TABLE OF CONTENTS The Board hereby adopts as final the new Part 742, Tiered Approach to Corrective Action Objectives. The Board has examined the substantive issues concerning the proposal initially filed by the Agency and the record and modification to the Agency s proposal developed during this rulemaking. The Board has reserved one issue for a separate Docket B. That issue is to what extent the mixture rule adopted today should be modified to insure that risk based remediation objectives determined using TACO are protective of human health. The Board concludes that the TAOC rules set forth in the attached order provide a tiered approach for assessing risk to human health when determining remediation objectives and the methodologies acceptable for doing so on a site-specific basis. The Board further finds that these rules are economically reasonable and technically feasible. The Board anticipates that these rules will be used successfully in conjunction with the remediation programs contained in other Board rules to remediate contamination at properties throughout Illinois based on risk of human exposure and that future uses of such properties will not be modified without consideration of the adequacy of the risk-based remediation. Finally, the Board looks forward to a proposal from the Agency addressing the risk-based methodology necessary to protect the environment.
