Mass. Gen. Laws ch. 150E § 5
The exclusive representative shall have the right to act for and negotiate agreements covering all employees in the unit and shall be responsible for representing the interests of all such employees without discrimination and without regard to employee organization membership.
The exclusive representative may require a non-member to pay for the reasonable costs and fees, including arbitrator fees and related attorney fees, for grieving or arbitrating a matter arising under an agreement negotiated pursuant to this section and brought at the non-member's request. The exclusive representative may require a non-member to pay any anticipated proportional costs and fees prior to a grievance or arbitration hearing. Failure to pay costs and fees shall relieve the exclusive representative of further responsibility to the non-member regarding the matter.
An exclusive representative's duty of fair representation to a public employee who is in the bargaining unit shall be limited to the negotiation and enforcement of the terms of agreements with the public employer. The laws of the commonwealth shall not prohibit an employee organization from providing only to its members legal, economic or job-related services or benefits outside of the collective bargaining agreement.
An employee may present a grievance to his employer and have such grievance heard without intervention by the exclusive representative of the employee organization representing said employee, provided that the exclusive representative is afforded the opportunity to be present at such conferences and that any adjustment made shall not be inconsistent with the terms of an agreement then in effect between the employer and the exclusive representative.
Mass. Gen. Laws ch. 150E, § 5