With the legalization of recreational cannabis in full effect, employers continue to grapple with the workplace implications of its use. However, having to balance statutory obligations under both health and safety and human rights legislation is not a new problem for employers. When doing so, employers must take into consideration their duties to protect worker health and safety under the applicable occupational health and safety legislation as well as the duty to accommodate medicinal cannabis users on a case-by-case basis under human rights legislation.

The recent decision by the Supreme Court of Newfoundland and Labrador, International Brotherhood of Electrical Workers, Local 1620 v Lower Churchill Transmission Construction Employers' Association Inc., 2019 NLSC 48, addressed the accommodation of employees who use medicinal cannabis in safety-sensitive workplaces. In doing so, it affirmed the Arbitrator's decision that the inability to measure residual impairment of cannabis constitutes undue hardship in a safety-sensitive workplace.

The decision involves a safety-sensitive workplace for the construction of infrastructure for the delivery of electricity from Muskrat Falls in Labrador to the island of Newfoundland (the "Project"). The employee, a General Labourer on the Project for just over one (1) year, suffered from chronic pain due to Chron's disease and osteoarthritis. Despite numerous modalities and therapies, the treatments were unable to relieve his pain. After a referral from his family doctor, the employee was prescribed medicinal cannabis. Throughout the material time, the employee consumed through vaporization about 1.5 grams of cannabis each evening following work hours.1

The employee's work on the Project overlapped with his prescription cannabis use until his eventual layoff. Despite the Collective Agreement containing priority hiring for vacant positions, the employee was not successful in obtaining a position because of concerns over whether his cannabis use would impair his ability to perform the job safely.2 The employee's union filed a grievance alleging that the refusal to hire him was based on discrimination.

At arbitration, the Arbitrator assessed the competing expert evidence with respect to the effects of cannabis and the potential duration of impairment. The experts at the arbitration included general practitioners, a family physician who practised as an occupational health consultant, a pharmacologist/toxicologist, and a doctor qualified to provide evidence in the area of pain management.

Ultimately, the Arbitrator decided that the employer's inability to measure and manage the risk of harm constituted undue hardship. Specifically, the Arbitrator stated,

[t]he safety hazard that would be introduced into the workplace here by residual impairment arising from the Grievor's daily evening use of cannabis products could not be ameliorated by remedial or monitoring processes. Consequently, undue hardship, in terms of unacceptable increased safety risk, would result to the Employer if it put the Grievor to work. As previously stated, if the Employer cannot measure impairment, it cannot manage risk.3 [Emphasis added].

Disagreeing with the decision, the employee's union filed an application for judicial review. On judicial review, the Supreme Court of Newfoundland and Labrador accepted that the Arbitrator based his findings on the expert evidence before him. The Court stated that the Arbitrator found that the duty to accommodate did not extend to a requirement that the employer accept a risk resulting from the possibility of impairment.4 As a result, the Court decided that the Arbitrator's decision was found to be within the range of reasonable outcomes and dismissed the employee's application. Specifically, the Court stated that the Arbitrator reasonably concluded that: 

  • impairment can last up to 24 hours after use;
  • the impairing effects may not be known to the user;
  • the use of marijuana can impair the ability of a worker to function safely in a safety-sensitive environment; and
  • there was no available means or method for accurately testing impairment from cannabis use in the workplace.5

Takeaways for Employers

For employers, the decision may provide support for a precautionary approach to the maintenance of a safe work environment. The decision stands for the proposition that, absent an available means or method for accurately testing impairment from cannabis use, the duty to accommodate (assessed on a case-by-case basis) may not require an employer to accept the risks of potential impairment from cannabis in a safety-sensitive environment. It remains to be seen whether this decision will be appealed and whether tribunals and courts in other jurisdictions will follow its reasoning in balancing occupational health and safety and human rights obligations.


[1] International Brotherhood of Electrical Workers, Local 1620 v Lower Churchill Transmission Construction Employers' Association Inc., 2019 NLSC 48, at para 10.

[2] Ibid. at para 34.

[3] Ibid. at para 43.

[4] Ibid. at para 44.

[5] Ibid. at para 42.

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