In Ontario, employers must investigate known or suspected harassment—even off the clock

By Meaghan MacMaster, CIPP/C, CPHR

A recent decision from the Ontario Court of Appeal in Metrolinx v. Amalgamated Transit Union, Local 1587[1] is a critical reminder for employers: your duty to investigate workplace harassment doesn’t end when employees leave the office. In Ontario, that duty is not just best practice, it is a legislative requirement under the Occupational Health and Safety Act (OHSA).

The case: Private chat, workplace consequences

Five Metrolinx employees were dismissed for cause after an internal investigation revealed they had exchanged lewd and derogatory messages in a private WhatsApp group. The messages included serious allegations about a female colleague, referred to as “Ms. A”, suggesting she had engaged in sexual activity in exchange for professional advancement.

Although Ms. A was hesitant to file a formal complaint, Metrolinx’s HR department initiated an investigation, citing its obligation to maintain a harassment-free workplace. The employer listed itself as the complainant, consistent with its policy that covers off-duty and social media conduct that negatively affects the work environment.

What the arbitrator found and why it was overturned

Initially, the arbitrator ruled in favour of the employees and ordered their reinstatement. The arbitrator reasoned that:

• The messages were exchanged off-duty, on personal devices, and through an encrypted platform, which was likened to a private backyard conversation.
• The harassment had not “manifested in the workplace” because Ms. A did not file a formal complaint and other employees were unaware of the messages.
• Metrolinx’s decision to treat itself as the complainant and to require an employee to disclose messages from a personal device raised procedural concerns.

However, the Divisional Court overturned the arbitrator’s decision, and the Ontario Court of Appeal upheld that ruling.

Key findings from the court of appeal

• Statutory Duty Ignored: The arbitrator failed to consider Metrolinx’s obligations under OHSA, which requires employers to investigate known or suspected harassment—even without a formal complaint.
• Impact on the Workplace: The court emphasized that off-duty conduct can be subject to discipline if it negatively affects the workplace. In this case, the WhatsApp messages created a hostile environment and undermined workplace trust.
• Privacy Doesn’t Shield Misconduct: The court rejected the notion that encrypted, off-duty communication is immune from scrutiny when it harms the workplace.

What this means for employers and HR professionals

• You must investigate, even without a complaint
  Under OHSA, employers are legally required to investigate both complaints and incidents of harassment they become aware of. Silence or reluctance from the affected employee does not relieve this obligation.
• Off-duty does not mean off-limits
  Harassment that occurs outside of work, such as in private chats or on social media, can still create a toxic work environment. If the effects are felt at work, the employer must respond.
• Common law duties reinforce the obligation
  Even where legislation is less prescriptive, courts have recognized a common law duty to investigate. Courts across Canada still expect employers to act reasonably and in good faith under common law principles. If off-duty conduct creates a hostile work environment or undermines employee safety, failing to investigate could expose employers to legal and reputational risk.
• A policy is not always enough. Enforcement matters.
  Having a policy is only the first step. Courts expect employers to enforce their policies consistently and fairly. In Metrolinx, the employer’s proactive response, even in the absence of a formal complaint, was a key factor in the court’s decision.

Steps for moving forward

• Review your policies: Ensure they explicitly cover off-duty conduct and digital communications. Include language that reflects your duty to investigate even when no complaint is made.
• Train your teams: Supervisors and managers should understand how to recognize and report conduct, even if it is off-duty, that may impact the workplace.
• Act proactively: If you become aware of harassment—whether through a complaint, observation, or informal report, you must investigate.
• Document everything: Keep detailed records of your process, findings, and actions taken. Transparency and fairness are critical.

Want to discuss your obligations with an experienced professional? Stewart McKelvey offers a comprehensive range of proactive and engaging legal services tailored to human resources management. These include compliance audits to ensure the workplace meets all legal obligations, training programs that equip teams with essential compliance and investigation skills, and support for conducting legally sound workplace investigations. With our expertise, employers can foster a safe, respectful, and engaged work environment while minimizing legal risk.

Bottom line: The Metrolinx decision serves as a strong reminder that workplace conduct is not confined to the office. Employers have both the authority and the legal responsibility to investigate off-duty behavior when it affects the workplace. As harassment policies continue to evolve across Canada, this case highlights the need for proactive, policy-driven strategies to foster safe and respectful work environments.

This client update is provided for general information only and does not constitute legal advice. If you have any questions about the above, please contact the authors, or a member of our Labour & Employment Group.

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[1] 2025 ONCA 415