1. (a)

   1. (1) Each new underground storage tank or piping connected to any new underground storage tank¹ shall be secondarily contained and monitored for leaks.
   2. (2) In the case of a new underground storage tank system consisting of one (1) or more underground storage tanks and connected by piping, the requirement to provide secondary containment shall apply to all underground storage tanks and connected pipes comprising the system.

2. (b)

   1. (1) Any existing underground storage tank or existing piping connected to an existing underground storage tank that is replaced² shall be secondarily contained and monitored for leaks.
   2. (2) In the case of a replacement of an existing underground storage tank or existing piping connected to the underground storage tank, the requirement to provide secondary containment shall apply only to the specific underground storage tank or piping being replaced, not to other underground storage tanks and connected pipes comprising the system.

3. (c)

   1. (1) Each installation of a new motor fuel dispenser system³, or replacement of an existing motor fuel dispenser system, shall include under-dispenser spill containment.

   2. (2) Under-dispenser spill containment must:

      1. (A) Be liquid-tight on its sides, bottom, and at any penetrations;
      2. (B) Be compatible with the substance conveyed by the piping; and
      3. (C) Allow for visual inspection and access to the components in the containment system and/or be monitored.

   3. (3) A motor fuel dispenser system is considered to have been replaced if:

      1. (A) An existing motor fuel dispenser and the equipment necessary to connect the motor fuel dispenser to the underground storage tank system are removed; and
      2. (B) Another motor fuel dispenser and the equipment necessary to connect the motor fuel dispenser to the underground storage tank system are put in its place.

4. (d) Secondary containment systems shall be designed, constructed, and installed to:

   1. (1) Contain regulated substances released from the tank system until they are detected and removed;
   2. (2) Prevent the release of regulated substances to the environment at any time during the operational life of the underground storage tank system; and
   3. (3) Be checked for evidence of a release at least every thirty (30) days.

5. (e) In addition to the requirements of subsection (d) of this section, double-walled tanks must be designed, constructed, and installed to:

   1. (1) Contain a release from any portion of the inner tank within the outer wall; and
   2. (2) Detect the failure of the inner wall.

6. (f) In addition to the requirements of subsection (d) of this section, external liners (including vaults) must be designed, constructed, and installed to:

   1. (1) Contain one hundred percent (100%) of the capacity of the largest tank within its boundary;
   2. (2) Prevent the interference of precipitation or groundwater intrusion with the ability to contain or detect a release of regulated substances; and
   3. (3) Surround the tank completely (i.e., it is capable of preventing lateral as well as vertical migration of regulated substances).
7. (g) Underground piping must be equipped with secondary containment that satisfies the requirements of subsection (d) of this section.

8. (h) In accordance with the requirement of subdivision (d)(3) of this section, interstitial monitoring shall meet at least one (1) of the following requirements:

   1. (1) For double-walled underground storage tank systems, the sampling or testing method can detect a release through the inner wall in any portion of the tank that routinely contains a regulated substance;

   2. (2) For underground storage tank systems with a secondary barrier within the excavation zone, the sampling or testing method used can detect a release between the underground storage tank system and the secondary barrier:

      1. (A) The secondary barrier around or beneath the underground storage tank system consists of artificially constructed material that is sufficiently thick and impermeable (at least ten to six centimeters per second (10 – 6 cm/sec) for the regulated substance stored) to direct a release to the monitoring point and permit its detection;
      2. (B) The barrier is compatible with the regulated substance stored so that a release from the underground storage tank system will not cause a deterioration of the barrier allowing a release to pass through undetected;
      3. (C) For cathodically protected tanks, the secondary barrier must be installed so that it does not interfere with the proper operation of the cathodic protection system;
      4. (D) The groundwater, soil moisture, or rainfall will not render the testing or sampling method used inoperative so that a release could go undetected for more than thirty (30) days;
      5. (E) The site is assessed to ensure that the secondary barrier is always above the groundwater and not in a twenty-five-year floodplain, unless the barrier and monitoring designs are for use under these conditions; and
      6. (F) Monitoring wells are clearly marked and secured to avoid unauthorized access and tampering; or
   3. (3) For tanks with an internally fitted liner, an automated device can detect a release between the inner wall of the tank and the liner, and the liner is compatible with the substance stored.

9. (i) The requirements of this section do not apply to:

   1. (1) Suction piping that meets the requirements of 40 C.F.R. § 280.41(b)(2)(i) – (v); or
   2. (2) Piping that manifolds two (2) or more underground tanks together.

Codification Notes: This section as promulgated prior to codification into the Code of Arkansas Rules contained footnotes to the following: Footnote to subdivision (a)(1) immediately following the term “underground storage tank” provided as follows: “1A new underground storage tank or its piping is subject to the secondary containment requirements under this section if it was installed after July 1, 2007.” Footnote to subdivision (b)(1) immediately following the phrase "that is replaced" provided as follows: "2An existing underground storage tank or existing piping is subject to the secondary containment requirements under this section if it was replaced after July 1, 2007." Footnote to subdivision (c)(1) immediately following the term "motor fuel dispenser system" provided as follows: "3A new motor fuel dispenser system is subject to the secondary containment requirements under this section if it was installed or replaced after July 1, 2007."