Pot Use in the Workplace: Legal Q & A


OCT 3, 2018  By Hugh McPhail, Q.C.

ALBERTA: In less than a month, possession of cannabis will become legal. October 17th is the date chosen by the federal government to make this profound change for Canadian society.

McLennan Ross LLP will be holding a webinar on the topic of legalized cannabis on October 17th where this topic will be addressed in detail. However, for those who want some basic answers before or who are unable to listen in to the webinar, we offer some answers to questions that many employers are probably thinking about:

1. Are all cannabis products a concern for employers?

No. Cannabis includes many chemicals. THC is the troubling one because it has an impairing effect and that effect continues even after a period of abstinence. CBD is another chemical in cannabis and there are some products which contain high concentrations of CBD and virtually no THC. There is some evidence to support medical benefits from the use of CBD products. It seems to be accepted by the medical authorities that CBD is not impairing. Many of the physician authorizations have been for the use of CBD products with negligible amounts of THC.

2. Will legalization spell the end of the “medical marijuana” authorization scheme?

Not yet. The Canadian Medical Association is in favour of bringing it to an end but some physicians want to preserve the authorization scheme. There are no plans to end it just yet.

3. Come October 17th, will I be unable to ask employees about their cannabis use?

It may be an invasion of privacy to compel employees to answer questions about their cannabis use unless there is a reason to know. There is probably a reason to know if they are employed in a safety sensitive position but employees in other positions are probably entitled to refuse to answer.

4. Will legalization mean that I cannot refuse to hire someone because they admit using cannabis products containing significant amounts of THC or if they test positive for THC?

In general, an employer can hire whom they want to unless it will mean breaking a specific law. The most relevant law here is the Alberta Human Rights Act which prohibits discrimination on the basis of disability. Addiction to cannabis products would be a disability. Casual use is not. Some individuals might also have a specific physical or mental disability of some kind where their physician recommends and authorizes a cannabis product for treatment purposes. If the individual fits one of these two categories, then the law might prevent you from refusing to hire them. You would have to show that it would be undue hardship for you to take the risk. There is a human rights duty to accommodate any disability to the point of undue hardship.

5. But what if they are working in a safety sensitive position?

That may not matter. It is not true in all cases that use of cannabis products is incompatible with working in a safety sensitive position. It depends first on whether the cannabis product contains THC which is the impairing ingredient. Secondly, although there are many experts who will say that regular use is incompatible with working in a safety sensitive position, some casual use may not be. It all depends.

6. The government permits blood testing to prove impaired driving and the legislation sets specific limits on the amount of THC in the blood that proves impairment for the purposes of Criminal Code offences. Is there anything similar for employers?

No. Governments have been urged to help with worksite safety instead of only focusing on road safety but nothing has been done yet to legislatively permit testing, require disclosure, or to set per se limits that will be of any use to employers.

7. Are there specific concentrations of THC as shown by oral swab testing or urine samples that prove impairment?


8. Will legalization mean that objections to random testing will ease?

No, there is no sign of that yet. Employers must still prove a significant problem with drugs in the workplace before implementing random drug testing on a worksite.

9. Will employers be able to automatically fire workers who repeatedly continue to use cannabis products while working in safety sensitive positions? Will recurrent positive tests justify termination?

It depends. An expert will have to evaluate whether the use is compatible with safety sensitive work or not.

10. Who is going to have to pay for all of these expert opinions?


11. What if your employee tells you some time after October 17th that they are a casual user of cannabis and you are concerned about them working in a safety sensitive job? Can you hold them off work to evaluate their fitness to work?

Yes, you have a responsibility, in those circumstances, under the Occupational Health and Safety Act to avoid the danger to themselves and others that their cannabis use may pose. If you have a legitimate and reasonable concern you are entitled to hold someone off work to evaluate their fitness to work.

12. If the worker is held off work for an evaluation, are they owed pay for time missed?

Unless a collective agreement or other employment contract says that someone is entitled to pay, workers are usually not entitled to be paid when they are not working.

13. What if the employee says they only smoke pot or ingest cannabis products many hours before the start of any work shift? Are they safe to work in a safety sensitive position?

It is doubtful that an employer could avoid occupational health and safety liability in all cases where they simply trusted that the worker would only smoke or ingest when they said so. In some cases, some unscheduled testing would probably be expected to test the veracity of the employee’s promised ingestion schedule. Experts would be able to determine what schedule would be safe, if any was.

14. If I am using cannabis after legalization, is there any risk in telling a United States border agent about it?

Yes, there is. One United States border official was widely quoted in the media as saying that he expects that at least some users and even people working for cannabis businesses could receive lifetime bans from entry to the U.S. Nevertheless, it is clear that individual border agents could easily choose to refuse entry to the U.S. to anyone who is a user of cannabis products or who refuses to answer questions about their cannabis use. Cannabis may be legal under the state laws in some states but it continues to be illegal under federal law in the United States and federal law governs the border. That puts Canadian pot users in a tough spot because lying to a border agent is also a serious offence.

15. Are employees entitled to smoke or otherwise ingest pot while at work?

Legalization does not mean that citizens can ingest or smoke everywhere. This is regulated by provincial law and by municipality bylaws and, on private property, it is controlled by the entity with legal control over the property. Municipal bylaws vary from place to place but, in general, smoking and vaping are often restricted like smoking tobacco. Private landowners can generally control what is allowed on their property although some human rights issues might sometimes arise.

16. Does the legalization of pot mean that employers no longer have a valid interest in prohibiting the use and possession of substances at work which impair fitness for duty?


17. Does legalization require a review of your drug policies?

This is such a significant change that it will often require changes to your policies and it also probably requires a clear communication of expectations so employees understand what they can and cannot do. For example, will you be allowing any cannabis products in the workplace? Will you be allowing vaping or smoking on the premises and environs? Are you going to require employees in safety sensitive position to disclose if they are using cannabis products? It is better to be clear in advance of legalization.


If you need assistance in handling this brave new world, McLennan Ross lawyers in the Labour/Employment Practice Group have considerable experience in navigating this area of the law.

This update is a general overview of the subject matter and cannot be regarded as legal advice. Please contact David Risling or Maurice Dransfeld in Edmonton, Alexis Moulton in Calgary, Michelle Thériault in Yellowknife, or any member of our Cannabis Industry Group for advice on this or any other cannabis law topic.