On or before July first in the odd-numbered years, the Governor shall appoint a commissioner to the Interstate Environmental Commission created by the agreement or compact entered into under the laws passed by the states of New York, New Jersey and Connecticut. The Attorney General, the Commissioner of Public Health and the Commissioner of Energy and Environmental Protection shall also be commissioners of the Interstate Environmental Commission. The Attorney General, the Commissioner of Public Health and the Commissioner of Energy and Environmental Protection may each designate, in writing, a representative to represent them respectively at all meetings, hearings and proceedings of the Interstate Environmental Commission with full power to vote and act in their behalf respectively. Each appointive commissioner shall hold office for a term of four years from July first in the year of his appointment and until his successor is appointed and has qualified. If any vacancy occurs in the office of any appointive commissioner, the Governor shall fill such vacancy for the unexpired portion of the term. The commissioners shall have the powers and duties and be subject to the limitations provided for in the compact and agreement entered into between the signatory states and, together with five commissioners from the state of New York and five commissioners from the state of New Jersey, shall form the Interstate Environmental Commission. The commissioners shall serve without compensation, but shall be paid their actual expenses incurred in and incident to the performance of their duties.