Attachment_J_-_N-RPT-2101230-0_Gibbs_Street-PII-III-FINAL-2023-06-15.pdf

355 Research Parkway ▪ Meriden, CT 06450 ▪ T (203) 630-1406 ▪ F (203) 630-2615 ▪ www.blcompanies.com

An Employee-Owned Company

PHASE III SITE INVESTIGATION AND

PRELIMINARY REMEDIAL ACTION PLAN

0 Gibbs Street New Haven, Connecticut

Prepared for:

Livable City Initiative City of New Haven

Attention: Mr. Jeffrey Moreno 165 Church Street, 3rd Floor

New Haven, CT 06510

Prepared By:

BL Companies, Inc.

355 Research Parkway

Meriden, CT 06450

June 2023 BL Companies Project No. 2101230

Phase III Site Investigation and Preliminary Remedial Action Plan 2101230 0 Gibbs Street, New Haven, Connecticut June 2023

This report was prepared by the individuals listed below. Any questions or comments regarding the information provided herein should be directed to these individuals.

Prepared by:

Wesley Johnson Project Scientist II

Reviewed by:

Christy Quagliaroli, LEP Senior Project Scientist I

Brian P. Lowry, LEP Project Manager II

Phase III Site Investigation and Preliminary Remedial Action Plan 2101230

TABLE OF CONTENTS

Section Description Page

1.0 INTRODUCTION

1.1 Site Description

1.2 Site History

2.0 ENVIRONMENTAL SETTING

2.1 Geology and Hydrogeology

2.2 Groundwater and Surface Water

3.0 REGULATORY FRAMEWORK

3.1 Connecticut Transfer Act

3.2 Remediation Standard Regulations

3.2.1 Soil Criteria

3.2.2 Groundwater Criteria

3.2.3 Soil Vapor Volatilization Criteria

3.3 Applicable RSR Criteria

4.0 PREVIOUS INVESTIGATIONS……….. ………

5.0 CONCEPTUAL SITE MODEL

5.1 Data Quality Objectives

5.2 AOC Summaries

5.2.1 AOC-1 Former 6,000-Gallon Oil Underground

Storage Tank – Location Unknown

5.2.2 AOC-2 Former Above Ground Storage Tank

5.2.3 AOC-3 Abandoned Underground Storage Tank

5.2.4 AOC-4 Former Fuel oil Tanks, Former Storage, and Office Building

5.2.5 AOC-5 Former 550-Gallon Gasoline Underground

Storage Tank

5.2.6 AOC-6 Former Concrete Mixer and Bins with Conveyor Belt ... 20

5.2.7 AOC-7 Site Wide Urban Fill Material

5.2.8 AOC-8 Former Residential Dwellings with Unknown Heating

Sources

5.2.9 AOC-9 Former Railroad Spur

5.2.10 AOC-10 Former Transformer Area

6.0 PHASE II/III AND PHASE III SITE INVESTIGATIONS

6.1 Summary of Work and Rationale

6.1.1 Soil Sampling

6.1.2 Groundwater Sampling

6.1.3 Groundwater Elevation Survey

6.2 Analytical Results and Comparison to RSR Criteria

6.2.1 Phase II/III and Phase III SI Soil Analytical Results

Phase III Site Investigation and Preliminary Remedial Action Plan 2101230

6.2.2 Groundwater Analytical Results

6.3 Data Quality Assessment/Data Usability Evaluation

7.0 CONCLUSIONS AND RECOMMENDATIONS

7.1 Summary of Findings

7.2 Recommendations

8.0 PRELIMINARY REMEDIAL ACTION

8.1 Environmental Conditions and Proposed Remediation Areas

8.2 Soil Management

8.3 Soil Excavation and Off-Site Disposal

8.4 Environmental Use Restriction

8.5 Required Public Notification

8.6 Decontamination

8.7 Post-Remedial Groundwater Monitoring

8.8 Reporting

9.0 LIMITATIONS

10.0 REFERENCES

APPENDICES

Appendix A Site Plans Site Location Map Site Plan (SP-01) Site Investigation Plan (SI-01) Groundwater Contour Plan – April 26, 2022 (GW-01) Remediation Plan (RP-01)

Appendix B Tables Table 1 – Soil Analytical Data Table 2 – Groundwater Analytical Data Figure 3 by DTC- Soil Analytical Results

Appendix C Boring Logs and Monitoring Well Diagrams

Appendix D Laboratory Analytical Data Reports

Phase III Site Investigation and Preliminary Remedial Action Plan 2101230

1.0 INTRODUCTION

BL Companies was retained by the City of New Haven to complete a Phase III Site Investigation (SI) and develop a Preliminary Remedial Action Plan (RAP) for the property located at 0 Gibbs Street, New Haven, Connecticut (the “Site”). The location of the Site is depicted on the Site Location Map and the Site layout is depicted on the Site Plan (SP-01) included in Appendix A.

BL Companies completed a Phase I Environmental Site Assessment (ESA) for the Site in March 2021. During the Phase I ESA, BL Companies reviewed a Phase II ESA completed at the Site by Diversified Technology Consultants (DTC), dated April 2004 (partial copy which did not include data tables and/or laboratory results), which identified historical releases of petroleum and metals at the Site. The Phase I ESA identified several Recognized Environmental Conditions (RECs), as defined by American Society for Testing and Materials (ASTM) 1527-13 and Areas of Concern (AOCs). The Connecticut Department of Energy and Environmental Protection (CTDEEP) Site Characterization Guidance Document (SCGD) defines AOCs as “locations where hazardous waste and/or hazardous substances (including petroleum products) have been or may have been used, stored, treated, handled, disposed, spilled, and/or released to the environment.” Based on the findings of the Phase I ESA, BL Companies recommended and subsequently completed a Phase II/III SI at the Site in May 2022 to further assess releases previously identified by DTC in Site soils, and to further evaluate the AOCs identified as part of the Phase I ESA.

Based on the data collected at the Site through May 2022, a supplemental Phase III SI was recommended and subsequently completed in April-May 2023 to further define the degree and extent of releases to soil and/or groundwater identified during DTC’s Phase II ESA (2004) and BL Companies’ Phase II/III SI (2022). The results of the environmental assessments completed at the Site were then utilized to develop a preliminary RAP to move the Site towards compliance with the Connecticut Remediation Standard Regulations (RSRs) in anticipation of future Site redevelopment. BL Companies understands that the City of New Haven intends to redevelop the Site as a park.

Investigations completed by BL Companies were conducted in general accordance with standard and accepted practices and the SCGD. The results of BL Companies’ 2022 Phase II/III SI and 2023 Phase III SI, and their regulatory implications are discussed in this report. The cumulative results for subsurface investigations completed at the Site from 2004 to 2023 were then utilized to develop a preliminary RAP for bringing the Site into compliance with the RSRs.

1.1 Site Description

The Site is located at 0 Gibbs Street, New Haven, Connecticut and is owned by the City of New Haven. The Site consists of one irregular-shaped parcel of land totaling approximately 1.15 acres. The Site is currently an asphalt parking lot and is situated in an area of primarily commercial, industrial, and residential land usage.

The northernmost portion of the Site primarily consists of overgrown vegetation. The remainder of the Site consists of asphalt paved areas utilized for parking and storage of various landscaping equipment. Access to the Site is provided via Gibbs Street to the west.

1.2 Site History

Based on a review of available historic records and other information obtained during completion of the March 2021 Phase I ESA, the Site consisted of a presumably vacant lot in 1886 and was developed with two (2) residential dwellings by 1901, which were located on the west-central portion of the Site. By 1923, the dwellings were removed from the Site and Gibbs Street was constructed through the central portion of the property.

Sometime between 1921 and 1934, multiple structures were constructed on the Site, which included, but was not limited to, one (1) large above ground storage tank (AST) in the northern portion of the Site. By 1941, the Site was depicted as a cement mixing plant owned by C.W. Blakeslee & Sons and a large iron AST was depicted in the northern portion of the Site (same AST as previously noted). In addition, a storage building, an office building, and a gasoline underground storage tank (UST) were depicted in the central portion of the Site. A concrete mixer and bins with conveyor belt were also depicted in the southcentral portion of the Site. A railroad siding/spur was depicted along the eastern Site boundary. By 1963, the Site was depicted as vacant and by 1966, the Site was utilized as a parking lot. The Site was reportedly occupied by United Nuclear Corp Naval Products Division (UNCVP) in 1978. The exact operations conducted at the Site by the UNCVP are unknown. The Site is currently used as a parking lot and storage area for various landscaping equipment.

2.0 ENVIRONMENTAL SETTING

2.1 Geology and Hydrogeology

Geologically, the Site is located in the Coastal Lowlands Physiographic Province of Connecticut and is underlain by the Triassic aged New Haven Arkose. The New Haven Arkose is characterized as a red, pink, and grey coarse grained, locally conglomeratic, poorly sorted and indurated arkosic sandstone (Rodgers, 1985). Bedrock outcrops were not observed at the Site and bedrock was not encountered during soil boring advancement. Depth to bedrock is deeper than 33 feet below grade surface (’ bgs), which was the deepest depth of drilling completed during BL Companies’ investigations.

According to the Surficial Soils Map of Connecticut, dated 1992, native soils at the Site are classified as glacial meltwater deposits consisting of sand and gravel overlying sand overlying fines. However, according to the Natural Resources Conservation Service's online Web Soil Survey, soils mantling the Site are classified as Urban Land. Based on observations during soil boring advancement, surficial materials consist of shallow fill material on top of native soils. Fill material was encountered across the entire Site at thicknesses ranging from at 1.5’ to 17’ bgs. Native soils encountered during drilling activities generally consisted of reddish-brown fine to coarse sand with varying amounts of gravel, silt, and clay. Soil lithologies encountered during the Phase II/III SI and Phase III SI are described on the boring logs included in Appendix C.

According to the USGS 7.5-Minute Topographic Map of New Haven, Connecticut, and Google Earth, the topography of the Site is relatively flat and it is situated at an elevation of approximately 60 feet above mean sea level. Topography in the vicinity of the Site generally slopes to the south towards the New Haven Harbor, approximately 2.61 miles away from the Site. Based on topography, groundwater in the vicinity of the Site was expected to mimic the surrounding topography and flow to the south. Groundwater flow direction was calculated as part of the Phase II/III SI (2022) and was confirmed to flow in a southerly direction. However, given the relatively narrow width of the Site and its orientation from north-northwest to south-southeast, the groundwater monitoring wells installed at the Site are aligned generally in a linear fashion. As a result, it is possible that the groundwater flow direction may also contain an easterly or westerly component that cannot be derived from the existing data.

2.2 Groundwater and Surface Water

The CTDEEP has classified groundwater beneath the Site as GB. The GB classification indicates that groundwater at the Site is presumed not suitable for human consumption without treatment. Groundwaters with a GB classification are designated for uses including industrial process water and cooling waters, and as baseflow for hydraulically connected water bodies. According to the CTDEEP mapping review, the Site is not located within an Aquifer Protection Area.

No surface water bodies were observed on the Site. The nearest surface water body is Beaver Pond, which is located approximately 1,600 feet to the west of the Site. The surface water quality of Beaver Pond is classified as "A”. A Class “A” designation indicates these surface water bodies have designated uses including habitats for fish and other aquatic life, potential drinking water supplies, recreation, navigation, and water supply for industry and agriculture. The New Haven Harbor, which is located approximately 2.61 miles south (downgradient) of the Site, is classified as an “SB” water body. An SB designation indicates these surface water bodies have designated uses including habitat for marine fish and aquatic life and wildlife, commercial shellfish harvesting, recreation, industrial water supply, and navigation.

3.0 REGULATORY FRAMEWORK

3.1 Connecticut Transfer Act

Connecticut General Statute (CGS) Section 22a-134 is known as the CTA and regulates the transfer, investigation, and remediation of Hazardous Waste Establishments. An Establishment is defined as any real property at which or any business from which:

• on or after November 19, 1980, there was generated, except as a result of remediation of polluted soil, groundwater or sediment more than 100 kilograms of hazardous waste in any one month;

• hazardous waste generated at a different location was recycled, reclaimed, reused, stored, handled, treated, transported or disposed of;

• the process of dry cleaning was conducted on or after May 1, 1967;

• furniture stripping was conducted on or after May 1, 1967; or

• a vehicle body repair facility was located on or after May 1, 1967.

Effective October 1, 2019, “Establishment” does not include any real property or any business operation from which more than one hundred kilograms of hazardous waste was generated in any one month solely as a result of either:

(i) the one-time generation of hazardous waste in any one month as a result of either the first time such waste was generated or such a one-time generation since the last time a Form I, Form II, Form III or Form IV was required to be submitted; or

(ii) one or more of the following: (I) remediation of polluted soil, groundwater or sediment (II) the removal or abatement of building materials or removal of materials used for maintaining or operating a building; (III) the removal of unused chemicals or materials as a result of the emptying or clearing out of a building, provided such removal is supported by facts reasonably established at the time of such removal; or (IV) the complete cessation of a business operation, provided the waste is removed not later than ninety days after such cessation and such cessation is supported by facts reasonably established at the time of such cessation.

Facilities that are considered Establishments under the CTA are subject to certain reporting requirements to the CTDEEP when a transfer of ownership occurs. One of four filing forms (Form I, II, III, IV) must be submitted to the CTDEEP. The type of filing depends on whether or not there has been investigation of potential release areas at the Site, whether or not there have been regulated compounds released to soil or groundwater, and/or whether or not remediation, if needed has been completed.

Based on the information reviewed by BL Companies during the March 2021 Phase I ESA, the Site does not appear to meet the requirements set forth in the CTA to be considered an Establishment. Therefore, the Site would not likely be subject to the legal and technical requirements of the CTA in the event of a transfer. The applicability of the CTA should be confirmed by legal counsel prior to any qualifying ownership transfer.

3.2 Remediation Standard Regulations

The RSRs are outlined in Sections 22a-133k-1 through 3 of the Regulations of the Connecticut State Agencies (RCSA) that were promulgated in January 1996 and subsequently amended in June 2013 and again in February 2021. The RSRs specify the allowable levels of regulated compounds in soil and groundwater that correspond with areas with groundwater classified as either GA (presumed suitable for drinking water purposes without treatment) or GB (presumed unsuitable for drinking without treatment).

The RSRs apply to Sites that are remediated pursuant to Chapter 445, Chapter 446k, or section 22a-208a(c)(2) of the Connecticut General Statutes. Chapter 445 of the Connecticut General Statutes pertains to certain hazardous waste facilities, sites undergoing remediation under CTDEEP’s Urban Sites remedial action program, sites that are subject to CTDEEP’s voluntary site remediation programs, and “establishments” as defined under section 22a-134 of the Connecticut General Statutes. Chapter 446k of the Connecticut General Statutes pertains to sites that are undergoing remediation pursuant to an enforcement action issued by the CTDEEP, sites with regulated USTs, sites with oil and chemical spills, sites where polychlorinated biphenyls (PCBs) have been released, and regional water pollution control facilities. Section 22a-208a(c)(2) of the Connecticut General Statutes pertains to permitted solid waste disposal facilities.

3.2.1 Soil Criteria

The RSRs define two criteria that apply to polluted soil: the Direct Exposure Criteria (DEC) and the Pollutant Mobility Criteria (PMC). Soil at sites that are subject to the RSRs must be remediated to concentrations that are equal to or less than the DEC and PMC or the background concentrations in soil. The DEC defines the maximum levels of regulated compounds allowed in soil to a depth of 15 feet bgs without posing a threat due to direct human exposure. The PMC set the maximum level of regulated compounds allowed in soil without posing a threat to groundwater quality. Each criteria type is further divided into two categories; the DEC is based upon Site usage (i.e., residential or industrial/commercial use), while the PMC is based on the groundwater classification (i.e., GA/GAA or GB). The Site is located in an area with a GB groundwater classification;

therefore, the soil must meet the GB PMC.

Demonstration of soil meeting background concentrations (in lieu of demonstrating compliance with DEC and PMC) requires a representative sampling program used to characterize the background concentration for soil that is:

o Of similar texture and composition, o Collected from the nearest location practicable outside the release area;

and, o Not affected by another discrete release of the same substance or having an effect on the concentrations of the same substance for which a background concentration is determined and either, all analytical results in the release area are equal to or less than the background concentration, or a statistical comparison of the background concentrations to the concentrations in the release area results in significant similarity.

The residential direct exposure criteria (RES DEC) must be met if a site is to be used for current or future residential purposes and is the default/baseline DEC criteria required by the RSRs. The CTDEEP and the RSRs define “residential activity” to mean any activity at: (A) a place intended for people to live, including but not limited to, a residence, dwelling, house, apartment, condominium, nursing home, or dormitory; (B) a pre-school, primary school, secondary school, day care center, playground, or outdoor recreational area; or (C) a hospital, solely for the purposes of compliance with volatilization criteria.

If a Site or property is not currently used or planned to be used in the future for residential purposes, then the industrial/commercial direct exposure criteria (I/C DEC) may be applied if an Environmental Use Restriction (EUR) is filed in the land records for the Site.

The EUR, which consists of either an Environmental Land Use Restriction (ELUR) or a Notice of Activity Use Limitation (NAUL), places certain usage limitations on a property, which includes but is not limited to, an industrial or commercial use restriction, prohibition of soil exposure or disturbance, or a no-build restriction. A NAUL can only be used in circumstances that are listed in section 22a-133k-1(e)(1)(B) of the RSRs. The current and anticipated future use of the Site meets the definition of industrial/commercial.

3.2.2 Groundwater Criteria

The RSRs include three criteria that apply to groundwater: the groundwater protection criteria (GWPC), the surface water protection criteria (SWPC), and the groundwater volatilization criteria (GWVC). Groundwater in GA areas typically must meet background concentrations in accordance with the RSRs. However, an RSR alternative indicates that groundwater in GA areas can meet the GWPC if a public water supply is available within 200 feet of the site where the release to groundwater is located, adjacent sites, and sites within the aerial extent of the groundwater plume. In addition, the GWPC can be applied in lieu to demonstrating compliance with background; provided, o The plume is not within an aquifer protection area;

o Prior to any remediation of soil or groundwater, the plume is a diminishing state;

and o Each substance in groundwater is remediated to GWPC and reduction of concentrations to background cannot be achieved.

The GWPC define the maximum levels of regulated compounds allowed in groundwater for protection of the groundwater as a potable water source. The Site is located in a GB groundwater classification area therefore, the GWPC does not apply to the Site.

The SWPC applies to impacted groundwater that is discharging to a surface water body, including streams, rivers, ponds, lakes, and Long Island Sound. The SWPC specifies the levels of compounds allowable in groundwater just prior to discharging into surface water.

One standard has been set for groundwater that discharges to surface water, regardless of the classification of such surface water. One method of demonstrating compliance with the SWPC is established at the point at which the groundwater plume discharges to the surface water body. For properties that do not have surface water, the point of compliance for the SWPC is typically considered to be the downgradient property boundary. The RSRs also contain additional options for demonstrating compliance with the SWPC, which includes but is not limited to, requests for an alternative SWPC based on available dilution in the receiving water body.

The GWVC sets the allowable levels of volatile organic compounds (VOCs) within certain distances of a building (within 10 feet bgs or lowest portion of a building for aromatic/petroleum VOCs and within 30 feet bgs or lowest portion of a building for chlorinated or non-petroleum VOCs). The GWVC are designed to protect humans from exposure to VOCs present in shallow groundwater that may migrate as vapors into an overlying building interior. The GWVC is dependent on a property’s usage, with residential GWVC (RES GWVC) and industrial/commercial GWVC (I/C GWVC) established in the RSRs. The RES GWVC is more stringent and the default/baseline GWVC criteria required by the RSRs. The I/C GWVC may be applied if a site is used for industrial/commercial purposes and an EUR is recorded for the property. Compliance with the GWVC may not be required if monitoring of soil vapor above the water table or indoor air quality demonstrates that there is no exposure hazard.

3.2.3 Soil Vapor Volatilization Criteria

The soil vapor volatilization criteria (SVVC) were developed to identify situations where VOCs present in soil vapor have the potential to migrate into an overlying building and pose a risk to human health from the inhalation of the contaminants by occupants of the building. The SVVC may be used as an alternative for assessing potential migration of VOCs into an overlying building in lieu of assessing groundwater relative to the GWVC.

Residential (Res) and industrial/commercial (I/C) SVVC have been established, with the Res SVVC being more stringent, and the I/C SVVC requiring the use of an EUR.

3.3 Applicable RSR Criteria

Because the Site is located in a GB groundwater classification area, the GB PMC apply to the soil that is present above the seasonal high-water table. In the absence of an EUR restricting the Site from residential use, the RES DEC applies to soil that is present within 15 feet bgs at the Site.

The SWPC and RES GWVC apply to the groundwater at the Site.

4.0 PREVIOUS INVESTIGATIONS

Phase I Environmental Site Assessment, 0 Gibbs Street, New Haven, Connecticut, prepared by Catalyst Environmental Consulting, Inc. (Catalyst), September 2003.

This report was not identified by BL Companies nor was it made available for review.

However, the results of this report were summarized in DTC’s Phase II ESA completed in April 2004.

Partial Copy (Laboratory Data Tables and Reports were not Available for Review) Phase II Environmental Site Assessment, 0 Gibbs Street, New Haven, Connecticut, prepared by Diversified Technology Consultants (DTC), prepared for Regional Growth Partnership, April 6, 2004.

The Scope of Work for the Phase II ESA completed by DTC consisted of the completion of a ground penetrating radar (GPR) survey of the Site, advancement of soil borings, test pits, and collection of soil and groundwater samples for analysis.

A Phase I ESA was reportedly prepared by Catalyst in September 2003 and the results were summarized by DTC in the Phase II ESA report. The Phase I ESA completed by Catalyst reportedly identified the Site as a 1.15-acre parcel of land that was vacant and paved with bituminous concrete. The Site was reportedly first developed between 1890 and 1901 with two (2) dwellings in the central portion of the Site. Between 1932 and 1961, a concrete mixing plant occupied the Site and consisted of an office building, fuel oil house and plant. At least one (1) gasoline UST and one (1) large AST were noted. According to a 1940 Site plan, a concrete plant was depicted in the southern portion of the Site and consisted of an office building, 1,000-gallon gasoline UST, and a fuel oil house containing eight (8) 8,000-gallon USTs. A railroad spur was depicted along the eastern Site boundary. A Site Plan included in the DTC report depicts an abandoned tank in the northern portion of the Site. The locations of former fuel oil tanks, former office and identified UST are depicted in the central portion of the Site. A former concrete mixer and bins with conveyor belt are depicted in the southeastern portion of the Site.

From 1965 through 1974, the Site was reportedly used as a paved parking lot for material storage. According to DTC’s summary of the Catalyst Phase I ESA, a 6,000-gallon oil tank was removed by Clean Harbors in June 2000. No additional information was found related to the tank.

As part of the 2004 Phase II, DTC oversaw a GPR survey to locate potential USTs at the Site. A subsurface anomaly located east of the Gibbs Street entrance and adjacent to the former fuel oil USTs, described as an approximately 6-foot by 4-foot square, was identified as a potential 550-gallon UST.

During the Phase II ESA completed at the Site in April 2004, DTC oversaw the advancement of two (2) soil borings (B-1 and B-2), which were completed as temporary groundwater monitoring wells installed to 28 feet below the ground surface (‘ bgs), and nine (9) test pits (TP-1 through TP-9) advanced to depths of 6 to 8’ bgs. Groundwater samples were collected from each of the soil borings using temporary stainless steel well points and bailers. A sheen and odor, "indicative of weathered No. 2 fuel oil", was observed in the groundwater sample collected from boring B-2 around 25-28 feet below grade. DTC concluded the sheen and odor may be associated with a release from off- Site to the east. A test pit (TP-3) was completed to determine the nature of the subsurface anomaly present to the east of the Site entrance. The anomaly was determined to be a 550-gallon steel UST and associated piping. According to DTC, no indications of a release were observed in surrounding soils.

Soil samples collected during the Phase II ESA were analyzed for VOCs, polynuclear aromatic hydrocarbons (PAHs), extractable total petroleum hydrocarbons (ETPH), Resource Conservation and Recovery Act (RCRA) 8 metals, Synthetic Precipitation and Leaching Procedure (SPLP) lead and/or arsenic, SPLP PAHs, and PCBs. Groundwater samples were analyzed for VOCs. A total of 32 soil samples and two (2) groundwater samples were collected for analysis. BL Companies was provided with an incomplete copy of the Phase II ESA report for review. Laboratory data tables and laboratory reports were not available for review. However, DTC did summarize the laboratory results for soil on Figure 3 (Soil Analytical Results) which has been included in Appendix B of this report for reference.

Based on the analytical results, DTC noted the following:

• Aromatic VOCs were detected in two (2) soil samples (B-1 [4-8’] and B-1 [8-10’]) at concentrations below regulatory criteria, which DTC opined was indicative of weathered gasoline.

• Chlorinated VOCs were detected in seven (7) soil samples “from sampling locations throughout the Site” at concentrations below regulatory criteria, which DTC believed may be attributed to impacted fill materials or minor Site-wide spillage. The laboratory data summary tables and laboratory reports were not available for review and these samples were not identified in the text. It is not clear where these samples were collected.

• PAHs were detected in 16 soil samples collected across the Site, three (3) of which

(TP-1 [0-2’], TP-4 [0-2’], and TP-8 [0-2’]) exceeded regulatory criteria and appear to be related to ash and slag associated with urban fill materials.

• Leachable PAHs, analyzed in two (2) samples (TP-1 [0-2’] and TP-8 [0-2’]), were not detected at concentrations above laboratory detection limits.

• ETPH was detected in 14 soil samples, 13 of which were collected from urban fill material and were below regulatory criteria. The remaining sample (B-1 [4-8’]) exceeded regulatory criteria and DTC concluded this may be due to a potential release from a historic AST.

• Total arsenic was detected at concentrations above applicable regulatory criteria in TP-5 (2-4’), TP-8 (0-2’), TP-8 (2-4’), and B-2 (4-8’).

• Total lead was detected at concentrations above applicable regulatory criteria in TP-8 (0-2’), TP-9 (0-2’), and B-1 (4-8’).

• Leachable lead was detected in each sample for which it was analyzed and was detected above regulatory criteria in two (2) samples (TP-8 [0-2’] and TP-9 [0-2’]).

Leachable arsenic was not detected in any of the samples for which it was analyzed.

• PCBs were not detected in the soil samples analyzed; however, a test pit proposed near a former transformer was relocated due to the presence of a gas line.

• Low VOC concentrations (below regulatory criteria) were detected in the two (2) groundwater samples collected during the Phase II ESA. The samples were not analyzed for any other constituents of concern.

Based on the findings of their Phase II ESA, DTC concluded and/or recommended the following:

• Removal of the 550-gallon UST and collection of closure samples.

• Urban fill is present throughout the Site with an average thickness of 4.4 feet, with some pockets extending to 11’ bgs. Fill materials consist of dense black ash, yellow/orange slag/cinders, concrete and sand. Soil samples collected from the fill material contained concentrations of PAHs, lead, and arsenic exceeding regulatory criteria. DTC concluded the native soil below the fill "does not appear to be impacted with significant concentrations of regulated compounds...and impacts appear to be limited to the urban fill."

• Soils impacted with ETPH, and lead, were identified in the northern portion of the

Site. DTC recommended a Phase III ESA be conducted to delineate the extent of ETPH and lead impacts to soil and a RAP should be prepared upon completion of the Phase III ESA. DTC concluded that based on the current information, the likely approach to remediate the ETPH and lead impacts at the Site would include excavation. DTC also concluded that the most cost-effective approach to address urban fill would be to render the fill inaccessible to human contact.

• DTC concluded that groundwater does not appear to be significantly impacted, but stated additional sampling may be necessary to support this finding.

Phase I Environmental Site Assessment, 0 Gibbs Street, New Haven, Connecticut, prepared by BL Companies, prepared for City of New Haven – Livable City Initiative, March 18, 2021.

BL Companies completed a Phase I ESA at the Site in March 2021. Relevant findings relating to the current Site layout at the time of the Phase I ESA and the Site history are discussed in Section 1.1 and Section 1.2 above.

BL Companies’ Phase I ESA included a review of the 2004 Phase II SI completed by DTC. DTC had recommended additional investigation and potential remediation be completed at the Site. However, no evidence of additional investigation or remediation was discovered during completion of BL Companies’ Phase I ESA.

The Phase I ESA did not reveal any evidence of historical recognized environmental conditions (HRECs) or Business Environmental Risks (BERs)/De Minimis Conditions.

The Phase I ESA did reveal the following RECs in connection with Site:

• Former 6,000-Gallon UST: According to the DTC Phase II ESA, a 6,000-gallon oil tank was removed in June 2000. No closure documents were found. The Catalyst Phase I ESA, reviewed by DTC, stated it was unclear if this UST was located on the Site or on the abutting property.

• Former AST: An iron AST was formerly located within the northern portion of the

Site.

• Abandoned Tank: According to the DTC Site Plan, an abandoned tank was depicted in the northernmost portion of the Site.

• Former Fuel Oil Tanks, Former Storage and Office Buildings: Based on review of the historical documents and the DTC Site Plan, a former storage building containing eight (8) 8,000-gallon fuel oil tanks and a former office building were depicted in the central portion of the Site. Samples collected from this area in 2004 by DTC indicated the presence of ETPH and total lead above regulatory criteria.

• Former Gasoline UST: A gasoline UST was depicted on the 1951 Sanborn map in the central portion of the Site. An abandoned approximately 550-gallon UST was found during GPR and test pit activities completed by DTC in 2004. DTC recommended that this UST be removed; however, it is unknown if the tank was removed, or if closure samples were collected.

• Former Concrete Mixer and Bins with Conveyor Belt: Historical documents depict a former concrete mixer with bins and conveyor belt on the southeastern portion of the Site. Samples collected from this area indicated the presence of arsenic above regulatory criteria. Test pits to the north of this area indicated the presence of total and SPLP lead as well as PAHs above regulatory criteria.

• Urban Fill: Urban fill was identified throughout the Site by DTC to an average depth of 4.4 feet below grade, and up to 11 feet below grade. Fill was observed to consist of black ash, slag/cinders, concrete, sand and other miscellaneous debris.

Soil samples from select locations within the urban fill contained ETPH, PAHs, lead, and arsenic at concentrations above and below regulatory criteria.

• Former Dwellings with Unknown Heating Sources: Based on review of the

1901 Sanborn map, two (2) dwellings were depicted in the west-central portion of the Site. The heating sources of the former dwellings are unknown.

• Railroad Spur: A railroad spur was depicted along the eastern Site boundary from approximately 1923 through 1973 and extended off-Site to the north and south.

• Soft Coal Storage Area: According to a 1940 Site Plan reviewed by Catalyst, a soft coal storage area was depicted on the southeastern portion of the Site.

• Past Site Usage: Based on review of the city directories, the Site may have been occupied by United Nuclear Corp Naval Products Division in 1978. The use of the Site by this company is unknown.

Based on the findings of the March 2021 Phase I ESA, BL Companies recommended the

• A Phase II/III Investigation should be completed to further evaluate the RECs/AOCs identified during this ESA. The purpose of the Phase II/III investigation would be to investigate areas that were not previously investigated, as well as to further define the extent of environmental impacts for redevelopment planning.

Phase II/III Site Investigation, 0 Gibbs Street, New Haven, Connecticut, prepared by BL Companies, prepared for Livable City Initiative – City of New Haven, May 2022.

The Scope of Work for this investigation consisted of the completion of a GPR survey, the advancement of 12 soil borings (SB-1 through SB-12), installation of four (4) groundwater monitoring wells (BLMW-1 through BLMW-4), and the collection of soil and groundwater samples for laboratory analysis based on the RECs/AOCs identified during BL Companies’ March 2021 Phase I ESA (and supplemented with observations made during this investigation).

As part of the May 2022 Phase II/III SI BL Companies oversaw a GPR survey to locate potential USTs in select areas of the Site and to clear proposed boring/well locations. No evidence of USTs or anomalies was identified during the completion of the GPR survey.

However, the survey was not completed for the entire parcel and was limited by overgrown vegetation (primarily on the northern portion of the Site) and stored materials at select portions of the Site.

BL Companies oversaw the advancement of the soil borings throughout the Site via a direct push Geoprobe drill rig. Four (4) of the soil borings were completed as permanent groundwater monitoring wells installed within the overburden aquifer. A gasoline odor was noted in soil and groundwater at the water table in BLMW-1, located in the southern portion of the Site. Petroleum odors were noted in soil and groundwater at the water table at SB-3/BLMW-2, located in the south-central portion of the Site. A strong, unidentified chemical odor was noted in soils at SB-7/BLMW-3, located in the north-central portion of the Site, at depths ranging from 2 to 6’ bgs; additionally, a faint petroleum odor was noted in soil and groundwater at the water table at SB-7/BLMW-3. Finally, a petroleum odor was noted in fill material from SB-8, located in the north-central portion of the Site, at depths ranging from 0.5 to 11.3’ bgs. Evidence of urban fill was observed in all 12 soil borings at thicknesses ranging from 1.5 to 17’ and was observed to be thickest in the vicinity of SB- 7, SB-8, and SB-9 in the north-central portion of the Site. Indicators of urban fill material observed within the soil consisted of asphalt, coal, ash, ceramics, slag, concrete, wood, metal, vinyl tile, and glass.

BL Companies collected groundwater samples for laboratory analysis from the four (4) monitoring wells via low-flow methodology. At that time a groundwater elevation survey was also completed. Overburden groundwater was calculated to flow in a southerly direction, towards New Haven Harbor.

Soil and groundwater samples were selectively analyzed for VOCs, PAHs, ETPH, and/or total RCRA 8 metals. Based on the analytical results, BL Companies noted/concluded the

• VOCs were detected in four (4) soil samples, including a detection of benzene at a concentration above the GB PMC in an intermediate sample from SB-7 and detections of various other VOC compounds in SB-7, SB-8, and SB-12 at concentrations below regulatory criteria. VOCs were not detected in the remaining eight (8) soil samples analyzed. Low-level aromatic VOCs related to petroleum were also detected in groundwater samples collected from BLMW-1, BLMW-2, and BLMW-3 located in the central and southern portions of the Site. BL Companies concluded that the VOCs were likely associated with the former UST area, urban fill materials, and/or the former railroad spur.

• PAHs were detected in three (3) soil samples, including two (2) samples which exceeded regulatory criteria and one (1) sample above laboratory reporting limits (but below applicable criteria). BL Companies concluded that the identified exceedances were likely related to urban fill material. PAHs were not detected in the remaining 10 soil samples analyzed. PAH constituent acenaphthylene was detected in groundwater collected from downgradient wells BLMW-1 and BLMW- 2 at concentrations above applicable criteria. Other PAH compounds were detected in groundwater at wells BLMW-1, BLMW-2, and BLMW-3 at concentrations below applicable criteria. BL Companies concluded that the PAHs in groundwater may be attributed to the PAHs detected in soils in select portions of the Site.

• ETPH was detected in five (5) soil samples, including a detection below applicable criteria in a shallow sample from SB-4 and detections above applicable criteria in a shallow sample from SB-5 and shallow and intermediate samples from SB-8.

Soil borings SB-4 and SB-5 were completed in the south-central portion of the Site and were collected from an interval of urban fill. As such, BL Companies attributed the impacts to urban fill material. Soil boring SB-8 was completed in the north-central portion of the Site in the vicinity of the former fuel oil tank area, and BL Companies concluded that the detections of ETPH in shallow and intermediate samples are likely due to the former USTs and may be comingled with polluted fill material. ETPH was not detected at concentrations above laboratory reporting limits in the remaining 12 soil samples analyzed. ETPH was detected above applicable criteria in groundwater samples collected from BLMW-1, BLMW-2, and BLMW-3 located in the central and southern portions of the Site. ETPH was not detected in the northernmost (upgradient) well. BL Companies concluded that the ETPH in groundwater appears to be associated with an on-Site source, however additional assessment would be needed.

• A total of 13 soil samples were analyzed for total RCRA 8 metals. Total arsenic and/or lead were detected at concentrations above regulatory criteria in three (3) surficial samples. BL Companies attributed the elevated levels of arsenic to urban fill and lead to urban fill or the east-adjacent railroad spur. Barium, cadmium, chromium, and/or mercury were detected in all samples at concentrations below applicable criteria (and likely consistent with background concentrations).

Selenium and silver were not detected above laboratory reporting limits in any samples. Select metals, including arsenic, barium, chromium, and/or lead, were detected in each groundwater sample at concentrations below applicable criteria (with highest concentrations detected in downgradient wells). BL Companies noted that turbidity was highest in downgradient wells and concluded that the detected metals in groundwater were likely due to sediment present in the groundwater samples.

Based on the findings of the Phase II/III SI, BL Companies recommended the following:

• Further investigation and delineation of the identified petroleum impacts (ETPH, PAHs, VOCs) identified at AOC-4 (former fuel oil tanks, former storage, and office buildings) and AOC-5 (former 550-gallon gasoline UST) in the north-central portion of the Site.

• Further investigation and delineation of the ETPH, PAHs, and metals impacts identified at AOC-2 (former AST), AOC-6 (former concrete mixer and bins with conveyor belt), and AOC-9 (former railroad spur). Those impacts appear to be associated with AOC-7 (urban fill material), which was observed throughout the Site, rather than a specific release from former on-Site activities.

• Further investigation of groundwater at the Site, which was impacted with ETPH, PAHs, and VOCs at concentrations above and below the RSR criteria. Additional investigation is warranted to better understand the source, nature, and full extent of the impacts and any associated connections with soil sources at the Site.

5.0 CONCEPTUAL SITE MODEL

BL Companies has prepared an updated Conceptual Site Model (CSM) for the Site based upon the geology, hydrogeology, and the current and historical use of the Site, as documented in BL Companies’ Phase I ESA, the results of the May 2022 Phase II/III SI, and supplemented with the observations made during the Phase III SI. A CSM is a description of the environmental system at a site that provides a framework for communicating the rationale for the site investigation process. The CSM describes all potential release areas as well as release mechanisms, contaminant fate and transport characteristics, and potential migration pathways at the Site. BL Companies prepared a preliminary CSM as described below.

The updated CSM was used to develop an investigative approach to characterize each AOC in accordance with the CTDEEP SCGD and RSRs. The goal of this Phase III SI was to further define the extent of soil impacts previously identified at the Site. Soil borings were advanced to collect soil samples for analysis for the presence of specific constituents of concern (COCs).

Based on the information, BL Companies identified a total of ten (10) AOCs at the Site, which included the following:

• AOC-1: Former 6,000-Gallon Oil Underground Storage Tank – Location Unknown

• AOC-2: Former Above Ground Storage Tank

• AOC-3: Abandoned Underground Storage Tank

• AOC-4: Former Fuel Oil Tanks, Former Storage, and Office Buildings

• AOC-5: Former 550-Gallon Gasoline Underground Storage Tank

• AOC-6: Former Concrete Mixer and Bins with Conveyor Belt

• AOC-7: Site Wide Urban Fill Material

• AOC-8: Former Residential Dwellings with Unknown Heating Sources

• AOC-9: Former Railroad Spur

• AOC-10: Former Transformer Area

5.1 Data Quality Objectives

Development, revision, and validation of the CSM processes are dependent upon the complexity of the site conditions and the project-specific data quality objectives (DQOs) that are established to adequately characterize the site. The DQOs for the site characterization process are developed to ensure data of sufficient quality and quantity are collected to support decisions and conclusions made during site characterization and to aid in the ultimate validation of the CSM.

DQOs are statements that clarify objectives, define the appropriate type and quantity of data to be collected, establish the appropriate conditions for data collection, and specify acceptable levels of error and laboratory reporting levels that will be used as the basis for establishing the quantity and quality of the data needed to support decisions made based upon the use of that data. The DQO process used on this project was developed to help guide data collection activities, to develop a defensible rationale for collecting samples and to ensure that the data used in the decision-making process were appropriate for the intended use.

5.2 AOC Summaries

This section provides summaries of the nature of the AOCs which have been the subject of the Phase II and Phase III activities conducted by BL Companies, as well as descriptions of the potential release mechanisms, potential migration pathways, and COCs that are associated with each AOC. These aspects of the CSM were used in guiding implementation of the SI activities described in Section 6.0 below.

Each of the AOCs is shown on the Site Plan (SP-01) and the Site Investigation Plan (SI-01), both included in Appendix A.

5.2.1 AOC-1: Former 6,000-Gallon Oil Underground Storage Tank – Location Unknown

A 6,000-gallon oil UST was reportedly closed and removed from the Site in June 2000.

According to the Catalyst Phase I ESA, which was summarized in the DTC Phase II ESA report (but not available for review by BL Companies), it was unclear if the UST was located on the Site or abutting the property. The Site plan included in the DTC Phase II ESA report did not include any specific call out for a former 6,000-gallon UST. No closure documentation was found during completion of the Catalyst Phase I ESA or the BL Companies Phase I ESA. In addition, this tank/tank grave was not identified using GPR during BL Companies’ Phase II/III activities in May 2022

Potential Release Mechanisms: Structural failures from the UST materials which would result in spills of petroleum products directly to subsurface soils.

Potential Migration Pathways: Releases to subsurface soils surrounding the UST, downward migration through subsurface soils toward the water table, and potential migration with groundwater.

Constituents of Concern: ETPH, PAHs, and VOCs.

5.2.2 AOC-2: Former Above Ground Storage Tank

BL Companies’ Phase I ESA identified a large iron AST which was depicted in the northern portion of the Site on a 1951 historical Sanborn map. By 1973, this tank was no longer depicted. Additional information regarding the contents, use, and closure was not available for review.

In May 2022, BL Companies advanced soil boring SB-9 and installed groundwater monitoring well BLMW-4 in the location of the former AST. Based on the results of the investigation, PAHs and lead were detected in shallow soil at concentrations above and below RSR criteria. The impacts are likely related to the presence of urban fill materials (AOC-7) observed in this area, rather than a release from AOC-2.

Potential Release Mechanisms: Structural failures from the AST materials which would result in spills of petroleum products directly to the surface.

Potential Migration Pathways: Releases to surface materials surrounding the AST, then downward through asphalt or concrete, if present, further migration downward through subsurface soils toward the water table, and potential migration with groundwater.

Constituents of Concern: ETPH, PAHs, and VOCs.

5.2.3 AOC-3: Abandoned Underground Storage Tank

An abandoned tank was depicted on the northernmost property border of the Site on the DTC Phase II Site plan. However, DTC does not specifically discuss any abandoned tank at this location, or at the Site, in their Phase II report. No other information is known at this time regarding the size, contents, or current status of this “abandoned” tank. It is possible that the abandoned tank depicted on the DTC Site plan may in fact be referring to the tank identified and discussed as AOC-1.

In May 2022, a release was not identified in the soil borings completed near and downgradient of the presumed location of AOC-3. However, the area where the UST was depicted on historical documents was inaccessible for investigation in 2022 and 2023 due to thick, heavy vegetation on the northern portion of the Site.

Potential Release Mechanisms: Structural failures from the UST materials which would result in spills of petroleum products directly to subsurface soils.

Potential Migration Pathways: Releases to subsurface soils surrounding the UST, downward migration through subsurface soils toward the water table,…