Employees testing positive for cannabis may not be stoned

Since it became legal for South Africans to use cannabis in private, it has become tricky to ensure safety at work. This is particularly important in jobs where impaired judgement, slower reactions or poor coordination could have serious consequences. President Cyril Ramaphosa signed the Cannabis for Private Purposes Act into law in 2024, formalising and regulating private adult use, cultivation and possession. Senior Occupational Medicine Practitioner at Workforce Healthcare, Dr Robin George, says workplace drug tests are limited because a positive cannabis test does not necessarily mean that an employee is currently under the influence or unable to do their job safely. “A positive cannabis test tells you that cannabis was used, or that cannabis metabolites are present in the body. It does not tell you that the person is currently intoxicated or impaired.” He notes that cannabis metabolites remain detectable in the body days or even weeks after use, unlike alcohol, adding that if cannabis is found in one’s system, the user may not necessarily be impaired at the time of the test. “This is where employers can get into difficulty if they treat a positive test as automatic proof of impairment,” says George. “The important question is whether the employee is fit to perform their duties safely. “An employee could, for instance, take a Valium or cough mixture, both legal substances, and be at work in no condition to operate machinery or properly complete their work. I advise companies to use experts to help formulate their company policy and avoid the minefield of complications around substance abuse in the workplace,” he adds. Cannabis dangers George adds that cannabis can affect concentration, judgement, reaction time, balance, coordination, and other functions important for safe work performance. The risks are particularly significant for people who drive, operate machinery, work at heights or perform other safety-critical tasks. He says the key is to take a risk-based approach rather than treating every positive test in the same way. “Employers should ideally have policies that define what it means to be fit for duty and explain the organisation’s approach to cannabis use and impairment. “Supervisors should also be able to recognise and objectively document possible signs of impairment, such as slowed responses, poor coordination, confusion, reduced alertness or difficulty following instructions.” Fitness-for-duty assessment George says that when there is concern, a fitness-for-duty assessment by a health professional may be appropriate. “Workplace substance policies need to move beyond a simple ‘positive test equals misconduct’ approach. The nature of the job, the potential safety risks and evidence of actual impairment all need to be considered.” He adds that employers should also remember that problematic cannabis use can be a health issue. Where appropriate, employee assistance, counselling, rehabilitation and other wellness interventions can form part of a responsible substance management programme. For employers, the message is to interpret testing carefully. “Employers have to balance two important responsibilities: protecting the health and safety of everyone in the workplace while also dealing fairly with employees,” says George.