AMAPCEO filed grievances asserting that Sergeants employed in correctional institutions should be covered by its collective agreement.
OPSEU sought to intervene, arguing that if the Sergeants are employees, they belong in OPSEU's correctional bargaining unit.
AMAPCEO objected, arguing that the Ontario Labour Relations Board had already decided the representational issue in a prior certification application by PSAC, and that issue estoppel applied.
The Arbitrator found that the OLRB's prior decision was not a final determination of whether AMAPCEO had abandoned or relinquished its bargaining rights after 1995.
Therefore, issue estoppel did not apply, and OPSEU was granted the right to intervene.