The responsible person must calculate Tier 2 action levels based on actual site conditions, as follows:

1. (1) Toxicity information must be obtained from sources consistent with EPA's "Risk Assessment Guidance for Superfund" (1989). The department may allow the development of a toxicity value if required and applicable toxicological data are available;
2. (2) The excess lifetime cancer risk may not exceed 1:100,000 for all pathways;
3. (3) The chronic noncancer risk may not exceed a hazard index of one for all pathways;
4. (4) Reasonable maximum exposure default values as determined in EPA's "Risk Assessment Guidance for Superfund" (1989) must be used for exposure assessments or site-specific exposure data may be used with the permission of the department;
5. (5) "Tier 2 RBCA Guidance Manual for Risk-Based Corrective Action" (1995a; 1995b) is the source for fate and transport models for development of Tier 2 action levels;

6. (6) The department shall approve the location of monitoring points to ensure compliance with the South Dakota groundwater quality standards in chapter 74:54:01 and the conditions listed in subdivisions (2) and (3) in this section.

   References: Pages 6-32 to 6-52, inclusive, and page 7-15, "Risk Assessment Guidance for Superfund, Volume I, Human Health Evaluation Manual (PartA)" December 1989, United States Environmental Protection Agency, Office of Emergency and Remedial Response, 401 M Street, SW(OS-230), Washington, DC 20460, (202)475-9486. Copies may be obtained from the address listed. Cost: $48.

   "Tier 2 RBCA Guidance Manual for Risk-Based Corrective Action," June 1995a, 48 pages, Groundwater Services, Inc., 5252 Westchester, Suite 77005, Houston, Texas 77005, (713)663-6600. Copies may be obtained from the address listed. Cost: $75 (includesAppendixBbelow).

   "Tier 2 RBCA Guidance Manual for Risk-Based Corrective Action, Appendix B: Tier 1/Tier 2 RBCA Modeling Guidelines and Spreadsheet System" June 1995b, 34 pages, Groundwater Services, Inc., 5252 Westchester, Suite 77005, Houston, Texas 77005, (713)663-6600. Copies may be obtained from the address listed. Cost: $75 (includesguidancemanualabove).

Source: 22 SDR 86, effective December 18, 1995; transferred from § 74:03:33:11, July 1, 1996

General Authority: SDCL 34A-2-93 , 34A-2-99 , 34A-2-101 , 34A-12-7.

Law Implemented: SDCL 34A-2-99 , 34A-2-101 , 34A-12-10.