Pretoria - The 2018 Constitutional Court decision to legalise the consumption of cannabis “in private” has created a number of challenges for employers and employees, according to experts.
Among them is the question on whether an employee could lose their job by consuming dagga outside working hours, especially in safety-sensitive industries where workers are prohibited from being under the influence of intoxicating liquor or drugs.
This is among one of the legal and ethical dilemmas raised by medico-legal experts from the University of Pretoria in a recent research article in the South African Medical Journal.
Dr JB Laurens, until recently a senior forensic toxicology researcher and lecturer at UP, and Professor Pieter Carstens, a professor of criminal and medical law, said the decision to legalise the consumption of dagga created challenges for employers and employees because labour laws such as the Occupational Health and Safety Act and the Machinery and Occupational Safety Act made it an offence for staff to be under the influence of intoxicating liquor or drugs at work.
To ensure that constitutional rights to privacy, freedom of religion, autonomy and other rights were properly balanced against the right of other members of the public to safety and health, Laurens and Carstens called for a “legally defensible” approach to the regulation of dagga by adopting a similar approach to regulation of legal alcohol use.
They noted, for example, that the psychoactive component of dagga was excreted slowly from the human body and could still be detected several days after having been consumed.
The psychoactive component, which is absorbed quickly when smoked and produces a rapid euphoric effect on the brain, peaks concentrations within nine minutes of the first puff. Effects can last for two to four hours, potentially impairing psychometric tasks, memory, sense of time, motor co-ordination and reaction speed.
They noted that the elimination half-life of THC – the chemical responsible for most of marijuana's psychological effects – was approximately one day in casual smokers and three to five days in chronic smokers, but it was also possible for measurable levels to be detected in passive smokers.
The methods used to test employees for dagga usage could also create difficulty.
While blood testing was seen as the best way to estimate impairment, collecting specimens of blood was very invasive and also required specialist staff.
While saliva and urine testing was seen as scientifically accurate and less invasive, the concentration levels could not necessarily be used to reach accurate conclusions about the level of impairment or intoxication.
They noted that it was essential that company policies on prohibited substance testing respect human rights to freedom and autonomy, and that employees provide consent for such testing.