Mass. Gen. Laws ch. 21I, § 18
Massachusetts residents may participate in monitoring and enforcement procedures as follows:
(C)
(1) The superior court shall have jurisdiction to enforce the requirements of this chapter in an action brought by any ten residents of the commonwealth against:
(3) The court, in issuing any final order in any action brought pursuant to this subsection, may award costs of litigation, including reasonable attorney and expert witness fees, to the prevailing or substantially prevailing party other than the commonwealth who advances the purposes of this chapter. The court may, if a temporary restraining order or preliminary injunction is sought, require the filing of a bond or equivalent security in accordance with the Massachusetts Rules of Civil Procedure.
Nothing in this subsection shall restrict or expand any right which anyone may have under any federal or state statute or common law to seek enforcement of any requirement or to seek any other relief.