Mass. Gen. Laws ch. 21 § 46
The attorney general may, upon request of the director, bring action for injunctive relief against any person violating a provision of this chapter, or of any permit, order, regulation or determination issued thereunder, and the superior court in equity shall have jurisdiction to enjoin such violation and to grant such further relief as it may deem appropriate. Notwithstanding any other provision of this chapter, if the director finds that a discharge or combination of discharges presents an imminent and substantial threat to the health, welfare or livelihood of any persons, he shall request the attorney general to bring suit, and the attorney general may bring suit in the superior court to enjoin forthwith the discharges causing such a threat or to require the offending discharges to take such other action as may be necessary.
Mass. Gen. Laws ch. 21, § 46