R311-211-6. UST Facility Cleanup Standards

  (a) This rule incorporates by reference the Initial Screening Levels table dated November 1, 2005. The table lists initial screening levels for UST sites.

  (b) If the Director determines that a release from an underground storage tank has occurred, the Director shall evaluate whether the contamination at the site exceeds Initial Screening Levels for the contaminants released. The Director may require owners and operators to submit any information that the Director believes will assist in making this evaluation.

  (c) If all contaminants are below initial screening levels, the Director shall evaluate the site for No Further Action determination.

  (d) This rule incorporates by reference the Tier 1 Screening Criteria table dated November 1, 2005. The table lists cleanup criteria for UST sites. Tier 1 screening levels are only applicable when the following site conditions are met:

  (1) No buildings, property boundaries or utility lines are located within 30 horizontal feet of the highest measured concentration of any contaminant that is greater than the initial screening levels but less than or equal to the Tier 1 screening levels in the tables referred to in subparagraphs (a) and (d) above, respectively, and;

  (2) No water wells or surface water are located within 500 horizontal feet of the highest measured concentration of any contaminant that is greater than the initial screening levels but less than or equal to the Tier 1 screening levels in the tables referred to in subparagraphs (a) and (d) above, respectively.

  (e) If any contaminants from a release are above the Initial Screening Levels, the Director shall require owners and operators to submit all relevant information required to evaluate the site using the Tier 1 Screening Criteria.

  (1) If all Tier 1 Screening Criteria have been met, the Director shall evaluate the site for No Further Action determination.

  (2) If any of the Tier 1 Screening Criteria have not been met owners and operators shall proceed as described below.

  (i) Owners and operators shall conduct a site investigation to provide complete information to the Director regarding the factors outlined in R311-211-5(c) and 40 CFR Part 280.

  (ii) When the site investigation is complete, owners and operators may propose for the evaluation and approval of the Director site-specific cleanup standards based upon an analysis of the factors outlined in R311-211-5(c). Alternatively, the owners and operators may propose for the approval of the Director the Initial Screening Levels established in R311-211-6(a) as the site-specific cleanup standards.

  (iii) A partial corrective action approach may be approved by the Director prior to completing the site investigation. However, if corrective action is implemented in separate phases, the Director will not make a No Further Action determination until all factors outlined in R311-211-5(c) are evaluated.

  (iv) Owners and operators may then propose and conduct corrective action approved by the Director to attempt to reach the approved site-specific cleanup standards. If the owners and operators demonstrate that the approved site-specific cleanup standards have been met and maintained based upon sampling at intervals and for a period of time approved by the Director, the Director shall evaluate the site for No Further Action determination.

  (v) If the owners and operators do not make progress toward reaching site-specific cleanup standards after conducting the approved corrective action, the Director may require the owners and operators to submit an amended corrective action plan or an amended site-specific cleanup standards proposal and analysis of the factors outlined in R311-211-5(c) for the Director's approval. The Director may also require further investigation to fully define the extend and degree of the contamination if the passage of time or other factors creates the possibility that existing data may no longer be reliable.