1. (a) At least 30 days prior to closure, or within a shorter period of time as permitted by the Unified Program Agency, an owner or operator who intends to permanently close an underground storage tank system must provide to the Unified Program Agency for approval a proposal for compliance with this section. During the time between cessation of hazardous substance storage and completion of permanent closure in accordance with this section, the applicable construction and monitoring requirements of articles 4 and 5 continue to apply. The time between cessation of hazardous substance storage and application for permanent closure must not exceed 90 days. Closure must be completed within a reasonable time as determined by the Unified Program Agency, but not to exceed 365 days from the date of approval by the Unified Program Agency.
2. (b) An underground storage tank system that has had an unauthorized release and that cannot be repaired must be permanently closed pursuant to the requirements of this section.
3. (c) For all portions of the underground storage tank, the owner or operator of an underground storage tank system subject to permanent closure must comply with subdivision (e) for underground storage tank removal or subdivision (f) for closure in place. It is not essential that all portions of an underground storage tank system be permanently closed in the same manner; however, all closure actions must be conducted in accordance with this section.
4. (d) Any compactable material that is imported onto the site for the purpose of backfilling an excavation while closing an underground storage tank must be clean compactable backfill.

5. (e) The owner or operator of an underground storage tank system subject to permanent closure must comply with applicable provisions of chapter 6.5 of division 20 of the Health and Safety Code and the following requirements:

   1. (1) All residual liquid, solids, and sludge must be removed and handled as hazardous wastes or recyclable materials.
   2. (2) If the underground storage tank contained a hazardous substance that could produce flammable vapors at standard temperature and pressure, it must be inerted to levels that will preclude an explosion or to lower levels as required by the Unified Program Agency.
   3. (3) When an underground storage tank system is disposed of, the owner or operator must document to the Unified Program Agency that proper disposal has been completed by providing the disposal documentation specified in subdivision (i)(4).

6. (f) The owner or operator of an underground storage tank system subject to closure in place must comply with the applicable provisions of chapters 6.5 and 6.7 of division 20 of the Health and Safety Code and the following requirements:

   1. (1) All residual liquid, solids, and sludge must be removed and handled as a hazardous waste or recyclable materials.
   2. (2) If the underground storage tank contained a hazardous substance that could produce flammable vapors at standard temperature and pressure, it must be inerted to levels that will preclude an explosion or to lower levels as required by the Unified Program Agency.
   3. (3) All piping connected to the underground storage tank must be removed and disposed of properly, or if removal might damage structures or other pipes that are being used and that are contained in a common trench, the piping must be closed by emptying it of all contents and capping it at each end.
   4. (4) The underground storage tank, except for piping that is closed in accordance with paragraph (3), must be completely filled with an inert solid, unless the owner intends to reuse or reinstall the underground storage tank in accordance with section 2683.

7. (g) The owner or operator of an underground storage tank system being permanently closed pursuant to this section must perform soil sample analysis, and if water is present in the excavation, groundwater analysis. Sampling must be performed as follows:

   1. (1) Soil and groundwater samples must be analyzed as required by the Cleanup Oversight Agency for all hazardous substances previously stored in the underground storage tank(s). Soil samples must be collected a minimum of two feet into native soil, immediately beneath:

      1. (A) Each end of the tank;
      2. (B) The midpoint of each tank with a capacity greater than 12,000 gallons;
      3. (C) Each internal bulkhead of compartmented tanks;
      4. (D) All hazardous substance piping at 20 linear-foot intervals, with additional samples collected at each change in direction for rigid piping; and
      5. (E) Each dispenser.
   2. (2) Soil sample collection must be performed immediately after removal of the tank or hazardous substance piping from the excavation. Groundwater sample collection must be done immediately after the water enters the excavation or is otherwise encountered.
   3. (3) Locations and collection methods for all required samples must be approved by the Unified Program Agency.
8. (h) Soil and groundwater samples must be analyzed by a laboratory certified by the Environmental Laboratory Accreditation Program for all constituents of previously stored hazardous substances and their breakdown or transformation products.

9. (i) Within 30 days of removal of the tank or piping, or collection of required soil or groundwater samples, the owner or operator must provide to the Unified Program Agency:

   1. (1) The laboratory reports containing the sample analytical results, chain-of-custody, quality assurance/quality control data, and any commentary or notes from the laboratory;
   2. (2) Information, such as site maps or drawings identifying the location at the facility, depth below grade and date of collection for each sample taken;
   3. (3) Boring logs, if applicable; and
   4. (4) Documentation demonstrating proper disposal of the tank, pipe, and any hazardous wastes generated as a result of closure activities.
10. (j) The detection of any release requires compliance with the applicable requirements of articles 7 and 10.

11. (k) Within 60 days of receipt of all the documentation in subdivision (i) and the submittal pursuant to subdivision (n), the Unified Program Agency must issue an Underground Storage Tank Closure Letter to the owner or operator that confirms that the underground storage tank system has been permanently closed in accordance with this section and includes all the following:

    1. (1) CERS ID, if applicable;
    2. (2) Facility name;
    3. (3) Facility address;
    4. (4) Owner name;
    5. (5) Operator name;
    6. (6) Date the underground storage tank was closed;
    7. (7) Type of closure (removed or closed in place);
    8. (8) CERS tank ID of each underground storage tank closed, if applicable; and
    9. (9) Name of the Cleanup Oversight Agency having jurisdiction.
12. (l) The owner or operator of an underground storage tank system that is permanently closed must maintain the analytical results of all soil and groundwater samples as specified in subdivision (g) for at least 36 months after the underground storage tank system is properly closed.
13. (m) The owner of a decommissioned tank does not need to comply with the closure requirements in this section unless the Cleanup Oversight Agency determines that there is evidence of an unauthorized release or a threat of an unauthorized release. The owner of a decommissioned tank must comply with requirements to report an unauthorized release in accordance with section 2671 and must comply with the corrective action requirements in article 10.
14. (n) The owner or operator must update all applicable data elements in the California Environmental Reporting System or local reporting portal within 30 days of removal of the underground storage tank from the excavation or, for closure in place, certification of the tank as non-hazardous after on-site cleaning, in accordance with section 2613(b).

Note: Authority cited: Sections 25299.3 and 25299.7, Health and Safety Code. Reference: Sections 25298 and 25404, Health and Safety Code; and 40 CFR Sections 280.71, 280.72, 280.73, 280.74 and 281.36(b).

History

1. Repealer and renumbering and amendment of former section 2682 to section 2681 filed 4-5-94; operative 5-5-94 (Register 94, No. 14). For prior history, see Register 92, No. 43.

2. Repealer and new section heading and section filed 10-28-2025; operative 1-1-2026 (Register 2025, No. 44).