Under Canadian law, it is reasonable for employers to expect employees to conduct their work while sober.
Yet, with the legalization of recreational cannabis expected later
this year and impairment difficult to detect, employers are concerned
about workplace safety.
“When it comes right down to it, I feel like we don’t really
understand what the safety implications are,” said Nancy Carnide,
post-doctoral fellow at the Institute of Work and Health in Toronto.
“Using it before work, using it at work, certainly that’s
problematic,” she said during the keynote address at a human rights
conference in Toronto in April.
“But using it on a Friday night… some people should be fine on a
Monday morning and others may not be. That’s dependent on the person.”
Cannabis is a complex plant in terms of its tetrahydrocannabinol
(THC) and cannabidiol (CBD) components, said Mark Ware, director of
clinical research at the Alan Edwards Pain Management Unit at the McGill
University Health Centre in Montreal, and vice-chair of the task force
that provided guidance to the Canadian government in its effort to
legalize and regulate marijuana.
“When you talk about cannabis, you’re talking about a complex
botanical substrate and THC is the predominant psychoactive drug,” he
said at the conference.
“It’s not a simple, easy subject to tackle... and coupled with that is individual responses are hugely varied.”
“The amount people use, the way they use it, the effects that it has
are enormously variable and this is very difficult to capture in simple,
Type of cannabis, the context in which it is ingested, and individual
response each play a role in the drug’s effect, clouding what
constitutes impairment, according to Ware.
Further confusing the discussion is the fact that impairing effects
of THC can reside within the human body for anywhere from six hours to
28 days, he said.
Cannabis versus alcohol
Comparing cannabis to a drug like alcohol is a mistake, said Dan
Demers, senior manager for strategic business development at CannAmm
Occupational Testing Services in North Bay, Ont.
While alcohol’s effects on the human body can be accurately predicted
and timed, the same linear patterns don’t exist with marijuana, he
“The lingering effects of cannabis — the hangover — is one that sort of sticks around far, far longer than alcohol.”
“It’s like comparing an apple to a hubcap,” said Demers. “It’s so
different. Alcohol presents itself in a way that is clearly impairing.
People have difficulty annunciating. Their fine and gross motor skills
kind of go out the window. It’s pretty obvious after two drinks that
somebody’s been drinking.”
“It’s more subtle with marijuana. Marijuana affects different regions
of the brain and functions in an entirely different way. It’s more
difficult… to identify on the job. You can talk to somebody who’s high
and they’re going to be able to annunciate just fine. They may even be
able to walk the shop and you have no idea… It presents itself
differently, which is one big piece that people are missing.”
With legalization on the near-horizon, Canadian employers should
expect consumption to increase across the board — in both administrative
and safety-sensitive roles, he said.
Cannabis is a “more subtle drug in terms of the symptoms that people
would see,” said Scott MacDonald, assistant director of research at the
University of Victoria’s Canadian Institute of Substance Use Research.
“I’d be much more concerned about somebody drinking on the job than
smoking a joint. Alcohol is by far the worst drug there is in terms of
safety, outstripping all the other drugs combined.”
Employers are putting a major emphasis on cannabis, with reasons based on morality rather than science, he said.
“We should be looking at what are the major causes of accidents and
focusing on those issues, not spending 90 per cent of our attention on
illicit drugs when they’re rarely used in the workplace,” said
MacDonald. “There’s all sorts of reasons for accidents in the
workplace... alcohol and drugs only count for a very tiny proportion of
all types of accidents.”
The nature of marijuana means there is no equivalent breath-testing
device to determine immediate impairment, said Barry Kurtzer, medical
director of DriverCheck, a workplace drug testing company based in Ayr,
As such, employers cannot simply rely on a drug test as a standalone
tool to identify workplace impairment, but must create a more meaningful
assessment program that sees tests run parallel to documented events
with multiple eyewitnesses, he said.
More research and court direction are necessary before workplace drug
testing will be considered “a beneficial tool versus a punitive witch
hunt,” said Kurtzer.
With definitions of impairment and appropriate testing still up in
the air, HR practitioners will have several issues to consider if faced
with a scenario of suspected cannabis usage, said Lisa Stam, employment
lawyer and founder of SpringLaw in Toronto.
If the employee in question has declared an addiction, or if the
usage is deemed medical in nature, the situation could require workplace
accommodation, she said.
“Your hands are very tied if it’s medical marijuana,” said Stam.
“You’ve got privacy and human rights law that are going to really impact
what you can do.”
Testing is an option for workers in safety-sensitive environments,
but not in office settings, she said. And without a safety-sensitive
job, obvious behaviour or clear performance impact, employers cannot
force staff to disclose usage.
“When it comes to marijuana, we’re all going to be like awkward
teenagers about it for a while… and have very different, inaccurate,
non-scientific perceptions of whether someone’s impaired, so there’s
going to be quite the learning curve in most workplaces,” said Stam.
“Avoid the moral judgment of whether someone should or should not be
consuming marijuana, which is shortly going to be a legal thing. I think
that’s going to be one of our biggest cultural shifts that everyone’s
going to have to get over.”
Safety-sensitive employers looking to implement a fit for duty
standard need to balance interests of safety and cut-off limits with
human rights and labour legislation, said Demers. This type of policy
can include compliance standards such as pre-employment, post-incident
and reasonable suspicion testing.
“Using cannabis on your own time is not acceptable in those
occupations that are inherently dangerous and complex,” he said. “What
that means is that what you do on your own time now becomes your
While a policy is not an obligation for all employers, they should,
at the very least, reflect on their business activity and need for
workplace standards, said Demers.
“Any organization would benefit from a policy that addresses
substance use in the workplace, whether they’re safety-sensitive or
not,” he said.
Post-legalization, employees who spend time in the United States
still won’t be able to cross the border while possessing the drug,
according to Kurtzer.
“Policy is going to be very important as we take this on.”
Advice for HR
Going forward, policy should shift towards the impact a drug could have on an employee’s ability to do their job, said Stam.
“What will be tricky is that you used to be able to have more of a
zero-tolerance policy approach, because it was an illegal substance, and
you could hang your hat on that,” she said. “You can’t do that anymore…
Tying it to the job description itself is probably one of the safest
things to do.”
“Zero-tolerance policies are always fairly dangerous because you
don’t distinguish between that recreational and medical issue. Anytime
it bumps up against human rights, there has to be an individual
Extending workplace drug policies to include cannabis alongside alcohol remains a solid starting point, however, said Stam.
“Then you probably have yourself largely covered off, other than the
impairment testing issues. And for that, we have to wait for science to
catch up, frankly.”
Policies should start conservatively, but be flexible, said Carnide.
“It’s a very tricky thing to really make a firm, clear-cut decision
on at this point,” she said. “The safest thing to do in the absence of
knowledge is really to be as conservative as possible... We have a long
way to go before we understand what’s actually happening in Canadian
Employers would be wise to call upon occupational health specialists
and other experts to write and review policy, as there can be different
approaches — depending on the province and collective agreements, said
“Sometimes, having an external set of eyes from an expert on these
things is very important, especially in these early days,” he said.
In the absence of research, training and education of both supervisors and staff are crucial, said Carnide.
“Educating workers about the potential risks, if any, on workplace outcomes is absolutely essential,” she said.
Health effects of cannabis
Short-term effects of cannabis on the brain can include:
• sleepiness (fatigue)
• an impaired ability to remember, concentrate, pay attention
• anxiety, fear or panic
• a reduced ability to react quickly.
Effects can be felt within seconds to minutes of smoking, vaporizing
or dabbing cannabis. These effects can last up to six hours or longer.
If a user eats or drinks cannabis, effects can occur within 30 minutes to two hours and can last up to 12 hours or longer.
Source: Government of Canada