7 Del. Admin. Code § 1351-E-3.0

Current through Register Vol. 28, No. 7, January 1, 2025

Section 1351-E-3.0 - Release Response Requirements

3.1 Department Authority to Assume Control of Releases

3.1.1 The Department reserves the right to assume control of any Release or indicated Release situation when it is determined that the Responsible Parties are not responding promptly or effectively. In such cases all liability, including payment to the Department of response costs, will remain with the Responsible Parties.

3.1.2 To protect human health, safety, and the environment the Department reserves the right for the Department or its contractors to enter and take appropriate actions on affected properties to investigate, abate and remediate contamination.

3.2 Initial Release Response Requirements

3.2.1 In response to a Release from an UST System, the Responsible Parties shall promptly take the following steps:

3.2.1.1 The cause of the Release shall be promptly identified through UST System tightness testing or other means approved by the Department; and

3.2.1.2 If a faulty UST System component is determined to be the cause of a Release, the component or, if necessary, the entire UST System, shall be taken Out Of Service or rendered Empty and shall not be returned to service until the UST System is functioning in compliance with all applicable portions of these Regulations; and

3.2.1.3 The Regulated Substance contained within the UST System shall be removed unless otherwise directed by the Department; and

3.2.1.4 No Responsible Parties shall put back into service any UST System that has caused a Release without prior approval from the Department; and

3.2.1.5 An investigation shall be conducted to determine an estimate of the amount and type of Regulated Substance Released; and

3.2.1.6 Responsible Parties shall implement the following to contain the Release:

3.2.1.6.1 If LNAPL is present, LNAPL Corrective Action shall be immediately initiated in accordance with Part E, subsection 3.3; and

3.2.1.6.2 Nearby receptors shall be protected from impacts of Regulated Substances through recovery and containment measures to prevent migration of Mobile and Migrating LNAPL. The Department shall be notified of all activities; and

3.2.1.6.3 All flammable material shall be properly handled and vapors shall be mitigated to prevent fires, explosions and impacts to receptors.

3.3 LNAPL Corrective Action Requirements

3.3.1 At sites where there is a Release of LNAPL, the Responsible Parties shall remove and remediate the LNAPL to the maximum extent practicable following the requirements established in Part E of these Regulations while continuing, as necessary, the Release confirmation steps and the investigation required in Part E of these Regulations.

3.3.2 The Responsible Parties shall formulate a LNAPL Conceptual Site Model (LCSM) to determine the most efficient and environmentally protective remedial approach for addressing the Release.

3.3.3 The Responsible Parties shall verbally communicate a preliminary LCSM to the Department within 48 hours of the discovery of a Release of LNAPL. The preliminary LCSM shall address as many of the criteria listed in Part E, subsection 3.3.4 as possible.

3.3.4 The LCSM shall at a minimum address the following factors with regard to the LNAPL Release:

3.3.4.1 The feasibility and necessity of an immediate response; and

3.3.4.2 Direct and potential impacts to human health, safety and the environment; and

3.3.4.3 The type and estimated volume of the LNAPL released; and

3.3.4.4 The evidence, or occurrence, of the LNAPL Release (Migrating LNAPL, Mobile LNAPL in a well, Residual LNAPL discovered during an investigation); and

3.3.4.5 The potential recoverability of all LNAPL phases; and

3.3.4.6 The geometry of the LNAPL Body; and

3.3.4.7 The estimated age and duration of the LNAPL Release; and

3.3.4.8 The characteristics of the subsurface soils; and

3.3.4.9 The chemical and physical properties of the LNAPL; and

3.3.4.10 Groundwater classification for the area such as wellhead protection areas, excellent recharge areas, or source water protection areas.

3.3.5 Responsible Parties shall base all short and long term Remedial Action decisions upon the information in the LCSM, which shall be updated, in writing and submitted to the Department, at a minimum of once every 3 calendar months, or on a schedule approved by the Department.

3.3.6 LNAPL removal shall be conducted in a manner that minimizes the spread of contamination, including dissolved and vapor phases, into previously uncontaminated areas by using recovery and disposal techniques appropriate to the hydrogeologic conditions at the site, and that properly treats, discharges or disposes of recovery by-products in accordance with all applicable local, state and federal requirements.

3.3.7 If LNAPL recovery is not practicable, and does not support site Remedial Action objectives as determined by the Department, the Responsible Parties may submit a written request for Department approval to discontinue LNAPL recovery. The request shall at a minimum include the following:

3.3.7.1 Technical feasibility of other proven groundwater and soil treatment techniques to further reduce LNAPL at the site; and

3.3.7.2 Costs, time frames, and resources involved to further reduce LNAPL levels employing the current and alternative method(s) proposed; and

3.3.7.3 A demonstration that the remaining LNAPL Body is not contributing to any unstable daughter plumes such as a dissolved plume and vapor migration; and

3.3.7.4 A demonstration that remaining LNAPL does not pose any risk to human health, safety, and the environment; and

3.3.7.5 An assessment of the persistence and fate of the LNAPL in the subsurface; and

3.3.7.6 A description of the individual site characteristics, including natural rehabilitative processes; and

3.3.7.7 Statements regarding current versus future land use of the site.

3.3.8 The Department may require the Responsible Parties to follow any applicable guidance or industry referenced standards in order to create a sound LCSM, from which optimal Remedial Action decisions can be made.

7 Del. Admin. Code § 1351-E-3.0

13 DE Reg. 1562 (06/01/10)
23 DE Reg. 581 (1/1/2020)
27 DE Reg. 533 (1/1/2024) (Final)