Ill. Admin. Code tit. 35, § 750.440 – Phase IV − Evaluation and Determination of Appropriate Response--Planned Removal and Remedial Action

a) The purpose of this phase is to determine the appropriate action when the preliminary assessment indicates that further response may be necessary or when IEPA finds that further response should follow an immediate removal action.
b) As soon as practicable, an inspection will be undertaken to assess the nature and extent of the release and to assist in determining its priority for Fund-financed response.
c)
1. 1) The IEPA may undertake investigations, monitoring, surveys, testing and other information gathering as appropriate. These efforts shall be undertaken jointly by the IEPA and those state officials responsible for enforcing legal requirements.
2. 2) A major objective of an inspection is to determine if there is any immediate danger to persons living or working near the facility. In general, the collection of samples should be minimized during inspection activities; however, situations in which there is an apparent risk to the public should be treated as exceptions to that practice. Examples of apparent risk include use of nearby wells for drinking water, citizen complaints of unusual taste or odor in drinking water, or chemical odors or unusual health problems in the vicinity of the release. Under those circumstances, a sampling protocol should be developed for the inspection to allow for the earliest possible detection of any human exposure to hazardous substances. The site inspection may also address:
  1. A) Determining the need for immediate removal action;
  2. B) Assessing amounts, types and location of hazardous substances stored;
  3. C) Assessing potential for substances to migrate from areas where they were originally located;
  4. D) Determining or documenting immediate threats to the public or environment.
d) Methods for Establishing Priorities
1. 1) IEPA shall prepare a State Priorities List. Such list shall be compiled using the Federal Hazard Waste Ranking System (40 CFR 300, Appendix A, as amended.)
2. 2) Ranking of Releases − Similar hazard ranking scores assigned to releases cannot accurately differentiate among risks represented by the releases. Thus, in order to avoid misleading the public that real differences in risk exist, similar scores may be grouped on the State Priorities List.
3. 3) IEPA shall publish a proposed State Priorities List in the Illinois Register for public comment.
4. 4) IEPA shall revise and publish the State Priorities List at least once annually. In addition, revisions shall give notice of the deletion (if any) of releases previously listed.