(a) For purposes of this section, “department” means a department or other organization that:
(1) performs emergency services, including a volunteer fire department, as defined by Section 614.101; and
(2) is not a for-profit entity.
(a-1) The governing body of a department may, in the manner provided for taking official action by the body, elect to participate in the pension system. The governing body of a department shall notify the executive director as soon as practicable of an election made under this subsection. Except as provided by Subsection (b), an election to participate under this subsection is irrevocable.

(b) The state board may adopt rules that allow the governing body of a participating department to revoke its election to participate in the pension system under Subsection (a-1) in a manner that maintains an actuarially sound pension system.