During a protracted strike, the union filed unfair labour practice complaints against the employer companies and a security company, alleging the security company provided an agent provocateur.
The union and the employers reached a settlement and the union sought to withdraw its complaint against the employers, but proceed against the security company.
The security company argued that as an agent, releasing the principal released it, relying on the common law doctrine of joint tortfeasors.
The Board rejected the application of the joint tortfeasor doctrine to the Labour Relations Act, finding that the security company was a 'person acting on behalf of an employer' and thus independently subject to the Act's prohibitions.
The Board allowed the withdrawal against the employers and directed the complaint against the security company to proceed.