1. (a) Applicability. A UST system shall be considered to be temporarily out of service, regardless of whether or not regulated substances remain in the UST system, when the following conditions apply.

   1. (1) The normal operation and use of the UST system is deliberately, but temporarily, discontinued for any reason.
   2. (2) The infrequent use of the UST system cannot be adequately justified as part of its purpose.
   3. (3) The operation, maintenance, and/or release detection procedures are determined to be inadequate or otherwise inconsistent with the monitoring procedures normally associated with in-service systems of similar type and purpose.

2. (b) All UST systems. Beginning no later than the date on which any UST system has been out of service for a continuous period of three months, regardless of whether or not regulated substances remain in the UST system, the owner or operator shall assure that the UST system is maintained in compliance with the following requirements for the balance of time that the UST system remains temporarily out of service.

   1. (1) All vent lines shall be kept open and functioning.
   2. (2) All other piping, pumps, manways, and ancillary equipment shall be capped, plugged, locked, and/or otherwise secured to prevent access, tampering, or vandalism by unauthorized persons.

3. (c) Protected and monitored systems. Any UST system may remain out of service indefinitely so long as the following requirements are met during the period that the UST system remains temporarily out of service.

   1. (1) The UST system shall be adequately protected from corrosion in accordance with the applicable requirements of §334.49 of this title (relating to Corrosion Protection).
   2. (2) Unless the UST system has been emptied of all regulated substances (as described under subsection (e) of this section) at the time it is temporarily removed from service, the UST system shall be monitored for releases in accordance with the applicable requirements of §334.50 of this title (relating to Release Detection).
   3. (3) The UST system shall be operated and maintained in accordance with the requirements of subsection (b) of this section.

4. (d) Unprotected and unmonitored systems.

   1. (1) Time limitation. If due to the phase-in of upgrades and improvements as allowed under §334.47 of this title (relating to Technical Standards for Existing UST Systems), any existing UST system is not yet adequately protected from corrosion (as provided under subsection (c)(1) of this section) and any existing nonempty UST system is not yet adequately monitored for releases (as provided under subsection (c)(2) of this section), such UST systems cannot remain out of service indefinitely and must meet the following requirements.

      1. (A) The UST system shall be operated and maintained in accordance with the provisions of subsection (b) of this section during the time the system is temporarily out of service, which shall not exceed 12 months.

      2. (B) Beginning no later than the date on which the UST system has been out of service for a continuous period of 10 months, regardless of whether or not regulated substances remain in the system, the owner or operator shall initiate appropriate activities or procedures to assure that no later than the date on which the system has been out of service for a continuous period of 12 months, the UST system is either:

         1. (i) permanently removed from service (by disposal in-place or removal from the ground), in accordance with the applicable provisions of §334.55 of this title (relating to Permanent Removal from Service);
         2. (ii) brought back into service in conformance with the requirements in paragraph (3) of this subsection; or
         3. (iii) appropriately upgraded such that the UST system is adequately protected from corrosion and adequately monitored for releases of regulated substances in a manner that will allow the system to remain temporarily out of service under the provisions of subsection (c) of this section.

   2. (2) Extension of time. For UST systems which are temporarily out of service, and for which the owner or operator determines that conformance with the schedule under paragraph (1)(B) of this subsection would be impractical or unreasonable, the owner or operator must secure prior approval from the executive director for an extension of time subject to the following conditions.

      1. (A) Any request for extension of time shall be in conformance with §334.43 of this title (relating to Variances and Alternative Procedures).
      2. (B) any request for extension of time shall be accompanied by written documentation adequate to justify the requested extension and the results of a site assessment conducted in accordance with §334.55(e) of this title (relating to Permanent Removal from Service).

   3. (3) Returning UST system to service. When an unprotected and unmonitored UST system that has been temporarily out of service for longer than six months is placed back into service, the owner or operator shall:

      1. (A) ensure the integrity of the system by the performance of a tank tightness test and piping tightness test that meet the requirements of §334.50(d)(1)(A) and (b)(2)(A)(ii)(I), respectively, of this title (relating to Release Detection) prior to bringing the system back into operation; and
      2. (B) ensure that the UST system is brought into compliance with all applicable corrosion protection, release detection, and spill and overfill prevention requirements of §334.49 of this title (relating to Corrosion Protection), and §334.50 of this title (relating to Release Detection), and §334.51 of this title (relating to Spill and Overfill Prevention and Control) in accordance with the applicable schedules in §334.44 of this title (relating to Implementation Schedules).

5. (e) Empty system. For the purposes of this section only, and specifically for the purpose of exempting certain UST systems (when temporarily out of service) from the release detection requirements of this chapter, an underground storage tank system shall be considered empty when the following provisions have been met:

   1. (1) all regulated substances have been removed as completely as possible by the use of commonly employed and accepted industry procedures;
   2. (2) any residue from stored regulated substances which remains in the system (after the completion of the substance removal procedures under paragraph (1) of this subsection) shall not exceed a depth of 2.5 centimeters at the deepest point and shall not exceed 0.3% by weight of the system at full capacity; and
   3. (3) the volume or concentration of regulated substances remaining in the system would not pose an unreasonable risk to human health and safety or to the environment if a release occurs during the period when the system is temporarily out of service.

6. (f) Other requirements.

   1. (1) Releases. If a release of a regulated substance is suspected or confirmed, the owner or operator of an underground storage tank system which is temporarily out of service shall comply with all release reporting, investigation, and corrective action requirements in Subchapter D of this chapter (relating to Release Reporting and Corrective Action).
   2. (2) Registration. At the time an underground storage tank system is temporarily taken out of service and at the time a UST system is brought back into service, the owner shall comply with the applicable tank registration requirements in §334.7 of this title (relating to Registration).
   3. (3) Fees. An underground storage tank which is temporarily out of service in accordance with this section shall remain subject to the commission's underground storage tank fees in Subchapter B of this chapter (relating to Underground Storage Tank Fees).

   4. (4) Recordkeeping for temporary removal from service.

      1. (A) Owners and operators shall maintain records adequate to demonstrate compliance with the requirements in this section, in accordance with §334.10(b) of this title (relating to Reporting and Recordkeeping).

      2. (B) At a minimum, the following records shall be maintained for at least five years after the UST system is temporarily removed from service:

         1. (i) date that the UST system was temporarily removed from service;
         2. (ii) name, address, and telephone number of the person who prepared the UST system for the period of non-use;
         3. (iii) documentation of the procedures used to prepare and empty the UST system;
         4. (iv) copies of all documentation relative to any requests and approvals of extensions of time;
         5. (v) name, address, and telephone number of the person who conducted the tank and piping tightness tests, prior to returning the UST system to service;
         6. (vi) results of any tank and piping tightness tests; and
         7. (vii) date that the UST system was returned to service.

Source Note:The provisions of this §334.54 adopted to be effective September 29, 1989, 14 TexReg 4714.