51.3(1)If before the commencement of a regulation designating a construction project as a major project a trade union or council of trade unions has been certified or has been granted voluntary recognition in a recognition agreement as the bargaining agent for a unit of employees, all members of the trade union or council of trade unions engaged in on-site work on or after the commencement of the regulation shall, for the purposes of this Act, be deemed to constitute a bargaining unit separate and apart from the bargaining unit consisting of members of the trade union or council of trade unions engaged in off-site work.

51.3(2)If before the commencement of a regulation designating a construction project as a major project the Board has accredited an employers’ organization as the bargaining agent for a unit of employers, all employers in the unit engaged in on-site work on or after the commencement of the regulation shall, for the purposes of this Act, be deemed to constitute a unit of employers separate and apart from the unit of employers consisting of employers engaged in off-site work.

51.3(3)Notwithstanding subsection (2), an employer in a unit of employers constituted under subsection (2) who is engaged in both on-site and off-site work retains, in addition to and distinct from the rights, duties and obligations under this Act in respect of the unit of employers constituted under subsection (2), all the rights, duties and obligations under this Act in respect of the unit of employers consisting of employers engaged in off-site work.

51.3(4)Notwithstanding section 57, any collective agreement in operation at the time a bargaining unit is constituted under subsection (1) that would but for this section be applicable in relation to both employees engaged in on-site and off-site work, ceases to apply in relation to the bargaining unit constituted under subsection (1).