Case In Point
Federal Replacement Worker Ban: First Reported Decision on the Merits
Date: July 7, 2026
Early this year, the Canada Industrial Relations Board (Board) released its decision in Canadian Union of Public Employees, Local 4317 v. Montreal Gateway Terminals Partnership, 2026 CIRB 1225. This Board merits decision is a first in interpreting the new replacement worker provisions under section 94(4) of the Canada Labour Code (Code), enacted by Bill C-58, An Act to amend the Canada Labour Code and the Industrial Relations Board Regulations (Bill C-58).
The Board dismissed the union’s complaint, finding that the employer did not violate section 94(4) of the Code. The decision provides important early guidance on the scope of the replacement worker prohibition and the evidentiary burden on complainants.
Background: Bill C-58 and the Replacement Worker Provisions
Bill C-58 received Royal Assent on June 20, 2024 and came into force one year later on June 20, 2025. It represents one of the most significant amendments to the federal labour relations framework in decades.
Under the previous regime, the Code only prohibited the use of replacement workers where the employer could be shown to have used them for the demonstrated purpose of undermining a union’s representational capacity. Bill C-58 replaced this with what was presented as a categorical prohibition on replacement labour during lawful work stoppages along with significant penalties for failures to comply.
The new section 94(4) prohibits an employer, during a lawful strike or lockout, from using the following categories of persons to perform the duties of bargaining unit employees:
- employees hired after the notice to bargain was given, or persons who perform management functions or confidential labour relations functions and were hired after the notice to bargain;
- contractors (other than dependent contractors) or employees of another employer;
- employees whose normal workplace is at a location other than the struck workplace, or who were transferred to the struck workplace after the notice to bargain; and
- volunteers, students, or members of the public.
CUPE Local 4317 v. Montreal Gateway Terminals
The CUPE Local 4317 workers at Montreal Gateway Terminals Partnership (MGTP) went on strike on September 22, 2025.
The union filed an unfair labour practice complaint alleging that MGTP was using five individuals to perform bargaining unit work in violation of section 94(4). The employer did not deny that these individuals performed bargaining unit work, but argued that none fell within the prohibited categories. All five had been hired before the notice to bargain was issued, and all worked at the same location.
The Board noted the following:
Section 94(4) is not a blanket prohibition
The Board emphasized that Parliament chose a targeted, categorical approach rather than a general ban. Critically, the Board stated:
“Section 94(4) does not contain a general prohibition on the use of replacement workers. In adopting Bill C-58, Parliament instead chose to prohibit only the use of certain categories of persons to perform the work of striking or locked-out employees.”
The onus of proof rests on the complainant
Unlike complaints under section 94(3) of the Code (where the burden shifts to the employer), section 94(4) does not reverse the onus. The union bears the burden of proving that the employer used a person falling within one of the prohibited categories.
The hiring date—not the training date—is determinative
Employees hired before the notice to bargain are not replacement workers within section 94(4)(a). While the Union stated these individuals were only trained on the bargaining unit work after notice to bargain, the Board stated plainly:
“It is the hiring date, not the training date, that is relevant to the application of section 94(4)(a).”
“Workplace” has a geographic component
The Board found that for purposes of section 94(4)(c), the relevant workplace was the physical terminal at 305 Curatteau Street. Even though these individuals had worked in offices at the site and not in the work area where the unionized workers usually carried out their duties, the Board found that they all normally worked at that “location” and were not transferred there after notice to bargain. As such, there was no violation.
Dependent contractors remain “employees”
One worker had transitioned from a supervisory role to dependent contractor status and the Union argued this change in legal status was a break in employment. The Board held that she remained an “employee” within the meaning of the Code, and because she was not hired after notice to bargain, no violation arose.
The Board also noted that while it accepted the legislative objectives of protecting the right to strike and bargaining unit integrity:
“[T]he clear meaning of the provisions does not allow the Board to find that Parliament intended to completely prohibit the use of replacement workers in every case or to prohibit the employer from continuing its operations in all circumstances.”
The decision signals that the Board will apply the statutory language as written and will not extend the prohibition beyond the specific categories Parliament enacted. This is meaningful clarity for federally regulated employers managing work stoppages.
Practical Implications for Federally Regulated Employers
Hiring dates play a central role
A central issue in the Board’s analysis was whether individuals were hired before or after the notice to bargain, illustrating the role that hiring-date evidence can play in labour relations disputes.
Training does not equal hiring
Cross-training employees on bargaining unit work after notice to bargain is not itself a violation—what matters is when the person was hired, not when they were trained.
Existing employees at the same workplace can perform bargaining unit duties
Managers, supervisors, and other employees who were hired before notice to bargain and who normally work at the struck workplace are not caught by sections 94(4)(a) or (c).
Understand the geographic dimension of “workplace”
The Board treated the physical work location as the relevant workplace. Transferring employees from another location after notice to bargain remains prohibited.
The union bears the burden of proof
The Board confirmed there is no reverse onus for section 94(4) complaints. Unions must present evidence that workers fall within a prohibited category.
The ban is categorical, not absolute
Not every use of non-bargaining-unit workers during a strike is prohibited—only the use of persons falling within the specified categories. Contingency planning should focus on which categories are permitted.
If you have any questions or require more information, please contact your Hicks Morley lawyer.
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