Ala. Code § 41-10-759

There is hereby irrevocably pledged and appropriated such amounts of the BP settlement revenues retained in the special fund, and earnings thereon, as shall be necessary to pay the principal, interest, and premium, if any, on the authority’s bonds, to redeem such bonds prior to maturity if called for redemption by the authority, and to pay the principal of, the interest, and premium, if any, on any refunding bonds issued to refund such bonds.