30 Tex. Admin. Code § 335.706
Within 60 days after receiving certifications from the owner or operator and a Texas licensed professional engineer that all hazardous secondary materials have been removed from the facility or a unit at the facility and that the facility or a unit has been decontaminated in accordance with the approved plan in accordance with § 335.705 of this title (relating to Removal and Decontamination Plan for Release), the executive director will notify the owner or operator in writing that the owner or operator is no longer required to maintain financial assurance under 40 Code of Federal Regulations §261.4(a)(24) for that facility or a unit at the facility, unless the executive director has reason to believe that all hazardous secondary materials have not been removed from the facility or unit at a facility or that the facility or unit has not been decontaminated in accordance with the approved plan. The executive director shall provide the owner or operator a detailed written statement of any such reason to believe that all hazardous secondary materials have not been removed from the facility or unit or that the facility or unit has not been decontaminated in accordance with the approved plan.
30 Tex. Admin. Code § 335.706