Court of Appeal Clarifies Nature and Scope of Duty to Investigate under the OHSA in Metrolinx v Amalgamated Transit Union, Local 1587

In a recent decision, Metrolinx v Amalgamated Transit Union, Local 1587, 2025 ONCA 415 (“Metrolinx”), the Ontario Court of Appeal took the unusual step of quashing the decision of a labour arbitrator. As the Court itself acknowledged, reviewing courts typically accord labour arbitrators a high degree of deference, and are reluctant to disturb decisions that arise in the ordinary course of labour relations. Here, though, both the Divisional Court and the Court of Appeal found the Arbitrator’s decision to be unreasonable.

It is important to note that the Court of Appeal was not, itself, situated as a reviewing court. As the Court of Appeal explained, the Divisional Court owed deference to the Arbitrator, but the Court of Appeal did not owe deference to the Divisional Court. The Divisional Court applied the reasonableness standard, and then the Court of Appeal “[stepped] into the shoes” of the Divisional Court and conducted the same analysis again.

The facts of Metrolinx are as follows: in 2020, Metrolinx became aware that a number of employees were using a private WhatsApp group to make sexist comments about a female colleague, who was identified throughout the proceedings as “Ms A.” Ms A never made a formal complaint, and she made it clear that she did not want the matter investigated. Nonetheless, Metrolinx concluded that it was bound by its own Workplace Discrimination and Harassment Prevention Policy (“the WDHP Policy”), as well as by the Occupational Health and Safety Act (“the OHSA”), to conduct an investigation. After receiving the investigator’s report, Metrolinx dismissed five employees for cause.

The employees’ bargaining agent, the Amalgamated Transit Union (“the ATU”), grieved the dismissals. The grievance was referred to arbitration before the Grievance Settlement Board and, after a lengthy hearing, the Arbitrator allowed the grievance in its entirety and ordered the dismissed employees reinstated. Metrolinx then sought judicial review.

The Divisional Court (with which the Court of Appeal agreed) identified four distinct errors in the Arbitrator’s reasons, but I will focus here on only one: the Arbitrator’s treatment of Metrolinx’s duty to investigate. As noted above, Ms A declined to make a formal complaint. In the Arbitrator’s view “that should have been the end of the matter.” This was an error of law, for two reasons.

Firstly, the Arbitrator did not engage with Metrolinx’s obligation under section 32.02.07 of the OHSA to investigate “incidents and complaints of workplace harassment.” In other words, there is a duty to investigate “incidents” even where there is no “complaint.” While the Court of Appeal acknowledged that, under the WDHP Policy, “the investigation process is initiated by a complaint”, a policy cannot narrow the scope of a legislative obligation.

Secondly, the Arbitrator read too much into the absence of a formal complaint. In his view, because Ms A did not make a formal complaint, the alleged harassment was less likely to have occurred. The Court of Appeal attributed this reasoning to reliance on “myths and stereotypes about how an employee in Ms A’s situation would respond”, observing that “there are many reasons why a victim of harassment might choose not to pursue an official complaint.”

Accordingly, the Court of Appeal dismissed ATU’s appeal, and remitted the matter back to the Grievance Settlement Board for determination on the merits by a different arbitrator.

The decision in Metrolinx should be welcomed. Most large employers now have detailed policies governing the conduct of investigations into alleged workplace misconduct, but it must always be remembered that the requirements of the OHSA are not a “backstop” that only come into play in the absence of an internal policy. Compliance with an internal policy is never a substitute for compliance with the OHSA.

Furthermore, the presence or absence of a formal complaint is increasingly something of a red herring. The duty to investigate can be triggered even where there is no complaint, and even where the apparent victim is actively opposed to an investigation. The Court of Appeal also left no room for doubt that it is an error of law to make the leap from “There was no complaint of harassment” to “There was likely no harassment.”

It is worth considering what might have happened if Metrolinx had deferred to the WDHP Policy and declined to conduct an investigation. In that scenario, Metrolinx would have been vulnerable to a finding that it had failed to comply with the OHSA, which protects the rights of all employees to a harassment-free workplace. As the Court of Appeal helpfully explained, the duty to investigate is a duty to all employees, not a duty to the alleged victim alone.