Mass. Gen. Laws ch. 149 § 30C
The service of all members of the uniformed members of the state police and land based environmental police officers of the division of law enforcement shall consist of an average of forty hours per week over a period of one or more work weeks not in excess of eight, as determined by the commissioner of the department in which they are respectively serving, and shall be restricted to not more than five normal work days, as so determined, in any consecutive seven-day period; provided, however, that all services in excess of the normal work day, as so determined, or in excess of forty hours per week, as so averaged, rendered by any such officer at the request of the commissioner of the department in which he is serving, shall be compensated for at the rate of one and one half times the regular hourly rate of such officer for every hour or fraction thereof of such services rendered.
The personnel administrator is empowered to make rules and regulations, subject to the approval of the commissioner of administration, to carry out the provisions of this section.
Mass. Gen. Laws ch. 149, § 30C