What Employers Need to Know About Cannabis in the Workplace

By: Sean O’Donnell

These blog posts are meant to provide educational content and are not to be taken as legal advice.


With the legalization of cannabis for recreational use in October 2018, there comes the question of how this affects workplace policy. As an employer, it is important to understand both your rights, and the rights of your employees, as those rights pertain to the use of cannabis for medicinal and/or therapeutic purposes. 

To be clear before we go any further, the legalization of cannabis does not give an employee the right to use it at work. It is comparable to the use of alcohol in that sense—just because it’s legal to consume does not make it okay to be impaired in the workplace. 

Impairment at Work and Workplace Safety

Both the employer and employee have obligations pertaining to workplace safety. For federally regulated workplaces, the federal government has provided relevant guidelines in Impairment and Cannabis in the Workplace:

Employers should ensure the health and safety of all employees, address physical and/or psychological workplace hazards, work with employee reps to implement a hazard prevention program, and include substance use and impairment policies when the use of cannabis or other causes of impairment presents a hazard.

Employees must work safely, understand the impact that using substances can have on safety, report hazardous conditions to the employer, disclose whether a medical condition or treatment may cause impairment, and follow all instructions provided by the employer relative to the health and safety of its employees. 

It is a shared responsibility to maintain workplace safety. If a prescription medication (including cannabis) is going to present a safety hazard, it becomes more complicated—but ultimately workplace safety is the highest priority. However, the employer has what is called a “duty to accommodate” employees who use cannabis for medicinal purposes.

What is a “Duty to Accommodate”?

The employer has a duty to accommodate an employee’s medical condition up to the point of “undue hardship”. This includes users of medical cannabis and those with substance dependence issues.

How this accommodation applies is assessed on an individual case-by-case basis, but is treated much like any prescription medication that poses a risk of impairment at work. Because the effects of cannabis vary upon individual users, the employer may have the employee undergo a medical assessment to determine if the employee is “fit to work”. The employee will visit a medical professional who will assess and report back to the employer whether the employee is fit, unfit, or fit to work subject to workplace modifications. 

While it is not the right of the employer to know why an accommodation is required, or medical findings, it is within their rights to ensure that an employee is fit to perform the requirements of their job. In the event that an employee is not fit for work, or fit for work with modifications, the medical professional can offer suggestions to the employer on how to assist the employee. It is the responsibility of the employer to make all reasonable attempts to modify the workplace environment in such a way that the employee is able to safely perform the duties of their job.


The employer has a right to prohibit impairment at work, and workplace safety is the number one priority for all involved. Therefore, employees cannot be impaired at work, smoke cannabis at work or endanger the safety of others under any condition. However, the employer does have a duty to accommodate users of medical cannabis and what that accommodation looks like will vary on a case-by-case basis.