Every public agency included in the agreement pursuant to ORS § 237.430 and 237.440 shall be liable for the contributions required to be remitted by an employer under the provisions of sections 3101 and 3111 of the federal Internal Revenue Code and amendments thereto, except that no contributions required by ORS § 237.460 shall be withheld or remitted prior to July 1, 1951, or prior to the approval of the agreement by the Federal Security Administrator (United States Secretary of Health and Human Services). [Amended by 1953 c.192 § 4; 1991 c.67 § 54; 1991 c.813 § 9]