71 Pa. Stat. § 1707.15
The effectuation of the authorized purposes of the Authority, created under this act, shall and will be in all respects for the benefit of the people of the Commonwealth for the increase of their commerce and prosperity and for the improvement of their health and living conditions, and since the Authority will be performing essential governmental functions in effectuating such purposes, the Authority shall not be required to pay any taxes or assessments upon any property acquired or used by it for such purposes, and the bonds issued by the Authority, their transfer, and the income therefrom (including any profits made on the sale thereof), shall at all times be free from taxation, other than inheritance and estate taxation, within the Commonwealth of Pennsylvania.
71 P.S. § 1707.15