56(1)There shall be only one collective agreement at a time between a trade union or council of trade unions and an employer or employers’ organization with respect to the employees in the bargaining unit defined in the collective agreement.

56(2)A collective agreement is, subject to and for the purposes of this Act, binding upon the employer and upon the trade union that is a party to the agreement whether or not the trade union is certified and upon the employees in the bargaining unit defined in the agreement.

56(3)A collective agreement between an employers’ organization and a trade union or council of trade unions is, subject to and for the purposes of this Act, binding upon the employers’ organization and each person who was a member of the employers’ organization at the time the agreement was entered into and on whose behalf the employers’ organization bargained with the trade union or council of trade unions as if it was made between each of such persons and the trade union or council of trade unions and upon the employees in the bargaining unit defined in the agreement and, if any such person ceases to be a member of the employers’ organization during the term of operation of the agreement, he shall, for the remainder of the term of operation of the agreement, be deemed to be a party to a like agreement with the trade union or council of trade unions, as the case may be.

56(4)A collective agreement between a certified council of trade unions and an employer is, subject to and for the purposes of this Act, binding upon each trade union that is a constituent union of such a council as if it had been made between each of such trade unions and the employer.

56(5)A collective agreement between a council of trade unions, other than a certified council of trade unions, and an employer or an employers’ organization is, subject to and for the purposes of this Act, binding upon the council of trade unions and each trade union that was a member of or affiliated with the council of trade unions at the time the agreement was entered into and on whose behalf the council of trade unions bargained with the employer or employers’ organization as if it was made between each of such trade unions and the employer or employers’ organization, and upon the employees in the bargaining unit defined in the agreement, and, if any such trade union ceases to be a member of or affiliated with the council of trade unions during the term of operation of the agreement, it shall, for the remainder of the term of operation of the agreement, be deemed to be a party to a like agreement with the employer or employers’ organization, as the case may be.