Mass. Gen. Laws ch. 127, § 151G
(f) Public notice shall be given of all meetings and all meetings shall be open to the public, except as set forth in the rules or as otherwise provided in the compact. The interstate commission shall promulgate rules consistent with the principles contained in the Government in Sunshine Act, 5 U.S.C. Section 552(b), as may be amended. The interstate commission and any of its committees may close a meeting to the public if it determines by 2/3 vote that an open meeting would be likely to:—
(9) specifically relate to the interstate commission's issuance of a subpoena, or its participation in a civil action or proceeding.
For every meeting closed pursuant to this subsection, the interstate commission's chief legal officer shall publicly certify that, in his opinion, the meeting may be closed to the public, and shall reference each relevant exempting provision. The interstate commission shall keep minutes which shall fully and clearly describe all matters discussed in any meeting and shall provide a full and accurate summary of any actions taken, and the reasons therefore, including a description of each of the views expressed on any item and the record of any roll call vote. All documents considered in connection with any action shall be identified in such minutes.