30 Tex. Admin. Code § 336.344
The licensee shall retain the records of prior occupational radiation dose and exposure history as specified in § 336.309 of this title (relating to Determination of Prior Occupational Dose) on form "Cumulative Occupational Exposure History" (§336.367, Appendix J of this title (relating to Cumulative Occupational Exposure History)) or equivalent until the commission terminates each pertinent license requiring this record. The licensee shall retain records used in preparing form "Cumulative Occupational Exposure History" (§336.367, Appendix J of this title) or equivalent for 3 years after the record is made. This includes records required under the standards for protection against radiation in effect before January 1, 1994.
30 Tex. Admin. Code § 336.344