29 C.F.R. § 570.9 – States in which State certificates of age are accepted.

(a) The States in which age, employment, or working certificates or permits have been found by the Administrator to be issued by or under the supervision of a State agency substantially in accordance with the provisions of §§ 570.6 and 570.7 and which are designated as States in which certificates so issued shall have the force and effect specified in § 570.5, except as individual certificates may be revoked in accordance with § 570.11 of this subpart, are:
Alabama, Arkansas, California, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Hawaii, Illinois, Indiana, Iowa, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Puerto Rico, Rhode Island, South Dakota, Tennessee, Vermont, Virginia, West Virginia, Wisconsin and Wyoming.
(b) State certificates requiring conditions or restrictions additional to those required by this subpart shall not be deemed to be inconsistent herewith.
(c) The designation of a State under this section shall have force and effect indefinitely unless withdrawal of such designation is deemed desirable for the effective administration of the Act. No withdrawal of the designation of a State under this section shall make any certificate invalid if it was issued by or under the supervision of a State agency as herein provided prior to such withdrawal.