Mass. Gen. Laws ch. 21A § 10D
Each deputy director of enforcement, chief of enforcement, deputy chief of enforcement, warden, environmental police officer or deputy environmental police officer, when on duty and in uniform shall wear on his outer clothing or otherwise display a metallic badge bearing the seal of the commonwealth and appropriate words to identify his position, together with a number to be assigned by the director.
The director may, with the approval of the secretary, prescribe by rules and regulations a standard form of uniform to be worn by such personnel. Such badge or uniform or any distinctive part thereof so prescribed shall be worn only by such personnel entitled thereto under the rules and regulations.
Whoever violates this section by wearing such badge or uniform without authority or by impersonating an officer authorized to wear such badge or uniform shall be punished by a fine of not less than $10 or more than $100 dollars.
Mass. Gen. Laws ch. 21A, § 10D