SEPA United States Environmental Protection Agency Explanation of Significant Differences MetaItec/Aerosystems Superfund Site Site Name: MetaItec/Aerosystems Superfund Site CERCLA ID #: NJD002517472 Site Location: Intersection of Maple, Gilson and Wildcat Roads Franklin Borough, New Jersey Support Agency: EPA, Region 2 Lead Agency: New Jersey Department of Environmental Protection Franklin, New Jersey I. Introduction This decision document presents an Explanation of Significant Differences (ESD) for the Metaltec/Aerosystems Superfund Site (Site), located in Franklin, New Jersey. The Record of Decision (ROD) selecting the remedy that is modified by this ESD is: Metaltec/Aerosystems Operable Unit 2 (OU2) ROD issued September 27, 1990. This ESD is issued in accordance with § 117(c) of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, as amended (CERCLA), 42 U.S.C. § 9601-9675, and the National Oil and Hazardous Substances Pollution Contingency Plan (NCP), 40 CFR § 300.435(c)(2)(i). This ESD will become part of the Administrative Record for the Metaltec/Aerosystems Superfund Site (NCP § 300.825(a)(2)), which has been developed in accordance with § 113 (k) of CERCLA, 42 U.S.C. § 9613 (k). This ESD and the Administrative Record are available for review online at http://www.epa.gov/superfund/rnetaltec- aerosvstems and at the information repositoiy maintained at the Sussex County Library Main Library at 125 Morris Turnpike, Newtown, New Jersey 07860 (M-Th, 8:30am-8:30pm; Friday Page 1 744536 ------- 8:30am-5:00pm; Saturday 9:00am-5:00pm); and at the U.S. EPA Region 2 Administrative Record File Room, 290 Broadway, 18th Floor, New York, NY, 10007, (212) 637-4308, Monday to Friday, 9:00am to 5:00pm. II. Statement of Purpose Since the OU2 ROD was issued in 1990, the Environmental Protection Agency (EPA) has identified the need to implement institutional controls (ICs) at the Site. The purpose of this ESD is to document EPA's decision to include ICs in the form of a Classification Exception Area/Well Restriction Area (CEA/WRA) under New Jersey law as part of the groundwater remedy selected in the OU2 ROD for the Site, see Figure 1. This ESD provides the public with an explanation of the modification to the selected remedy, summarizes the information that supports this modification, and confirms that the revised remedial action complies with the statutory requirement of Section 121 of CERCLA, 42U.S.C. § 9621. Section 117(c) of CERCLA and Section 300.435(c)(2)(i) of the NCP require publication of an ESD when it is determined by EPA that changes to the original selected remedy are significant, but do not fundamentally alter the remedy selected in the ROD with respect to scope, performance, or cost. III. Site History and Contamination Site History The Site is a Fund-financed National Priorities List (NPL) site. In September 1983, the Site was placed on the NPL of Superfund sites. In June 1984, EPA began a remedial investigation/feasibility study (RI/FS) at the Site to determine the nature and extent of contamination, characterize the Site risks, and develop and evaluate remedial alternatives. Following the RI/FS, in a First Operable Unit (OU1) ROD issued by EPA on June 30, 1986, EPA selected a remedy to address sources of groundwater contamination and provide an alternate water supply to residents whose private wells had been impacted by the contamination. The 1986 ROD estimated that 10,000 cubic yards (yd3) of soil were contaminated with various volatile organic compounds (VOCs) in an area referred to as Parcel 1; an estimated 4,000 yd3 of soil were contaminated with inorganic compounds and semivolatile organic compounds in areas referred to as Parcels 2, 3, and 4; and both the shallow and bedrock aquifers beneath the Site were contaminated with elevated levels of the contaminants. In accordance with the 1986 ROD, between July and November 1988, EPA excavated 4,800 yd3 of contaminated soils from Parcels 2, 3 and 4. Contaminated soils were disposed of at an approved off-site facility. Also, pursuant to the 1986 ROD, in February 1991, EPA completed the construction of an alternate water supply pipeline at the Site. From June 1994 to January 1995, EPA excavated and thermally treated 5,583 yd3 of contaminated soil related to Parcel 1. In addition, 3,008 tons of oversized debris were disposed of off-site. The New Jersey Department of Environmental Protection (NJDEP) and EPA agree that the source control remedy is complete and cleanup standards have been achieved. On September 27, 1990, EPA issued the OU2 ROD for groundwater which provided for the extraction and treatment of contaminated groundwater and restoration of the groundwater to drinking water standards, with surface water discharge of the treated groundwater. To date, approximately 100 million gallons of contaminated groundwater have been extracted and treated to meet New Jersey surface water discharge requirements, with the treated groundwater being discharged to a stream. In September 2020, EPA transferred the responsibility for operation and maintenance of the OU2 remedy to NJDEP. Page 2 ------- In May 2024, EPA conducted a Third Five-Year Review (FYR) to evaluate the protectiveness of the implemented OU1 and OU2 remedies at the Site. The Third FYR notes that NJDEP implemented the CEA/WRA in April 2024. Site Contamination The contaminants found at the Site are VOCs, primarily trichloroethylene (TCE). Some or all of the contaminants identified are hazardous substances as defined in § 104(14) of CERCLA, 42 U.S.C. § 9601(14), and 40 C.F.R. § 302.4. Although VOCs remain elevated above drinking water standards in select overburden and bedrock wells, the overall concentration trend for VOCs appears to be stable or decreasing and the bedrock plume does not appear to be expanding. IV. Selected Remedy The OU2 ROD, which addressed groundwater contamination at the Site, was issued by EPA on September 27, 1990. Previously, on June 30, 1986, EPA issued a ROD for OU1, the source area. These documents are available in the Superfund Enterprise Management System (SEMS) under SEMS ID Numbers 99993 and 98887. The remedy selected in the OU2 ROD includes: • Extraction of contaminated groundwater and restoration of the groundwater to drinking water standards; • Treatment of extracted groundwater to levels attaining New Jersey surface water discharge limitation requirements; • Discharge of treated groundwater to a surface water body; and • Appropriate environmental monitoring to ensure the effectiveness of the remedy. The remedial action objective for OU2 is to restore the groundwater to the more stringent of the federal or state Maximum Contaminant Levels. V. Description of Significant Differences and Basis for the ESD The remedy selected in the OU2 ROD does not include ICs for groundwater. Due to hazardous substances, pollutants, or contaminants remaining at the Site above levels that allow for unlimited use and unrestricted exposure to groundwater, EPA has determined that inclusion of ICs in the form of a CEA/WRA as part of the OU2 remedy for the Site is necessary to minimize the potential for human exposure to contaminated groundwater. CEA/WRAs are ICs that provide notice of restrictions on well installations and other uses of groundwater in a localized area where water quality standards are not being met. VI. Support Agency Comments EPA consulted with the NJDEP and provided it the opportunity to comment on this ESD in accordance with NCP § 300.435 (c)(2) and CERCLA § 121(f). The NJDEP concurred with this ESD in a letter dated September 17, 2024. VII. Statutory Determinations EPA has determined that the remedy, as modified by these significant changes, complies with the statutory requirements of CERCLA Section 121, 42 U.S.C. § 9621, is protective of human health and the environment, complies with federal and state requirements that are applicable or relevant and appropriate to the remedial action, remains cost- effective, and utilizes permanent solutions and alternative treatment technologies to the maximum extent practicable. Page 3 ------- Because the remedy selected in the 0U2 ROD, as modified by this ESD, will not leave hazardous substances, pollutants or contaminants on site above levels that allow for unlimited use and unrestricted exposure but requires five or more years to complete, a policy review will be conducted no less often than every five years to ensure that the remedy is, or will be, protective of human health and the environment. VIII. Public Participation The public participation requirements set out in CERCLA § 117(d) and the NCP § 300.435(c)(2) will be met by publishing this ESD, making it available to the public in the Administrative Record, and publishing a notice summarizing the ESD in a major local newspaper. The ESD and the documents that provide the basis for the ESD will be placed in the Administrative Record for the Site in accordance with § 300.825(a)(2) of the NCP, and the information repository maintained at the address set forth in Section I, above. The ESD will also be placed on EPA's Site page located at http://www.epa. gov/ superfund/metaltec- aerosvstems. U.S. Environmental Protection Agency Digitally signed by Evangelista, By. Evangelista, Pat Date:2024.09.24210321 -04'00' Pat Evangelista Director Superfund and Emergency Management Division EPA, Region 2 Date: September 24, 2024 IX. Authorizing Signature EPA has determined the remedy for the Site, as modified by this ESD, is protective of human health and the environment, and will remain so provided the actions presented in this report are implemented as described above. This ESD documents the significant changes related to the remedy at the Site. EPA selected these changes with the concurrence of NJDEP. Page 4 ------- CEA Boundary Map 04/24/2024 ------- |