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Cannabis in the workplace – Mthembu an uncertain first step

Author: Yuri Tangur – Candidate Attorney

*Supervised by Lavery Modise – Consultant


On 18 September 2018, the Constitutional Court decriminalised private cultivation, possession and use of cannabis.[1]

At the time the judgment was handed down, it seemed unlikely that the workplace would fall within the scope of the judgment and unlikely that any reasonable employee would attempt to consume cannabis while at work. However, contrary to what the judgment contemplated, it happened that an employee consumed the drug outside working hours and thereafter reported for work. The Cannabis for Private Purposes Bill is currently going through the legislative process and it is accordingly opportune to review the Mthembu case.

Ground Zero: Mthembu

In the Mthembu matter, some employees may have had the mistaken belief that since private use of cannabis had been decriminalised, employers would find nothing wrong with consumption of the drug outside working hours by an employee, without knowing that the drug would stay in their systems during working hours in a dangerous working environment (the wood and chip industry in this case).

The employees were dismissed for misconduct (testing positive for cannabis while at work). After the employees were dismissed, they referred the dispute to the Commission for Conciliation, Mediation and Arbitration (CCMA), which found the dismissal to have been fair on the basis of the reasonableness of the employer’s zero-tolerance policy and because the employees were aware of the policy.

This case is ground zero for what could be many employment matters related to cannabis and is especially important since legislative clarity is expected later this year as the Cannabis for Private Purposes Bill develops. Until then, both employers and employees must navigate through the uncertainty. What follows are some potential concerns that employers should address.

Substantive fairness

The commissioner rightfully considered substantive fairness and the guidelines in cases of dismissal. The reasoning of the commissioner is clear but, despite the regular discussions at the workplace, the employees seemed genuinely ignorant about the application of the employer’s policy in relation to use of cannabis in the workplace.[2] Formally, the employer followed the correct procedures. However, in relation to substantive fairness, it is arguable that the employees could not have reasonably been expected to be aware of the prohibition on having cannabis in their systems while at work if it had not been specifically explained to them prior to their dismissal, nor does it appear to have been specifically provided for in workplace policy.

Zero Tolerance

The employer’s policy seems to have been intended to guard against employees “being under the influence of an intoxicating substance while on duty” and to apply a zero-tolerance approach toward substance abuse. It is not clear, however, what the threshold for being under the influence of an intoxicating substance is, or whether a spoonful of cough medicine containing alcohol would push an employee over the limit. These uncertain aspects would need to be addressed explicitly in an employer’s policy to prevent confusion.

Medical Testing

In this case, a trained medical professional conducted a test with the consent of the employees and samples were sent to a laboratory for further testing. Medical testing of employees is regulated by section 7 of the Employment Equity Act (EEA) which briefly provides that medical testing of an employee is prohibited unless legislation permits it or it is justifiable in light of the prevailing circumstances at the time of testing.[3] Consent might not always be possible, especially in circumstances where a clause in an employment contract “giving consent” might be found to be unlawful and unenforceable. This lack of consent may compromise employers and consequently attract liability.

It is also unclear whether, when an employer conducts a test, it would be doing so to ascertain the mere presence of a substance or whether there is a threshold to be met regarding the nature of various substances and duration of the effect of the intoxication. Even if it was clear, the Labour Relations Act (LRA) requires that such rules be both valid and reasonable and that the employee has some form of awareness of the rule.[4] Another potential issue may be the validity of the form of testing when considering whether a dismissal was fair.

In upholding the employees’ dismissal, the commissioner considered the highly physically dangerous working environment. It seems that employees who work in a highly dangerous environment are more susceptible to dismissal than employees who work in a less dangerous environment.

Would mere detection of cannabis in employees justify dismissal in all cases that are considered relatively dangerous, particularly considering that eating forms of cannabis can also negatively influence the cognition of employees in circumstances where such consumption happens without an employee being aware of having done so?


Workplace policies about cultivation, use, and possession of cannabis need to be clear, and dismissals (despite zero-tolerance policies) would need to be both procedurally and substantively fair. Medical testing as it currently stands remains problematic. In order to have certainty it may be a good idea to have a threshold for cannabis found in the blood stream and to take into account that consumption may have taken place outside of a particular period, as well as to provide written reasons to justify any action an employer may take. This is uncharted territory that is likely to change with the Cannabis for Private Purposes Bill, although as it stands, it requires significant amendment to address these concerns.


[1] Minister of Justice and Constitutional Development and Others v Prince (Clarke and Others as intervening parties, Doctors for Life International Inc as amicus curiae) and related matters 2018 (10) BCLR 1220 (CC).

[2] Par 35, 68, 86. The employees consistently and without hesitation admit that they smoked outside of work. That seems to indicate that they have a genuine belief that what they did was not in contravention of the employer’s policies. It is also unclear to me, and I’m sure other employees (since everyone takes different periods of time to metabolise the substance out of the system) when they would be able to consume the drug in relation to work.

[3] So far it seems that parties have to resort to litigation to determine what is justifiable or not.

[4] LRA Schedule 8(7) guidelines in cases for misconduct.


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