Cannabis Impairment in the Workplace: Easy to Discuss, Difficult to Detect

Published on July 27, 2017 · Last updated July 28, 2020
Shot of coworkers using a computer together in a modern office

In advance of Canada’s proposed legalization of adult-use cannabis, the Canadian Centre for Occupational Health and Safety has issued guidelines “to help workplaces prepare for the potential challenges and impact this new legislation may have on workplace safety.”

The CCOHS’s nearly 10,000-word white paper addresses everything from “the potential for impairment as part of a hazard assessment” to establishing “a concise policy and program on the use of any substance that can cause impairment.” But one major component of the story is tellingly under-addressed: exactly how “workplace impairment” will be determined.

“Unlike testing for blood alcohol levels, obtaining a positive test result that indicates the presence of cannabis is not necessarily a clear indication of the risk of impairment,” observes CCOHS’s Workplace Strategies: Risk of Impairment from Cannabis. “Therefore, there is a reliance on observation to determine possible impairment (e.g., if there is a change in behaviour or ability) that could lead to the risk of injury, illness, or incident to that person, others or the environment.”

Among the areas of observation suggested by the CCOHS: “Does the person have the ability to perform the job or task safely (e.g., driving, operating machinery or equipment, use of sharp objects)? Is there an impact on cognitive ability or judgement? Are there other side effects of the medical condition or the treatment that need to be considered?”

Such questions abound, but conclusive answers about how best to determine real-time cannabis impairment remain elusive. (One semi-promising possibility: sobriety tests, involving everything from classic stand-on-one-foot physical challenges to computer quizzes that track cognitive impairment.)

For now, we can only appreciate the mystery and quest for clarity around identifying marijuana impairment in the workplace, which is ably explored in Ronald Alsop’s BBC report The Hazy Issue of Weed and Work.

“Drug testing practices and laws vary widely across the globe,” writes Alsop. “In Norway, for example, drug testing is considered a violation of the personal integrity of an employee or job applicant and should be conducted only when strictly necessary, such as to protect the safety of the worker or other people.”

Meanwhile, “Canadian employers generally have much less freedom to conduct drug tests than US businesses,” reports Alsop, who hits up Toronto lawyer Darryl Hiscocks for specifics: “Pre-employment testing isn’t typically allowed and most employers can’t do random testing either,” as Hiscocks tells Alsop. “Employers often feel caught in the middle. They have to meet their health and safety obligations such as with workers who may drive a vehicle, but they also have to accommodate medical marijuana users and employees addicted to marijuana, which can be considered a disability.”

Onward. Stay tuned.

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Dave Schmader
Dave Schmader
Dave Schmader is the author of the book "Weed: The User's Guide." Follow him on Twitter @davidschmader
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