Legalisation of cannabis poses headaches for construction industry

The ruling by the Constitutional Court on 18 September 2018 that the private use of cannabis would be decriminalised has raised important questions for the construction industry. Gerhard Roets, Construction Health & Safety Managerat the Master Builders Association North, says that companies and their health advisors need consider the impact of the new legislation on their business from an occupational health and safety management view point.

“One needs to understand that the Court’s ruling only decriminalises the possession, consumption and private cultivation of cannabis for private use in a private space. This means that employers remain responsible for providing and maintaining a work environment that is safe for all, as per the Occupational Health and Safety Act 85 of 1993 and applicable regulations,” Roets says. “In practical terms, the issue for employers is how to determine whether workers are under the influence of cannabis or not when they come to work.”

The problem is that the metabolism of cannabis is complex. Delta 9-tetrahydrocannabinol (THC) is the psychoactive substance in cannabis that provides the “high” that users seek. It is most abundant in the flowering parts of the female plants, and its effects are heightened when it is used in a cigarette. 

By contrast, hemp oils derived from cannabis seeds are used medicinally – the health benefits are associated with the non-psychoactive cannabidol (CBD). However, hemp products may contain a certain quantity of THC, and would thus also show up in drug tests. 

All of this raises two issues for employers. One is that a standard urine test is no longer useful, because it simply screens for the metabolites of cannabis, which may be present long after the psychoactive effects of cannabis have worn off – some days, in the case of recreational, occasional users, to weeks in the case of habitual users. When cannabis was illegal, the urine test was considered enough to institute disciplinary action, but clearly this will no longer suffice as the drug may have been used in the workers private time.

The second issue is that to date there is no real standard in South Africa for determining whether an individual is over or under some sort of limit, as there is in the case of alcohol. In other words, merely having used cannabis in the past is not necessarily an indication that the individual is at present “under its influence”. Saliva tests only screen for THC, so the hope is that they could be used to determine whether a person is actually “under the influence” of cannabis, and thus a health and safety risk. Considerable research has been done internationally on testing for driving under the influence of cannabis, and some jurisdictions have specified limits of cannabis in the saliva and blood. 

“This research could be incorporated into South African workplace practice, but it is critical that we start by directing our focus to the development of sufficiently sensitive on-site tests in order to keep our work places safe” Roets says.

Because this legislation creates grey areas in terms of both the law and practice, the MBA North is advising members to proceed with caution. Decriminalisation could possibly result in increased use of cannabis recreationally, and it is presumed that such changes are likely in the construction industry which (anecdotally) is considered to have a higher than average incidence of substance abuse. It is thus important that employers and their health advisors inform themselves about cannabis and related products, and their effects on the human body, as well as legal precedent as it is created. 

It is of particular importance that substance abuse and testing policies are amended in line with the changed circumstances, and that employees, especially line managers, are given training in this regard. 

The policy should regulate cannabis in the same manner as alcohol and other drugs. The policy should provide clear guidelines that prohibit the use of such substances at the workplace, which should be classified as a public space, and thus falling outside of the ambit of the Constitutional Court ruling. 

As in all cases where an employee is suspected of being under the influence of any drug, he or she must be denied access to the work area and steps taken to undertake testing as mandated in the policy. The policy should stipulate the disciplinary procedures and sanctions to be applied. 

“Health and safety remain paramount on construction sites and managers need to know how to identify individuals that might be under the influence of cannabis,” Roets concludes. “However, until the testing issue is resolved, and the state of being ‘under the influence of cannabis’ is medically defined, employers will have to tread carefully.” 

The MBA North, in partnership with SAFCEC an IWH, will be hosting a seminar on 27 November to help members come to grips with the implications of this new legislation. For more information, please


About the Master Builders Association North

The Master Builders Association North is the amalgamation of the former Master Builders Associations of Johannesburg (founded in 1894) and Pretoria (founded in 1903). The organisations merged to form the Gauteng Mast Builders Association in 1996, and was renamed Master Builders Association North, representing four regions: Gauteng, North West, Mpumalanga and Limpopo. It is a chapter of the Master Builders Association South Africa. 

Based in Halfway House, the Master Builders Association North represents the interests of employers in the building and allied trade industries in the abovementioned four regions. It aims to serve its members by facilitating best practice within its membership and the building industry as a whole. 

Contact details

MBA North

Boitumelo Thipe

Marketing & Business Development Manager

Tel:           011 805 6611


About the Author

Share on

Share on facebook
Share on google
Share on twitter
Share on linkedin