As medical marijuana gains traction as a treatment option for a host of conditions including chronic pain and other conditions, Canadian employers could find themselves grappling with a sticky issue.

"Individuals have the right to equal treatment ... without discrimination on the grounds of disability," says Jan Robinson, managing principal at human resources firm Morneau Shepell.

"Medical cannabis now needs to be viewed like every other doctor-prescribed drug."

But although employers have a duty to accommodate workers' medical conditions, experts say that duty must be balanced with the need to keep the workplace safe. That can be challenging, especially if employees perform duties such as operating machinery.

"There's no hard or fast rule to this," says Natalie MacDonald, an employment lawyer and the co-founder of Rudner MacDonald LLP. 

"It's got to be determined on a case-by-case basis, as most things in employment law do."

Caveat to the duty to accommodate

Experts says the duty to accommodate comes with an important caveat: It...