News

Avoid heavy machinery for 24 hours after using cannabis

Published on June 13, 2025 by Pat Bulmer

Workers should avoid safety-sensitive tasks for at least 24 hours after using cannabis, a new study advises.

The Canadian Centre of Recovery Excellence (CoRE) has released the study, Cannabis in Safety-Sensitive Industries, which is undergoing peer review.

Written by Dr. Charl Els, a clinical professor in psychiatry and medicine at the University of Alberta, and endorsed by the Occupational and Environmental Medical Association of Canada, the paper updates guidance issued in 2018.

It is meant to help “OEMAC members, employers, and stakeholders understand the effects of cannabis use on safety-sensitive and decision-critical jobs.”

“Accessing seven years of case law and new scientific evidence, this research offers useful recommendations for employers and health professionals to ensure workplace safety,” an email accompanying the news release said.

A key recommendation is: “Workers should avoid safety-sensitive tasks for at least 24 hours after using cannabis, as scientific evidence suggests potential for residual impairment beyond immediate intoxication.”

Even if cannabis users don’t appear impaired, “cannabis impairs cognitive, motor, and psychological functions through intoxication, residual effects, withdrawal, and chronic use,” the release said.

“These effects can persist long after consumption, especially with frequent or high-dose use, posing safety risks even when intoxication is not obvious,” a report summary says.

But each case must be evaluated on its own, the report adds.

“In contrast to the U.S., employers in Canada must make case-by-case evaluations of impairment,” the release said.

“Canada’s case-by-case approach empowers employers to make informed, fair decisions about cannabis use and workplace safety. One-size-fits-all policies simply won’t stand up — legally or scientifically,” said Kym Kaufmann, CoRE CEO.

CoRE is an Alberta government agency.