Ala. Code § 16-17-14

The authority, the property and income of the authority, all bonds issued by the authority, the income from such bonds, conveyances by or to the authority and leases, mortgages and deeds of trust by or to the authority shall be exempt from all taxation in the State of Alabama. No license or excise tax may be imposed on any authority in respect of the privilege of engaging in any of the activities authorized by this chapter.