In order to secure better administration of the act, employers may require of all applicants for work who are over 18 and under 21 years of age, a proof of age certificate authorized by the Attendance Bureau of the Department of Education and issued and signed by the proper officers of the local school board after obtaining the proper evidence of age that is required for the issuance of employment certificates. This certificate may be retained in the files of the employer during term of employment of the minor but shall be returned to the minor when employment terminates or when the minor reaches the age of 21 years.
34 Pa. Code § 11.48