(a) A rule takes effect 20 days after the date on which it is filed in the office of the secretary of state, except that:
(1) if a later date is required by statute or specified in the rule, the later date is the effective date;
(2) if a state agency finds that an expedited effective date is necessary because of imminent peril to the public health, safety, or welfare, and subject to applicable constitutional or statutory provisions, a rule is effective immediately on filing with the secretary of state, or on a stated date less than 20 days after the filing date; and
(3) if a federal statute or regulation requires that a state agency implement a rule by a certain date, the rule is effective on the prescribed date.
(b) A state agency shall file with its rule the finding described by Subsection (a)(2), if applicable, and a brief statement of the reasons for the finding. The agency shall take appropriate measures to make emergency rules known to persons who may be affected by them.

(c) A rule adopted as provided by Subsection (a)(3) shall be filed in the office of the secretary of state and published in the Texas Register.