EXPLANATION OF SIGNIFICANT DIFFERENCES

LCP CHEMICALS, INC. SUPERFUND SITE Site Name and Location LCP Chemicals, Inc. Superfund Site Linden, Union County, New Jersey Introduction The purpose of this Explanation of Significant Differences (ESD) is to explain the United States Environmental Protection Agency’s (EPA) changes to the remedy selected in its February 25, 2014 Record of Decision (ROD) for the LCP Chemicals, Inc. Superfund Site (Site). The ROD was prepared by EPA as lead agency for the Site, in consultation with the New Jersey Department of Environmental Protection (NJDEP). The selected remedy described in the ROD represents the first and only planned remedial phase, or operable unit, for the Site. Under Section 117(c) of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, as amended (CERCLA or Superfund), 42 U.S.C. § 9617(c), EPA is required to publish an ESD when, after issuance of a ROD, subsequent enforcement or remedial actions lead to significant, but not fundamental, changes in the selected site remedy. Sections 300.435(c)(2)(i) and 300.825(a)(2) of the National Oil and Hazardous Substances Pollution Contingency Plan (NCP), 40 C.F.R. §§ 300.435(c)(2)(i) and 300.825(a)(2), set forth the criteria for issuing an ESD and require that an ESD be published if the remedy is modified in a way that differs significantly in scope, performance, or cost from the remedy selected in the ROD for the site. This ESD presents the significant differences to the remedy selected in the Site’s ROD. This ESD also provides a brief history of the Site, describes the original remedy, and explains how, subsequent to the finalization of the decision document, issues concerning the scope and performance of the selected remedy have been identified. This ESD and the documents that provide the basis for the ESD decision will be incorporated into the administrative record maintained for the Site in accordance with Section 300.825(a)(2) of the NCP, 40 C.F.R. § 300.825(a)(2). The administrative record file is available for review during business hours at the EPA Region 2 Superfund Records Center, 290 Broadway, New York, NY 10007 (Monday through Friday, 9:00 AM–5:00 PM); at the information repository at the Linden Public Library, 31 East Henry Street, Linden, NJ 07036 (Monday through Thursday, 9:00 AM–9:00 PM; Friday, 9:30 AM–5:00 PM; Saturday, 9:00 AM–5:00 PM); and online at: https://cumulis.epa.gov/supercpad/cursites/csitinfo.cfm?id=0200455. Site Location, History, Contamination Problems, and Selected Remedy The 26-acre Site is located in an industrial area on the Tremley Point peninsula in Linden, Union County, New Jersey. The Site is bordered by the Arthur Kill to the east; the former GAF Corporation (GAF) site to the north (addressed under NJDEP authority); and facilities owned by Northville Industries, BP Corporation, and Mobil to the northeast, south, and west, respectively. South Branch Creek, a manmade drainage ditch that empties into the Arthur Kill, flows through a portion of the Site (Figure 1).

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From the 1880s into the 1950s, Tremley Point’s tidal wetlands were filled to allow for industrial development. Most of the industrial production facilities in the region are no longer operating. The primary current use of the area is bulk storage and transport of petroleum products and aggregates. In 1955, GAF constructed and began operating a chlor-alkali plant on the Site. In 1972, Linden Chlorine Products, Inc. purchased the 26-acre property and the chlor-alkali operation. At some point, the company became known as LCP Chemicals, Inc. (LCP). An additional chlor-alkali cell building was added by LCP in the early 1970s. The chlor-alkali manufacturing operations ceased in the mid-1980s and the facility was then used as a terminal for products produced at other locations. In 1991, LCP, then named Hanlin Group, Inc., filed a petition for relief under Chapter 11 of the U.S. Bankruptcy Code and liquidated its assets by 1994. As part of the bankruptcy, Hanlin Group abandoned the LCP property. In August 1994, EPA conducted a site visit and confirmed that the chlor-alkali cell buildings were decommissioned, the facility was no longer functional, and the property had been vacated by LCP employees. The Site was placed on the National Priorities List in 1998. In 1999, a potentially responsible party (PRP), ISP Environmental Services Inc., and EPA entered into an Administrative Order on Consent to perform a remedial investigation and feasibility study (RI/FS) at the Site. The LCP property has been abandoned since the last tenant, Active Water Jet, Inc. (a pipe cleaning facility), vacated the property in 2000. Currently, the Site is fenced and secured. The buildings, particularly the chlor-alkali cell buildings, are in an advanced state of disrepair. Under the oversight of EPA, the PRP’s consultants sampled and analyzed soil, sediments, groundwater, surface water, and biota. The results of the sampling events, which are summarized below, can be found in the RI report. The RI results formed the basis for the FS. Both the RI and FS reports are part of the Site’s administrative record. Site soils are contaminated with constituents including mercury, arsenic and other metals, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated naphthalenes (PCNs), as well as volatile organic compounds (VOCs), at levels above the New Jersey non-residential soil remediation standards. Mercury, at unacceptable concentrations, is dispersed across the Site. EPA considers mercury to be the primary contaminant of concern (COC) due to its persistence, toxicity, and overall mass at the Site. Mercury in Site soils is typically in the elemental or mercuric sulfide form and is present at the highest levels (>7,000 milligrams/kilogram (mg/kg)) in the anthropogenic fill. In areas near the chlor-alkali cell buildings, free elemental mercury is present down to a depth of about 17 feet. EPA considers the soil with visible mercury to be the Site’s principal threat waste (PTW). Sediment samples were collected from transects across the South Branch Creek and adjacent to the creek’s mouth in the Arthur Kill. Mercury, arsenic, barium, and PCBs were the most frequently detected COCs in the South Branch Creek sediments. The mean concentration of mercury in the sediments was 196 mg/kg, with a high concentration of 901 mg/kg. Similar to the findings in soils, mercury speciation showed the most common types of mercury were elemental and mercuric sulfide.

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Samples of the overburden groundwater showed exceedances of the applicable New Jersey groundwater standards for several constituents, including mercury, arsenic, and some VOCs. Dissolved mercury concentrations ranged from non-detect (ND) to 164 parts per billion (ppb). Concentrations of other constituents, such as chlorobenzene (from ND to 16,200 ppb), benzene (ND to 848 ppb), and arsenic (up to 275 ppb), showed high levels of exceedances. On February 25, 2014, EPA issued the Site’s ROD, which listed the following remedial action objectives:

• Reduce or eliminate potential current and future unacceptable risks to human and ecological receptors resulting from ingestion and dermal contact with soils and groundwater.

• Reduce or eliminate potential current and future unacceptable risks to human receptors

resulting from inhalation of mercury vapors emanating from soils and marsh deposits.

• Reduce or eliminate migration of soil contamination to groundwater or surface water.

• Prevent or minimize migration of contaminated groundwater, and, to the extent practicable, remediate to applicable standards outside the waste management area.

• Reduce or eliminate unacceptable risks to human and ecological health as a result of

ingestion or dermal contact with Site sediments.

• Reduce or eliminate human exposure to contaminated building materials and physical hazards that may result in potentially unacceptable risk.

In order to meet those objectives, the ROD’s selected remedy called for the following actions:

• Installation of a capping system to prevent direct contact with soils and exposure to mercury vapor;

• Treatment of the soil containing visible elemental mercury by mixing it with sulfur to

convert the mercury to mercuric sulfide;

• Excavation and on-site disposal of sediments and marsh soils from the Northern Off-Site Ditch and the downstream portion of the South Branch Creek;

• Restoration of the excavated areas;

• Controlled demolition of the Site’s buildings, recycling of non-porous material, and

placement of porous material under the cap;

• Containment and collection of the overburden groundwater layer by a barrier wall and collection/disposal system;

• Groundwater monitoring; and

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• Implementation of institutional controls in the form of a deed notice and a Classification Exception Area.

Description of Significant Differences In the ROD, EPA recognized that the selected remedy included an innovative treatment approach for addressing soil contaminated with visible elemental mercury (i.e., the PTW). Therefore, the ROD identified two contingency remedies in case the selected remedy did not meet the goals, i.e., the measures of success developed during pre-design studies. If EPA decided that treating the PTW to full depth (i.e., 17 feet) was not technically practicable, EPA would use the first contingency remedy, treatment of the PTW to mid-depth (i.e., 6 feet). If EPA determined that treating the PTW would not meet goals at any depth, however, EPA would use the second contingency remedy. The second contingency remedy is the same as the selected remedy, except without treatment of the PTW. Prior to initiating a pilot study, EPA’s contractors ran a “bench scale” study to test the conversion of mercury to mercuric sulfide through mixing with elemental sulfur (as described in the ROD) and also with reactive sulfides. The goals were (1) to convert the elemental mercury to mercuric sulfide, and (2) to reduce the solubility of the mercury. Briefly, conversion of the elemental mercury to mercuric sulfide by mixing the contaminated soil with elemental sulfur was unsuccessful. Conversion to mercuric sulfide was more successful when the soil containing elemental mercury was mixed with reactive sulfides, except that the resulting compound did not reduce the mercury’s solubility. Instead, the results indicated that the opposite had occurred: mercury solubility had increased after mixing with reactive sulfides, in some cases by several orders of magnitude. The results of the bench scale study can be found in the Bench Scale Study Treatability Report, LCP Chemicals, Inc. Superfund Site (CDM Smith 2018). An assessment of the report can be found in a February 7, 2018 letter from the United States Army Corps of Engineers to EPA. Both of these documents are located in the administrative record maintained for the Site. Since the results failed at the bench scale level, EPA determined the results would fail at both depths called for in the selected remedy, and in the shallower depth called for in the first contingency remedy. The ROD’s selected remedy included treatment of the PTW through in-situ mixing of sulfur and elemental mercury, as well as a sulfur treatment layer beneath the cap. This ESD modifies the remedy by eliminating all treatment of the PTW because it is impracticable. In particular, the treatments are either ineffective at converting the elemental mercury to mercuric sulfide, or would increase the solubility of the mercury. All other elements of the primary remedy remain the same, including capping of contaminated Site soils to prevent direct contact with and inhalation of mercury. This ESD modification is consistent with the second contingency remedy described in the ROD, Section 300.430 of the NCP, 40 C.F.R. § 300.430, and EPA’s guidance on addressing PTW. Implementation of the second contingency remedy will achieve substantial and long-term risk reduction through containment and will prevent human and ecological exposure to Site contaminants in soils, sediments, groundwater, and building materials. This modification will

reduce the estimated capital costs developed for the ROD from about $36 million to about $25 million.

Support Agency Comments The State of New Jersey does not concur with this ESD, which modifies the selected remedy by selecting the second contingency remedy described in the ROD. The State's letter providing its reasons for non-concurrence and EPA' s response are located in the administrative record maintained for the Site.

Affirmation of Statutory Determinations EPA, after consultation with NJDEP, is issuing this ESD to select the second contingency remedy, which satisfies the requirements of Section 121 ofCERCLA, 42 U.S.C. § 9621.

The remedy, as modified by this ESD, will be protective of human health and the environment and will comply with federal and state requirements that are legally applicable or relevant and appropriate to the remedial action.

The modified remedy is technically feasible, cost-effective, and represents the maximum extent to which permanent solutions and treatment technologies can be used in a practicable manner at the Site.

In addition, the modified remedy includes statutory five-year reviews to ensure that the remedy is, or will be, protective of human health and the environment.

Public Participation Compliance In accordance with the NCP, a formal public comment period is not required when issuing an ESD. A notice briefly summarizing this ESD will be published in a major local newspaper of general publication in accordance with Section 300.435(c)(2)(i) of the NCP, 40 C.F.R. § 300.435(c)(2)(i).

This ESD and the documents that provide the basis for the decision to use the ROD's second contingency remedy will be incorporated into the administrative record maintained for the Site in accordance with Section 300.825(a)(2) of the NCP, 40 C.F.R. § 300.825(a)(2). The administrative record file is available for review during business hours at the EPA Region 2 Superfund Records Center, 290 Broadway, New York, NY 10007 (Monday through Friday, 9:00 AM-5:00 PM); at the information repository at the Linden Public Library, 31 East Henry Street, Linden, NJ 07036 (Monday through Thursday, 9:00 AM-9:00 PM; Friday, 9:30 AM-5 :00 PM; Saturday, 9:00 AM-5:00 PM); and online at: https://cumulis.epa.gov/supercpad/ cursites/csitinfo.cfm?id=0200455.

Pat Evange'hsta, Actmg Director Superfund & Emergency Management Division U.S. EPA, Region 2

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