SUMMARY
There is increasing concern regarding the impact of the consumption of cannabis by construction site workers on workplace safety and performance. This preliminary study explores the use of cannabis as a psychotropic drug and its consequences and effects on construction workers, considering the decriminalisation of its private use and personal consumption in South Africa. These consequences and effects can be characterized as being behavioural, perceptual, physiological, emotional and cognitive. This study is a precursor for a more detailed ongoing study. The article was developed based on a review of empirical and theoretical studies previously published in a wide range of journals and commissioned reports. Literature relating to drug and substance use in the construction workplace was obtained from research databases. The keywords “cannabis” and “construction industry” were used to search the databases. Of the number of related articles found, a total of 41 articles and reports were cited in the study. The study reveals that cannabis use has short-term health effects such as acute mental illnesses, which could result in impaired reasoning and perceptions. Long-term effects of frequent and continuous cannabis use include respiratory infections and hyperactivity. Furthermore, the after-effects of the use and abuse of cannabis by construction workers poses numerous threats to the workplace safety of the construction industry. The article identifies loss of concentration and low productivity on site, abnormal and irrational behaviour, absenteeism from work and poor work quality as impacts of cannabis use on construction sites. The article highlights the need for site supervisors and construction employers to introduce improvement mechanisms to control the use of cannabis on construction sites.