. 0UNITED STATES ENVIRONMENTAL PROTECTION AGENCYV

1 REGION 4j ATLANTA FEDERAL CENTER° 61 FORSYTH STREET

ATLANTA, GEORGIA 30303-8960

August 24, 2006

4WD-SRTSB

MEMORANDUM

SUBJECT: Request for ApprovalSecond Five-Year Review ReportB.F. Goodrich/Airco Superfund SiteCalvert City, Marshall County, Kentucky

FROM: Brad JacksonRemedial Project ManagerSuperfund Remedial and Technical Support Branch

THROUGH: Jeaneanne M. Gettle, ActingSuperfund Remedial and Technical Support Branch

TO: Beverly A. Banister, Acting Directorvi^ rWaste Management Division

Attached for your approval is the revised Second Five-Year Review Report for the B.F.Goodrich/Airco Superfund Site located in Calvert City, Kentucky. You were briefed on theresults of this review on July 17, 2006, and revisions were requested regarding therecommendations provided in the Report.

The revisions primarily dealt with Section 8 (Issues) and Section 9 (Recommendationsand Follow-up Actions) of the Report. Section 8 of the report detailed the issues identified fromthe review, but the recommendations were not clearly defined in a fashion that was consistentwith the issues. Section 9 was revised to include a summary table (Table 14) that contrasts theissues and recommendations along with the entity responsible for implementing and overseeingthe recommendation.

At the time of the briefing, the State of Kentucky had been given a copy of the Five-YearReview Report, but had not provided any formal response. On July 25, 2006, the KentuckyEnvironmental and Public Protection Cabinet notified EPA via e:mail that it had reviewed theReport and had no comments.

10448880

Internet Address (URL) • http://www.epa.govRecycled/Recyclable • Printed with Vegetable Oil Based Inks on Recycled Paper (Minimum 30% Postconsumer)

Recommendations from the Second Five-Year Review Report include the following:

• Implement deed restrictions pursuant to the Record of Decision that prohibitresidential use of the property and restrict installation of potable drinking waterwells on the property;

• Revise the remedy to address the remediation of dense non-aqueous phase liquid(DNAPL);

• Evaluate design/location of extraction wells in an effort to more effectivelyaddress the source area contamination;

• Investigate and characterize additional potential source areas contributing to theDNAPL contamination. Develop corresponding source area remedial options.

Another question from the briefing was whether the recommendations regardingadditional source investigation and remediation were appropriate if the intent of the ROD wasgroundwater containment and not groundwater cleanup. The ROD was reviewed again in aneffort to better discern the intent of the remedy. Unfortunately, with respect to the groundwatercomponent, there are references to both groundwater containment and cleanup. However, basedon the source removal and groundwater collection and treatment components of the remedy;establishment of groundwater cleanup standards versus only discharge standards; and agroundwater cleanup time-frame often years; there is an expectation in the ROD for groundwatercleanup, not just indefinite hydraulic containment to prevent discharge to the Tennessee River.Because the ROD anticipates the eventual cleanup of groundwater, the recommendations thatpertain to additional source characterization and treatment should be included in the Report.

For reference, attached is a copy of the briefing sheet from the July 17, 2006, briefing.The site project code for the BF Goodrich site is 0461RAOO and the Airco Site is 0460RAOO.Please let me know if you have any questions or need additional information.

Attachments

Second Five-Year Review Report

Final

for

BF Goodrich Landfill / AIRCO Landfill

EPA ID: KYD006370167 / KYD041981010

Calvert City, Marshall County, Kentucky

July 2006

PREPARED BY:

US Army Corps of Engineers, Louisville District

for

United States Environmental Protection Agency

Region IV

Atlanta, Georgia

Approved bvVjUJL fl .M*ft>fi Date: S - l l - l o O f r

Beverly H. Banister, Acting Director,

Waste Management Division

Table of Contents

List of Acronyms v Executive Summary vii Five-Year Review Summary Form viii

1.0 INTRODUCTION AND PURPOSE 1 1.1 GENERAL 1 1.2 AUTHORITY 1 1.3 LOCAL REPOSITORY 1

2.0 SITE CHRONOLOGY 2 3.0 SITE DESCRIPTION AND BACKGROUND 3

3.1 GENERAL SETTING AND LAND USE 3 3.2 NATURAL PHYSICAL SETTING 3 3.3 AFFECTED POPULATION 3 3.4 BFG/AIRCO SITE OPERATIONS HISTORY 4 3.5 BFG/AIRCO SUPERFUND SITE INVESTIGATIONS 6

4.0 REMEDIAL ACTIONS 9 4.1 REMEDY SELECTION 9 4.2 REMEDY IMPLEMENTATION 11

4.2.1 Impose Deed Restrictions Preventing Residential Development and Groundwater Use 11

4.2.2 Construction of Flood Protection Dike 12 4.2.3 Landfill Cover Improvements 13 4.2.4 Leachate Collection System 13 4.2.5 Groundwater Extraction System 13 4.2.6 Consolidation of Surface Soil and Drainage Ditch Sediment 15 4.2.7 Vapor Recovery System 15 4.2.8 RCRA Cover System over Burn Pit Area 16 4.2.9 Site Fencing 16 4.2.10 Environmental Monitoring 16

4.2.10.1 Groundwater Monitoring Program 174.2.10.2 Surface Water Monitoring 18

4.3 SYSTEM OPERATIONS/OPERATIONS AND MAINTENANCE (O&M) 18

5.0 PROGRESS SINCE THE LAST FIVE-YEAR REVIEW 22 6.0 FIVE-YEAR REVIEW PROCESS 25

6.1 ADMINISTRATIVE COMPONENTS 25 6.2 COMMUNITY INVOLVEMENT 25 6.3 DOCUMENT REVIEW 25 6.4 DATA REVIEW 26

6.4.1 Groundwater Elevation Data 26 6.4.2 Water Quality Data 26

6.4.2.1 Effectiveness Monitoring Wells 27 6.4.2.2 Groundwater Extraction Wells 27 6.4.2.3 Downgradient Monitoring Wells 28

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6.4.2.4 Background Monitoring Wells 29 6.4.2.5 Surface Water Sampling 29

6.4.3 Soil Vapor Extraction System Data 29 6.5 SITE INSPECTION 30 6.6 INTERVIEWS 30

7.0 TECHNICAL ASSESSMENT 31 7.1 QUESTION A: IS THE REMEDY FUNCTIONING AS INTENDED BY

THE DECISION DOCUMENTS? NO 31 7.1.1 Remedial action performance 31 7.1.2 System operations/operation and maintenance (O&M) 32 7.1.3 Costs of system operations/O&M 32 7.1.4 Implementation of institutional controls and other measures 32 7.1.5 Monitoring activities 32 7.1.6 Opportunities for optimization 32 7.1.7 Early indicators of potential remedy problems 33

7.2 QUESTION B: ARE THE EXPOSURE ASSUMPTIONS, TOXICITY DATA, CLEANUP LEVELS, AND REMEDIAL ACTION OBJECTIVES USED AT THE TIME OF THE REMEDY STILL VALID? NO 337.2.1 Changes in Standards and To Be Considereds 33

7.2.1.1 RCRA ARARs 34 7.2.1.2 Ground Water ARARs 36 7.2.1.3 100-Year Floodplain ARARs 36 7.2.1.4 NPDES ARARs 36 7.2.1.5 ARAR Evaluation Conclusion 36

7.2.2 Changes in Exposure Pathways, Toxicity, and Other ContaminantCharacteristics 37

7.3 QUESTION C: HAS ANY OTHER INFORMATION COME TO LIGHT THAT COULD QUESTION THE PROTECTIVENESS OF THE REMEDY? NO 37

7.4 TECHNICAL ASSESSMENT SUMMARY 37 8.0 ISSUES 38

8.1 DEED RESTRICTIONS DO NOT PROHIBIT RESIDENTIAL USE AND THE INSTALLATION OF DRINKING WATER SUPPLYGROUNDWATER WELLS ON THE BFG/AIRCO SUPERFUND SITES 38

8.2 NO DECREASING TREND IN THE EDC CONCENTRATIONS IN THE SHALLOW GROUNDWATER PLUME 38

8.3 LIMITED EFFECTIVENESS OF SOURCE AREA EXTRACTION WELLS SW-1942 AND SW-1943 39

8.4 UNCERTAINTY REGARDING THE EXTENT OF THE PRINCIPAL EDC CONTAMINANT SOURCE ZONE 39

9.0 RECOMMENDATIONS AND FOLLOW-UP ACTIONS 40 10.0 PROTECTIVENESS STATEMENT 41 11.0 NEXT REVIEW 42 12.0 LIST OF REFERENCES 43

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TABLES Table 1. Chronology of Site Events 2 Table 2. 2002 RFA SWMU/AOC Summary for Units Within or Near the

BFG/AIRCO Superfund Site 9 Table 3. PCAP Extraction Well Network 11 Table 4. Groundwater Monitoring Network 17 Table 5. Remedial Systems Operations and Maintenance Matrix 19 Table 6. Summary of Major Maintenance Activities from 2001 to 2006 20 Table 7. BFG/AIRCO Superfund Site Annual O&M Costs 21 Table 8. ACLs and MCLs for Site Specific Constituents 23 Table 9. Actions Taken Since Last Five-Year Review 24Table 10. Burn Pit SVE System - Liquid and Vapor Samples 30Table 11. Regulatory Review of Promulgated MCLs, MCLGs, or AWQCs for

Site 35 Table 12. Comparison of Current and 1988 BFG/AIRCO RODs ARAR

Values 36 Table 13. Issues 38Table 14. Recommendations and Follow-Up Actions 40

FIGURES Figure 1 General Site Location Map Figure 2 Site Layout and Surrounding PropertiesFigure 3 Location of SWMUs within Barge Slip Area Figure 4 Site Plan and Shallow EDC Plume August 2005 Figure 5 Layout of SVE System Figure 6 SVE Process DiagramFigure 7 Shallow Potentiometric Surface October 1987 Figure 8 Shallow Potentiometric Surface July 2001Figure 9 Shallow Potentiometric Surface July 2002 Figure 10 Shallow Potentiometric Surface July 2003Figure 11 Shallow Potentiometric Surface October 2004 Figure 12 Shallow Potentiometric Surface July 2005 Figure 13 Shallow EDC Plume July 2001 Figure 14 Shallow EDC Plume July 2002Figure 15 Shallow EDC Plume July 2003 Figure 16 Shallow EDC Plume October 2004 Figure 17 Shallow EDC Plume August 2005Figure 18 Pre-Remediation Shallow EDC Plume October 1987Figure 19 Deep EDC Plume July 2001 Figure 20 Deep EDC Plume July 2002 Figure 21 Deep EDC Plume July 2003 Figure 22 Deep EDC Plume October 2004 Figure 23 Deep EDC Plume August 2005Figure 24 >1% Aqueous Solubility of EDC Concentration Map

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Appendix A Site Inspection Photographs

Appendix B Copies of Deed Restrictions

Appendix C Annual Ground water Monitoring Reports 2001 through 2005

Appendix D Public Coordination Documentation

Appendix E 5-Year Review Site Inspection Checklist

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LIST OF ACRONYMS

ACL Alternate Concentration Limit AOC Areas of Concern ARAR Applicable or Relevant and Appropriate Requirements AWQC Ambient Water Quality Criteria BFG BF Goodrich bgs below ground surface BOC Brins Oxygen Corporation (formerly AIRCO) BW barrier well CAW Corrective Action Workplan CCCAT Calvert City Community Advisory Team CERCLA Comprehensive Environmental Response, Compensation, and Liability Act of 1980 cfm cubic feet per minute CFR Code of Federal Regulations CX Center of Expertise cy cubic yards DCA 1,1 dichloroethane DNAPL dense non-aqueous phase liquid DWM Division of Waste Management EDC 1,2 dichloroethane FRP fiberglass reinforced pipe FS Feasibility Study GCL geosynthetic clay liner gpm gallon per minute HOPE high-density polyethylene hp horsepower HSWA Hazardous and Solid Waste Amendment HTRW hazardous, toxic, and radioactive waste ID inner diameter IWS Industrial Well Services, Inc. KDEP Kentucky Department of Environmental Protection kg kilogram KPDES Kentucky Pollution Discharge and Elimination System KRS Kentucky Regulation Statute lb pound MCL maximum contaminant levels MCLG maximum contaminant level goals mg/L milligram per liter msl mean sea-level NCP National Oil & Hazardous Substances Pollution Contingency Plan NPL National Priorities List O&M operation and maintenance ORW outstanding resource water PAH poly-aromatic hydrocarbons PCAP Plantwide Corrective Action Plan

v

LIST OF ACRONYMS (CONTINUED)

PCB polychlorinated biphenyl PCE tetrachloroethene ppm parts per million PR preliminary review PVC polyvinyl chloride PRP potential responsible party RAL remediation action levels RCRA Resource Conservation and Recovery Act RFA RCRA Facility Assessment RI Remedial Investigation ROD Record of Decision rpm revolution per minuteSARA Superfund Amendments & Reauthorization Act SCME Sitewide Corrective Measure Evaluation SVE soil vapor extraction SW source well SWMU Solid Waste Management Unit TCA trichloroethane TCE 1,1,2 trichloroethene TCL Target Compound List TAL Target Analyte List TVOC total volatile organic compounds USACE United States Army Corps of Engineers USC United States Code USEPA United States Environmental Protection Agency µg microgram VCM vinyl chloride monomer VOC volatile organic compound VSI visual site inspection

vi

EXECUTIVE SUMMARY

The second five-year review of the BF Goodrich/AIRCO Superfund Site in Calvert City, Kentucky, wasinitiated April 25, 2006 with a joint site visit by representatives from the US Army Corps of Engineers,Kentucky Department of Environmental Protection, BF Goodrich, URS, and the US EnvironmentalProtection Agency. The site as referenced actually represents two adjacent NPL sites, the BF Goodrich NPLSite and the AIRCO NPL Site. The BF Goodrich Site is located approximately 2 miles northeast of CalvertCity and lies on the southern bank of the Tennessee River. The BF Goodrich Site consists of a 2.0 acrelandfill and a former burn pit area. The AIRCO NPL Site borders the BF Goodrich Site on the east andconsists of a 2.75 acre landfill. Because of the proximity and common history of use, these two sites havehistorically been studied together and have undergone a combined cleanup.

The remedy as outlined in the 1988 ROD includes: groundwater monitoring, deed restrictions preventingresidential development and the installation of drinking water supply groundwater wells, flood protectiondike around the landfills, upgraded landfill clay caps, groundwater plume extraction and abovegroundtreatment, excavation of surface soil and disposal in the Burn Pit Area, RCRA cover (engineered cap) forthe Burn Pit Area, and soil vapor extraction at the Burn Pit Area. The primary contaminant is1,2-dichloroethane (EDC) and groundwater cleanup goals are established for twelve indicator chemicals.

On July 9, 2001, the first five-year review of the BFG/AIRCO Superfund Site was completed. The five-yearreview report indicated that the remedy had been implemented in accordance with the decision documents,and that the contamination was being addressed in a manner that was protective of human health and theenvironment. The following deficiencies were identified during the first five-year review: lack of DailyHealth and Safety Meeting Logs, Applicable or Relevant and Appropriate Requirements (ARAR) valueschanged for EDC, carbon tetrachloride, benzene, and trichloroethane, and limited effectiveness of remedialactions to address groundwater contaminant movement from within or beneath source areas. Thesedeficiencies were not considered significant enough to impact the protectiveness of the remedial operationas long as corrective actions were taken. In response to these deficiencies the following corrective actionswere taken: the Daily Health and Safety Meeting Log requirement removed from Health and Safety Planon 16 July 2001, new ACLs were implemented for groundwater monitoring and reporting on 16 July 2001,and the soil vapor extraction system (SVE) at the Burn Pit Area was expanded. The SVE system expansionincluded the installation of ten dual-phase extraction wells, the installation of sipper tubes within extractionwells BP-18 through BP-23, and the installation of sipper tubes within the 13 existing SVE wells (BP-1through BP-13). Predesign of the expanded SVE system was complete by December 2001 and the systemstartup occurred on 6 January 2003.

Results of the second five-year review indicate the remedy is currently protective of human health and theenvironment in the short term. However, follow-up actions needed to address long-term protectiveness arerecommended for the following items: deed restrictions do not prohibit residential use and the installationof drinking water supply groundwater wells on the BF Goodrich/AIRCO Superfund Sites; groundwatercleanup goals have not been achieved in the anticipated time frame, no decreasing EDC concentration trendin the shallow groundwater plume, limited effectiveness of the source area groundwater extraction wells,and uncertainty regarding the extent of the principal EDC contaminant source zone.

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EPA Five-Year Review Signature CoverPreliminary Information

SITE IDENTIFICATION

Site name: BF Goodrich Landfill

AIRCO Landfill

Region: 04 State: Kentucky

EPA ID: KYD006370167

KYD041981010

City/County: Calvert City / Marshall County

SITE STATUS

NPL status: C~~FinaT^>Deleted Other (specify)" ""

Remediation Status (choose all that apply): Under Construction (Operating} Complete

Multiple OUs? YESCNCD

LIRA* (highlight): Y N

Fund/PRP Lead: PRP

Construction completion date:

BF Goodrich: September 29, 1997

AIRCO: September 27, 1997

Has Site been put into reuse? YES C_NO^)

REVIEW STATUS

Lead agency: (jLP\) State Tribe Other Federal /^aencv

Author Name: Douglas Buchanan PG, Robert Miles Jr EFT

Author Title: Geologist , Chemical Engineer

Author Affiliation: US Army Corps of Engineers, Louisville District

Review Period: 02/07/06 To: 07/16/06 Date(s) of site visit: 04/25/06

Type of Review: Cjost-SARj) Pre-SARA NPL-Removal Only

Non-NPL Remedial Action Site NPL State/Tribe LeadRegional Discretion

Review Number: 1 (first)

Issues:

Issues identified that currently prevent the response action from being considered protective in the long-termor are indicators of potential remedy problems include:

• Deed restrictions do not prohibit residential use and the installation of drinking water supplygroundwater wells on the BFG/AIRCO Superfund Sites

• Groundwater cleanup goals have not been achieved in the anticipated time frame

• No decreasing trend in the EDC concentrations in the shallow groundwater plume

• Limited effectiveness of the source area extraction wells SW-1942 and SW-1943

• Uncertainty regarding the extent of the principal EDC contaminant source zone

Recommendations:

A remedial optimization study is recommended to address the items listed in the above section as "issues."In support of the optimization study, it is also recommended that a source zone confirmation study beconducted to address the uncertainty associated with the extent of the EDC source zone at the BFG/AIRCOSuperfund Site.

The above recommendations are made to ensure the long-term protectiveness of the remedy.

Protectiveness Statement(s):

The remedy is considered protective of human health and the environment in the short-term. However,follow-up actions are needed to address the issues identified above that prevent the response action frombeing considered protective in the long-term.

Other Comments:

As stated within the RODs, overall implementation of the recommended alternative was estimated to taketen years following the design and contract award. The time required to address the landfills, surface soils,and subsurface soils was estimated to be approximately one year. Ground water extraction and treatmentwould continue until the groundwater remediation achieves the clean-up goals. The estimated time for theseclean-up goals to be met was ten years after the initiation of the extraction and treatment system, whichoccurred in 1992. Based upon this timeframe, the anticipated date for achieving the groundwater cleanupgoals was 2002.

The total O&M cost for the remedy since implemented is currently $1.395 million greater than the originalestimate included in the ROD. Because current levels of groundwater contamination (1000 mg/L EDC) donot appear to be declining and remain more than three orders of magnitude above cleanup goals (0.64mg/L), cumulative O&M costs associated with the existing site remedy are predicted to continueindefinitely.

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BF Goodrich/AIRCO Superfund Site EPA ID: KYD006370167 / KYD041981010

SUPERFUND SECOND FIVE-YEAR REVIEW REPORT

1.0 INTRODUCTION AND PURPOSE

1.1 GENERAL

The present document delivers findings from the second five-year review for the BF Goodrich (BFG)/AIRCO Superfund Site (Site) in Calvert City, Kentucky. During April and May 2006, the U.S. Army Corpsof Engineers (USACE), Louisville District, on behalf of the U.S. Environmental Protection Agency(USEPA), Region 4, conducted a review of the remedy implemented at the BFG/AIRCO Superfund Site,Marshall County, Kentucky. This report documents the results of that review. The purpose of five-yearreviews is to determine whether the remedial actions are or will be protective of human health and theenvironment. The methods, findings, and conclusions of reviews are documented in five-year reviewreports. In addition, any deficiencies identified during the review will be presented, along withrecommendations to address them. This five-year review follows guidance issued by USEPA 540-R-01-007,June 2001.

1.2 AUTHORITY

This review is required by statute. Section 300.430(f)(4)(ii) of the National Oil and Hazardous SubstancesPollution Contingency Plan (NCP), 40 Code of Federal Regulations (CFR) Part 300, implements Section121(c) of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980(CERCLA), 42 United States Code (USC) 9601 et seq., as amended by the Superfund Amendments andReauthorization Act of 1986 (SARA). The statute requires five-year reviews "if a remedial action is selectedthat results in hazardous substances, pollutants, or contaminants remaining at the site above levels that allowfor unlimited use and unrestricted exposure." The five-year review requirement in the NCP applies only toRecords of Decisions (RODs) adopted after SARA (i.e. after October 16, 1986). Such reviews are referredto as "statutory reviews". Statutory reviews must continue at least every five years until contaminant levelsallow for unlimited use and unrestricted exposure.

1.3 LOCAL REPOSITORY

This review will be placed in the site files and local repository. The repository is located at the MarshallCounty Public Library, Calvert City Branch, 1315 Fifth Avenue, Calvert City, Kentucky 42029(270.395.5745).

Note: Throughout this report, text has been extracted, summarized, and/or edited from the following BFG/AIRCO Site documents: EPA Record of Decision (RODs) dated June 24, 1988 and the RODs abstract(http://www.epa.gov/superfund/sites/sitedocs.htm), Groundwater Collection & Treatment System (Revision2), BF Goodrich/AIRCO Site dated August 10, 1995, 5-Year Review, BF Goodrich/AIRCO Superfund Sitedated July 9, 2001, RCRA Facility Assessment of BF Goodrich Company dated March 19, 2002, andRemediation System Expansion Construction Completion Report, BF Goodrich/AIRCO Superfund Sitedated March 18, 2003.

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2.0 SITE CHRONOLOGY

A chronology of the major events for the BFG/AIRCO Superfund Site is summarized in Table 1.

Table 1. Chronology of Site Events Event Date

BFG plant operations begin. 1953

AIRCO Landfill activities begin 1956

BFG leases portion of AIRCO Landfill and BFG landfill/burning activities begin 1962

BFG purchases leased portion of land from AIRCO 1964

AIRCO Landfill leased to Air Products and Chemicals Inc. 1971

BFG Landfill closed with a clay cap and vegetative cover 1980

Site Investigation initiated by Kentucky Department of Environmental Protection 1980

AIRCO Landfill closed with a clay cap and vegetative cover 1981

BFG Landfill listed on National Priorities List 1983

AIRCO Landfill listed on National Priorities List 1984

Remedial Investigation/Feasibility Study of BFG/AIRCO Superfund Site completed 1988

Records of Decisions signed for BFG/AIRCO Superfund Site 1988

Six groundwater extraction wells (four barrier wells and two source wells) installed 1991

Consent Decree between USEPA, BFG, and the BOC Group (formerly AIRCO) signed 1992

Remedial Design/Remedial Action Workplan approved by USEPA 1992

Excavation /consolidation of surface soil and drainage ditch sediment into Burn Pit Area 1996

RCRA cover system installed over Burn Pit Area 1996

Clay and vegetative cover system replaced over BFG and AIRCO Landfills 1996

Installation of soil vapor extraction system in Burn Pit Area (13 Wells) 1996

Installation of leachate extraction system (six sumps) in BFG/AIRCO Landfills 1996

Construction of flood protection dike completed 1996

Leachate redirected to steam stripper owned by BFG and operated by Westlake Monomers 1997

Vapor from soil vapor extraction system redirected to steam-stripper operated by Westlake 1998

First Five-Year Review of BFG/AIRCO Superfund Site completed 2001

Groundwater extraction well (BW-1954) installed and activated 2001

Ten dual-phase extraction wells installed west and north of Burn Pit Area 2002

Existing Burn Pit SVE wells (13 wells) modified for dual phase extraction 20022

3.0 SITE DESCRIPTION AND BACKGROUND

3.1 GENERAL SETTING AND LAND USE

The Site is actually two adjacent Superfund sites, the 2.0-acre BFG Landfill and the 2.75-acre AIRCOLandfill. The BFG and AIRCO sites were named on the National Priorities List (NPL) in 1983 and 1984,respectively. The Site contains two landfills, one flood protection dike, and a former burning and burial areareferred to as the Burn Pit Area. Structures within the Site include a equipment shed, office trailer, threemaintenance storage buildings, and one covered Resource Conservation and Recovery Act (RCRA)hazardous and non-hazardous waste storage area. The BFG and AIRCO Landfills are studied as one entitybecause they are adjacent and share a somewhat common history of use.

The BFG/AIRCO site is located in Marshall County, Kentucky, approximately 1.5 miles northeast ofCalvert City, Kentucky near the southern bank of the Tennessee River (Figure 1). The Site is believed tooccupy a former creek channel. This former channel (now a slough) forms an approximate boundarybetween the floodplain of the Tennessee River and an alluvial terrace. As such, the landfills are located onthe floodplain and the Burn Pit Area is located on the terrace. The Site is bordered on the north by deciduoustrees and then by the Tennessee River. Located east and adjacent to the AIRCO Landfill is a slough anddeciduous forest. Open cropland, owned by Westlake Monomers, is located east and adjacent to the BurnPit Area. South of the Site is property owned by Westlake Monomers, State Route 1523, and thenagricultural cropland. The Site is bordered to the west by the Westlake Monomers Calvert City Plant, whichwas formerly owned and operated by BFG (Figure 2). Land use at the Site and surrounding properties hasnot changed since implementation of the RODs.

3.2 NATURAL PHYSICAL SETTING

The Site is located within the Jackson Purchase Area of Kentucky, as defined by the boundaries of the Ohio,Tennessee, and Mississippi Rivers. The Purchase area forms a distinct physiographic province characterizedby gently rolling uplands and wide shallow valleys of low relief. The geographic coordinates of the Site are37/ 02' 59" N latitude and 88/ 19' 23" W longitude. The normal pool elevation of the Tennessee River is 302feet above mean sea level (msl) and the active floodplain reaches approximately 320 feet above msl. Theriver bank rises abruptly at the edge of the active floodplain to the terrace level, which is typically greaterthan 340 feet above msl. The 100-year floodplain elevation is approximately 344.10 feet above msl. Theformer Burn Pit Area is located on the terrace area at an elevation of approximately 345 feet above msl.Surface water drainage follows the topographic features at the Site. There is a man-made drainage ditch thatdiverts a majority of surface water from the former Burn Pit Area north to the BFG/AIRCO Landfills, wherethe surface water is then directed east and into the slough via a culvert and 24-inch corrugated metal pipeconstructed under the flood protection dike. Appendix A provides photographic views of the Site.

3.3 AFFECTED POPULATION

The BFG/AIRCO site is located within the industrialized area of Calvert City, Kentucky which includesseveral major chemical and industrial plants that were developed in the 1950s. Human population withinCalvert City is estimated as 2,701 based upon the 2000 US Census demographic profile. The majority ofthe population within Calvert City is located south of Calvert City Road and 5th Avenue, which are locatedapproximately 2.5 miles south of the BFG/AIRCO site. According to the 2000 US Census data (Census

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Blocks 4009 and 4010, Block Group 4, Tract 402), human population across the Tennessee River and southof State Highway 453 (approximately 2.5 miles north of Site) within the southern portion of LivingstonCounty is estimated as 104.

The Site is currently fenced and the contaminated soils and sediments are contained within the fenced areaunder a low-permeability cap. Human resources near the Site include the Tennessee River and the CalvertCity Water Works wellfield. Ecological resources near the Site also include the Tennessee River. Inestablishing cleanup requirements for the Site, the USEPA considered the theoretical possibility ofresidential development within the immediate vicinity of the Site. However, residential development nearthe Site is unlikely due to the heavy industry zoning classification of the area encompassing the Calvert CityIndustrial Complex along State Route 1523.

The Tennessee River is generally classified for use as domestic water supply, primary and secondaryrecreation, warm water aquatic habitat, and navigation. From Tennessee River Mile 13, below the lastindustrial discharge in Calvert City to the Kentucky Dam (River Mile 22.4), the Tennessee River isclassified as Outstanding Resource Water (ORW) due to the discovery of endangered species of TennesseeRiver mussels. Warm water aquatic habitat criteria are to be maintained for this segment of the TennesseeRiver.

The Calvert City Water Works provides drinking water supply service to approximately 2,500 customerswithin an approximate five-mile radius. The city obtains its water from a wellfield located upgradient,approximately 1.5 miles southwest, from the BFG/AIRCO site near the Calvert City Country Club. Themaximum production capacity for the system is 1,440,000 gallons per day.

3.4 BFG/AIRCO SITE OPERATIONS HISTORY

The following operations history of the Site is a compilation of information taken from the 2001 5-YearReview BFG/AIRCO Superfund Site Report, 2002 RCRA Facility Assessment Report, and 2003Remediation System Expansion Construction Completion Report.

In 1956, AIRCO began disposing of industrial waste in the landfill now known as the AIRCO LandfillSuperfund Site. In 1962, a portion of the AIRCO Landfill was leased to BFG for waste disposal at the Site.In July 1964, BFG purchased the leased landfill property now known as the BFG Landfill Superfund Site.The size of the BFG and AIRCO Landfills were approximately 2.0 and 2.75 acres, respectively. The depthof the landfill ranged from six to eight feet below ground surface (bgs).

The AIRCO Landfill was used to dispose of waste material from the AIRCO Calvert City Plant. Anestimated total of 18,000 tons of caustics, acids, volatile organic compounds (VOCs), zinc, mercuric acetate,and mercuric chloride were alleged to have been disposed in the AIRCO Landfill. In October 1968, AIRCOwas granted a Solid Waste Disposal Operation Permit by Kentucky Department of Environmental Protection(KDEP)-Division of Waste Management (DWM). In 1971 AIRCO sold its Calvert City Chemical Divisionto Air Products and Chemicals Inc (Air Products) and signed an "Omnibus Easement Agreement" allowingAir Products to lease the AIRCO Landfill. When the AIRCO Landfill was leased by Air Products in 1971,KDEP-DWM issued a renewal permit for Air Products to operate the landfill. From 1971 to 1980, AirProducts used the landfill to dispose of approximately 14,000 tons (dry basis) of ashes from coal operatedboilers, off-grade polyvinyl chloride (PVC) solids, inert ferric hydroxide sludge from the waste water

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treatment plant, and a small amount of non-combustible construction waste. The KDEP-DWM landfilloperating permit was cancelled in 1980 when Air Products discontinued use of the AIRCO Landfill. AirProducts submitted a closure plan to KDEP-DWM for capping the landfill. The plan was approved byKDEP-DWM in October 1980 and the AIRCO Landfill was closed with a clay cap and vegetative cover inSeptember 1981.

Wastes were both buried and burned in the BFG Landfill. According to BFG, from an unspecified date until1971, approximately 41 tons per month of solid waste and 3,670 gallons per month of organic liquids weretransported to the unlined BFG Landfill and Burn Pit Area. Solid wastes were disposed of in the landfill,while liquid wastes were burned in open pits. A total of 54,500 tons of "inert and construction-type wastes"were disposed of in the landfill by BFG. Between 1963 and 1968, approximately 2.6 million gallons ofchlorinated hydrocarbons were buried in disposal site trenches. In August 1968, BFG submitted anapplication to KDEP-DWM for a Solid Waste Disposal Operation Permit. Operation of the BFG Landfillcontinued under the permit until 1973 when industrial waste disposal at the landfill was curtailed. Between1973 and 1980, BFG personnel claim that the landfill received only excavation dirt and construction rubble.KDEP-DWM approved the closure plan submitted by BFG and the landfill was closed with a three-footthick clay cap and vegetative cover in 1980. From 1970 to 1983, scrap lumber and fuel oil were burned inthe Burn Pit Area two to three times a year for fire-fighting training. In 1983 and 1984 the BFG and AIRCOLandfills were listed on the NPL of hazardous waste sites, respectively.

In the late 1960s, an unknown amount of oil/water separator sludge from the BFG ethylene processing areawas disposed of within an area, identified as Landfill 4 (Ethylene Plant Oily Sludge Landfill), located southof the Burn Pit Area. Approximately 370 cubic yards (cy) of mercury brine waste was also disposed of inan area, identified as the Brine Sludge Burial Area, located south and adjacent to the Burn Pit Area duringa one-time disposal event in 1972. Figure 2 provides the locations of the sludge disposal area, Burn Pit Area,and BFG/AIRCO Landfills.

Waste disposal activities were also conducted within three other units located west of the BFG Landfillwithin an area identified as the Barge Slip Area (Figure 3). An unlined half-acre disposal unit, known asLandfill L-3 and identified as Solid Waste Management Unit (SWMU) 3, was operated between 1962 and1965. The following wastes were disposed and/or burned at Landfill 3: 3,368 cy of chlorinated organics,1,727 cy of plant refuse, 403 cy of catalysts tubes, and 2,307 cy of non-chlorinated organics. In 1966,material within this landfill was bulldozed to the BFG Landfill. The unit is now covered with gravel andused for vehicle parking.

An unlined 1.7-acre disposal unit, known as the Inert Material Landfill Salt Dock and identified as SWMU6, located within the Barge Slip Area was used to dispose of soil from excavations at various locationsthroughout the BFG plant from 1981 to 1991. Two concrete lined drainage routes (identified as SWMU123), one running north-south and the other running east-west, were constructed to serve as a compactedfill dike between the Inert Material Landfill Salt Dock and the Tennessee River in order to prevent flow ofleachate and erosion of the fill cover from the Inert Material Landfill Salt Dock. By 1995, two 140 by 40foot concrete pads had been installed on the landfill and used to station roll-off boxes containing hazardous(low concentrations of EDC and benzene) and non-hazardous filter cake generated from the BFG plantwaste water treatment system.

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An unlined 1.7-acre disposal unit, known as Inert Material Landfill Beside CERCLA Site Landfill L-7 andidentified as SWMU 140, located within the Barge Slip Area was used to dispose of approximately 20,000cy of reportedly inert materials consisting of soils excavated from various locations within the BFG plantfrom 1982 to 1984. Soils disposed of within this unit included material excavated during the digging of afire water pond located approximately 600 feet south of Landfill 3. In 1984, SWMU 140 was graded leveland operations at the unit ceased.

3.5 BFG/AIRCO SUPERFUND SITE INVESTIGATIONS

On January 25, 1980, KDEP requested that BFG provide the agency with a list of all industrial waste(including chemical composition and quantity) that was disposed of in BFG Landfill. On June 3, 1980,KDEP noted a leaching problem at the BFG Landfill during a site inspection. The leachate was lateridentified as coke solids, dichlorobutene, and naphthalene.

On November 12, 1985, USEPA, BFG, and Erin's Oxygen Company (BOC) Group, formerly AIRCO,entered into an Administrative Order on Consent. The order directed BFG and BOC Group to conduct aRemedial Investigation and Feasibility Study (RI/FS) at the combined BFG and AIRCO Landfill site.Investigative activities conducted for the RI included: installation of permanent groundwater monitoringwells; sampling of soils, groundwater, sediments and surface water; examining the integrity of the existinglandfill caps; and sampling the Calvert City groundwater well field. According to the 1988 RI Report, theresults indicated that organic subsurface soil contamination existed in the former Burn Pit Area; organicsurface soil contamination existed around portions of the landfill perimeters; and a groundwatercontamination plume, containing a number of organic compounds, existed downgradient of the Burn PitArea. The final indicator chemical list included 1,2 dichloroethane (EDC), carbon tetrachloride, chloroform,benzene, 1,1,2-trichloroethane (TCA), polynuclear aromatic hydrocarbons (PAHs), tetrachloroethene (PCE),1,1,2,2-tetrachloroethane, trichloroethene (TCE), chlorobenzene, 1,1-dichloroethane (DCA), bis(2-chloroethyl) ether, and polychlorinated biphenyls (PCBs) (in soil sediment only). Surface water andsediment did not appear to be impacted by the landfills. None of the contamination appeared to be migratingoff-site, and the Calvert City well field was not found to be impacted. The preferred remedial alternativewithin the FS included the extraction and treatment of contaminated groundwater, the installation of sumpsin the landfills to extract leachate, excavation of contaminated surface soils and subsequent placement inthe Burn Pit Area, construction of a landfill cover and organic vapor recovery system over the Burn PitArea, construction of a flood protection dike around the west and north side of the landfills, installation ofa leachate extraction system, and upgrading the existing landfill clay caps.

A RCRA Facility Assessment: (RFA) was conducted in 1987 for the entire BFG plant, including the BFG/AIRCO Superfund Site. A total of 119 SWMUs and no Areas of Concern (AOCs) were identified withinthe BFG plant. Between 1987 and 2001, the facility added SWMUs 120 through 196 to the list, although19 of these SWMUs were simply "Reserved" by the facility. In 2002 an additional RFA was conducted forthe entire Westlake Monomers Plant (formerly BFG plant), including the BFG/AIRCO Superfund Site.Based upon a Preliminary Review (PR) of USEPA Region 4 and KDEP files and a Visual Site Inspection(VSI) conducted in 2001, SWMUs 197 through 222 and AOCs A through M were identified within the 2002RFA.

SWMUs identified within the BFG/AIRCO Superfund Site include: SWMU 125 (BFG Landfill), SWMU126 (Burn Pit Area), SWMU 127 (Brine Sludge Burial Area Next to Burn Pit Area), and SWMU 185

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(Superfund Site Leachate Tank). Three SWMUs were also identified within the Barge Slip Area locatedwest of the BFG Landfill. Units within the Barge Slip Area include: SWMU 3 (Landfill L-3), SWMU 6(Landfill L-10 or Inert Material Landfill Salt Dock), and SWMU 140 (Inert Material Landfill BesideCERCLA Site Landfill L-7).

According to the 2002 RFA, contamination of underlying soils and groundwater at SWMUs 3 and 6 havebeen documented, but the releases were not distinguishable from other sources of contamination includingthe BFG/AIRCO Superfund Site. Significant concentrations of EDC are present in the capillary fringe,upper saturated soils, and upper aquifer in the Barge Slip Area. A SVE/air sparging system (SWMU 219)has been installed in this area to address subsurface contamination between the ground surface and the watertable. However, final installation/operation of the system has been delayed due to ownership changes (fromBFG to Westlake) at the plant and disagreements over the use of emission control equipment (owned byWestlake) necessary to control extracted vapors from the SVE/air sparging system. The 2002 RFArecommended a RCRA Facility Investigation (RFI) for SWMUs 3 and 6. Groundwater contamination wasalso identified at SWMU 140 within the CERCLA ground water monitoring wells GW-31 thought GW-36.Since SWMUs 123 through 128 were believed to be the source of this contamination, the 2002 RFA did notrecommend a RFI for SWMU 140. The 2002 RFA findings for the SWMUs identified within or near theBFG/AIRCO Superfund Site are provided within Table 2. The locations of these SMWUs are providedwithin Figures 2 and 3.

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Table 2. 2002 RFA SWMU/AOC Summary for Units Within or Near the BFG/AIUCO Superfund Site

SWMU/AOC3. Landfill

L-3

6. LandfillL-10

125. BFGLandfill

126. BurnPit Area

127. Brine SludgeBurial Area Nextto Burn Pit Area

140. Inert MaterialLandfill BesideCERCLA Site L-7

185. Superfund SiteLeachate TransferTank

Typeof UnitOpenBurnArea /LandfillLandfill

Landfill

Landfill

Landfill

Landfill

Landfill

Period ofOperation1962 to1965

1981 to1991

1965 to1980

1965 to1968

1972

1981 to1984

Unknownto Present

Wastes ManagedThe unit managed chlorinated organics, plantrefuse, catalyst tubes, and non-chlorinated organics

The unit managed soil potentially contaminatedwith hazardous constituents from various soilexcavation locations around plantThe uni t managed construction debris, plant trash,excavated dirt, chlorinated organics, catalyst tubes,and non-chlorinated organics from and throughoutthe facility.The unit managed liquid chlorinated organics, scraplumber and fuel oil from various on-site processareasThe unit managed mercury contaminated brinesludge from the Chlorine Plant

The unit managed inert material consisting of soilsfrom excavations from various plant locations

The unit manages leachate from the BFG Landfill,vapors and contaminated groundwater from theSuperfund Site (SWMUs 125, 126, 127).

PollutionMigrationPathways1

A, SWSSGW, S

A, SWGW, SS, S

A, SWSSGW, S

A, SWSS, GW, S

A, SWSSGW, SA, SW, SSGW, S

A, SW,SS, GW, S

ExposurePotential2

LMH

LM

LMH

LH

LMHL

L

EvidenceofRelease3

Yes

Yes

Yes

Yes

Yes

No

No

SuggestedFurtherActionRF1

RFI

CERCLA

CERCLA

CERCLA

NoFurtherAction

NoFurtherAction

1. For Pollution Migration Pathways; 'A' designates Air; 'GW designates Ground Water; 'S' designates Soil; 'SS' designates Surface Gas; and 'SWdesignates Surface Water2. For Exposure Potential; 'H' designates High; 'M' designates Moderate; 'L' designates Low; and 'IT designates Unknown exposure potential3. Evidence of Releases is defined as visual signs of contamination; analytical documentation of a release; discharge permit violations; facility representativestatements; or file material which indicates a release.

4.0 REMEDIAL ACTIONS

4.1 REMEDY SELECTION

On June 24, 1988, the USEPA issued a Record of Decision (ROD) for the BFG Superfund Site and AIRCOSuperfund Site selecting the preferred remedy described within the FS for the BFG/AIRCO Site. The RODsalso established the following groundwater alternative concentration limits (ACLs): 8.5 milligram per liter(mg/L) EDC, 8.5 mg/L carbon tetrachloride, 0.32 mg/L chloroform, 8.5 mg/L benzene, 8.5 mg/Lfluoroethane, 8.5 mg/L acenaphthene, 1.0 mg/L 1,1,2-TCA, 1.5 mg/L PCE, 0.29 mg/L1,1,2,2-tetrachloroethane, 8.5 mg/L TCE, 8.5 mg/L chlorobenzene, 8.5 mg/L DCA, and 0.051 mg/Lbis(2-chloroethyl) ether.

As stated within the RODs, the purpose of remedial action at the BFG/AIRCO Superfund Site is to mitigateand minimize potential risks to public health, welfare, and the environment posed by site soils, sediments,and ground water contamination. The following cleanup objectives were determined based on regulatoryrequirements and levels of contamination found at the Site:

• Contain the on-site contaminated ground water plume by extraction and treatment

• Eliminate leachate production in the Burn Pit Area

• Bring the landfills into compliance with Kentucky statutes regarding structures on a 100-yearfloodplain

• Protect the public and environment from exposure to on-site contaminated soils and sediments

An initial screening of applicable technologies was performed to identify those which best meet the criteriaof Section 300.68 of the NCP. Following the initial screening technologies, nine potential remedial actionalternatives were identified and analyzed. Alternative No. Three was selected by the USEPA, as stated inthe June 24, 1988 RODs, as the recommended alternative and contains the following components:

• Ground water monitoring • Impose deed restrictions preventing residential development and ground water use • Construct flood protection dike around landfills • Upgrade landfill clay caps • Install leachate extraction system in landfills and Burn Pit Area • Pump contaminated ground water plume and treat by air stripping • Excavate surface soils and place in Burn Pit Area • Install organic vapor recovery system in Burn Pit Area and cover with a RCRA cap • Secure entire Site

As stated within the RODs, overall implementation of the recommended alternative was estimated to taketen years following the design and contract award. The time required to address the landfills, surface soils,and subsurface soils was estimated to be approximately one year. Ground water extraction and treatmentwould continue until the groundwater achieves the clean-up goals. The estimated time for these clean-upgoals to be met would be ten years after the initiation of the extraction and treatment system. The estimated

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present worth cost (1988 dollars) of the project was $6.09 million. The estimated capital cost (1988 dollars)was $2.96 million and the total O&M costs were estimated to be $3.13 million (1988 dollars).

On June 29, 1992, the Consent Decree between the USEPA, BFG, and the BOC Group was finalized, afterbeing changed slightly to allow KDEP "sufficient participation in the remainder of the cleanup process."On October 27, 1995, BFG submitted the Final Design for Remedial Action Activities at the BFG/AIRCOSuperfund Site. The activities described in the document incorporated the components of the remedydescribed in the June 24, 1988 RODs for the Site and the June 29, 1992 Consent Decree. It also reflectedthe applicable requirements of the Remedial Design/Remedial Action Work Plan approved by the USEPAon November 10, 1992. The following remedial action activities were proposed and implemented betweenMay 1996 and June 1997, with the final inspection being conducted on June 4, 1997.

Attachment I of the Consent Decree further refined the selected remedy to include the following:

• Provide geologic assurance that the flood protection dike would adequately protect the landfills.

• If necessary, installation of leachate sumps as part of remedial design activities and attempt tocorrelate water levels within the leachate sumps and monitoring wells with the Tennessee Rivestage.

• Expand soil remediation activities to include removal of surface soils exceeding soil remediationaction levels (RALs) to be established for specific indicator parameters.

• Provide assurances that groundwater flow into the landfills shall be minimized such that releasesfrom the landfill, if any, shall not result in a statistically significant increase in site-relatedcontaminants to the Tennessee River upon attainment of groundwater clean-up goals as defined inthe RODs.

• Provide assurances that the flood protection dike, as set forth in the RODs, meets the design andperformance requirements of Kentucky Regulation Statute (KRS) 151 for construction within a100-year floodplain.

• Provide assurances that the flood protection dike shall be able to maintain structural integritythrough repeated flood events.

In 1990 and 1991, BFG investigated groundwater contamination for the entire BFG plant, including theBFG/AIRCO Superfund Site, and presented the results in the Remedial Environmental Investigation Reportdated October 29, 1991. Between June 1990 and March 1991, BFG installed 93 groundwater monitoringwells to delineate the vertical and horizontal extent of groundwater contamination and flow patterns beneaththe plant property and adjoining properties. EDC and benzene were used as indicator parameters forgroundwater contamination because the two constituents were generally present in the highestconcentrations, covered the most aerially extensive areas, and each was associated with specific practicesin specific areas of the facility. The investigation confirmed a site-wide groundwater contamination plumeand discharge of contaminated groundwater to the Tennessee River. Limited soil sampling was also conducted, but results were not correlated within individual SWMUs. Elevated concentrations of mercury,EDC , 1,1,2-TCA, chloroform, chlorodibromomethane, and PCB 1248 were detected in soils on the plantproperty.

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On January 21, 1992, BFG submitted a Sitewide Corrective Measures Evaluation (SCME), including theBFG/AIRCO Superfund Site, for groundwater which served as a follow-up to the Remedial EnvironmentalInvestigation Groundwater Assessment. In the SCME, various remedial technologies were evaluated andassembled into corrective measures alternatives. The SCME recommended that groundwater contaminationat the BFG plant be addressed through the following corrective measures:

• Hydraulic barrier to Tennessee River • Hydraulic control and extraction of off-site plume • Extraction and treatment of groundwater contamination from on-site source areas • Augmentation of on-site treatment capacity to treat extracted groundwater

In September 1992, BFG submitted a draft Corrective Action Workplan (CAW) which detailed the design,implementation, and monitoring of the Plantwide Corrective Action Program (PCAP). The PCAP iscomprised of three networks of groundwater extraction wells and subsequent on-site treatment of theextracted groundwater by steam stripping. The PCAP was developed to meet the requirements of thefacility's RCRA hazardous waste permit and Hazardous and Soil Waste Amendment (HSWA) permit. Aportion of the PCAP for the BFG/AIRCO Superfund Site also addresses the groundwater remediationrequirements set forth in the RODs for the Site. The well networks are distinguished by the performancegoals they serve, as provided within Table 3.

Table 3. PCAP Extraction Well Network Well Network Performance Goal

Tennessee River Barrier Wells Prevent discharge of contaminated groundwater above RCRAACLs to the Tennessee River.

Source Remediation Wells Restore on-site groundwater quality and prevent future releasesfrom SWMUs and process areas.

Off-site Remediation Wells Prevent further off-site migration of contaminated groundwaterand restore off-site groundwater to Maximum Contaminant Level

4.2 REMEDY IMPLEMENTATION

Implementation of the recommended alternative involved imposing deed restrictions preventing residentialdevelopment and groundwater use, construction of the flood protection dike, construction of landfill coverimprovement, installation of the leachate extraction system, groundwater extraction system, consolidationof surface soil and drainage ditch sediment, installation of vapor recovery system, construction of a RCRAcover system over the Burn Pit Area, installation of site fencing, and groundwater monitoring. Theseactivities are described in the following sections.

4.2.1 Impose Deed Restrictions Preventing Residential Development and Groundwater Use

Notices of deed restrictions for the BFG and AIRCO Superfund Sites were certified by the Marshall CountyClerk for the BFG Superfund Site and for the AIRCO Superfund Site on 20 January 1999 and 28 January2000, respectively. The notices of deed restrictions for both the BFG and AIRCO Superfund Sites areprovided in Appendix B. Both notices of deed restrictions included the following terms:

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• The Site contains hazardous substances as defined by the Comprehensive Environmental Response,Compensation, and Liability Act of 1980, 42 U.S.C § 9601.

• The owner, its successors and assigns, and all future owners hereby covenant that the site will notbe used in any manner that would disturb the integrity of the final cover, the integrity of thecontainment or treatment system, or the function of any monitoring system on the Site, unless theEnvironmental Protection Agency Regional Administrator determines that the disturbance is (a)necessary to the proposed use of the property and will not increase the potential hazard to humanhealth or the environment, or (b) is necessary to reduce a threat to human health or the environment.

• The owner hereby grants permission to the Plaintiff, United States of America, EPA and the"Settling Parties" (as identified in the Consent Decree) and their respective authorizedrepresentatives to enter upon the Site for puiposes of effectuating and monitoring all terms of thesaid Consent Decree; performing any work required under the Consent Decree and the Record ofDecision (or "ROD", as identified in said Consent Decree); and performing the Operation andMaintenance Activities (or O&M "Activities" as defined in said Consent Decree). The owner agrees,and transferees agree, not to interfere with or disturb the Plaintiffs, EPA or the Settling Parties'performance of any work pursuant to the Consent Decree and said O&M Activities, and owner andany transferee will inform any person or entity that acquires any title, ownership, leasehold,easement, or other interest in said Site, or any portion thereof, appurtenances thereto, of theexistence of said Consent Decree and of the requirements, conditions, and operative effect ofParagraph VI.F of the Consent Decree.

• The restrictions and covenants set forth above shall run with the land and shall be binding upon theowner and any and all persons, corporations or entities and their successors and assigns who nowor may hereafter acquire any title, ownership, leasehold, easement, or other interest in the Site or anyportion thereof.

4.2.2 Construction of Flood Protection Dike

The approved design required that the flood protection dike be constructed to a minimum elevation of 347.0above msl, which is approximately 2.9 feet above the estimated 100-year flood elevation. The floodprotection dike was situated with the outboard crest located approximately five feet riverward of theestablished unit boundaries. Due to the proximity of the AIRCO Landfill with the slough located east of theSite, it was necessary to construct a portion of the dike over the slough area.

In addition to the flood protection dike, a storm water drainage system consisting of a culvert and 24-inchcorrugated metal pipe extending through the flood protection dike, a sluice gate near the culvert outlet, andtwo storm water pumps were installed near the northeast corner of the AIRCO Landfill. During floodconditions (e.g. when the river pool is above the outlet of the culvert), the sluice gate is manually loweredby maintenance personnel and storm water is permitted to temporarily pond on the landfill cover. Followingthe closing of the sluice gate, water is pumped from the landfill by the two storm water pumps equippedwith float switches.

Approximately 45,000 cubic yards of fill material was placed for construction of the flood protection dike.Minor modifications were made to the design and included the utilization of rip-rap on the exterior face of

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the dike instead of seeding with crown vetch, utilizing Kentucky Standards Specifications for Road andBridge Construction Seed Mixture instead of crown vetch for the interior face of the dike, constructing agravel roadway on the crest of the dike, and constructing stairways to the culvert located at the base of theflood protection dike.

4.2.3 Landfill Cover Improvements

A compacted low-permeability clay and a 12-inch layer of vegetative fill was installed to achieve the desiredgrades (five to 25 percent) within the limits of the BFG and AIRCO Landfills. In July 1996 several isolatedareas of apparently stained surficial materials were observed in the vicinity of the BFG/AIRCO Landfills.After USEPA acceptance, these areas were excavated to a depth not exceeding 18 inches bgs andconsolidated within the Burn Pit Area (beneath the RCRA cover system). Excavated areas within the limitsof the BFG/AIRCO Landfills were backfilled and compacted with approved low permeability soil material.In May 1999, a black tar-like material was observed on the surface of the AIRCO Landfill. Based upontoxicity characteristic leaching procedure analytical results, the material was classified a non-hazardouswaste. The wax material and associated stained landfill cover soils were excavated, containerized, andincinerated at an incinerator facility operated by LWD Inc. and located in Calvert City. Approximately 31tons of stained soil material was removed and disposed of as part of the excavation effort. New clay materialwas keyed into the existing landfill clay cover in order to provide a continuous barrier. Following clayreplacement, an approximately 18-inch topsoil layer was placed over the distributed area and the area wasseeded on October 4, 1999.

4.2.4 Leachate Collection System

A leachate collection system was installed to remove leachate that may accumulate above the underlyingrelatively low-permeability strata beneath the BFG/AIRCO Landfills and the Burn Pit Area. The leachatecollection system consists of a series of six sumps located within the BFG/AIRCO Landfills. Sumps LS-1,LS-2, LS-3, LS-4, LS-5, and LS-6 were installed to depths identified during pre-design investigations(which were two feet below the landfill bottom elevations). Each sump was equipped with a positive airdisplacement pump to convey leachate, which collects in the sumps. Each of the pumps was individuallypiped to the Equipment Shed where discharge was combined through a manifold and temporarily stored inthe Transfer Tank. In June 1997, the design of the leachate collection system was revised to permanentlyconvey collected leachate from the Transfer Tank to the C-Stripper located within the Westlake MonomersPlant. In 2005, the positive air displacement pumps were replaced with electric submersible pumps withinall six sumps.

4.2.5 Groundwater Extraction System

As part of the PCAP, two types of groundwater extraction wells were installed at the BFG/AIRCOSuperfund Site. Three extraction barrier wells, BW-1944, BW-1945, and BW-1946, were installed to createa hydraulic barrier to minimize discharge of contaminated groundwater to the Tennessee River. Twoextraction source wells, SW-1942 and SW-1943, were installed to extract and allow for subsequenttreatment of contaminated groundwater from the plume associated with the Site. As required within theRODs, the extraction wells were required to operate at a combined rate of 100 gallons per minute (gpm) inorder to intercept groundwater flowing to the Tennessee River from the Site. An additional extraction barrierwell (BW-1947), was installed as part of the plant-wide RCRA "Tennessee River Barrier Well System" near

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the southwest corner of the Barge Slip Area (Figure 4). The six groundwater extraction wells were installedin 1991 and activated in 1992.

The extraction wells were constructed with six-inch diameter well materials. Screen material consists ofType 304 stainless steel with screen lengths of 20 feet. The remaining riser pipe (to the surface) is made ofsix-inch inner diameter (ED) low carbon steel casing. A two-foot stainless steel sediment sump with cappedend is attached below the screen. Well screen slot sizes were determined based on the gradation of the filterpack sand, with slot size selected to retain approximately 90 percent of filter pack material. Each extractionwell was equipped with a variable speed submersible pump placed above the top of the well screen. Themajority of the wells have 7.5 horsepower (hp) pumps (SW-1943 is equipped with a 1.5 hp pump) equippedwith a variable speed drive. The outlet lines from the wells are three-inch, Type 304 stainless steel. Thestainless steel lines tie into either fiberglass reinforced pipe (FRP) or high density polyethylene (HOPE).FRP was used for above ground piping and the HDPE was used below ground. All aboveground three-inchlines are insulated and include an electric heat trace for freeze protection. The three-inch lines connect toa header, which transports the flow to a 1,000 gpm capacity steam stripper, identified as the C-Stripper,which is owned by BFG and operated by Westlake within the Westlake Monomers Plant (formerly BFGPlant). The header and automated controls for the extraction well pumps are contained within a concreteshed, identified as Well House 2, which is located west of the Site within the Barge Slip Area.

The groundwater sent to the C-Stripper is pretreated with acid to reduce the feed pH to the four to fiverange. This reduces calcium carbonate precipitation in the column and associated equipment. Thegroundwater is preheated (150/ F to 185/ F depending on the amount of fouling within heat exchanger) andis distributed across the top an 11.5-foot diameter, 30-foot deep packed bed of polypropylene rings withinthe stripping column. Low-pressure steam at 15,000 to 30,000 pound per hour (depending upon heatexchanger fouling) is introduced to the bottom of the column and flows counter current through the fallinggroundwater, thereby effectively removing the organic constituents. The organic condensate from thestripping process is pumped through a feed/bottoms heat exchanger prior to discharge to the Westlake EDC/vinyl chloride monomer (VCM) process. Treated groundwater is discharged to the Tennessee River via adiffuser outfall permitted under the Kentucky Pollutant Discharge and Elimination System (KPDES).Vapors from the stripping column are sent through a water-cooled overhead condenser. The non-condensedstream is further chilled by a glycol condenser. Condensate is sent to a decanter where it is then divertedto the Westlake EDC/VCM process or back to the feed tank. The non-condensed vapors are sent to carbonvapor absorption system or to a Westlake owned and operated incinerator in accordance with the KDEP AirPermit.

Three additional groundwater extraction wells were installed under the RCRA program during the secondhalf of 1996. BW-1951, BW-1952, and BW-1953 were installed along the eastern side of the Barge SlipArea. BW-1951 was rehabilitated and activated in May 2001. Groundwater extraction well BW-1954,located between the BFG/AIRCO Superfund Site and the Barge Slip Area, was installed and activated inAugust 2001. The well was connected to the existing piping for BW-1944 (Figure 4). Since the connectionis upstream of the flow meter for BW-1944, the flow for groundwater extraction well BW-1954 is accountedfor in the flow rate shown for BW-1944.

As stated within the RODs, groundwater extraction and treatment will continue until the groundwaterachieved the clean-up goals. The RODs state that the anticipated timeframe for achieving the cleanup goalsis ten years from the initiation of the extraction and treatment system. Based upon this timeframe, theanticipated date for achieving the groundwater cleanup goals was 2002.

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4.2.6 Consolidation of Surface Soil and Drainage Ditch Sediment

The uppermost 18 inches of contaminated soils within an approximate 100-foot by 100-foot square area,identified as the Soil Contamination Area, located immediately southwest of the Burn Pit Area and withinan approximate 100-foot wide strip of land (drainage ditch) located north of the BFG/AIRCO landfill wasremoved and consolidated within the Burn Pit Area (Figure 5). Excavation and consolidation from the SoilContamination Area and drainage ditch was completed on June 26, 1996 and August 15, 1996, respectively.Additional excavation was also conducted within and around the former Surface Contamination Area inorder to construct a storm water drainage ditch and storm water culvert.

4.2.7 Vapor Recovery System

An organic vapor recovery system was installed to remove organic constituents from the subsurface soilbeneath the Burn Pit Area. A total of 13 vapor recovery wells, BP-1 through BP-13, were installed withinthe limits of the Burn Pit Area (Figure 5). The vapor recovery wells were constructed with slotted four-inchdiameter stainless steel well screens (20-foot length) connected to the risers and installed such that the baseof the screen interval corresponded to an elevation of 317 feet above msl. Positive air displacementsubmersible pumps (operated by an air compressor located in a building immediately north of the Burn PitArea identified as the Equipment Shed) were installed within the sumps of each vapor recovery well totransport liquid to the 1,000-gallon Transfer Tank. A positive displacement blower (located in theEquipment Shed) was also installed to induct a negative pressure in each of the wells.

The blower system was connected to the wells through a network of Schedule 40 PVC pipe. The PVC pipewas connected to the top of each well using a vacuum-rated well cap. At each well cap, a vacuum shut-offvalve and pressure gauge was installed. Originally, vapor extracted from the well system was treatedutilizing two 1,000-pound activated carbon units, operated in series. The carbon units and blower wereinstalled in the Equipment Shed located immediately north of the Burn Pit Area. In May 1998, vaportreatment was changed such that vapor is now piped through a knockout tank, located within the EquipmentShed, and then sent to the C-Stripper. In October 1999, the efficiency of the SVE system was evaluated andthe vacuum was adjusted in five wells to provide a higher overall removal rate. These adjustments resultedin an approximate 176 percent increase in the organic removal rate as compared to the average from the fourprevious sampling events. BP-1 and BP-2 were shut off in July 2000 after showing consistently lowconcentrations in order to optimize performance of the remaining SVE wells extracting higher vaporconcentrations.

As recommended within the 2001 Five-Year Review, a predesign investigation was conducted in December2001 to determine candidate locations for the installation of dual-phase extraction wells. The systemexpansion design utilized a dual-phase extraction setup employing a "sipper" tube. The sipper tube is avacuum extraction tube that extends into the water table. When the end of the sipper tube is slowly advancedto the groundwater surface (with vacuum applied), higher airflow results as the tubing approaches the water.Alternatively, the sipper tube may be positioned just above the water table before the vacuum is applied.When the vacuum is applied, the water table is drawn up to the sipper tube and groundwater is extracted asdescribed above.

Ten dual-phase extraction wells, BP-14 through BP-23, were installed west and north of the Burn Pit Area(Figure 5). Well casings and screens were constructed from six-inch diameter stainless steel materials. Wells

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were completed to a depth of 35 feet below grade surface (bgs). Each dual-phase extraction well wasconstructed with a 1-foot sump, 20 feet of 0.040-slot stainless steel well screen, and stainless steel risersufficient for partially subgrade wellhead vault construction. The annular space between the screenedsection and the borehole was backfilled with FELTERSIL® #2 sand pack. The annular space between theriser and the borehole was backfilled with Pure Gold ® Medium bentonite chips to the base of each wellvault. While sipper tubes were installed within extraction wells BP-18 through BP-23, extraction wellsBP-14 through BP-17 were equipped with electrical submersible pumps to extract collected leachate.

In addition to the installation of the ten-dual phase extraction wells, the 13 existing SVE wells within theBurn Pit Area were retrofitted with the sipper tube technology. The sipper tubes were constructed using0.75-inch HDPE tubing cut at a 45/ angle on the sipping end. Stainless steel centralizers were installed atthe end of each sipper tube to keep it centered within each well. Each wellhead was sealed using acompression well seal. The new wells were connected to the existing system using buried four or six-inchHOPE pipe for vapor/water extraction. The 13 existing Burn Pit wells were connected to the system usingthe existing dual-phase one-inch line (formerly the liquid line). The new wells (BP-14 through BP-23) wereplumbed to a vapor/liquid connector located between BP-18 and BP-19. Liquid from this connector ispumped directly to the 1,000-gallon Transfer Tank and vapor is drawn from the wells and through theknockout tank using the existing blower (Figure 6). A new sheave was installed on the blower in 2002,resulting in approximately 200 cubic feet per minute (cfm) and 140 inches of water at 1,400 revolutions perminute (rpm).

4.2.8 RCRA Cover System over Burn Pit Area

A RCRA cover system was installed over the limits of the Burn Pit Area in accordance with the designdocuments. The RCRA cover system consisted of a two-foot thick layer of engineered fill overlain by ageosynthetic clay liner (GCL), a 40-mil HDPE liner, a one-foot thick granular drainage layer, and a two-footthick vegetative cover layer. Prior to installation of the cover system, fill material was placed to achieve therequired minimum slope of three percent over the unit. Following completion of the earthwork activities,the disturbed areas were fertilized, adjusted with lime, seeded, and mulched. Silt fences and rock checkdams were utilized to prevent erosion until the vegetative cover was established within the Site.

4.2.9 Site Fencing

A chain-linked fence system was installed around the Burn Pit Area, the BFG/AIRCO Landfills, and alongthe outer crest of the flood protection dike. The fence system consists of six-foot chain link fence and isequipped with three strands of barbed wire at the top. Minor modifications were made to the securityfencing design in order to facilitate maintenance activities and included the relocation of the proposed fencealignment adjacent to the Burn Pit Area to the west of the access road and the omission of the proposedfence separating the BFG and AIRCO Landfills.

4.2.10 Environmental Monitoring

Monitoring of groundwater and surface water is required during the post-closure care period. Detailedinformation regarding the groundwater and surface water monitoring requirements, schedules, procedures,and parameter list is provided in the Groundwater and Surface Water Monitoring Program. As required bythe Consent Decree, the Settling Parties are required to notify the USEPA in writing at least 21 days in

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advance of sample collection activity, with subsequent verbal notice not less than three working days priorto implementation of these activities. The Consent Decree also requires that the laboratories used foranalyses perform such analyses in accordance with the USEPA Contract Laboratory Program (CLP)protocol. Laboratory analyses and validation activities are performed in accordance with the site-specificQuality Assurance Plan for Pre-Design and Remedial Design Activities dated October 21, 1992.

4.2.10.1 Groundwater Monitoring Program

The objectives of the groundwater monitoring program are to:

• Monitor groundwater quality at the outer edges of the plume to determine if the plume is migratingtoward the Tennessee River or laterally due to dispersion

• Monitor the effectiveness of the groundwater extraction system

• Provide a warning of hazardous constituent releases that may represent an environmentallysignificant change in conditions, as indicated by the exceedance of alert levels

Groundwater is collected from wells selected to achieve the goals of downgradient monitoring, remediationeffectiveness monitoring, and background monitoring. The downgradient horizontal and vertical extent ofthe plume boundary is monitored from the Downgradient Monitoring Well Group. The EffectivenessMonitoring Well Group and the Extraction Well Group are used to monitor the effectiveness of plumeremediation within the core of the plume. The Background Monitoring Well Group monitors water qualityupgradient of the Site and beyond the influence of the extraction system. The monitoring wells are arrangedin clusters of consecutively numbered shallow and deep wells, with the odd numbered wells having theshallow depth. The classification and identification of the monitoring and extraction wells are providedwithin Table 4.

Table 4. Groundwater Monitoring Network Downgradient

Monitoring Wells Effectiveness

Monitoring Wells Extraction Wells Background Wells

GA-21 GA-22 GA-25 GA-26 GA-27 GA-28 GA-29 GA-30

GA-1 GA-2 GA-11 GA-12 GA-33 GA-34 GA-35 GA-36

BW-1944 BW-1945 BW-1946 SW-1942 SW-1943

GA-37 GA-38

During the aquifer restoration period, the remediation monitoring program consists of the followingactivities. Groundwater samples are collected annually from the effectiveness monitoring wells, includingthe extraction wells, and analyzed for indicator parameters in order to evaluate the effectiveness of thepumping system. Annual groundwater samples for indicator parameters are collected from the backgroundwells and downgradient monitoring wells to evaluate background water quality and the position of the

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plume. Semiannual groundwater samples are collected from the five extraction wells (BW-1944, BW-1945,BW-1946, SW-1942 and SW-1943) and analyzed for the indicator parameters EDC and benzene only. Inaddition, piezometric levels are measured from the wells listed within Table 4 as well as six additionalmonitoring wells (GA-15, GA-16, GA-23, GA-24, GA-31, and GA-32) and the Tennessee River stage aremeasured on a semiannual basis.

When the sampling results indicate that ACLs are being achieved in the effectiveness monitoring group (i.e.when the concentration of EDC and benzene in any given well approaches 125 percent of the respectiveACL for two consecutive monitoring events), and at the option of the Settling Parties, quarterly indicatorand piezometric monitoring may be initiated. Quarterly indicator monitoring will be conducted to assesswhether ACLs have been achieved. For each indicator parameter, four quarters of monitoring data will becompared to the ACLs. If the ACL exceeds the detected value of each indicator parameter, it will bedetermined that the remediation goals for the aquifer have been achieved, and the groundwater collectionsystem will be shut off. Once this occurs, the 30-year post-remediation monitoring period will commence.

4.2.10.2 Surface Water Monitoring

The overall goal of the collection well network is to eliminate the discharge of contaminated groundwaterto the Tennessee River. During the remediation monitoring program, monitoring of the Tennessee River willbe triggered only if downgradient wells GA-27 and GA-28 both show confirmed levels of indicatorparameters at concentrations greater than or equal to the ACLs. If confirmation occurs, the Tennessee Riverwill be monitored annually for indicator parameters and every five years for Target Compound List(TCL)/Target Analyte List (TAL) constituents.

4.3 SYSTEM OPERATIONS/OPERATIONS AND MAINTENANCE (O&M)

The Operations and Maintenance Plan, BFG/AIRCO Superfund Site dated May 1997 was prepared toaddress post-closure care requirements and activities. Operation, inspection, and maintenance of theremedial units located on-site and associated groundwater extraction wells located off-site are performedby Industrial Well Services, Inc. (IWS) of Calvert City, Kentucky under the direction of Christian J. Orsbornthe Potential Responsible Party (PRP) representative for BFG/BOC Group. IWS also provides dailyoperation and maintenance support for the Site. Daily activities include: mowing the lawns located on theSite, lubrication of process equipment, and monitoring of system operation. On a semi-annual basis, IWSconducts the following inspections as required within the O&M plan:

• Inspection of the site security fence and gates • Inspection of the landfill/Burn Pit Area cover systems for excessive erosion • Inspection of drainage ditches for excessive sediment accumulation • Verification that the storm water pumping system is functioning effectively • Inspection of the groundwater monitoring wells • Inspection of the leachate extraction well pumping systems • Inspection of the SVE system equipment • Review of the equipment maintenance schedules in order to verify preventative maintenance is

performed in accordance to manufacturer's recommendations

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Operation and maintenance of the C-Stripper, which treats extracted groundwater, leachate, and soil vaporfrom the Site, is performed by Westlake Monomers. Downtime due to C-Stripper maintenance is noted inthe semi-annual RCRA PCAP Effectiveness Monitoring Reports. The activated carbon beds located on theSite are no longer operational. As a result, treatment of the leachate, groundwater, and soil vapor is solelydependent on the operation of the C-Stripper. Table 5 provides the owner, operator, and responsible partyfor each remedial unit associated with the BFG/AIRCO Superfund Site.

Table 5. Remedial Systems Operations and Maintenance Matrix SYSTEM LOCATION OWNER OPERATOR

(O&M) RESPONSIBLE

PARTY

AIRCO LANDFILL On-Site BOC Group IWS BOC Group

Cover On-Site BOC Group IWS BOC Group

Leachate On-Site BOC Group IWS BOC Group

Dike On-Site BOC Group IWS BOC Group

Storm water On-Site BOC Group IWS BOC Group

Inspections On-Site BOC Group IWS BOC Group

Groundwater Sampling On-Site BOC Group IWS BOC Group

Leachate Treatment Off-Site BFG Westlake BOC Group

BFG LANDFILL

Cover On-Site BFG IWS BFG

Leachate On-Site BFG IWS BFG

Dike On-Site BFG IWS BFG

Storm water On-Site BFG IWS BFG

Inspections On-Site BFG IWS BFG

Groundwater Sampling On-Site BFG IWS BFG

Leachate Treatment Off-Site BFG Westlake BFG

BURN PIT AREA

SVE System On-Site BFG IWS BFG

Vapor Treatment Off-Site Westlake Westlake BFG

GROUND WATER

Withdrawal Wells On/Off-Site BFG IWS BFG

Groundwater Treatment Off-Site BFG Westlake BFG

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In addition to the daily and semi-annual operation, inspection, and maintenance activities, major repairs andprocess component replacements were performed by IWS from 2001 to 2006 as provided within Table 6.

Table 6. Summary of Major Maintenance Activities from 2001 to 2006 Year Process Equipment ID Description of Maintenance Activity

2002 Knock Out Tank New level control system installed

2002 SVE System Ten dual-phase extraction wells installed

2002 SVE System The existing 13 Burn Pit SVE wells modified for dual-phaseextraction capabilities

2002 SVE System New sheave installed on blower

2003 Knock Out Tank New pump installed

2003 Transfer Tank New motor for Transfer Tank pump installed

2004 SVE System Installed new pump and motor in extraction wells BP-16 and BP-17

2005 Leachate Collection System Replaced positive air displacement pumps with electric submersiblepumps within LS-1 through LS-6

2006 Transfer Tank Existing 1-inch line from Transfer Tank to C-Stripper was replacedwith a 2-inch line

As stated within the BFG/AIRCO RODs, the projected present worth (1988 dollars) for the selected remedywas $6.09 million. The capital cost and O&M costs (1988 dollars) were estimated to be $2.96 million and$3.13 million, respectively. The overall implementation of the selected remedy was estimated to take tenyears following the design and contract award. The time required to address the landfills, surface soils, andsubsurface soils was estimated to be approximately one year. Ground water extraction and treatment wouldcontinue until the clean-up goals were achieved. The estimated time that clean-up goals would be met wasten years from the initiation of the extraction and treatment system. The effective life of the leachatecollection system was estimated to be 15 years and would require replacement at that time. Table 7 providesthe annual O&M costs for the Site with and without costs associated with the C-Stripper. Costs associatedwith the C-Stripper are primarily dependent upon energy costs (i.e. costs to generate steam). As a result,O&M costs for treatment of the groundwater, leachate, and soil vapor dramatically increased in 2003 and2005 due to higher energy costs. Costs associated with O&M for the on-site remedial systems have steadilydecreased since implementation of the systems with the exception of 2002 when the ten dual-phase SVEwells were installed and 13 Burn Pit SVE wells were modified for dual-phase extraction capabilities.

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Table 7. BFG/AIRCO Superfund Site Annual O&M Costs

Year Total Cost $1

Cost for Ground water,Leachate, and Vapor

Treatment (C-Stripper) $1

Cost for On-site RemedialSystem Support and

Monitoring $1

1997 555,800 335,700 220,100

1998 493,400 242,100 251,300

1999 362,300 213,100 149,200

2000 459,900 360,600 99,300

2001 426,100 350,000 76,100

2002 544,100 336,000 208,100

2003 537,600 434,000 103,600

2004 385,400 308,000 77,400

2005 760,500 686,000 74,500

10 Year Total: 4,525,100 3,265,500 1,259,600

10 Year Average: 452,500 326,600 126,000 1 Annual costs rounded to nearest hundred dollars

The total O&M cost for the remedy since implementation is currently $1.395 million greater than theoriginal estimate provided within the RODs ($3.13 million), which is primarily due to increased energycosts associated with the operation of the C-Stripper. Since current levels of groundwater contamination atthe Site are substantially higher than the established ACL, the total cumulative O&M costs are anticipatedto continue to increase. In addition, higher O&M costs for the on-site extraction systems are anticipated asthe process equipment approaches the end of the projected effective life and replacement is required.

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5.0 PROGRESS SINCE THE LAST FIVE-YEAR REVIEW

On July 9, 2001, the first five-year review of the BFG/AIRCO Superfund Site was completed. The five-yearreview report indicated that the remedy had been implemented in accordance with the decision documents,and that the contamination was being addressed in a manner that was protective of human health and theenvironment. The following conclusions were reached in support of the protectiveness statement:

• No Changes in Known Contaminants, Sources, or Pathways at the Site: No new contaminants,sources, or exposure pathways were identified as part of the five-year review.

• Changes in Known Hydrologic/Hydrogeologic Conditions: Operation of the groundwaterextraction system has altered the natural groundwater flow pattern, as intended in the RODs. Thecones of depression around the Tennessee River Barrier Wells indicate that under current conditionsthe system is providing a hydraulic barrier between the regulated units and the Tennessee River.

• Remedy Performance: As documented in the semi-annual operation and maintenance (O&M)Reports and confirmed during the site inspection for the five-year review, groundwater and soilvapor treatment systems, the Burn Pit cap, Soil Vapor Extraction (SVE) system and leachatecollection wellheads, the BFG and AIRCO Landfill cap, groundwater extraction wells, the floodprotection dike, and the site access controls are in place and performing in accordance with designdocuments. The remediation goal of containing the plume of contaminated groundwater is being metby the operation of the groundwater extraction system. Indicator constituent concentrations in thedowngradient group of monitoring wells indicate no surface water sampling of the Tennessee Riveris required, although for shallow well GA-29, concentrations have increased since 1987, includingan Alternate Concentration Limit (ACL) exceedance for EDC in 2000.

• Contaminant Mass Removal from Groundwater: For the groundwater extraction and treatmentsystem, approximately 98 percent of the cumulative mass of removed Total Volatile OrganicCompounds (TVOCs) was extracted by wells BW-1944 and BW-1945. Cumulative mass removalsince activation of the five extraction wells in 1992 is on the order of 20,000 pounds (lbs). Most ofthe effectiveness monitoring wells show a larger number of decreasing indicator constituentconcentrations between 1987 and 2000. However, the primary indicator, EDC, shows no decreasingconcentration trend in any of the shallow effectiveness monitoring wells.

• Contaminant Mass Removal from the Vadose Zone: Cumulative EDC mass removal is on theorder of 57,000 lbs for the SVE system and 3,800 lbs for the leachate collection system.

• Need for Optimization: Given the performance of the remediation systems, it may be possible tooptimize the groundwater and SVE system performance by increasing the output from extractionpoints characterized by high constituent mass removal and reducing or deactivating points have lowmass removal.

• Early Indicators of Potential Remedy Failure: Costs and maintenance activities have beenconsistent with expectations. Timely maintenance of affected systems has prevented significantdowntime and remedy failure. The increase in indicator constituent concentrations in downgradientshallow monitoring well GA-29 represents a potential shallow plume migration issue not adequatelycontrolled by the current extraction system.

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• Change in Applicable or Relevant and Appropriate Requirements (ARARs): ARARs for fourof the contaminants of concern have become more stringent since the signing of the RODs in 1988.These changes affect the protectiveness of the cleanup levels. As a result, the revised cleanup levelsof EDC, carbon tetrachloride, benzene, and trichloroethene are lower than the previous levels in the1988 RODs as presented in Table 8.

Table 8. ACLs and MCLs for Site Specific Constituents

Constituent 1988 RODs ACLs

[mg/1]2001 5-Year Review

ACLs [mg/1] 2006 MCLs

[mg/1]

EDC 8.5 0.64 0.005

Carbon tetrachloride 8.5 0.43 0.005

Benzene 8.5 2.04 0.005

Trichloroethene 8.5 4.59 0.005

The 2001 Five-Year Review did note that Daily Health and Safety Meeting logs were not being generatedand kept on file as required by the Health and Safety Plan. This deficiency was not considered significantenough to impact the protectiveness of the remedial operation as long as corrective actions were taken.Based upon this deficiency and conclusions stated above, the following recommendations provided withinTable 9 were stated in the 2001 Five-Year Review Report.

As recommended within the 2001 Five-Year Review, a predesign investigation was conducted in December2001 to determine candidate locations for the installation of dual-phase extraction wells. Ten dual-phaseextraction wells, BP