Authority: IC 13-12-3-2; IC 13-14-8; IC 13-19-3; IC 13-23-13-7; IC 13-24-1; IC 13-25-4

Affected: IC 13-12-3-2; IC 13-25-4

Sec. 1. (a) The department shall utilize an objective method to assess, on the basis of available information, the relative potential threat to human health or the environment from hazardous substances response sites or releases. The method used to assess hazardous substances response sites or releases will be called the priority ranking system (PRS).

(b) After the department receives the notification of release, the site or release will be prioritized under the PRS and placed in the appropriate priority as follows:

1. (1) If the department determines, based on the notification of a release submitted to the department, that one (1) of the following has occurred, then the site or release is considered a high priority:

   1. (A) Vapors from a listed or characteristic hazardous waste, a hazardous substance, petroleum, petroleum constituent, or contaminant are detected in a habitable structure or other structure such as a utility conduit, storm sewer, or sanitary sewer at a level that exceeds:

      1. (i) the chronic, long term risk-based exposure for a contaminant of concern; or
      2. (ii) ten percent (10%) of the contaminant of concern's lower explosive limit (LEL).
   2. (B) A listed or characteristic hazardous waste, a hazardous substance, petroleum, petroleum constituent, or contaminant is detected in surface water or a drinking water well at or above MCLs or cleanup levels for ground water that are above the risk based remediation standards under IC 13-12-3-2.
   3. (C) Free product is present.
   4. (D) An ecologically sensitive area or a geologically sensitive area is detrimentally affected by the release.
   5. (E) Ground water contaminated by the release is located within three thousand (3,000) feet of a fixed radius of a wellhead or a one (1) year time of travel of a delineated, approved wellhead protection area for a community water system.
   6. (F) Hazardous substances are identified in surface soil, which has a direct soil contact exposure pathway, at levels exceeding the risk based remediation standards under IC 13-12-3-2.

2. (2) If the department determines, based on the notification of a release submitted to the department, that one (1) of the following has occurred, then the site or release is considered a medium priority:

   1. (A) None of the conditions set forth in subdivision (1) are applicable.
   2. (B) Ground water contaminated by the release is located within a five (5) or ten (10) year time of travel of a delineated, approved wellhead protection area for a community water system or within three thousand (3,000) feet of a fixed radius of a wellhead.
   3. (C) A listed or characteristic hazardous waste, a hazardous substance, petroleum, petroleum constituent, or contaminant is detected in ground water at any concentration.

3. (3) If the department determines, based on the notification of a release submitted to the department, that one (1) of the following has occurred, then the site or release is considered a low priority:

   1. (A) None of the conditions set forth in subdivisions (1) and (2) are applicable.
   2. (B) No hazardous substance, petroleum, petroleum constituent, or contaminants are detected in ground water.
   3. (C) A listed or characteristic hazardous waste, a hazardous substance, petroleum, petroleum constituent, or contaminant is detected in soil, which does not have a direct soil contact exposure pathway, at concentrations exceeding the risk based remediation standards under IC 13-12-3- 2.

(c) For purposes of this section, "surface soil" and "direct soil contact exposure pathway" are defined or further explained in the risk based remediation standards under IC 13-12-3-2.

(Solid Waste Management Division; 329 IAC 7.1-4-1; filed Jun 5, 2008, 11:19 a.m.: 20080702-IR-329060147FRA; filed Jan 30, 2013, 12:29 p.m.: 20130227-IR-329120379FRA; readopted filed Jun 14, 2019, 2:00 p.m.: 20190710-IR-329190249BFA; readopted filed Oct 16, 2024, 11:58 a.m.: 20241113-IR-329230812RFA)