Me. Rev. Stat. tit. 22, § 2067

The exercise of the powers granted by this chapter will be in all respects for the benefit of the people of the State, for the increase of their commerce, welfare and prosperity, and for the improvement of their health and living conditions, and will constitute the performance of an essential governmental function, and neither the authority nor its agent shall or may be required to pay any taxes or assessments upon or in respect of a project or projects or any property acquired, used by the authority or its agent or under the jurisdiction, control, possession or supervision of the same or upon the activities of the authority or its agent in the operation or maintenance of a project or projects under this chapter, or upon income or other revenues received therefrom, and any bonds, notes and other obligations issued under this chapter, their transfer and the income therefrom, including any profit made on the sale thereof, as well as the income and property of the authority, are at all times exempt from taxation of every kind by the State and by the municipalities and all other political subdivisions of the State.