Me. Rev. Stat. tit. 38, § 493

The commission consists of 5 commissioners from each signatory state, each of whom must be a resident voter of the state from which the commissioner is appointed. The commissioners must be chosen in the manner and for the terms provided by law of the state from which they are appointed. For each state there must be on the commission a member representing the state health department, a member representing the state water pollution control board, if such exists, and, except where a state in its enabling legislation decides that the best interests of the state will be otherwise served, a member representing municipal interests, a member representing industrial interests and a member representing an agency acting for fisheries or conservation.