Okla. Stat. tit. 59, § 1013
The Commissioner shall, upon proper application and payment of fee, register as plumber's apprentice, and shall issue a certificate of such registration to, such person or persons who furnish proof satisfactory to the Commissioner that he or they are sixteen (16) years of age or over and are enrolled in a recognized school or training course for plumber apprentices, or have arranged for employment as a plumber's apprentice with a licensed plumbing contractor. Certificate of an apprentice shall expire at the end of four (4) years from date of issuance, at which time the Commissioner may issue a new certificate.
Laws 1955, p. 369, § 13; Amended by Laws 1980, c. 1, § 4, eff. July 1, 1980.