Study finds workers who use cannabis after work at no greater risk of injury

Aug., 3, 2023 – A study published by the Institute for Work & Health (IWH) suggests workers who use cannabis are at greater risk of having an injury at work — but only those who use cannabis during or before a work shift.

The study, published in the Canadian Journal of Public Health Workers, says workers who only use cannabis outside of work hours are at no greater risk of getting injured at work than workers who do not use cannabis at all. This study claims to be the first to distinguish cannabis use during or before a work shift from use outside of work hours when examining its relationship with work injury risk.

“Our study findings demonstrate that it’s important to consider when cannabis use is taking place,” said Nancy Carnide, IWH lead scientist on the study, in a release. “Rather than considering any cannabis use as an occupational safety risk, I think employers may need to reframe their approach and focus on use that is likely to lead to impairment at work.”

The study finds workers who report consuming cannabis during work or before work are twice as likely to get hurt on the job as those who don’t use cannabis. Regardless of whether a worker’s job is safety-sensitive or not, workplace cannabis use poses a risk to future workplace injury, the study shows.

The study was conducted as part of a research project that began in June 2018, before the legalization of non-medical cannabis in October 2018. The project’s objective was to understand changes in workers’ cannabis use, and their perception of use, before and after legalization.

“Employers’ concerns about workplace impairment associated with cannabis use shouldn’t be minimized. Workers should be educated about the workplace safety risks of using cannabis before or during work hours, which we clearly observed,” says Carnide.