Toronto, Canada: Marijuana legalization is not associated with an uptick in the percentage of employees consuming cannabis either during or prior to work, according to data provided in a briefing paper by the non-profit research organization Institute for Work & Health. 

Researchers with the group assessed workers’ attitudes and behaviors toward cannabis following Canada’s adoption of adult-use marijuana legalization. (The Canadian government legalized retail cannabis sales for those 18 or older in 2018.) Investigators reported “no change in workers’ consumption of cannabis before or at work” during the years surveyed. 

Consistent with prior studies, researchers acknowledged that those who reported consuming cannabis products while away from their jobs possessed no greater risk of occupational injury than those who abstained. By contrast, employees who reported using cannabis during work hours possessed a nearly two-fold increased risk of accident compared to those who did not. 

“These findings underscore the importance of distinguishing cannabis use at work from cannabis off work,” the paper’s authors concluded. “Rather than considering any cannabis use as an occupational safety risk, workplaces need to reframe their focus to use that is likely to lead to impairment at work and craft policies that center on preventing and managing impairment, as well as fitness for duty.”

Most workplace drug testing policies rely on urinalysis screening, which detects the presence of the inert metabolite carboxy-THC. This metabolite remains present in urine for days, weeks, or even months after past use – long after any psychoactive effects of the drug have worn off. 

By contrast, blood tests detect the presence of THC, cannabis’ primary psychoactive agent. However, THC is also fat-soluble. As a result, it may also remain detectable for several days following past exposure.

NORML has repeatedly argued that employers should not presume that the detection of either THC or its primary metabolite is evidence of impairment. Rather, NORML has called for the expanded use of performance-based tests, like DRUID or Predictive Safety’s AlertMeter.

Lawmakers in several states – including California and New York – have recently amended their employment laws so that most public employers may no longer terminate workers solely based on a positive drug test for the presence of THC metabolites.

The full text of the briefing paper, “Cannabis use by workers before and after legalization in Canada,” is available online. Additional information is available from the NORML Fact Sheet, ‘Marijuana Legalization and Impact on the Workplace.’