1. (a) Closure.

   1. (1) The owner or operator of a tank or piping undergoing closure shall notify the commissioner at least 30 days before beginning such closure. Notice of such closure shall be provided on a form and manner prescribed by the commissioner in accordance with section 22a-449(d)-114 of the UST regulations.

   2. (2) When closure is undertaken, the owner or operator of an UST system shall ensure that:

      1. (A) A person with the training specified in this subparagraph who is responsible for conducting such closure is present at the underground storage facility. Such person responsible for conducting closure shall, before such closure, have received a certification of successful completion of 40-hour Hazardous Waste Operations and Emergency Response training under 29 CFR 1910.120, successfully passed the International Code Council Decommissioning Exam U2 or an examination listed on the department’s internet website, and received at least 8 hours of annual Hazardous Waste Operations and Emergency Response refresher training required under 29 CFR 1910.120, as applicable;
      2. (B) The entire UST system is emptied and cleaned by removing all liquids and accumulated sludges in accordance with a code of practice developed by a nationally recognized association, provided the owner or operator shall not use a method to comply with this subsection if the commissioner has posted on the department’s internet website that use of such method is unacceptable.
      3. (C) After removal of such liquids and sludges:

2. (i) For each tank or UST not being closed in place, remove from the ground; or(ii) For each tank or UST being closed in place, prior to filling the UST with a solid inert material, conduct the requirements prescribed in subdivisions (D), (E) and (F) of this subsection; and(iii) All piping shall be removed from the ground or capped.

   1. (D) Not later than 5 days after completing the events described in subparagraphs (B) and (C) of this subdivision, the owner or operator shall retain a person with a minimum of 3 years of experience and training in selecting and taking samples who shall have an understanding of the appropriate analytical methods for products stored in the UST system. Such person shall perform an assessment evaluating all locations where contamination is most likely to be present at the underground storage facility to determine whether no further action is required or whether additional action is required due to the presence of a confirmed release or suspected release at the underground storage facility. This evaluation shall include sampling from all sides and the bottom of the area where a tank has been removed or closed in-place, areas of staining, areas where holes or perforation in the removed tank are visible, and areas where spill buckets, containment sumps, or dispensers were used. The evaluation of piping undergoing closure shall include at least one sample taken at every 10-foot interval of piping where contamination is most likely to be present, but for any interval of less than 10 feet, at least one sample shall be taken. The selection of sample types, sample locations, and analytical methods shall take into account: the nature of any stored substance, the type of backfill, the depth to ground water, the presence of rainwater or groundwater, and other factors appropriate for identifying the presence of a suspected or confirmed release;
   2. (E) Sample collection and analysis conducted for the assessment required by subparagraph (D) of this subdivision shall comply with appropriate chain-of-custody procedures to ensure sample integrity and all samples shall be analyzed by a laboratory that is either certified by the Connecticut Department of Public Health or approved in writing by the commissioner; and(F) All analytical data used to comply with this section shall be scientifically valid and defensible, with a level of precision, accuracy, and sensitivity commensurate with its intended use. All analytical data shall include an analytical data quality assessment and data usability evaluation prepared by individuals qualified to make such assessment or evaluation in accordance with the requirements in the RSRs. If the commissioner determines that analytical data is not scientifically valid and defensible, or not of a sufficient level of precision, accuracy, and sensitivity to support the intended use of the data, the commissioner shall identify in writing the reasons for such conclusions and such data shall not be relied upon to demonstrate compliance with this section.

   3. (3) If at any time during closure a release is:

      1. (A) Suspected, then the owner or operator of the UST system shall comply with section 22a-449(d)-105 of the UST regulations; and(B) Confirmed, then the owner or operator of the UST system shall comply with section 22a-449(d)-106 of the UST regulations.

   4. (4) Closure is complete only after a determination in the assessment completed in accordance with subdivision (2)(D) of this subsection finds that:

      1. (A) No further action is required;
      2. (B) Additional actions are required under section 22a-449(d)-105 of the UST regulations; or(C) Additional actions are required under section 22a-449(d)-106 of the UST regulations.
3. (b) Closure notification.The owner or operator of a tank or piping undergoing closure shall notify the commissioner not less than 30 days before beginning closure and not later than 30 days after completion of such closure. Notices of such closure shall be provided on a form and manner prescribed by the commissioner in accordance with section 22a-449(d)-114 of the UST regulations.

4. (c) Closure report.

   1. (1) Not later than 60 days after the removal of or rendering an UST unusable or removal of piping, the owner or operator shall ensure that a detailed report is prepared regarding the closure. Such report shall include, at a minimum:

      1. (A) A description of the underground storage facility, including UST systems in use or removed from the facility and general characteristics of the area in which the facility is located;
      2. (B) A detailed description of the activities undertaken to close the tank or piping;
      3. (C) A detailed description and justification for the sample locations, sample depths, analytical methods used, and quality assurance/quality control measures taken;
      4. (D) A detailed analysis of the analytical results. This analysis shall include:

5. (i) All sampling results and a justification for disregarding or not using any sampling result;

   1. (ii) A description of the distribution and concentration of any substance in soil or groundwater that is or may have been released from the underground storage facility;
   2. (iii) A description of the general characteristics of soil in the vicinity of the underground storage facility;
   3. (iv) A map showing the extent and concentration of all releases, including the location of samples;
   4. (v) The tabulated analytical results of all laboratory analysis of soil and groundwater;
   5. (vi) A description of the experience and training of the person undertaking the assessment required by subsection (a)(2)(D) of this section; and(vii) Any other information specified by the commissioner.

   6. (2) The owner or operator shall retain the closure report and, within 30 days of completion of such report, notify the commissioner on a form prescribed by the commissioner that such report has been completed. In addition, the closure report shall be submitted to the commissioner, on a form and in a manner specified by the commissioner if:

      1. (A) The results of the assessment undertaken pursuant to subsection (a)(2)(D) of this section indicate an exceedance of any applicable criterion of the RSRs or indicate the presence of substance for which there is no criterion under the RSRs; or(B) The commissioner requests in writing that the closure report be submitted. The report shall be submitted within the time frame specified in any such request. If no time frame is specified in the request, the report shall be submitted to the commissioner not later than 30 days from the receipt of a request.
6. (d) Additional actions.If the actions undertaken pursuant to subsection (a) of this section, or the closure report prepared pursuant to subsection (c) of this section are not satisfactory to the commissioner, the commissioner shall notify the owner or operator in writing identifying what the commissioner deems unsatisfactory, including the reasons why and what additional actions are necessary. The owner or operator shall undertake any action requested by the commissioner within a time frame specified by the commissioner. If no time frame is specified in any such request, the requested actions shall be undertaken not later than 60 days from the date of any such request.
7. (e) Applicability to previously closed systems.If a release or potential release from an UST system closed before July 28, 1994 may, in the judgment of the commissioner, pose a current or potential threat to human health or the environment, when directed by the commissioner, the owner or operator shall comply with the closure procedures in this section and comply with section 22a-449(d)-105 of the UST regulations or section 22a-449(d)-106 of the UST regulations, as applicable.

(Effective July 28, 1994; Amended May 7, 2025)