1. (a) Requirement to Tier Releases Not more than one year following discovery of a release, such release shall be assigned to a cleanup tier if it remains present in the land and waters of the state and has not achieved compliance with the cleanup standards sections of the RBCRs.

2. (b) Establishment of Cleanup Tiers (1) There shall be established the following:

   1. (A) tier 1A;
   2. (B) tier 1B;
   3. (C) tier 2; and(D) tier 3.
   4. (2) Releases shall be assigned to such tiers using the checklist specified in section 22a-134tt-App1 of the RBCRs.
   5. (3) Releases presenting the highest risk to human health and the environment shall be assigned to tier 1A. Releases presenting less risk to the environment shall be assigned to tier 1B or tier 2, as specified. Releases that have reached groundwater and remain only as a diminishing state groundwater plume may be assigned to tier 3.

3. (c) Tier Assignment (1) Not more than one year after discovery of a release, such release shall be assigned to a cleanup tier if a release remediation closure report has not been submitted for such release. To assign a release to a cleanup tier, a tier assignment form shall be submitted to the commissioner, which shall include:

   1. (A) A complete tier checklist, including an LEP’s verification;
   2. (B) All characterization information necessary to complete the tier checklist, pursuant to section 22a-134tt-4 of the RBCRs;
   3. (C) A copy of the immediate action plan and immediate action report, if immediate action was performed;
   4. (D) The applicable fee specified by subsection (f) of this section; and(E) Any other information specified by the commissioner on such form.

   5. (2) A release may be assigned to a different cleanup tier when a release has been partially remediated such that risk to human health or the environment has been reduced, or shall be assigned to a different cleanup tier not more than 30 days after additional information has identified previously unaccounted for risks to human health or the environment, in order for continued remediation to occur in a cleanup tier corresponding with the risk to human health and the environment presented by such release as specified by section 22a-134tt-App1 of the RBCRs. To change the tier assignment, a change in tier assignment form shall be submitted to the commissioner on a form prescribed by the commissioner, which shall include:

      1. (A) A complete tier checklist, including an LEP’s verification;
      2. (B) All characterization information necessary to complete the tier checklist, pursuant to section 22a-134tt-4 of the RBCRs;
      3. (C) Copies of each approval issued by the commissioner when a remedy requiring the approval of the commissioner has been implemented;
      4. (D) A list of LEP-approved remedies that have been implemented, and all documentation necessary to demonstrate that such remedy has been properly selected and implemented;
      5. (E) The fee specified by subsection (f) of this section, if applicable; and(F) Any other information specified by the commissioner on such form.

   6. (3) A release may be assigned to tier 3 provided that soil impacted by the release has been remediated to the standards identified by section 22a-134tt-9 of the RBCRs, and that the plume of groundwater created by such release is in a diminishing state without need for further active remediation and is being monitored for natural attenuation. In addition to the information specified in subdivision (2) of this subsection, a tier assignment form or change in tier assignment form submitted for the purpose of assigning a release to tier 3 shall include:

      1. (A) Any document or information specified by sections 22a-134tt-9 and 22a-134tt-12 of the RBCRs to demonstrate that soil impacted by the release has been remediated to such cleanup standards;
      2. (B) A conceptual site model, supported by sufficient characterization data, that demonstrates that the plume of groundwater created by such release is in a diminishing state and is naturally attenuating;
      3. (C) A groundwater monitoring plan and schedule, including the name, business address, and contact information for the person who will be conducting such monitoring; and(D) Any other information requested by the commissioner on such form.

   7. (4) The commissioner may audit a tier assignment or change in tier assignment pursuant to section 22a-134tt-13 of the RBCRs. As a result of such audit, the commissioner may reject the tier assignment or change in tier assignment if all required information is not provided or a release is assigned to the incorrect tier. Upon rejection of a tier assignment or a change in tier assignment, the commissioner may:

      1. (A) require the submission of additional information;
      2. (B) require additional investigation or characterization of a release; or(C) assign the release to an appropriate tier, which shall include but shall not be limited to, tier 1A;
   8. (5) For the purposes of calculation of time, the date of tier assignment for a release shall be the day a tier assignment is first submitted pursuant to this section.

4. (d) Cleanup Oversight Remediation of releases shall be overseen as follows:

   1. (1) Releases assigned to tier 1A shall be supervised by the commissioner who may direct certain tasks to be performed by an LEP or other qualified professional and may exercise all authority over an emergency or exigent circumstance provided by section 22a-134tt-5(b);
   2. (2) Releases assigned to tier 1B shall be supervised by an LEP;
   3. (3) Releases assigned to tier 2 shall be supervised by an LEP; and(4) Releases assigned to tier 3 shall be supervised by an LEP or other qualified professional, except that the performance of certain tasks including compliance monitoring, and the preparation of a verification shall require the supervision of an LEP.

5. (e) Deadlines for Remediation (1) Not more than one year following the date of tier assignment, a release assigned to tier 1A shall be closed, or assigned to tier 1B, tier 2, or tier 3.

   1. (2) Not more than 2 years following the date of tier assignment, a release assigned to tier 1B shall be closed, or assigned to tier 2 or tier 3.
   2. (3) Not more than 4 years following the date of tier assignment, a release assigned to tier 2 shall be closed, or assigned to tier 3.
   3. (4) Not more than 5 years following the date of tier assignment, a release assigned to tier 3 shall be closed.
   4. (5) All timelines specified by this subsection shall run concurrently.

   5. (6) Extensions of the deadlines specified in this subsection may be granted as follows:

      1. (A) For releases assigned to tiers 1A, 1B, and 2, the commissioner may approve 1-year extensions of the deadlines specified by this subsection for good cause shown. A request for extension shall be made on a form prescribed by the commissioner, and shall include the fee calculated pursuant to subsection (f) of this section. The request for extension shall be made not less than 30 days prior to the expiration of the deadline on a form prescribed by the commissioner; and(B) An LEP may approve a single 1-year extension of the deadlines specified in this subsection for a release assigned to tier 1B or tier 2. Notice of such extension shall be made not less than 30 days before the expiration of such deadline on a form prescribed by the commissioner, and shall include the fee specified by subsection (f) of this section. Any additional extension of the deadline for the remediation of such release shall be approved by the commissioner.
      2. (C) A request for an extension of time for a release assigned to tier 3 shall be submitted to the commissioner, on a form prescribed by the commissioner. Notwithstanding subparagraphs (A) and (B) of this subdivisions:

6. (i) The commissioner shall approve a 5-year extension of the deadline specified in this subsection for a release assigned to tier 3 provided that the laboratory analysis of groundwater samples demonstrates that the groundwater plume caused by such release remains in a diminishing state and is naturally attenuating at a rate consistent with the conceptual site model submitted pursuant to subsection (c)(3)(B) of this section;

   1. (ii) The commissioner shall approve as many 5-year extensions as are necessary, provided the groundwater plume created by a release assigned to tier 3 remains in a diminishing state and is naturally attenuating at a rate consistent with the conceptual site model submitted pursuant to subsection (c)(3)(B) of this section; and(7) For the purposes of this subsection, a release is considered closed if a remediation closure report has been prepared pursuant to the requirements of section 22a-134tt-12 of the RBCRs and submitted to the department, if such report is required to be submitted pursuant to said section.

7. (f) Fees (1) Tier Assignment Fees The following fees shall be paid at the time a tier assignment is submitted to the commissioner. If a tier assignment is rejected, and the release is subsequently assigned to a different tier, the difference between the fee paid and the fee due shall be paid not more than 30 days following the date of tier assignment.

   1. (A) For a release assigned to tier 1A, 3,000 dollars;
   2. (B) For a release assigned to tier 1B, 1,500 dollars;
   3. (C) For a release assigned to tier 2, 1,000 dollars; and(D) For a release assigned to tier 3, 500 dollars.

   4. (2) Annual Fees (A) An annual fee shall be due one year following the date of tier assignment, and each year thereafter until a release is verified. The base annual fee shall be:

      1. (i) For a release assigned to tier 1A, 3,000 dollars;
      2. (ii) For a release assigned to tier 1B, 1,500 dollars;
      3. (iii) For a release assigned to tier 2, 1,000 dollars; and(iv) For a release assigned to tier 3, 500 dollars.
      4. (B) The annual fee shall be calculated as follows: [FEE] + (.1[FEE] x [number of years since tier assignment date]) = annual fee dueWhere:FEE is equal to the base annual fee for the tier to which the release is assigned on the date the annual fee is due.

   5. (3) Fees for Extension of Time (A) If a 1-year extension of time is approved by the commissioner or an LEP pursuant to subsection (e)(6) of this section, a fee equal to the annual fee calculated pursuant to subdivision (2)(B) of this subsection shall be paid to the commissioner.

      1. (B) There shall be no fee for a 5-year extension of time approved pursuant to subsection (e)(6)(C) of this section.
   6. (4) Single Deadline for Annual Fees Notwithstanding the requirements of this subsection, the commissioner may authorize the payment of the annual fees for multiple releases for which the same creator or maintainer is responsible on a date specified by the commissioner. A request for a single deadline for annual fee payments shall be submitted to the commissioner in accordance with section 22a-134tt-1(c) of the RBCRs.

   7. (5) 1-Year Exemption for Compliance Monitoring Notwithstanding the requirements of this subsection, there shall be no tier assignment fee for a release that has impacted groundwater, provided that at the time such release is first assigned to a tier:

      1. (A) all soil impacted by the release has been remediated to the standards identified by the cleanup standards sections of the RBCRs; and(B) The only remaining remediation of groundwater required is compliance monitoring pursuant to section 22a-134tt-10(h) of the RBCRs.

   8. (6) Notwithstanding any provisions of this subsection:

      1. (A) No fee assessed by this subsection shall be required to be paid by the owner of an owner-occupied single family home; and(B) Any fee charged pursuant to this subsection shall be reduced by 50 percent if paid by one of the following entities:

8. (i) An owner of residential properties with 4 or fewer dwelling units(ii) The state or any political subdivision of the state;

   1. (iii) Any nonprofit organization recognized under section 501(c)(3) of the Internal Revenue Code;
   2. (iv) Any municipal economic development agency or entity created or operating under chapter 130 or 132 of the Connecticut General Statutes; or(v) Any person receiving federal, state, or municipal brownfields funding for investigation or remediation.

9. (g) Noncompliance by Prior Maintainers (1) If a release that was discovered by a creator or maintainer who maintained the release in violation of the provisions of chapter 445b of the Connecticut General Statutes and the RBCRs is assigned to tier 1A by a person who did not create and was not maintaining the release at any time during the first year following discovery of the release, the tier assignment form submitted to the commissioner shall include:

   1. (A) A statement, signed by the person maintaining the release, that identifies the date such release was discovered and the date that the person became a maintainer of the release;
   2. (B) A statement, verified by an LEP, that the release is not a significant existing release or an emergent reportable release; and(C) A schedule for completing any work necessary to reassign the release to tier 1B, tier 2 or tier 3 or for the submission of a release remediation closure report prepared pursuant to section 22a-134tt-12, provided such schedule shall not exceed 1 year from the date of tier assignment.
   3. (2) The commissioner may approve the schedule submitted, or may reject the schedule and provide, in writing, an alternate schedule for completing any work necessary to reassign the release.
   4. (3) The commissioner may monitor compliance with a schedule approved or provided pursuant to this subsection, but may not further direct remediation of the release except when the person maintaining the release has not completed the work specified by such schedule by the deadlines specified in such schedule.
   5. (4) A person who did not create and was not maintaining the release at any time during the first year following discovery of the release shall not be required to pay a tier assignment fee for any release assigned to tier 1A. An annual fee shall be due 1 year following the date of tier assignment, and each year thereafter.

10. (h) Grouping Releases for Tier Assignment (1) If more than one release is discovered on the same parcel, each release discovered may be grouped for assignment into a cleanup tier, provided that:

    1. (A) Each release was discovered in the same 90 day period;
    2. (B) The group of releases is assigned to a cleanup tier not more than 365 days following the date the first release in the group was discovered;
    3. (C) The tier checklist specified at section 22a-134tt-App1 of the RBCRs is completed for each release; and(D) No release in the group is required to be assigned to tier 1A.

    4. (2) A group of releases shall be assigned to:

       1. (A) tier 1B, if one or more releases in the group requires assignment to tier 1B;
       2. (B) tier 2, if no release in the group requires assignment to tier 1B but one or more releases in the group requires assignment to tier 2; and(C) tier 3, if no releases in the group require assignment to tier 1B or tier 2.
    5. (3) A single tier assignment fee and annual fee shall apply to a group of releases. The total tier assignment fee and annual fee for the group of releases shall be the same as the fee for a single release assigned to the tier to which the group is assigned.

(Effective March 1, 2026)