A recent Ontario Superior Court decision offers important guidance for both employers and employees on when a dismissal for just cause may be legally justified.

In McCarthy v. Bison Transport Inc., 2026 ONSC 3729, the Court upheld the dismissal of a commercial truck driver, who failed a second random drug test after previously receiving a warning and an opportunity to return to work. The decision highlights the importance of workplace safety, clear employer policies, and an employer’s obligation to consider accommodation before terminating employment.

What Happened?

The employee worked as a long-haul truck driver in a safety-sensitive position and acknowledged Bison Transport’s Drug and Alcohol Policy, which prohibited drivers from working with drugs in their system.

After testing positive for cannabis in 2014, the employer did not immediately terminate his employment. Instead, it referred him for assessment, confirmed that he did not suffer from a substance dependency, required him to complete return-to-work requirements, and issued a written warning that another failed drug test could result in dismissal.

Three years later, the employee again tested positive for THC during a random drug test. He admitted to recreational cannabis use, confirmed he was not addicted, and acknowledged he understood the company’s policy. Bison Transport terminated his employment for just cause.

Why the Court Found Just Cause

The Court concluded that dismissal for cause was justified because:

  • the employee held a safety-sensitive position where impairment posed significant public safety risks;
  • the employer had a clear and consistently enforced drug and alcohol policy;
  • the employee knew a second violation could result in termination; and
  • there was no evidence that the employee suffered from a disability requiring accommodation.

The Court emphasized that while employers have a duty to accommodate employees with substance dependencies, that duty does not arise where the employee is simply a recreational user and no disability exists.

What This Means

This decision does not mean that every failed drug test justifies dismissal for cause. Just cause remains one of the highest standards in employment law, and every case depends on its own facts.

For employers, the case underscores the importance of having clear workplace policies, enforcing them consistently, conducting a fair investigation, and considering accommodation obligations before making termination decisions.

For employees, the decision is a reminder that an employer’s allegation of “just cause” is not always legally correct. Many employees dismissed for cause may still have valid wrongful dismissal claims depending on the circumstances.

How Pelsmakher Law Can Help

At Pelsmakher Law, we advise both employers and employees throughout Ontario on just cause dismissals, wrongful dismissal claims, workplace investigations, employment contracts, and human rights issues.

If you are facing a workplace termination or need advice regarding employee discipline, contact Pelsmakher Law to discuss your rights and legal options.

Frequently Asked Questions

Can an employer terminate an employee for failing a drug test?

Not automatically. Courts consider the employee’s role, workplace policies, prior discipline, safety concerns, and whether there is a disability requiring accommodation.

What is a safety-sensitive position?

A safety-sensitive position is one where impairment could create a significant risk to the employee, co-workers, or the public, such as commercial truck driving or operating heavy machinery.

No, employers can still prohibit workplace impairment and enforce reasonable drug and alcohol policies, particularly in safety-sensitive workplaces. However, employers are still required to accommodate employees on the basis of a disability (such as a drug-dependency). Failure to do so can result in a claim for wrongful dismissal and human rights damages.