Wednesday, 13 March 2019 16:17

Legalisation of cannabis poses headaches for construction industry

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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 Manager at 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.

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.

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.”

Last modified on Wednesday, 13 March 2019 16:27

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