Section 742.500  Tier 1 Evaluation Overview

a)         A Tier 1 evaluation compares the concentration of each contaminant of concern detected at a site to the baseline remediation objectives provided in Appendix B, Tables A, B, C, D, E, G, H and I.  Use of Tier 1 remediation objectives requires only limited site-specific information:  concentrations of contaminants of concern, groundwater classification, land use classification, and, if appropriate, soil pH.  (See Appendix B, Illustration A.)

b)         Although Tier 1 allows for differentiation between residential and industrial/commercial property use of a site, an institutional control under Subpart J is required where remediation objectives are based on an industrial/commercial property use.

c)         For the indoor inhalation exposure route:

1)         Appendix B, Tables H and I apply only when the existing or potential building has a full concrete slab-on-grade or a full concrete basement floor and walls; and

2)         Institutional controls under Subpart J are required to use remediation objectives in Appendix B, Table H or Table I.

d)         Any given exposure route is not a concern if the concentration of each contaminant of concern detected at the site is below the Tier 1 value of that given route.  In such a case, no further evaluation of that route is necessary.

(Source:  Amended at 37 Ill. Reg. 7506, effective May 15, 2013)