N.C. Gen. Stat. § 160A-562: Tax contract by the State.

The State of North Carolina covenants with the purchasers and with all subsequent holders and transferees of bonds issued by the authority pursuant to this Article, in consideration of the acceptance of and payment for the bonds, that the bonds of the authority issued pursuant to this Article and the income therefrom, and all moneys, funds and revenues pledged to pay or secure the payment of such bonds, shall at all times be free from taxation except for transfer and estate taxes. (1951, c. 779, s. 17; 1979, 2nd Sess., c. 1247, s. 44.)