Unifor officials say they are not impressed with the way employers are treating legal cannabis.

With the approaching legalization of recreational cannabis in Canada, most employers will be updating their drug policy to reflect the new reality. And while some have chosen to treat marijuana in the same way they do alcohol, others are opting for outright bans. That means many adults across the country won't be able to partake in a joint even where they're off company time, and Canada's largest private sector union is not impressed.

"We're seeing zero-tolerance policies, but it's not just zero-tolerance for impairment, it's zero-tolerance for use," Niki Lundquist, a lawyer for Unifor, a union representing 315,000 workers across Canada told The London Free Press. "It's as though an employer suddenly thinks it has the right to police off-duty conduct."

However, Mario Torres, an Ottawa-based labor-employment lawyer, says there may be legitimate reasons for employers to want to control off-duty consumption.

"The culture of the workplace should determine whether you’ll have an issue as to the time period before your employee arrives to work before consuming cannabis," he said.

Safety concerns like these may be the reason some employers are implementing random drug testing - a practice that Lundquist says Unifor is prepared to fight in court.

"Absent some link to damage to the employer’s operation or reputation, they don’t have that right," Lundquist said. "Employers have fought really hard to subject workers to alcohol and drug testing, and workers have fought back because of the intrusion on...privacy rights."

The longstanding prohibition and the stigmas surrounding cannabis use will likely lead many businesses to write highly restrictive policies. However, as cannabis use becomes increasingly normalized in a post-legalization Canada, it will become much more ethically difficult to control a worker's off-duty consumption. If Unifor is successful in their battle against cannabis bans, that will be one big step in the right direction.