(a) The open burn pit registry fund is a special fund in the state treasury outside the general revenue fund. The fund is composed of:
(1) money transferred to the fund at the direction of the legislature;
(2) gifts and grants contributed to the fund;
(3) the earnings of the fund; and
(4) money deposited to the credit of the fund under § 504.679, Transportation Code.
(b) Money in the fund may be appropriated only to the department. The department may use the money only for the creation and maintenance of the open burn pit registry established under § 99.003, except that the department may use the money for any other purpose of the department consistent with legislative appropriation of the money if the department finds that the registry is adequately funded and contributions to the fund exceed the amount necessary for the registry to be adequately funded.