-making ability."
There is little correlation between recent consumption of cannabis and impairment.
"Research shows that cannabis can affect a user days after a moderate social dose, and without the user even knowing they are impaired," Hardy said.
Health and safety at work is paramount. Employers must eliminate the risk of impairment by drugs where it poses a risk to health and safety.
Employers may test for traces of alcohol and drugs to assess the risks an employee may pose to themselves or others. Drug and alcohol tests may take place pre-employment, for reasonable cause and post-accident or incident, and in near-miss situations. Random testing is generally reserved for safety sensitive roles, such as in forestry, farms, and factories.
Workplace drug testing is an effective tool for identifying and mitigating health and safety risks by checking for the presence of drugs and alcohol in a person's body.
Otherwise, employers should not dictate what an employee does outside of work.
While workplaces may continue to enforce cannabis testing procedures for staff in safety-sensitive roles, employers may require more robust methods of testing for staff in other roles.
Employers will need to balance their health and safety responsibilities with allowing staff to engage in lawful activities: like smoking cannabis in their spare time.
Testing procedures
Drug testing procedures under the ASNZ testing standards measure traces of THC, the psychoactive chemical in cannabis.
The most common and reliable testing procedure for THC is urine sample testing, a procedure that can accurately identify cannabis use over the past 30 days.
Oral fluid testing can identify more recent consumption of cannabis by detecting traces of cannabis use over the last 24 hours. A developing technology, oral fluid testing is not as reliable as urine sample testing. For example, it will not detect cannabis if someone swallows THC gel caps or gummies.
Drug testing procedures detect the risk level of impairment rather than "actual impairment" or "fitness to work".
Actual impairment depends on many factors, including the type of substances and effects on the individual, and how long before the test drugs were consumed. If staff smoke a spliff during their annual holidays, they may have THC present in their system but have not been impaired at work.
If cannabis is legalised, workplaces may need to consider using both urine and oral fluid testing to identify risk of impairment, particularly for staff in non-safety sensitive roles.
Tips for reviewing drug and alcohol policies:
If cannabis is legalised, employers should consider the following tips for reviewing drug and alcohol policies:
• Require staff to attend work in a fit and proper state. Staff have a responsibility to work safely and properly perform their duties. No employee should be under the influence of cannabis while at work. Nor should they light up a joint on their break.
• Clarify expectations at work events. Clarify whether staff can consume cannabis at Christmas parties and other work-related events. If cannabis is allowed on an employer's private property, remind staff of your expectations around behaviour. Consider alternative transport arrangements to keep staff safe.
• Review testing procedures. Consider whether your current procedures are reasonable, particularly for staff in non-safety sensitive roles. What level of THC would you consider acceptable within an employee's system? Employers must balance an employee's entitlement to engage in lawful activities with keeping their workplace safe.
- For more information, see Julia Shallcrass' KiwiBoss webinar "Drug and Alcohol Policies and Testing 2020" through CCH Learning, live on 13 October 2020 and on demand.
