Positive dagga test at work? Why it may not be grounds to fire you

A positive cannabis test at work does not prove you were high on the job, and South Africa's Labour Appeal Court has already ruled that firing an office worker on that basis alone was automatically unfair (Bowmans). The issue is back in the news after an occupational doctor warned employers on 12 November not to treat every positive test as misconduct (The Citizen).

"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," said Dr Robin George of Workforce Healthcare (IOL).

Why doesn't a positive test prove you were high?

Cannabis stays detectable for days or even weeks after use, long after the effects wear off. Alcohol clears far faster (The Citizen). So a worker who smoked at home over the weekend can still test positive on Wednesday.

Urine tests do not reliably show recent use or impairment, according to a 2025 South African Medical Journal article by J B Laurens of Expert Laboratory Services, cited by IOL. The same article notes that some effects, such as on memory and time estimation, can last up to 24 hours, so use the night before can still matter.

What did the Labour Appeal Court decide?

In April 2024 the Labour Appeal Court ruled on the case of a Barloworld Equipment category analyst who was dismissed after a urine test came back positive for cannabis under the company's zero-tolerance policy (Bowmans). The full judgment is published by De Rebus.

The court found:

• The dismissal was automatically unfair because it amounted to unfair discrimination, and the employee was awarded 24 months' pay as compensation.
• The zero-tolerance policy was too broad when applied to an office worker who did not work with heavy machinery.
• Alcohol users could test negative the next day while cannabis users could not, which put cannabis users at a disadvantage.

Source: Bowmans

The court also stressed that the result may differ for employees in other roles and environments (Bowmans).

Can you still be fired over cannabis?

Yes, in some cases. The ruling did not ban workplace drug testing, and testing still needs a rational reason (IOL). The Occupational Health and Safety Act bars employers from letting anyone who is, or appears to be, under the influence of drugs enter or stay at work (IOL).

Lawyers reading the judgment say employers relying on a substance policy must prove intoxication, unless they can show that a zero-tolerance rule is an inherent requirement of that particular job (Bowmans). Drivers, machine operators and people working at heights are where the safety risk is highest, Dr George says (The Citizen).

Is cannabis legal at home now?

The 2018 Constitutional Court ruling in the Prince case protects adults who grow, possess and use cannabis privately for personal use. Buying and selling remain illegal (IOL).

The Cannabis for Private Purposes Act was signed in May 2024, but it only takes effect on a date the President proclaims, so its detailed limits are not yet enforceable (IOL).

What should employers check instead?

Dr George's advice to employers is a risk-based approach (The Citizen):

• A written fitness-for-duty policy that explains how the company deals with cannabis use and impairment.
• Supervisors trained to spot and record signs such as slowed responses, poor coordination or confusion.
• A fitness-for-duty assessment by a health professional when there is concern.
• Employee assistance, counselling or rehab where cannabis use is a health problem.

If you believe you were dismissed unfairly, the CCMA or a bargaining council handles unfair dismissal disputes, and a labour lawyer or your union can advise on your specific case.