Idaho Admin. Code r. 58.01.24.200

Current through September 2, 2024

Section 58.01.24.200 - RISK EVALUATION PROCESS

The following risk evaluation process shall be used for petroleum releases in accordance with the Petroleum Release Response and Corrective Action Rules described in IDAPA 58.01.02, "Water Quality Standards," Section 852.

01.Screening Evaluation. The screening evaluation may be performed at any time during the release response and corrective action process described in IDAPA 58.01.02, "Water Quality Standards," Section 852. The screening evaluation shall include, at a minimum:

a. Collection of media-specific (soil, surface water, ground water) data; and

b. Identification of maximum soil, ground water, and soil vapor petroleum chemical concentrations for the chemicals identified in Section 800, table of chemicals of interest for various petroleum products, as appropriate for the petroleum product or products released.

c. Comparison of the maximum media-specific petroleum contaminant concentrations to the screening levels identified in the table of screening level concentrations for soil, ground water, and soil vapor in the Idaho Risk Evaluation Manual for Petroleum Releases. If the maximum media-specific petroleum contaminant concentrations at a site do not exceed the screening levels, the owner and/or operator may petition for site closure, subject to other Department regulatory obligations. If the maximum media-specific concentrations at a site exceed the screening levels, the owner and/or operator shall proceed to:

i. Adopt the screening levels as cleanup levels and develop a corrective action plan to achieve those levels pursuant to Subsection 200.03; or

ii. Perform a site specific risk evaluation pursuant to Section 300. The Department may require the collection of additional site-specific data prior to the approval of the risk evaluation.

02.Results of Risk Evaluation. If the results of the approved risk evaluation do not exceed the acceptable target risk level, acceptable target hazard quotient, or acceptable target hazard index specified in Section 300, the owner and/or operator may petition for site closure, subject to other Department regulatory obligations. If the results of the approved risk evaluation indicates exceedance of the acceptable target risk level, acceptable target hazard quotient, or acceptable target hazard index specified in Section 300, the risk evaluation shall:

a. Be modified by collection of additional site-specific data, or review of chemical toxicological information, and resubmitted to the Department for review and approval; or

b. Provide the basis for the development of risk based concentrations, establishment of remediation standards as described in Section 400, and development of a corrective action plan.

03.Development and Implementation of Corrective Action Plan. A Corrective Action plan required as a result of the risk evaluation process described in Section 200 shall include, but not be limited to, the following information, as applicable:

a. Description of remediation standards, points of exposure, and points of compliance where remediation standards shall be achieved;

b. Description of remedial strategy and actions that will be taken to achieve the remediation standards;

c. Current and reasonably anticipated future land use and use of on-site and immediately adjacent off- site ground water, and surface water;

d. Activity and use limitations, if any, that will be required as part of the remedial strategy;

e. Proposed environmental covenants, developed to implement activity and use limitations, in accordance with Section 600;

f. Estimated timeline for completion; and

g. Monitoring Plan to monitor effectiveness of remedial actions.

h. Description of practical quantitation limits as they apply.

i. Description of background concentrations as they apply.

04.Department Review and Approval of Risk Evaluation or Corrective Action Plan. Within thirty (30) days of receipt of the risk evaluation or corrective action plan, the Department shall provide in writing either approval, approval with modifications, or rejection of the risk evaluation or corrective action plan. If the Department rejects the risk evaluation or corrective action plan, it shall notify the owner and/or operator in writing specifying the reasons for the rejection. If the Department needs additional time to review the documents, it will provide written notice to the owner and/or operator that additional time to review is necessary and will include an estimated time for review. Extension for review time shall not exceed one hundred eighty (180) days without a reasonable basis and written notice to the owner and/or operator.

Idaho Admin. Code r. 58.01.24.200

Effective March 31, 2022