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###### Environmental Protection Agency

          - 40 CFR Part 300
          - [EPA-HQ-SFUND-1989-0011; FRL-9981-00—Region 1]

# AGENCY:

Environmental Protection Agency (EPA).

# ACTION:

Proposed rule; notice of intent.

# SUMMARY:

The Environmental Protection Agency (EPA) Region 1 is issuing a Notice of Intent to Delete the Union Chemical Co., Inc. Superfund Site (Site) located in South Hope, Maine, from the National Priorities List (NPL) and requests public comments on this proposed action. The NPL, promulgated pursuant to section 105 of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980, as amended, is an appendix of the National Oil and Hazardous Substances Pollution Contingency Plan (NCP). The EPA and the State of Maine, through the Department of Environmental Protection (MEDEP), have determined that all appropriate response actions under CERCLA, other than operation and maintenance, monitoring and Five-Year Reviews, have been completed. However, this deletion does not preclude future actions under Superfund.

# DATES:

Comments must be received by August 20, 2018.

# ADDRESSES:

Submit your comments, identified by Docket ID no. EPA-HQ-SFUND-1989-0011, by one of the following methods:
      -  http://www.regulations.gov . Follow the on-line instructions for submitting comments. Once submitted, comments cannot be edited or removed from                          Regulations.gov . The EPA may publish any comment received to its public docket. Do not submit electronically any information you consider to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Multimedia submissions (audio, video, etc.) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents located outside of the primary submission (                         i.e.,                          on the web, cloud, or other file sharing system). For additional submission methods, the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit                          http://www2.epa.gov/​dockets/​commenting-epa-dockets .                    
      -  Email: connelly.terry@epa.gov                          or                          purnell.zanetta@epa.gov .                    
      - Mail:

Terrence Connelly, U.S. EPA, 5 Post Office Square, Suite 100, Mail Code OSSR 07-1, Boston, MA 02109-3912

ZaNetta Purnell, U.S. EPA, 5 Post Office Square, Suite 100, Mail Code OSSR 01-1, Boston, MA 02109-3912

*Hand delivery:*                         U.S. EPA, 5 Post Office Square, Suite 100, Boston, MA. Such deliveries are only accepted during the Docket's normal hours of operation, and special arrangements should be made for deliveries of boxed information.                    

*Instructions:*                         Direct your comments to Docket ID no. EPA-HQ-SFUND-1989-0011. EPA's policy is that all comments received will be included in the public docket without change and may be made available online at                         *http://www.regulations.gov,*                         including any personal information provided, unless the comment includes information claimed to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through                         *http://www.regulations.gov*                         or email. The                         *http://www.regulations.gov*                         website is an “anonymous access” system, which means EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an email comment directly to EPA without going through                         *http://www.regulations.gov,*                         your email address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the internet. If you submit an electronic comment, EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects or viruses.                    

*Docket:*                         All documents in the docket are listed in the                         *http://www.regulations.gov*                         index. Although listed in the index, some information is not publicly available,                         *e.g.,*                         CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, will be publicly available only in the hard copy. Publicly available docket materials are available either electronically in                         *http://www.regulations.gov*                         or in hard copy at:                    

U.S. EPA Region 1, Superfund Records Center, 5 Post Office Square, Suite 100, Boston, MA 02109, Phone: 617-918-1440, Monday- Friday: 9:00 a.m.-5:00 p.m., Saturday and Sunday—Closed.

# FOR FURTHER INFORMATION CONTACT:

                        Terrence Connelly, Remedial Project Manager, U.S. Environmental Protection Agency, Region 1, Mail Code OSSR 07-1, 5 Post Office Square, Boston, MA 02109-3912, (617) 918-1373, email                         *connelly.terry@epa.gov*.                    

# SUPPLEMENTARY INFORMATION:

## Table of Contents

I. Introduction

II. NPL Deletion Criteria

III. Deletion Procedures

IV. Basis for Site Deletion 

## I. Introduction

                    EPA Region 1 announces its intent to delete the Union Chemical Co., Inc Superfund Site (Site) from the National Priorities List (NPL) and requests public comment on this proposed action. The NPL constitutes Appendix B of 40 CFR part 300 which is the National Oil and Hazardous Substances Pollution Contingency Plan (NCP), which EPA promulgated pursuant to section 105 of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) of 1980, as amended. EPA maintains the NPL as the list of sites that appear to present a significant risk to public health, welfare, or the environment. Sites on the NPL may be the subject of remedial actions financed by the Hazardous Substance Superfund (Fund). As described in 40 CFR                           ( print page 34509)                        300.425(e)(3) of the NCP, sites deleted from the NPL remain eligible for Fund-financed remedial actions if future conditions warrant such actions.                

                    EPA will accept comments on the proposal to delete this site for thirty (30) days after publication of this document in the                     **Federal Register**                    .                

Section II of this document explains the criteria for deleting sites from the NPL. Section III discusses procedures that EPA is using for this action. Section IV discusses the Site and demonstrates how it meets the deletion criteria.

## II. NPL Deletion Criteria

The NCP establishes the criteria that EPA uses to delete sites from the NPL. In accordance with 40 CFR 300.425(e), sites may be deleted from the NPL where no further response is appropriate. In making such a determination pursuant to 40 CFR 300.425(e), EPA will consider, in consultation with the State, whether any of the following criteria have been met:

i. Responsible parties or other persons have implemented all appropriate response actions required;

ii. all appropriate Fund-financed response under CERCLA has been implemented, and no further response action by responsible parties is appropriate; or

iii. the remedial investigation has shown that the release poses no significant threat to public health or the environment and, therefore, the taking of remedial measures is not appropriate.

Pursuant to CERCLA section 121(c) and the NCP, EPA conducts Five-Year Reviews to ensure the continued protectiveness of remedial actions where hazardous substances, pollutants, or contaminants remain at a site above levels that allow for unlimited use and unrestricted exposure. EPA conducts such Five-Year Reviews even if a site is deleted from the NPL. EPA may initiate further action to ensure continued protectiveness at a deleted site if new information becomes available that indicates it is appropriate. Whenever there is a significant release from a site deleted from the NPL, the deleted site may be restored to the NPL without application of the hazard ranking system.

## III. Deletion Procedures

The following procedures apply to deletion of the Site:

(1) EPA consulted with the State before developing this Notice of Intent to Delete.

(2) EPA has provided the State 30 working days for review of this notice prior to publication of it today

(3) In accordance with the criteria discussed above, EPA has determined that no further response is appropriate;

(4) The State of Maine, through its Department of Environmental Protection (MEDEP), has concurred with deletion of the Site from the NPL.

                    (5) Concurrently with the publication of this Notice of Intent to Delete in the                     **Federal Register**                    , a notice is being published in a major local newspaper, the Bangor Daily News. The newspaper notice announces the 30-day public comment period concerning the Notice of Intent to Delete the Site from the NPL.                

(6) The EPA placed copies of documents supporting the proposed deletion in the deletion docket and made these items available for public inspection and copying at the Site information repository identified above.

                    If comments are received within the 30-day public comment period on this document, EPA will evaluate and respond appropriately to the comments before making a final decision to delete. If necessary, EPA will prepare a Responsiveness Summary to address any significant public comments received. After the public comment period, if EPA determines it is still appropriate to delete the Site, the Regional Administrator will publish a final Notice of Deletion in the                     **Federal Register**                    . Public notices, public submissions and copies of the Responsiveness Summary, if prepared, will be made available to interested parties and in the Site information repository listed above.                

Deletion of a site from the NPL does not itself create, alter, or revoke any individual's rights or obligations. Deletion of a site from the NPL does not in any way alter EPA's right to take enforcement actions, as appropriate. The NPL is designed primarily for informational purposes and to assist EPA management. Section 300.425(e)(3) of the NCP states that the deletion of a site from the NPL does not preclude eligibility for future response actions, should future conditions warrant such actions.

## IV. Basis for Site Deletion

The following information provides EPA's rationale for deleting the Site from the NPL:

### Site Background and History

The Union Chemical Co., Inc. Superfund Site, CERCLIS ID: MED042143883, is located in South Hope, Knox County, Maine, on the south side of Route 17 in a rural residential area. The Site is bounded by Quiggle Brook, a southerly flowing stream, on the east and southeast, by undeveloped forested land to the south and southwest and a vacant residential lot to the west.

Union Chemical Company began operations in 1967, as a paint stripping and solvent manufacturing business. Initially, patented solvents were manufactured and utilized on the premises, and distributed nationally. The Company expanded operations to include the recycling of used stripping compounds and solvents from other businesses. Operations were further expanded in 1982 to include a full-scale, fluidized-bed incinerator to treat waste solvents and other compounds. Operations ceased in 1985.

The risk assessment conducted during EPA's Remedial Investigation indicated that there would be unacceptable carcinogenic and non-carcinogenic risks from future ingestion of the groundwater at the Site due to concentrations of contaminants.

                    On June 24, 1988, EPA proposed the Site for listing on the NPL and on October 4, 1989, listing on the NPL was finalized. The                     **Federal Register**                     citations for these notices are FR Vol. 53, No. 122, 23978-23986 and FR Vol. 54, No. 191, 41015-41025, respectively.                

MEDEP closed the hazardous waste treatment operations at the Site in June 1984. At that time approximately 2,000-2,500 55-gallon drums and 30 liquid storage tanks were present at the Site. These drums, their contents, and the contents of the storage tanks were removed by EPA and MEDEP by the end of November 1984.

At present, contamination remains in the groundwater at the Site that EPA, with consent from MEDEP, determined in 2013 to be technically impracticable to restore. In 2017, a Declaration of Environmental Covenant, which among other things, prohibits the use of groundwater, was recorded in the chain of title for the properties comprising the Site. This deed restriction limits how the Site can be redeveloped.

### Remedial Investigation and Feasibility Study (RI/FS)

                    The scope of the Remedial Investigation was comprehensive, evaluating the nature and extent of contamination in the facility's buildings and underlying soils, unsaturated and saturated soils on the rest of the property, in groundwater in the overburden soils and in bedrock, and in surface water. Additionally, the Remedial Investigation collected soil samples from nearby properties to identify potential airborne contamination which may have occurred as a result of Union Chemical                           ( print page 34510)                        Company's past operation of the Site's hazardous waste incinerator.                

The Feasibility Study screened seven on-site soil remedial alternatives, six alternatives for groundwater and surface water, five alternatives for the facilities, and two alternatives for off-site soils. All but one on-site soil alternative was retained for detailed analysis. The on-site soil alternatives analyzed in detail included No-Action; Limited Action; Site Capping; Soil Excavation and Low-Temperature Thermal Aeration Treatment; In-Situ Soil Aeration; and Soil Excavation and High-Temperature Thermal Treatment. The groundwater and surface water alternatives analyzed in detail included No-Action; Limited Action; Groundwater Extraction with On-Site Treatment and Discharge to Quiggle Brook; Vacuum-Enhanced Groundwater Extraction with On-Site Treatment and Discharge to Quiggle Brook; Groundwater Extraction with On-Site Treatment and Reinjection; and Vacuum-Enhanced Groundwater Extraction with On-Site Treatment and Reinjection. The five alternatives for the facilities included No-Action; Limited Action; Facilities Decontamination only; Facilities Decontamination and Demolition; and Facilities Demolition and Disposal without Decontamination. The two off-site soil alternatives were No Action and Limited Action.

### Selected Remedy

In the 1990 Record of Decision (ROD) EPA selected a remedy that specified decontamination and demolition of facilities with off-site disposal of debris; soil excavation with on-site low-temperature thermal aeration; vacuum-enhanced groundwater extraction, on-site treatment, and discharge of treated groundwater to Quiggle Brook with institutional controls; and limited action for off-site soils.

The Remedial Investigation identified eight Remedial Action Objectives:

1. Prevent further leaching and migration into the groundwater of contaminants in the soils on the Site, by removal and treatment of contaminants above specific concentrations throughout the Site.

                    2. Provide rapid restoration of the contaminated groundwater throughout the Site, to concentrations that will protect current and future users, as well as natural resources (                    *i.e.,*                     wildlife) that come into contact with the contaminants contained within the groundwater.                

3. Protect off-site groundwater and surface waters (particularly Quiggle Brook) by preventing further migration of the contaminated on-site groundwater.

4. Prevent ingestion or absorption of contaminants (particularly dioxins) contained within the incinerator equipment remaining on the Site.

5. Prevent inhalation of friable asbestos from the Still Building.

6. Remove all existing structures located on the Site to allow for the cleanup of contaminated soils found throughout the Site.

7. Remove all other contaminated materials from the facilities so that the Site will be suitable for all potential future uses.

8. Further evaluate and, if necessary, minimize and/or mitigate any potential risks to public health and the environment from potential soil impacts due to contaminants which were previously emitted from the Union Chemical Company incinerator.

In 1992, EPA entered into a Consent Decree with certain Settling Defendants to conduct Remedial Design and Remedial Action at the Site under EPA oversight.

The remedy selected in the 1990 ROD was modified in 1994, 1997, and 2001 by three Explanations of Significant Differences (ESD) and in 2013 by a ROD Amendment. In June 1994 EPA approved a request from the Settling Defendants to change the soil cleanup technology from low-temperature thermal aeration to soil vapor extraction (SVE) with hot air injection. In addition to the change in technology, EPA also set a deadline of five years for achieving the soil cleanup standards.

EPA issued a second ESD for the Site in September 1997 that modified the remedy for off-site soils. The 1997 ESD changed the length of time specified in the ROD for meteorological data collection from five years to three years, thus moving forward the timeframe for collection of off-site soil samples to determine whether the operations of the Union Chemical Company incinerator resulted in deposition of contaminants off-site.

                    A third ESD was issued in September 2001 that documented a change in the technical approach for treatment of contaminated groundwater and changed the location for discharge of treated groundwater. Three innovative                     *in situ*                     addition treatment technologies, (                    *i.e.,*                     potassium and sodium permanganate, concentrated hydrogen peroxide, and molasses and sodium lactate) were injected into groundwater in specific portions of the Site to treat contaminated groundwater. With fewer extraction wells needed to control contaminant migration, discharge of treated water changed from surface water discharge to reinjection into the ground upgradient of the extraction wells.                

                    In November 2013, EPA issued a ROD Amendment in which it waived groundwater cleanup levels due to technical impracticability. The ROD Amendment was necessary because (1) the original groundwater remedy had reached the limits of its effectiveness, (2) the three innovative                     *in situ*                     technologies had proven unsuccessful in attaining the groundwater cleanup standards, and (3) an evaluation of cleanup alternatives indicated that no technology was available for achieving groundwater cleanup standards in a reasonable timeframe due to Site-specific hydrogeological and contaminant conditions. The ROD Amendment also adjusted institutional control requirements for the Site.                

### Response Actions

In October 1993 EPA approved the Facilities Remedial Design, and the decontamination and demolition of facilities and off-site disposal of debris was completed in the spring of 1994.

Beginning in 1994 and continuing into 1996, on-site meteorological data was collected to support the off-site soils component of the ROD. In October 1996 EPA and the Settling Defendants performed joint off-site soil investigation and in September 1997 EPA issued an ESD documenting no further action was necessary for the off-site soils.

In April 1995 EPA approved the SVE and groundwater Remedial Design. Construction included 28 SVE wells, 94 hot air injection points, 33 groundwater extraction wells, and the integrated treatment system and was completed in December 1995. Both systems began operation in January 1996. In April 1997 EPA and MEDEP performed a final inspection for both systems and declared that the remedy was operational and functional.

                    The rate of mass removal of VOCs decreased dramatically between 1996 and 1999 using the groundwater extraction system, indicating that the extraction system was becoming less efficient due to the Site-specific hydrogeologic and chemical limitations. EPA and MEDEP approved the Settling Defendants' request to employ innovative                     *in situ*                     technologies to enhance the reduction of contaminant concentrations. The first technology involved the injection of permanganate. As a strong oxidizer, the permanganate was expected to accelerate the destruction of dissolved chlorinated VOCs. A potassium permanganate pilot study was completed in October 1997. Based on the results of that study,                           ( print page 34511)                        potassium and sodium permanganate were used on an expanded basis in the summers of 1998, 1999, and 2000 in an attempt to achieve further reductions in VOC concentrations.                

                    The second                     *in situ*                     approach was carried out in June 2000 with the injection of 5% hydrogen peroxide solution into injection well P-17. This well was selected as it is in the central area of the source area where the highest VOC concentrations had been detected. Due to the low capacity of P-17 and concerns about the integrity of the mixing tank, EPA decided to discharge the remaining solution to several additional wells located immediately adjacent to well P-17. Comparison of baseline sampling results to four-week post addition results revealed VOC concentrations rebounded to their baseline levels, indicating that the VOC reductions initially achieved were short-term and not sustained.                

Given the relative short half-lives of permanganate and hydrogen peroxide, carbon sources in the form of molasses and sodium lactate were added in August and November 2001 to create a reducing environment to enhance degradation of chlorinated ethane compounds by reductive dechlorination. Lactate addition was carried out again in August 2002.

### Cleanup Levels

After EPA and MEDEP approval in March 1998, the Settling Defendants' operation of the SVE system and hot air injection was discontinued to allow the soils to return to equilibrium prior to the closure-sampling program. Closure sampling was completed in the fall of 1998. Statistical analysis of the data by three groups working independently indicated that the soils had been cleaned up to below the ROD-specified cleanup levels.

Post-ROD groundwater and surface water monitoring began in the summer of 1992. The monitoring well network includes wells in the source area, in areas with the highest groundwater concentrations, and perimeter wells, near the downgradient boundaries of previously detectable concentrations. The monitoring leading up to the 2007 Five-Year Review did not show any concentration increases in the perimeter wells, indicating that the plume had not expanded since the extraction system was deactivated in 2000. Subsequent monitoring has confirmed that the plume has stabilized, yet remains above the ROD-established performance standards. Consequently, EPA issued the ROD Amendment in 2013 that included a Technical Impracticability waiver recognizing groundwater performance standards would not be attained in a reasonable timeframe because of Site geology, hydrology, and characteristics of the contaminants. Long-term groundwater monitoring will continue to be performed to ensure that the plume is stable and not migrating out of a designated Technical Impracticability Zone, which reaches the Site property boundaries except for the upgradient northwest corner of the Site.

### Operation and Maintenance

The Operation and Maintenance (O&M) activities associated with the Site have been periodically updated as the on-site soil component was completed and again when active groundwater restoration ceased. O&M activities now consist of annual inspections, long-term monitoring of groundwater and surface water every other year, and ongoing decommissioning of the treatment building and redundant monitoring wells. These activities are outlined in bi-annual work plans that are submitted and implemented after EPA and MEDEP review and approval.

Following acceptance of the soil closure sampling results, unused wells and piping were decommissioned in accordance with the O&M Plan.

The extraction system has been deactivated. The effluent discharge line from the treatment building was flushed out, then disconnected below the ground surface and grouted. The external piping from the groundwater extraction wells was removed, and groups of extraction wells were decommissioned in 2005, 2006, and 2010.

The 1990 ROD and 2013 ROD Amendment required the implementation of institutional controls for the Site Property and nearby properties to protect human health and the environment. On August 2, 2017, MEDEP recorded a Declaration of Environmental Covenant in the chain of title for the two lots comprising the Site (collectively, Site Property) at the Knox County Registry of Deeds (Volume 5192, Page 306). Pursuant to Maine's Uniform Environmental Covenants Act, MEDEP, as the receiver of the Site Property pursuant to a 1986 court order, granted the property rights under the Declaration of Environmental Covenant to itself, and will also serve as the holder of these property interests. EPA has third party rights of enforcement under the instrument. Among other things, the Declaration of Environmental Covenant: (1) Prohibits the extraction of groundwater; (2) prohibits the destruction, obstruction, tampering, or disruption of wells; (3) prohibits the discharge or injection of liquids to the subsurface; (4) prohibits the accumulation, storage, or stockpiling of wastes, as defined in Maine Solid Waste Management Rules, Chapter 400, and operation of a junkyard or automotive scrapyard, as defined in 30 M.R.S. § 3752; (5) requires a sub-slab vapor barrier and ventilation system or a sub-slab depressurization system for any constructed buildings, and (6) provides for EPA and MEDEP access to the Site Property.

                    In addition to institutional controls for the Site Property, the 1990 ROD also identified a number of institutional controls that could be taken for properties beyond the Site Property. These controls included a restriction on the use of groundwater from existing bedrock wells that are hydraulically connected to the Site, specifically the well on Town of Hope's Tax Map 8 Lot 45, and advisory controls (                    *e.g.,*                     well advisories) on surrounding properties.                

The Settling Defendants entered into a Lease and Indenture Agreement with the owners of Map 8 Lot 45 on May 18, 1992 and the State of Maine, acting by and through MEDEP. This agreement prohibited the use of the bedrock well in perpetuity unless released by the Settling Defendants and MEDEP.

The 2013 ROD Amendment also calls for environmental deed restrictions or other mechanisms to limit the use of properties adjacent to the Site, as deemed necessary by EPA based on new information including but not limited to the development (or installation of drinking water wells) on properties adjacent to the Site or movement of the leading edge of either plume. To date, EPA has not determined that it is necessary to implement other land use restrictions on the properties adjacent to the Site.

With the recording of the Declaration of Environmental Covenant, the criteria for EPA's Sitewide Ready for Anticipated Use Government Performance and Results Act Measure were complete, and EPA Region 1 signed the Superfund Property Reuse Evaluation Checklist for Reporting on August 17, 2017.

### Five-Year Review

EPA conducts Five-Year Reviews of the Site because hazardous substances, pollutants, or contaminants remain on-site above levels that allow for unlimited use and unrestricted exposure. These reviews are statutory and four have been completed with the most recent one completed in September 2017.

                    The 2017 Five-Year Review concluded the remedy currently                           ( print page 34512)                        protects human health and the environment because MEDEP is the court-appointed receiver of the Site Property and as such, use of the Site Property is controlled by MEDEP, there is no evidence of current exposure, institutional controls are in place, access to the Site is assured, and long-term monitoring continues. The 2017 Five-Year Review identified one issue, the potential presence of the chemicals perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), and 1,4-dioxane, and recommended they be included in an upcoming monitoring event to determine if these compounds are associated with the Site.                

Pursuant to that Five-Year Review recommendation, on October 23, 2017, the Settling Defendants collected groundwater and surface water samples for PFOA and PFOS from two overburden wells, two bedrock wells, and two surface water locations. The samples were analyzed via EPA Method 537, Version 1.1. Modified, and QA/QC review determined that results were of acceptable quality. Three of the four wells had concentrations below EPA's drinking water advisory level of 70 ng/L (nanograms per liter or parts per trillion) for both PFOA and PFOS.

The overburden well with the exceedance of both PFOA and PFOS is historically the most contaminated well in the ongoing long-term Site monitoring and is located immediately downgradient of the former facility's discharge trench. The other overburden well and the two bedrock wells are located 150-450 feet farther downgradient from the well with the exceedance (and for the bedrock wells, the property boundary is another 200 feet or more downgradient beyond them). All the wells are within the Technical Impracticability Zone created under the 2013 ROD Amendment.

In the two surface water samples collected from Quiggle Brook, PFOS and PFOA were not individually detected at concentrations exceeding the method detection limit of 1.0 ng/L but had estimated PFOA concentrations at the instrument detection limit of 1.0 ng/L at the location upstream of the Site and 0.8 ng/L at the long-term surface water monitoring location. There is no EPA advisory level for surface water. Maine Center for Disease Control has established a surface water advisory level of 170 ng/L based on recreational exposure (swimming and wading) and these sample results are below that surface water advisory level.

In 2010, 1,4-dioxane was added to the monitoring program. Due to the elevated levels of other compounds in eight of the ten wells in the monitoring program, the samples were diluted for analysis and correspondingly, the Reported Detection Limits (RDL) were raised. Consequently, the 1,4-dioxane levels were reported as below the specific reporting limit, ranging from <20 ppb to <2,000 ppb. However, in the four monitoring events, 2010, 2012, 2014, and 2016, as the RDL has dropped in five of the eight wells, 1,4-dioxane remained below the reporting limit. Of the two wells where 1,4-dio+xane has been detected, the concentrations have decreased so that the latest results are now also below their respective reporting limits of <20 and <100 ppb. There is no Maximum Contaminant Level standard for 1,4-dioxane nor was 1,4-dioxane included the 1992 Maine Maximum Exposure Guidelines (ME MEGs), which is the Applicable or Relevant and Appropriate Requirement. The current, but unpromulgated ME MEG for 1,4-dioxane is 4 ppb.

With the recent PFAS sampling indicating one exceedance in four monitoring wells in the Technical Impracticability Zone, PFAS will be added to the long-term monitoring program coincident with every monitoring event that precedes a Five-Year Review.

### Community Involvement

                    There was an established community group, Hope Committee for a Clean Environment (HCCE) that was active during the RI/FS and received support through an EPA technical assistance grant. From 1992 through the early 2000s, while Remedial Design and then active remediation of the on-site soils and groundwater, and investigation of the off-site soils were underway, HCCE met regularly with EPA, MEDEP, and the Settling Defendants' Project Coordinator. With the termination of the                     *in situ*                     technologies, these meetings ceased. Communication between HCCE, EPA, and MEDEP is now primarily through email. In 2005-2006, EPA convened meetings with community members to develop re-use options.                

EPA and MEDEP have met frequently with the Hope Town Administrator and have periodically updated the Board of Selectmen. In June 2015, EPA and MEDEP attended the Town of Hope's Annual Meeting. At that meeting, the Town voted not to assume ownership of the Site Property should MEDEP's receivership of the Site Property end. The Town reaffirmed this position in an October 10, 2017 letter to MEDEP. Beyond these meetings and periodic communication with HCCE and owners of a right-of-way easement across the Site Property, there has been little participation or involvement from other members of the local community.

EPA discussed the deletion process with the Town Administrator and offered to meet with the Board of Selectmen if the Town desired a presentation. Additionally, EPA contacted the HCCE to inform the group of EPA's plan to delete the Site.

### Determination That the Site Meets the Criteria for Deletion in the NCP

Remedial Design and Remedial Action (RD/RA) activities at the Site were consistent with the ROD, as modified by the ESDs and the ROD Amendment, and consistent with EPA RD/RA Statements of Work provided to the Settling Defendants. RA plans for all phases of construction included a Quality Assurance Project Plan (QAPP) dated February 17, 1995 and QAPP Revision 1, dated September 22, 2001. The QAPP incorporated all EPA and Maine quality assurance and quality control procedures and protocols (where necessary). All procedures and protocols were followed for soil, groundwater, and surface water sampling during the RA. EPA analytical methods were used for all validation and monitoring samples during all RA activities. EPA has determined that the analytical results are accurate to the degree needed to assure satisfactory execution of the RA, and are consistent with the ROD and the RD/RA plans and specifications.

All institutional controls are in place and currently EPA expects that no further Superfund response is needed to protect human health and the environment, except future Five-Year Reviews and ongoing long-term monitoring. O&M activities were agreed upon by EPA and the Settling Defendants and are documented in the October 2006 O&M Manual. These activities include continuing decommissioning of redundant wells, securing the functioning wells, and maintenance of the soil cap.

This Site meets all the site completion requirements as specified in OSWER Directive 9320.2-09-A-P, Close Out Procedures for National Priorities List Sites. All cleanup actions specified in the ROD, as modified by the ESDs and ROD Amendment have been implemented and the implemented remedy has achieved the degree of cleanup or protection specified in the ROD, as modified by the ESDs and ROD Amendment, for all pathways of exposure.

                    Confirmatory groundwater monitoring and institutional controls provide further assurance that the Site no longer poses any threats to human health or the                           ( print page 34513)                        environment. The only remaining activity to be performed are Five-Year Reviews, monitoring, and O&M activities described above. A bibliography of all reports relevant to the completion of this Site under the Superfund program is in the administrative record for this deletion.                

# List of Subjects in 40 CFR Part 300

      - Environmental protection
      - Chemicals
      - Hazardous waste
      - Hazardous substances
      - Intergovernmental relations
      - Penalties
      - Reporting and recordkeeping requirements
      - Superfund
      - Water pollution control
      - Water supply

Authority:33 U.S.C. 1321(d); 42 U.S.C. 9601-9657; E.O. 13626, 77 FR 56749, 3 CFR, 2013 Comp., p. 306; E.O. 12777, 56 FR 54757, 3 CFR, 1991 Comp., p. 351; E.O. 12580, 52 FR 2923, 3 CFR, 1987 Comp., p. 193.

Dated: July 9, 2018.

Alexandra Dunn,

Regional Administrator, Region 1.

[FR Doc. 2018-15622 Filed 7-19-18; 8:45 am]

BILLING CODE 6560-50-P