Mass. Gen. Laws ch. 22C, § 27: Vacancies in titles of lieutenant colonel and major

Section 27. Any vacancy that occurs in the title of lieutenant colonel shall be filled by the colonel from uniformed members who hold the title of major or captain.

Any vacancy that occurs in the title of major shall be filled by the colonel from uniformed members who hold the title of captain. The colonel shall promulgate regulations establishing any requirements for promotion to the title of major, including, but not limited to, any required length of term of service for promotion to the title of major.