7 Del. Admin. Code § 1375-9.0

Current through Reigster Vol. 28, No. 6, December 1, 2024

Section 1375-9.0 - Investigation

9.1 Initial Investigation

9.1.1 The purpose of the initial investigation is to determine if sufficient information is available for the Department to determine if a release or imminent threat of release of a hazardous substance has occurred, and, if so, to perform an initial hazard ranking of the facility based on the Delaware Hazard Ranking Model as described and specified in Section 3.3 of these Regulations.

9.1.2 Information shall be analyzed using quality assurance/quality control procedures to determine if the quality of the information is acceptable to the Department for the objective of the initial investigation.

9.1.3 The Department may determine that a Phase I Environmental Site Assessment, all appropriate inquiry (AAI), or a Preliminary Assessment satisfies the requirements of an initial investigation.

9.1.4 Based on the information obtained about the facility during the initial investigation, the Department may:

9.1.4.1 Require a facility evaluation or a remedial investigation;

9.1.4.2 Require an interim action;

9.1.4.3 Place the facility on the priority list prepared by the Department;

9.1.4.4 Take any other action, or no action, as determined by the Department to be appropriate.

9.2 Facility Evaluation

9.2.1 The purpose of the facility evaluation (FE) includes:

9.2.1.1 Developing information and sampling data which will meet the data quality objectives;

9.2.1.2 Confirming the release or imminent threat of release;

9.2.1.3 Identifying the hazardous substances with sufficient data to determine future action at the facility. The FE does not require that the full extent of contamination be identified or that a full risk assessment be performed;

9.2.1.4 Identifying facility characteristics that could result in hazardous substances entering and moving through the environment; and

9.2.1.5 Performing an initial screening as described in Section 9.3 in order to evaluate the threat to public health, welfare, and the environment.

9.2.2 The Department may determine that a Phase II Environmental Site Assessment, a site inspection, site specific assessment satisfies the requirements of a FE; or

9.2.3 The Department may determine that existing information constitutes the equivalent of all or part of a FE.

9.2.4 The scope of the FE will depend on the specific characteristics of the facility. Sufficient information shall be collected to perform an initial screening as defined in Section 9.3.

9.2.5 A FE shall be conducted in accordance with the criteria, procedures, and time schedules established and agreed to by the Department.

9.2.6 Based on the information obtained about the facility during the FE and the initial screening, the Department will:

9.2.6.1 Revise the relative priority of the facility by performing a hazard ranking based on the FE results;

9.2.6.2 Conduct or require the performance of a remedial investigation and/or a feasibility study;

9.2.6.3 Enter into a Settlement Agreement with any person that offers to conduct a remedial investigation and/or feasibility study;

9.2.6.4 Conduct or require an immediate remedial action or interim action;

9.2.6.5 Conduct or require any other action, or no action, as determined by the Department; or

9.2.6.6 Issue a Conditional No Further Action Determination.

9.2.7 A Conditional No Further Action Determination pursuant to 9.2.6.6 of these Regulations does not preclude the Department from requiring further action based on additional information or other circumstances as it deems appropriate.

9.3 Initial Screening

9.3.1 The methodology described in this Section shall apply to a facility evaluation (FE) or equivalent investigation as specified in Section 9.2 of these Regulations.

9.3.2 The purpose of the initial screening shall be to determine whether, based on available data, a release at a facility poses a potential risk to human health, welfare, or the environment above the acceptable site specific risk.

9.3.3 The initial screening shall identify the maximum observed concentrations of analytes found in environmental samples and utilize representative data from each environmental media to perform a preliminary risk assessment.

9.3.3.1 Any laboratory confirmed analyte concentration, in excess of the screening levels approved by the Department, may require further evaluation.

9.3.3.2 The scope of the initial screening shall include an ecological screening to determine whether an Ecologically Sensitive Area (ECSA) is present on site or immediately adjacent to the site. If an ECSA is present, further ecological evaluation shall be performed.

9.4 Remedial Investigation

9.4.1 The purpose of the remedial investigation (RI) includes:

9.4.1.1 Characterizing the nature and extent of the release or the potential release of hazardous substances;

9.4.1.2 Collecting data to perform a risk assessment as specified in Section 10.0; and

9.4.1.3 Identifying the specific conditions that require potential remediation.

9.4.2 A Department approved Sampling and Analysis Plan (SAP), as specified in Section 9.6, is required prior to conducting a RI.

9.4.3 The Department may determine that the existing information regarding a facility satisfies all or part of the requirements of a RI.

9.4.4 The scope of the RI will depend on the specific characteristics of the facility and will meet the data quality objectives specified in the SAP.

9.4.5 A RI shall be conducted in accordance with the criteria, procedures, and time schedules determined by the Department.

9.4.6 The results of the RI will be evaluated to determine if data quality objectives, as described in the SAP, have been met.

9.4.7 Based on the information obtained about the facility during the RI and risk assessment, the Department may:

9.4.7.1 Require a Feasibility Study, as specified in Section 12.4, to evaluate potential remedies for the facility;

9.4.7.2 Require or conduct additional investigation or remedy (interim action); and/or

9.4.7.3 Issue a Proposed Plan of Remedial Action.

9.5 Brownfield Investigation

9.5.1 The Brownfield investigation, applicable to Certified Brownfields, shall meet the requirements of the remedial investigation as specified in Section 9.4.

9.6 Sampling and Analysis Plan - The following requirements are applicable to all stages of investigation:

9.6.1 Analytical procedures, including field screening methods, must be conducted in accordance with all applicable provisions of the Standard Operating Procedures of the Hazardous Substance Cleanup Act for Chemical Analytical Programs (SOPCAP), as issued or amended by the Department, or other methods or procedures preapproved by the Department.

9.6.2 Data shall be evaluated against accepted quality assurance/quality control parameters to determine data usability.

9.6.3 Sampling of the environmental media should be performed to collect representative samples that reflect the data quality objectives of the investigation.

7 Del. Admin. Code § 1375-9.0

19 DE Reg. 65 (7/1/2015)
22 DE Reg. 781 (3/1/2019) (Final)