CUPE, Local 5001 v. University Health Network, 2026 CanLII 27323 (ON LA)
Andrew Tremayne, Arbitrator — March 16, 2026

CUPE argued that UHN could not consider an employee for a new posting if the employee had been in their current role for less than six months, unless the move was a promotion or change in status. The arbitrator dismissed the grievance, finding that the collective agreement gave the Hospital discretion to consider such employees and that estoppel was not established.

Background

The dispute arose after UHN awarded a Ward Clerk position to the most senior applicant, even though that employee was a few weeks short of six months in his current role. The Union viewed him as ineligible because the posting was not a promotion or status change.

Article 9.05(d) stated that successful employees “need not be considered” for other vacancies within six months unless the opportunity allowed a change in permanent status or a move into a permanent position with a higher base rate of pay. The Union argued that the parties had treated this language as a strict “6-month rule.”

The Hospital argued that “need not” created discretion, not a prohibition. It also denied that its past conduct created an estoppel.

Decision

The arbitrator found that Article 9.05(d) was clear and unambiguous. The Hospital was required to consider an employee for a promotion or status change where the employee had been in their present position for less than 6 months and had discretion to consider that employee for other types of vacancies..

Because the language was not ambiguous, past practice was not available as an interpretive aid. The arbitrator then turned to estoppel and held that the Union had not established that UHN knowingly surrendered its discretion under Article 9.05(d).

The evidence fell short of the compelling and unequivocal standard required for estoppel. Some transfer letters referred to a six-month restriction and others did not, and the letters were not a clear statement of the Hospital’s labour relations position. The key labour relations communications showed that UHN maintained its position that “need not” was discretionary.

The grievance was dismissed.