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1242189-R8 SDMS

Five-Year Review Report

Fourth Five-Year Review Report for

Wasatch Chemical Co. (Lot 6) UTD000716399

Salt Lake City Salt Lake, Utah

September 2012

Prepared By: Skeo Solutions

921 Second Street SE Charlottesville, Virginia

22902

For: United States Environmental Protection Agency

Region 8 Denver, Colorado

Approved by: Date:

%<ft^ Howard M. Cantor, for Assistant Regional Administrator Office of Ecosystems Protection and Remediation


Wasatch Cheinical Co. (Lot 6) 1987 South 700 West

Salt Lake City Salt Lake, Utah

List of Acronyms 3

Executive Summary 4

Five-Year Review Summary Form 6

LO Introduction 10

2.0 Site Chronology 11

3.0 Background 12

3.1 PHYSICAL CHARACTERISTICS 12

3.2 L A N D AND RESOURCE USE 15

3.3 HISTORY OF CONTAMINATION 15

3.4 INITIAL RESPONSE ,. 16

3.5 BASIS FOR TAKING ACTION 17

4.0 Remedial Actions 19

4.1 REMEDY SELECTION 19

4.2 REMEDY IMPLEMENTATION 22

4.3 OPERATION AND MAINTENANCE (O&M) 25

5.0 Progress Since the Last Five-Year Review 26

6.0 Five-Year Review Process 27

6.1 ADMINISTRATIVE COMPONENTS 27

6.2 COMMUNITY INVOLVEMENT 28

6.3 DOCUMENT REVIEW 28

6.4 DATA REVIEW 33

6.5 SITE INSPECTION 38

6.6 INTERVIEWS 39

7.0 Technical Assessment 41

7.1 QUESTION A: Is THE REMEDY FUNCTIONING AS INTENDED BY THE DECISION

DOCUMENTS? 41

7.2 QUESTION B : ARE THE EXPOSURE ASSUMPTIONS, TOXICITY DATA, CLEANUP LEVELS AND

RAOS USED AT THE TIME OF REMEDY SELECTION STILL VALID? 42 7.3 QUESTION C: H A S A N Y OTHER INFORMATION C O M E TO LIGHT THAT COULD C A L L INTO

QUESTION THE PROTECTIVENESS OF THE R E M E D Y ? 43

7.4 TECHNICAL ASSESSMENT SUMMARY 43

8.0 Issues 45

9.0 Recommendations and Follow-up Actions 45

10.0 Protectiveness Statements 46

11.0 Next Review 47

Appendix A: List of Documents Reviewed A-1

Appendix B: Press Notice B-1

Appendix C: Interview Forms C-1

Appendix D: Site Inspection Checklist D-1

Appendix E: Photographs from Site Inspection Visit E-1

Appendix F: Data Review Supporting Data and Figures F-1

Figures Figure 1: Site Location Map 13 Figure 2: Detailed Site Map 14 Figure 3: Institutional Control Base Map 32 Figure 4: Concentrations of Cis-1,2-DCE and Vinyl Chloride in Well EX-11, October 2007 to

November 2011 34 Figure 5: Concentrations of TCE and 1,1-DCE in Well EX-11, October 2007 to November 2011

35 Figure 6: Concentrations of PCE, TCE, Vinyl Chloride and PCP in Well ES-01, October 2007 to

November 2011 35 Figure 7: Concentrations of TCE, Cis-l,2-DCEand Vinyl Chloride in Well EX-02, October 2007

to November 2011 , 36 Figure F-1: Concentrations of TCE, Cis-1,2-DCE and Vinyl Chloride in Well EX-02, October

2007 to November 2011 .F-1

Tables Table 1: Chronology of Site Events..... 11 Table 2: Groundwater and Soil Contaminants at the Site 19 Table 3: Action Levels and Indicator Chemical Concentrations in Source Area Sludge and Soils

21 Table 4: Action Levels and Indicator Chemical Concentrations in Groundwater 22 Table 5: Progress on Recommendations from the 2007 FYR 27 Table 6: ARAR Review for Groundwater COCs 29 Table 7: Properties Included in 2009 Environmental Covenant 30 Table 8: Institutional Control (IC) Summary Table 30 Table 9: Property Parcel Identification in Institutional Control Base Map 31 Table 10: 2011 Deep Aquifer Groundwater Monitoring Well Results 36 Table 11: 2011 Soil Sampling Results , 38 Table 12: Current Site Issues 45 Table 13: Recommendations to Address Current Site Issues 45 Table F-1: Shallow Aquifer Groundwater Plumes Reported by PRP in April 2012 F-5

List of Acronyms ACL Alternative Concentration Limit ARAR Applicable or Relevant and Appropriate Requirement AOC Administrative Order on Consent BNA Base-Neutral-Acid Extractables BSHW Utah Bureau of Solid and Hazardous Waste CERCLA Comprehensive Environmental Response, Compensation, and Liability Act CFR Code of Federal Regulations CIC Community Involvement Coordinator COC Contaminant of Concern DERR Division of Environmental Response and Remediation DNAPL Dense Non-Aqueous Phase Liquid DRGWR Denver and Rio Grande Western Railroad DWRi Utah Division of Water Rights EPA United States Environmental Protection Agency ESD Explanation of Significant Differences FFS Focused Feasibility Study FYR Five-Year Review GWCC Great Western Chemical Company HCB Hexachlorobenzene IC Institutional Control ISV In-Situ Vitrification MCL Maximum Contaminant Level [ig/L Micrograms per Liter mg/kg Milligram per Kilogram MNA Monitored Natural Attenuation NCP National Contingency Plan NPL National Priorities List O&M Operation and Maintenance OSWER Office of Solid Waste and Emergency Response OU Operable Unit ppb parts per billion PCE Tetrachloroethylene PCP Pentachlorophenol PRG Preliminary Remediation Goal PRP Potentially Responsible Party RAO Remedial Action Objective RCRA Resource Conservation and Recovery Act RI/FS Remedial Investigation/Feasibility Study ROD Record of Decision RPM Remedial Project Manager SDWA Safe Drinking Water Act SVOC Semi-volatile Organic Compound TBC To-Be-Considered TCE Trichloroethylene TCL Target Compound List UDEQ Utah Department of Environmental Quality VOC Volatile Organic Compound

Executive Summary

Introduction

The Wasatch Chemical Co. (Lot 6) Superfiand Site (the Site) is located near the intersection of 700 West and 2100 South Streets in an industrial area of Salt Lake City, Salt Lake County, Utah. The approximately 18-acre Site includes property owned by Questar InfoComm, Inc. (Questar) and portions of adjacent properties.

Between 1957 and 1971, operations at the Site included the warehousing, production and packaging of industrial chemical products. Pesticides, herbicides, fertilizers, industrial chemicals and cleaners were blended and packaged at the Site from 1973 until June 1978. From July 2001 to April 2002, site facilities included vehicle storage, warehousing and office space. The Site currently includes a steel warehouse, a plumbing supply company and several office buildings.

Throughout the history of activities at the Site, disposal practices and spills released hazardous substances. In 1990, an endangerment assessment and risk assessment identified that soils, sludges, dioxin removal wastes and groundwater had been contaminated with volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), pesticides, herbicides, dioxins and furans.

The United States Environmental Protection Agency (EPA) listed the Site on the National Priorities List (NPL) in 1991. This is the fourth Five-Year Review (FYR) for the Site. The Site consists of one operable unit (OU). The triggering action for this statutory review is the third FYR, completed in September 2007.

Technical Assessment

The review of documents, Applicable or Relevant and Appropriate Requirements (ARARs), risk assumptions, institutional controls and the site inspection indicate that portions of the remedy may not be functioning as intended by site decision documents.

The soil remedy that included excavation and landfarming of hydrocarbon-contaminated soils, consolidation of materials, placement of a clean soil cap, and treatment of staged soils, sludges and dioxin removal wastes by thermal destruction of contaminants through in-situ vitrification (ISV) was completed. Verification samples of the vitrified material showed the remedy was effective in reducing chemical concentrations below the risk-based action levels established for the Site in 1996.

Remedial contractors recently detected additional shallow soil contamination during drilling activities associated with the groundwater monitoring program. Soil sampling detected VOCs and pentachlorophenol (PCP) in soil samples collected from two of the four new groundwater monitoring wells, including concentrations of trichoroethylene (TCE) and tetrachloroethylene (PCE) that exceed the soil performance standards for the Site. Further investigation is necessary to delineate the extent of this recently identified area of soil contamination and remedial actions may be needed to address soil contamination at levels above performance standards for the Site.

Groundwater extraction and treatment was implemented and subsequently halted to evaluate possible alternative remedies for groundwater. EPA is working with the Site's potentially responsible parties (PRPs) to identify additional data necessary to fully review outstanding issues with the draft focused feasibility study (FFS). EPA is evaluating the effectiveness of monitored natural attenuation (MNA) before issuing a final decision regarding whether or not to reinstate the pump-and-treat remedy or evaluate other remedial alternatives.

The Utah Division of Water Rights (DWRi) implemented a formal notification process that acts as a groundwater institutional control at the Site. In addition, an environmental covenant containing land use and groundwater restrictions, and requiring notification of building demolition, vapor intrusion risk assessment and mitigation associated with new building construction is in place for a portion of the Site. Some areas of the Site do not have institutional controls fiilfilling the objective to assess risks related to vapor intrusion. In order to ensure long-term protectiveness, EPA will evaluate the need for institutional controls on the remaining properties at the Site.

Several changes related to the toxicity for contaminants of concern (COCs) at the Site have occurred. First, there have been changes in cancer slope factors and oral reference doses for PCE and TCE. EPA will work to evaluate how these changes affect risk estimates at the Site. In addition, EPA has released a final reassessment resulting in a non-cancer dioxin toxicity number. The cancer toxicity number is expected to follow as soon as possible. EPA is working to reevaluate the risk associated with dioxins in site soil to determine the impacts on protecfiveness.

Initial vapor intrusion data collection and analysis occurred in early 2012. EPA has determined that additional sampling and analysis are necessary to evaluate the potential risk from vapor intrusion.

Exceedances of the vinyl chloride maximum contaminant level (MCL) occurred throughout the FYR period; multiple samples contained vinyl chloride concentrations as high as two orders of magnitude above the MCL. Current work plans regard vinyl chloride, a degradation product of TCE and PCE, as a COC. When decision documents are developed to address sitewide groundwater, vinyl chloride should be included as a COC.

Conclusion

A protectiveness determination of the remedy cannot be made at this" time until fiirther information is obtained. This will require additional sampling and analysis to fully determine the potential for vapor intrusion at the Site and a dioxin toxicity reassessment at the Site. It is expected that these actions will take approximately 36 months to complete. At that time, a protectiveness determination will be made. The remedy at the Site has resulted in the excavation and landfarming of hydrocarbon-contaminated soils, consolidaUon of materials, placement of a clean soil cap, and treatment by ISV to reduce chemical concentrations below risk-based action levels established for the Site in 1996; implementation of land use and groundwater institutional controls for a portion of the Site; and an evaluation of the effectiveness of the remediation of groundwater.

Five-Year Review Summary Form

SITE IDENTIFICATION

Site Name: Wasatch Chemical Co. (Lot 6)

EPA ID: UTD000716399

Region: 8 State: UT City/County: Salt Lake City/Salt Lake

NPL Status: Final

Multiple OUs? No

Has the site achieved construction completion? Yes

Lead agency: EPA If "Other Federal Agency" was selected above, enter Agency name: Click here to enter text.

Author name: Treat Suomi and Lynette Wysocki (Reviewed by EPA)

Author affiliation: Skeo Solutions

Review period: January 2012 - September 2012

Date of site inspection: 03/20/2012

Type of review: Statutory

Review number: 4

Triggering action date: 09/28/2007

Due date (five years after triggering action date): 09/28/2012

Five-Year Review Summary Form (continued)

Issues/Recommendations

OU(s) without Issues/Recommendations Identified in the Five-Year Review:

N/A

Issues and Recommendations Identified in the Five-Year Review:

OU(s): 1 Issue Category: Remedy Performance OU(s): 1

Issue: The selected remedy for groundwater, pump and treat, is not currently in operation. MNA is in the process of evaluation.

OU(s): 1

Recommendation: Evaluate the effectiveness of MNA and issue a final decision regarding whether or not to reinstate the pump-and-treat remedy or evaluate other remedial alternatives.

Affect Current Protectiveness

Affect Future Protectiveness

Implementing Party

Oversight Party

Milestone Date

No Yes EPA EPA 09/29/2013

OU(s): 1 Issue Category: Institutional Controls OU(s): 1

Issue: Some areas of the Site do not have institutional controls fulfilling the objective to assess risks related to vapor intrusion.

OU(s): 1

Recommendation: Evaluate the need for institutional controls on additional portions of the Site.



implementing Party

Oversight Party

Milestone Date



Issue: Dioxin toxicity values have changed.

OU(s): 1

Recommendation: Re-evaluate the risk associated with dioxins in site soil.



Implementing Party

Oversight Party

Milestone Date

No Yes EPA EPA ^ 09/29/2015

OU(s): 1 Issue Category: Remedy Performance

Issue: Additional sampling and analysis is required to evaluate the potential risk from vapor intrusion.

Recommendation: Collect necessary data and evaluate how sampling results affect risk estimates.



Implementing Party

Oversight Party

Milestone Date

No Yes PRP/EPA EPA 03/31/2014


Issue: Changes in cancer slope factors and oral reference doses have occurred for PCE and TCE.

OU(s): 1

Recommendation: Evaluate how changes in toxicity factors affect risk estimates.



Implementing Party

Oversight Party

Milestone Date


OU(s): 1 Issue Category: Changed Site Conditions OU(s): 1

Issue: VOCs and PCP were detected in soil samples collected during installation of two new groundwater monitoring wells, including concentrations of TCE and PCE that exceed soil performance standards for the Site.

OU(s): 1

Recommendation: Delineate the extent of the newly identified area of soil contamination and determine if response actions are needed to address soil contamination at levels above performance standards for the Site.



Implementing Party

Oversight Party

Milestone Date


OU(s): 1 Issue Category: Changed Site Conditions OU(s): 1

Issue: Vinyl chloride exceeded MCLs throughout the FYR period. Although current work plans regard vinyl chloride as a COC, vinyl chloride is not officially listed as a COC.

OU(s): 1

Recommendation: When decision documents are developed to address sitewide groundwater, vinyl chloride should be included as a, COC.



Implementing Party

Oversight Party

Milestone Date


Protectiveness Statement(s)

Operable Unit: 1

Protectiveness Determination: Protectiveness Deferred

Addendum Due Date (if applicable): 10/15/2015

Protectiveness Statement: A protectiveness determination of the remedy cannot be made at this time until further information is obtained. This will require additional sampling and analysis to fully determine the potential for vapor intrusion at the Site and a dioxin toxicity reassessment at the Site. It is expected that these actions will take approximately 36 months to complete. At that time, a protectiveness determination will be made. The remedy at the Site has resulted in the excavation and landfarming of hydrocarbon-contaminated soils, consolidation of materials, placement of a clean soil cap, and treatment by ISV to reduce chemical concentrations below risk-based action levels established for the Site in 1996; implementation of land use and groundwater institutional controls for a portion of the Site; and an evaluation of the effectiveness of the remediation of groundwater.

Sitewide Protectiveness Statement (if applicable)

For sites that have achieved construction completion, enter a sitewide protectiveness determination and statement.

Protectiveness Determination: Protectiveness Deferred

Addendum Due Date (if applicable): 10/15/2015

Protectiveness Statement: A protectiveness determination of the remedy cannot be made at this time until further information is obtained. This will require additional sampling and analysis to fully determine the potential for vapor intrusion at the Site and a dioxin toxicity reassessment at the Site. It is expected that these actions will take approximately 36 months to complete. At that time, a protectiveness determination will be made. The remedy at the Site has resulted in the excavation and landfarming of hydrocarbon-contaminated soils, consolidation of materials, placement of a clean soil cap, and treatment by ISV to reduce chemical concentrations below risk-based action levels established for the Site in 1996; implementation of land use and groundwater institutional controls for a portion of the Site; and an evaluation of the effectiveness of the remediation of groundwater.


Wasatch Chemical Co. (Lot 6) Superfund Site

1.0 Introduction

The purpose of a Five-Year Review (FYR) is to evaluate the implementation and performance of a remedy in order to determine if the remedy will continue to be protective of human health and the environment. The methods, findings and conclusions of FYRs are documented in FYR reports. In addition, FYR reports identify issues found during the review, if any, and document recommendations to address them.

The United States Environmental Protection Agency (EPA) prepares FYRs pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Section 121 and the National Contingency Plan (NCP). CERCLA Section 121 states:

"If the President selects a remedial action that results in any hazardous substances, pollutants, or contaminants remaining at the site, the President shall review such remedial action no less often than each five years after the initiation of such remedial action to assure that human health and the environment are being protected by the remedial action being implemented. In addition, if upon such review it is the judgment of the President that action is appropriate at such site in accordance with section [104] or [106], the President shall take or require such action. The President shall report to the Congress a list of facilities for which such review is required, the results of all such reviews, and any actions taken as a result of such reviews."

EPA interpreted this requirement further in the NCP; 40 Code of Federal Regulations (CFR) Section 300.430(f)(4)(ii), which states:

"If a remedial action is selected that results in hazardous substances, pollutants, or contaminants remaining at the site above levels that allow for unlimited use and unrestricted exposure, the lead agency shall review such actions no less often than every five years after the inifiation of the selected remedial action."

Skeo Solutions, an EPA Region 8 contractor, conducted the FYR and prepared this report regarding the remedy implemented at the Wasatch Chemical Co. (Lot 6) Superfiand site (the Site) in Salt Lake City, Salt Lake, Utah. This FYR was conducted from January to September 2012. EPA is the lead agency for developing and implementing the remedy for the potentially responsible party (PRP)-lead cleanup at the Site. The Utah Department of Environmental Quality (UDEQ), as the support agency representing the State of Utah, has reviewed all supporting documentation and provided input to EPA during the FYR process.

This is the fourth FYR for the Site. The triggering action for this statutory review is the Site's 2007 FYR. The FYR is required due to the fact that hazardous substances, pollutants or contaminants remain at the Site above levels that allow for unlimited use and unrestricted exposure. The Site consists of one operable unit (OU), which is addressed in this FYR.

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2.0 Site Chronology

Table 1 lists the dates of important events for the Site.

Table 1: Chronology of Site Events

Event Date EPA discovered contamination August 1, 1980 EPA conducted a preliminary site assessment April 1, 1981 State conducted a preliminary site assessment December 1, 1984 EPA and site PRP began removal negotiations August 15, 1985 EPA conducted site inspection September 30, 1985 EPA issued Unilateral Administrative Order March 13, 1986 EPA began short-term removal action to stabilize the Site March 19, 1986 EPA and PRP completed removal negotiations EPA signed Administrative Order on Consent (AOC)

April 1, 1986

EPA proposed the Site for listing on National Priorities List (NPL) January 22, 1987 EPA completed short-term removal action to stabilize the Site June 30, 1988 State issued Consent Decree September 28, 1988 EPA began endangerment assessment and health assessment PRP began remedial investigation/feasibility study (RJ/FS) EPA completed endangerment assessment and health assessment October 23, 1989 EPA performed removal assessment August 30, 1990 EPA began removal assessment January 1, 1991 EPA finalized Site on NPL February 11, 1991 PRP completed Rl/FS EPA signed Record of Decision (ROD) for final selected remedy

March 29, 1991

EPA signed AOC May 22, 1991 PRP began short-term removal action to stabilize the Site June 12, 1991 EPA completed Removal Assessment June 17, 1991 PRP completed short-term removal action to stabilize the Site July 3, 1991 EPA, UDEQ, and PRP signed a Consent Decree ' September, 1991 PRP began remedial design September 30, 1991 CD finalized September 30, 1992 PRP completed remedial design October 16, 1992 PRP began remedial action for landfarming EPA began removal assessment February 18, 1993 PRP completed remedial design PRP began remedial action for in-situ vitrification (ISV)

September 10, 1993

PRP completed remedial action for landfarming January 19, 1994 PRP began remedial action for groundwater extraction and water October 11, 1994 treatment PRP completed remedial design March 8, 1995 EPA issued Explanation of Significant Differences (ESD) November 30, 1995 PRP completed remedial action for ISV May 31, 1996 PRP completed remedial action for groundwater extraction and water August 29, 1997 treatment PRP completed remedy construction EPA prepared Preliminary Close-out Report Site achieved Construction Complete status

September 30, 1997

EPA signed first FYR October 24, 1997 EPA signed second FYR September 25, 2002

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Event Date EPA-approved discontinuation of groundwater extraction and treatment system and start of MNA evaluation

January 2003

PRP conducted enhanced biodegradation activities May 2004 PRP conducted enhanced biodegradation activities July 2006 EPA signed third FYR September 28, 2007 PRP assessed 700 West Ditch for purposes of potentially establishing Alternative Concentration Limits

October 2007

Environmental Covenant was completed for a portion of the Site January 2009 PRP submitted a draft FFS February 2010 PRP completed the installation of additional groundwater monitoring wells

October 2011

PRP collected vapor samples for analysis of vapor intrusion March 2012

3.0 Background

3.1 Physical Characteristics

The Site is located near the intersection of 700 West and 2100 South Streets in an industrial area of Salt Lake City, Salt Lake County, Utah (Figures 1 and 2). The approximately 18-acre Site includes property owned by Questar InfoComm, Inc. (Questar) and portions of adjacent properties.

Site boundaries identified in the Site's 1991 Record of Decision (ROD) were the Denver and Rio Grande Western Railroad (DRGWR) tracks to the east, 2100 South Street to the south, 700 West Street to the west, and a line of demarcation across the ESfSTEL Steel West (fNSTEL) (formally known as STEELCO) property 80 feet from the northern edge of Lot 6 to the north. Later investigations indicated that groundwater contamination extended past site boundaries described in the 1991 ROD. The northern site boundary was extended to coincide with the DRGWR rail spur in the south-central portion of the INSTEL property. Contaminants are not located on the Mega Foods property on the southern boundary of the Site. Therefore, the southern boundary now excludes the Mega Foods property. Current site boundaries, which include the areal extent of contaminat ion, are as follows: the DRGWR tracks to the east, 2100 South Street to the south, excluding the Mega Foods property, 700 West Street to the west, and the DRGWR rail spur in the south-central portion of the INSTEL property to the north.

The Site's topography is flat with an elevation variance of no more than several feet. Soils consist of clays, silts, and fine to medium sand. Most surface drainage flows west toward a small drainage ditch (700 West Ditch) that connects to other industrial drainage ways, with ultimate discharge to the Great Salt Lake. Ditch sediments consist of locally derived materials, similar to site soils. A shallow aquifer directly beneath the Site flows to the north and northwest, with some suspected discharge to the drainage ditch. Annual precipitation is 12 to 13 inches.

The Site lies near the center of the Jordan River Valley, which is underlain by a thick aquifer that supplies much of the region's water. This aquifer is considered the only aquifer in the Salt Lake Valley. It consists of deep and shallow portions separated by a

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Figure 1: Site Location Map

/ A

1 \

Salt Lal< ii City.TrT"

11

Antelope Island State Park

Wasatch Chemical Co. (Lot 6)

Ogden-Layton

0.25 0.5 I Miles

0 sl<eo O NORTH

Wasatch Chemical Co. (Lot 6) Salt Lake City, Utah

Disclaimer: This map and any boundary lines within the map are approximate and subject to change. The map is not a survey. The map is for informational purposes only rsgarding EPA's response actions at the Site, and is not intended for any other purpose.

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Figure 2: Detailed Site Map

Source: Questar, March 2012. Disclaimer: This map and any boundary lines within the map are approximate and subject to change. The mep is not a survey. The map is for informational purposes only regarding EPA's response actions at the Site, and is not intended for any other purpose.

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discontinuous confining layer. Groundwater in the shallow portion of the aquifer at the Site is approximately 2 feet below the land surface, flows toward the northwest and is currently unclassified. Water quality in the shallow portion of the aquifer is highly variable. Some localized areas are suitable for use as drinking water. While the water contained in the shallow portion of the aquifer at the Site is not currently being used as a source of drinking water, it has potential for fiiture use. In addidon, there is a potential for hydraulic connection between the deep and shallow portions of the aquifer, especially in light of the potential for heavy pumping of the deeper portion of the aquifer in conjunction with the region's increasing water demands.

3.2 Land and Resource Use

Commercial and industrial areas are located in the immediate vicinity of the Site. The nearest residential area is approximately one quarter-mile northwest of the Site. Approximately 5,000 people live within a one-mile radius of the Site. The Site is not located in a flood zone.

Between 1957 and 1971, operations at the Site included the warehousing, production and packaging of industrial chemical products. Wasatch Chemical Company (Wasatch) began production and warehousing of agricultural and industrial chemicals on site in 1957. Mountain Fuel Supply purchased Wasatch in 1968 and formed Entrada Industries to operate the facilities. In 1970 and 1971, operations expanded to include fertilizer manufacturing. In 1973, a liquid and dry pesticide formulation building was built on site. Pesticides, herbicides, fertilizers, industrial chemicals and cleaners were blended and packaged at the Site from 1973| until June 1978. In 1978, the agricultural chemical business moved off site. In 1978, Entrada divested its agricultural chemicals business and sold Wasatch business and assets to Great Western Chemical Company (GWCC). The industrial chemicals business remained on site and continued to operate on a limited basis through August 1992. Vehicle storage, warehousing and office space were located on site from July 2001 to April 2002. The Site currently includes a steel warehouse, a plumbing supply company and several office buildings.

Groundwater near the Site is not used for drinking water, bathing or recreational purposes. Businesses at the Site connect to and receive water from the public water system operated by the Salt Lake City Department of Public Utilities.

3.3 History of Contamination

Throughout the Site's history, disposal practices and spills released hazardous substances. During the 1970s, industrial and process waste materials were discharged to a septic tank and drain field until waste lines were realigned. In the late 1970s, following closure of an evaporation pond and discontinuafion of the blending of pesticides, herbicides and fertilizers at the Site, connections to the evaporation pond were reportedly severed. Wastewater from remaining operations was discharged onto the ground surface through underground drains or from surface runoff

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Site operations used the former evaporation pond at the Site for disposal of process wastewater. In 1980, that pond was filled in with earthen materials and capped with concrete. The associated drain lines contained hazardous substances, as did septic and yard drain systems. Contaminants are believed to have migrated from these systems into the environment. Other disposal activities at the Site resulting in releases of hazardous substances included:

• In 1969, three unlined settlement ponds were reportedly used for process wastewater discharge. The exact locations of these ponds are unknown.

• During 1969 and 1970, a new sepdc tank and absorption field were installed and industrial and process waste materials were reportedly discharged to a septic tank and drain field underneath an on-site building until January 5, 1970, when waste lines were realigned.

• Between June 1978 and June 1982, trucks carrying fertilizers, herbicides and pesticides reportedly routinely washed out the insides of the tanks and drained this wash water into yard drains next to the boiler room.

• In 1982, a GWCC waste and wastewater survey indicated that wastewater generated from aluminum nitrate production and chlorine cylinder reconditioning was dumped on the ground. Waste clean-out water was discharged to the railroad tracks.

• In August 1983, GWCC installed a line to the Salt Lake City Department of Public Utilities sewer system for discharge of waste material. Salt Lake City was not aware of this connection until it was discovered during on-site visits in the spring of 1986.

Numerous spills of varying hazardous substances have also occurred on various parts of the Site.

In June 1984, the Utah Bureau of Solid and Hazardous Waste (BSHW) advised the Site's PRPs of an alleged release or threatened release of chemicals from the property to the environment. Based on field investigations, BSHW completed a preliminary site assessment and site investigation in 1984.

3.4 Initial Response

BSHW and EPA conducted additional field investigations of groundwater, surface water, soils and sediments in 1985 and 1986. An Administrative Order on Consent (AOC) was entered into between EPA, Entrada and GWCC on April 10, 1986, regarding performance of an emergency removal action at the Site. In January 1986, the State of Utah filed a lawsuit in federal district court against the PRPs. On July 2, 1986, the State filed a First Amended Complaint seeking past and fiiture response acfion costs and injunctive relief under Section 107 of CERCLA and Section 7002 of the Resource Conservation and Recovery Act (RCRA) and related state law claims under the Solid and Hazardous Waste Act and the Water Pollution Control Act.

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In early 1986, UDEQ required proper disposal of drums, containers, cylinders, and contaminated soils and waters. In June 1986, in cooperation with BSHW, EPA conducted an emergency removal acUon to remove approximately 50 drums, cylinders and other containers of chemical waste from the Site and to provide temporary on-property storage of several drums containing dioxin waste.

In January 1987, EPA proposed the Site for listing on the National Priorities List (NPL). In April 1988, UDEQ entered into a Consent Decree with the Entrada Group, including Entrada Industries, Inc. (subsidiary to Questar Corporation), Mountain Fuel Supply Company, Inc. and Interstate Brick Company that initiated a remedial invesfigation/feasibility study (RI/FS) for the Site. Additional PRPs were identified as the Great Western Group. These PRPs included McCall Oil and Chemical Company and GWCC. On April 1, 1986, the Entrada and Great Western Groups signed an AOC requiring the PRPs to reimburse EPA for a portion of the Agency's site response and oversight costs. On February 11, 1991, EPA listed the Site on the NPL.

3.5 Basis for Taking Action

Contamination at the Site has been divided into three categories: source areas, soils and groundwater. Source areas include the process drain system, which includes the former evaporation pond, yard drain system and septic system. Dioxin waste consolidated during the removal action conducted by EPA in 1986 constitutes the remainder of the source material. Soil contamination at the Site was widespread and consisted of herbicides, pesticides, dioxins, volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs). Soil contamination occurred as the result of numerous spills, runoff accumulation in topographic low points, and transport of contamination from source areas. Groundwater contamination was from VOCs, SVOCs, herbicides and pesticides. Groundwater contamination at the Site was continuous through the shallow portion of the aquifer.

In March 1990, Harding Lawson Associates completed a remedial investigation on behalf of site PRPs. Several media were investigated at the Site: waste (sludge and liquid), soil, sediment, surface water, groundwater and air. In each medium, samples were analyzed for target compound list (TCL) chemicals. The TCL chemical classes were VOCs, base-neutral-acid extractables (BNAs), herbicides, pesticides, dioxins/fiarans and metals.

Site PRP Questar performed an endangerment assessment in January 1990 to evaluate potential adverse impacts to human health and the environment. Using the data collected during the remedial investigation, the assessment chose 12 indicator chemicals, identified pathways and calculated risk levels.

The endangerment assessment examined three potential receptor populations. These included off-site residents, off-site workers and on-site workers. Exposure pathways with the highest potential for exposure (primary pathways) included:

• Incidental ingestion of soil.

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• Dermal contact with soil. • Inhalation of fugitive dusts. • Inhalation of chemicals volatilizing from soil and groundwater.

Since groundwater is not used for drinking water, bathing or recreational purposes, it was not identified as a pathway. The assessment quantified risk levels for each receptor population and exposure pathway. The assessment concluded that no significant current risks exist at the Site.

While the assessment analyzed current risks, Questar and EPA determined future potential risks were of greatest concern. Questar and EPA performed subsequent calculations to further evaluate fiature on-site worker exposures, residential exposures and acute exposures. EPA performed additional evaluations to assess potential acute exposure risks as well as subchronic exposure risks associated with direct exposure to contaminants in sludges in the process and yard drain system. Action levels for soils, sludges and dioxin removal wastes were developed during the risk assessment process and based on the potential risks to human health and the environment for future nonresidential use.

Based on site hydrogeology, EPA and UDEQ determined that a potential for fiiture human exposure to contaminated groundwater does exist. Maximum contaminant levels (MCLs) and proposed MCLs established under the Safe Drinking Water Act were therefore adopted as groundwater cleanup standards fully protective of human health.

The risk analysis evaluated future uses of groundwater, including:

• Ingestion by fiiture workers using a shallow well in the contaminated aquifer. • Household use of groundwater by residents.

Residential exposure assessment included ingestion of contaminated groundwater, as well as inhalation of volatile chemicals while showering and cooking. Results of the analysis suggest the following:

• Chronic exposure to contaminated groundwater could result in unacceptable risks of cancer to both fiiture workers and residential users.

• Exposure to trichoroethylene (TCE) and tetrachloroethylene (PCE) present substantial potential risk for both workers and residents.

• The potential exposure concentration for pentachlorophenol (PCP) exceeded the proposed MCL.

The risk assessment process included analysis of potential risks to the environment. Vegetation samples and tissue samples from mice and pigeons were collected on site and analyzed for pesticides, herbicides and metals. In addition, dioxins and fiirans were analyzed in aquatic and upland vegetation samples. The ecological risk assessment concluded that site contaminants do not affect critical wildlife habitats, endangered species or habitats of endangered species.

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Table 2 shows indicator chemicals identified at the Site.

Table 2: Groundwater and Soil Contaminants at the Site

Chemical Class Indicator Chemicals VOCs TCE VOCs

PCE VOCs

Vinyl chloride SVOCs Hexachlorobenzene (HCB) SVOCs

PCP Pesticides Chlordane Pesticides

4,4'-DDT Pesticides

4,4'-DDE

Pesticides

4,4'-DDD

Pesticides

Heptachlor Herbicides 2,4-D Herbicides

2,4,5-T Dioxins and furans Dioxins (all detected congeners)

4.0 Remedial Actions

In accordance with CERCLA and the NCP^ remedial actions are required to protect human health and the environment and comply with applicable or relevant and appropriate requirements (ARARs). A number of remedial alternatives were considered for the Site, and final selection was made based on an evaluation of each alternative against nine evaluation criteria that are specified in Section 300.430(e)(9)(iii) of the NCP. The nine criteria include:

1. Overall Protectiveness of Human Health and the Environment 2. Compliance with ARARs 3. Long-Term Effectiveness and Permanence 4. Reduction of Toxicity, Mobility or Volume of Contaminants through Treatment 5. Short-term Effectiveness 6. Implementability 7. Cost 8. State Acceptance 9. Community Acceptance

4.1 Remedy Selection

EPA signed the Site's ROD on March 29, 1991. The ROD addressed sources of soil, sludges and groundwater contamination at the Site. The remedial action objecfives (RAOs) identified in the ROD include:

• Treatment of soils, sludges and dioxin removal wastes so that the level of contaminants remaining in these materials does not pose an unacceptable risk to human health or the environment.

• Restoring contaminated groundwater to action levels suitable for potential fiiture use as a source of drinking water.

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• Protecting uncontaminated groundwater by minimizing the migration of contaminants.

• Ensuring that the level of contaminants remaining in groundwater do not pose unacceptable risk to human health and the environment.

The remedy selected for the Site in the 1991 ROD included:

• Excavation of all soils containing indicator chemicals above action levels and sludges from the yard and process drain systems and the septic system.

• Consolidation of these contaminated materials and dioxin removal wastes (approximately 3,587 cubic yards of soils and sludges and 650 gallons of liquid waste) in the former evaporation pond.

• Treatment of staged soils, sludges and dioxin removal wastes by thermal destruction of contaminants through in-situ vitrification (ISV).

• Excavation and landfarming of approximately 1,111 cubic yards of hydrocarbon-contaminated soils.

• Surface sealing of site soil by asphalt paving. • Extraction of on-site contaminated groundwater until MCLs and proposed MCLs

are met and treatment, to the extent necessary, of extracted groundwater by air stripping to meet publicly owned treatment works or Utah pollution discharge elimination system standards.

• Disposal of any residuals remaining from the treatment of groundwater at an off-site hazardous material disposal facility.

• Implementation of institutional controls such as deed restrictions to restrict use of groundwater and prevent site properties from being used for non-industrial purposes.

EPA issued an Explanation of Significant Differences (ESD) on November 30, 1995, to document the following modifications to the remedy selected in the 1991 ROD:

• Extension of the site boundary to coincide with the DRGWR rail spur in the south-central portion of the FNSTEL property and to exclude the Mega Foods property.

• Removal of the paving component of the remedy. The 1991 ROD requires unpaved areas to be cleaned to risk-based levels selected to protect fiiture occupants from unacceptable health risks. In addition, surface soils above soil action levels have been removed from the existing unpaved areas of the Site. In addition, asphalt paving would significantly increase the amount of storrnwater discharged to the 700 West Ditch and increase potential for flooding in the area.

In consideraUon of potential future risks to human health, the 1991 ROD set the following performance standards:

• Stage and treat all soils, sludges and dioxin removal wastes containing indicator chemicals at levels in excess of soil action levels so that contaminant levels

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remaining in the vitrified dioxin removal wastes do not exceed land disposal restriction treatment standards.

• Reduce the levels of contaminants by at least 50 percent within the first five years, as compared to baseline levels prior to remediation.

• Reduce contaminant levels in groundwater within the area of attainment to MCLs and proposed MCLs.

• Meet all ARARs identified in the ROD for the remediation of soils, sludges, dioxin removal and groundwater.

Tables 3 and 4 below detail the action levels and the concentrations of indicator chemicals in source area sludge, soils and groundwater as reported in the 1991 ROD.

Table 3: Action Levels and Indicator Chemical Concentrations in Source Area Sludge and Soils

Compound Maximum SludgeValue (parts per billion / ppb)

Maximum Soil Value

(ppb)

Action Levels

(ppb)

VOCs

TCE 440,000 1,800 103,000

PCE 200,000 22,000 22,000

SVOCs

HCB 49,000 66,0000 7,000

PCP 460,000 250,000 —-Herbicides

2,4-D 634 30,768 —

2,4,5-T 300 1,111 ... .

Pesticides

4,4'-DDD 280 400 26,000

4,4'-DDE 6,300 4,500 19,000

4,4-DDT 2,800 8,100 19,000

Alpha-chlordane 520,000 520,000 7,000

Gamma-chlordane 680,000 890,000 7,000 Heptachlor 26,000 5,300 2,000

Dioxins

TCDD (Total) 13 11 20

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Table 4: Action Levels and Indicator Chemical Concentrations in Groundwater

Compound Maximum Value (micrograms per liter / ng/L)

Geometric Mean (tig/L)

Action Level / M C L

(Jig/L) VOCs

PCE 1,400 (MW-12) 21 5

TCE 8,000 (MW-07) 78 5

1,1-DCE 230 (MW-12) 53 7 SVOCs

PCP 630(MW-10) 508 1 Herbicides and Pesticides

2,4-D 26 (MW-12) 7.6 70

The Site's Consent Decree set forth that if the concentrations of the indicator chemicals remain below MCLs for three years during the post-compliance period, an application for Certificate of Completion may be made. If evaluation of hydraulic enhancements and treatment enhancement indicate no reasonable alternatives for improving system operations exist, a petifion for alternate performance standards may be submitted for consideration.

4.2 Remedy Implementation

In September 1991, EPA, UDEQ and Entrada Industries, Inc. (a subsidiary of Questar) signed a Consent Decree for Questar to implement the remedy selected in the ROD. This agreement was lodged in the U.S. District Court on November 12, 1991. Questar then conducted the Site's remedial design from September 30, 1991 to September 10, 1993.

Remediation of source material and groundwater at the Site encompassed four stages:

1. Excavation and landfarming of hydrocarbon-contaminated soils. 2. Excavations and ISV treatment of highly contaminated soils and debris. 3. Groundwater extraction and treatment. 4. Groundwater pilot study of alternative remedies.

Stages one and two were completed. The groundwater extraction and treatment stage was implemented and subsequently halted. A groundwater pilot study was then implemented to evaluate possible alternative remedies for groundwater. Each of these stages is discussed below.

Excavation and landfarming of hydrocarbon-contaminated soils Questar began the landfarming portion of the remedial action on October 23, 1992. Questar excavated approximately 1,000 cubic yards of hydrocarbon-contaminated material and placed the material in an on-site containment cell. Excavation occurred to a depth of approximately 2 feet below the groundwater table, which ranged from 1 to 4 feet ^ below the ground surface. Questar completed the activities on April 26, 1993. Addition of nutrients to the landfarm cell as well as pH adjustment aided in optimum biodegradation of the hydrocarbon wastes. Confirmation sampling was performed. Soil sections meeting

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the standard were used as backfill in their original location. Remaining landfarm soils were applied as cover material, which were subsequently treated with ISV. Questar completed the landfarming portion of the remedial action in December 1994. EPA certified its completion in January 1994.

Excavations and ISV of highly contaminated soils and debris ISV was selected to remediate soil exceeding action levels. Contaminated soils, sludges and debris were placed in the on-site concrete evaporation pond. Residual soils from the landfarm remediation were placed on top of the consolidated material in the evaporation pond. A clean soil cap was placed over the treatment zone and a clean soil berm was placed around the concrete evaporation pond. ISV required 37 melts (the process of melting soil in place using electricity) across the entire evaporation pond. Verification samples of the vitrified material showed the ISV process effectively reduced chemical concentrations below the risk-based action levels established for the Site. The process remediated approximately 5,600 tons of contaminated material. The ISV portion of the remedial acfion was completed in January 1996. EPA and UDEQ certified its completion in May 1996.

EPA and UDEQ issued the Construction Completion Report for the soils remedy in January 1996. The report confirmed the attairmient of performance standards and completion of remedial activities for soils, sludges and dioxin removal wastes.

Groundwater extraction and treatment Installafion of the groundwater extraction wells and construction of the treatment facility was completed in March 1995. The first quarterly groundwater sampling event, representing baseline conditions, occurred in March 1995. System operations began in August 1995. In accordance with the Site's Groundwater Monitoring Plan, groundwater samples were collected on a quarterly basis from 1995 through 2000. Samples were then collected and analyzed semi-armually, beginning in May 2001.

Monitoring data indicated that the groundwater collection system significantly reduced contaminant concentrations in groundwater at the Site (with the exception of EX-01) and partially removed contaminants over its period of operation. Contaminant concentrations in EX-01 remained relafively constant or have increased slightly over time. Due to the presence of foam in EX-01, which created severe problems in the groundwater treatment system, the extraction well was pumped at a very low rate during 1996. Pumping ceased in December 1996. In September 1997, an extraction trench (ES-01) was designed and installed in the general area of EX-01 to address these problems. In July 2001, 11 monitoring wells (MW-18, MW-16, MW-07, EX-03, WP-05, WP-01, MW-13, MW-05, WP-03, MW-03 and MW-04) were abandoned with EPA and UDEQ approval and in accordance with State regulations. MW-12, although approved for abandonment, could not be located.

In October 2001, Questar proposed modifying the groundwater extraction scheme to pump only from two extracfion trenches, EX-11 and ES-01. Computer modeling evaluated the minimum pumping rates needed at these two locations to ensure hydraulic

23

containment of groundwater contaminants. EPA approved the two-location pumping scenario in December 2001. The modification was implemented later that month.

Groundwater pilot study of alternative remedies In August 2002, EPA approved temporary modifications to the groundwater extraction scheme to avoid damage to pumps during drought-related, low-water conditions. Questar then proposed to discontinue groundwater extraction and treatment and submitted a long-term monitoring plan to EPA and UDEQ for review and approval. In January 2003, EPA approved a work plan to investigate and analyze the possibility of monitored natural attenuation (MNA) as an alternative remedy. In 2004, EPA aproved an enhanced in-shu bioremediation pilot study.

Quarterly sampling resumed in 2003 to obtain a representative baseline for evaluation of MNA as a possible alternative remedy. Sampling reverted to semi-aimual frequency in 2004. MNA and the use of enhanced biodegradation processes are considered interim pilot studies. The efficacy of these alternative remedial measures will be evaluated before a final decision is reached regarding disposition of the groundwater extraction and treatment system. EPA is currently evaluating existing data and requesting additional data collection and information to fully evaluate remedy options.

To allow adequate monitoring of natural attenuation, EPA added vinyl chloride to the list of VOCs reported to assess the presence of all transformation products of PCE and TCE. Sulfate/sulfite, nitrate/nitrite and iron(II)/iron(III) were also added to assess the availability of electron acceptors used in microbial metabolism.

To accelerate degradation of chlorinated hydrocarbons at the Site, enhanced biodegradation activities were conducted in May 2004 and July 2006.

Assessment of the 700 West ditch for purposes of potentially implementing an Alternative Concentrafion Limit (ACL) approach was performed in 2007. The interaction between Site groundwater and surface water in the 700 West Ditch was evaluated to determine if the use of ACLs was applicable for determining potential alternafive performance standards for groundwater. In November 2007, water velocity measurements were collected from the 700 West Ditch along the west side of the Site to determine if the ditch is impacted by Site groundwater. Measurements collected indicate no measurable flow was occurring in the ditch at that time. To investigate the possibility that the ditch may be losing water, groundwater elevations in Well MW-06 near the 700 West Ditch were compared with available ditch flowline elevation data. The highest groundwater elevations recorded from Well MW-06 were consistently below the corresponding ditch flowline elevation, indicating groundwater at the site does not discharge to the 700 West Ditch. Thus, there is not a receiving surface water body, that is required for the ACL approach, and it was concluded that this ACL method was not applicable for the Site.

The Utah Division of Water Rights (DWRi), led by the State Engineer, implemented a formal process in February 2008 to send a warning email notificafion to Utah Department

24

of Environmental Quality (UDEQ) - Division of Environmental Response and Remediation (DERR) and EPA whenever DWRi receives an application from a potential water user to divert water from the Site.

EPA, UDEQ and Questar signed an environmental covenant requiring land use restrictions, notification of building demolition, vapor intrusion risk assessment and mitigation associated with new building construction, and groundwater restrictions and recorded it with the Salt Lake County Recorder's office on January 14, 2009.

In 2010, Questar submitted a draft Focused Feasibility Study (FFS) to EPA to identify goals, objectives and remediafion altemafives based on pilot study results. EPA is working with Questar to identify additional data necessary to fully review outstanding FFS issues. To complete the FFS, EPA has determined that updated vapor intrusion sampling and analysis are necessary. In addition, EPA is waiting for completion of additional groundwater studies to fully evaluate MNA as a remedy alternative.

In October 2011, Questar installed four additional groundwater monitoring wells (MW-30, MW-31D, MW-32D and MW-33D).

4.3 Operation and Maintenance (O&M)

Operation and maintenance (O&M) activities currently include monitoring of groundwater and reporting of sampling results in accordance with the 2002 Monitoring Plan for Natural Attenuation at Wasatch Chemical. In addition, Questar is conducting additional sampling and analysis to complete the FFS and evaluate alternative remedial options. As a result of work installing additional monitoring wells and completing the FFS, Questar was unable to separate O&M costs from the additional investigative work being conducted and was unable to provide cost data for inclusion in the current FYR.

During preparation for the semi-annual groundwater monitoring activifies in October 2007, excavation and construction activities were observed on the northern portion of the Site on the FNSTEL property. INSTEL was building a metal storage building on its property. Questar took immediate action to protect the monitoring and extraction wells and associated conveyance piping and electrical lines near the construction. INSTEL completed construction of a 58,650-square-foot metal storage building, two outdoor 15-ton craneways, and a new stormwater management system near the Site's groundwater monitoring and remediation facilities. Questar and personnel from the PRP remedial contractor MWH marked well locations before and during construction and visited the Site to check on these facilities. When necessary, Questar and MWH persormel made repairs to electrical conduits damaged during construction of the stormwater management system associated with the building.

Because of the construction of the new warehouse and associated changes in the surrounding grade, wellhead modifications were needed for some wells. Two wells (EX-04 and MW-21) are now located inside the new warehouse. Four wells (EX-09, MW-20, PZ-2 and PZ-3) are in areas where ground surface regrading was conducted. After

25

installation of the new storage building floor, it was discovered that well EX-04 had been inadvertently buried beneath the concrete. Questar located and gained access to this well by removing the concrete and the overburden covering it. Wells MW-20, EX-09, PZ-2 and PZ-3 were inadvertently covered with fill material during construction. Questar located each of the wells and removed the overburden to attain access for repairs and modifications. In the fall of 2008, a new asphalt parking lot west of the warehouse inadvertently covered monitoring point PZ-2, preventing access to this piezometer. Despite efforts to find PZ-2, which was used for groundwater level measurements, it could not be located.

In addition, Questar had a geotechnical review conducted to assess potential impacts on soil permeability due to the added loads of the new FNSTEL facilities. The review focused on the Geotechnical Investigation Report and engineering drawings for the FNSTEL construction project and indicated potential impacts are expected to be limited. Although several inches of settlement are expected due to the anticipated building and steel storage loads on the fine-grained native soils, any effect of soil consolidation due to the loading is considered minor given the already low permeability of site soils and the shallow hydraulic gradient on site. Further discussion of the geotechnical assessment is included in the 2008 Impacts of the New Steelco Warehouse on Groundwater Remediation Activities Report.

In October 2011, remedial contractors drilled four new groundwater monitoring wells: a shallow aquifer well (MW-30) and three deeper aquifer wells (MW-31D, MW-32D and MW-33D) to assess the potential presence of dense nonaqueous phase liquid (DNAPL) in the deeper aquifer. During these drilling activities, remedial contractors detected additional shallow soil contamination. Soil sampling detected VOCs and PCP in soil samples collected from two of the four new groundwater monitoring wells, including concentrations of TCE and PCE that exceed the soil performance standards for the Site. Further investigation is necessary to delineate the extent of this recently identified area of soil contamination and remedial actions may be required to address soil contamination at levels above performance standards for the Site.

5.0 Progress Since the Last Five-Year Review

The protectiveness statement from the 2007 FYR for the Site stated the following:

"The remedy as implemented is currently protective of human health and the environment. Contaminated groundwater remains within the Site boundaries and no evidence of groundwater use was identified. Soils and wastes containing contaminants above performance standards were successfully and permanently treated. Institutional controls prohibiting residential land use are in place."

The recommendations in the 2007 FYR and their current status are discussed below (Table 5).

26

Table 5: Progress on Recommendations from the 2007 FYR

Recommendations Party Responsible

Milestone Date

Action Taken and Outcome Date of Action

Evaluate site data against criteria for waiver or modification of the action level performance standards for groundwater.

EPA 09/30/2008 Questar submitted draft FFS to EPA for review.

02/15/2010

Modify land use restriction institutional control to require an assessment of risks related to contaminant vapor intrusion prior to approval of a building permit for occupied structures.

Questar 09/30/2008 Environmental covenant filed. 01/14/2009

Implement restriction through Utah Division of Water Rights.

Questar 12/31/2007

The Utah Division of Water Rights (DWRi), led by the State Engineer, implemented a formal process to send a warning email notification to UDEQ and EPA whenever there is an application to divert water from the Site.

02/15/2008

Consider the addition of vinyl chloride to the list of indicator chemicals.

EPA 09/30/2008

Current work plans regard vinyl chlorides a COC. EPA anticipates completion of this item in an upcoming decision document.

ongoing

6.0 Five-Year Review Process

6.1 Administrative Components

EPA Region 8 initiated the FYR in January 2012 and scheduled its completion for September 2012. The EPA site review team was led by EPA Remedial Project Manager (RPM) Sam Garcia and also included EPA Community Involvement Coordinator (CIC) Peggy Lirm. Contractor support was provided to EPA by Skeo Solutions. In January 2012, EPA held a scoping call with the review team to discuss the Site and items of interest as they related to the protectiveness of the remedy currently in place. A review schedule was established that consisted of the following activities:

• Community notification. • Document review. • Data collection and review. • Site inspection. • Local interviews. • FYR Report development and review.

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6.2 Community Involvement

In March 2012, a public notice was published in the Salt Lake Tribune newspaper announcing the commencement of the FYR process for the Site, providing contact information, and inviting community participation. The press notice is available in Appendix B. No one contacted EPA as a result of this advertisement.

Interviews were conducted as part of the community involvement process and are summarized in section 6.6.

The FYR Report will be made available to the public once it has been finalized. Copies of this document will be placed in the designated site repository: UDEQ offices, 195 North 1950 West, Sah Lake City, Utah 84114. In addition it will be placed in the EPA Superfund Records Center.

6.3 Document Review

This FYR included a review of relevant, site-related documents including the ROD, remedial action reports, and recent monitoring data. A complete list of the documents reviewed can be found in Appendix A.

ARARs Review

CERCLA Section 121(d)(1) requires that Superfund remedial actions attain "a degree of cleanup of hazardous substance, pollutants, and contaminants released into the environment and of control of further release at a minimum which assures protection of human health and the environment." The remedial action must achieve a level of cleanup that at least attains those requirements that are legally applicable or relevant and appropriate. Applicable requirements are those cleanup standards, standards of control, and other substantive requirements, criteria or limitations promulgated under federal environmental or state environmental or facility siting laws that specifically address a hazardous substance, remedial action, location or other circumstance found at a CERCLA site. Relevant and appropriate requirements are those standards that, while not "applicable," address problems or situations sufficiently similar to those encountered at the CERCLA site that their use is well suited to the particular site. Only those state standards that are more stringent than federal requirements may be applicable or relevant and appropriate. To-Be-Considered (TBC) criteria are non-promulgated advisories and guidance that are not legally binding, but should be considered in determining the necessary remedial action. For example, TBCs may be particularly usefiil in determining health-based levels where no ARARs exist or in developing the appropriate method for conducting a remedial action.

Chemical-specific ARARs are health- or risk-based numerical values or methodologies which, when applied to site-specific conditions, result in the establishment of numerical values. These values establish an acceptable amount or concentration of a chemical that may remain in, or be discharged to, the ambient environment. Examples of chemical-

28

specific ARARs include MCLs under the federal Safe Drinking Water Act (SDWA) and ambient water quality criteria enumerated under the federal Clean Water Act.

Action-specific ARARs are technology- or activity-based requirements or limits on actions taken with respect to a particular hazardous substance. These requirements are triggered by a particular remedial activity, such as discharge of contaminated groundwater or in-situ remediation.

Location-specific ARARs are restrictions on hazardous substances or the conduct of the response acfivities solely based on their location in a special geographic area. Examples include restrictions on activities in wetlands, sensitive habitats and historic places.

Remedial actions are required to comply with the ARARs identified in the ROD. In performing the FYR any newly promulgated standards, including revised chemical-specific requirements (such as MCLs, ambient water quality criteria), revised action and location-specific requirements, and State standards if they were considered ARARs in the ROD, are reviewed to establish whether the new requirement indicates that the remedy is no longer protective.

Groundwater ARARs According to the ROD, SDWA MCLS are the chemical-specific ARARs for groundwater contaminants of concern (COCs). MCLs from the ROD were compared to current MCLs to identify any changes (Table 6). Current MCLs remain the same as those identified in the ROD.

Table 6: ARAR Review for Groundwater COCs

COC 1991 ROD

ARARs (ng/L) Current*

ARARs (ng/L) ARARs Change

PCE 5 5 None TCE 5 5 None 1,1-DCE 7 7 None PCP 1 1 None 2,4-D 70 70 None

a. Based on SDWA MCLs, available at: http://water.epa.eov/drinkycontaminants/index.cfm (last accessed 5/07/2012).

Institutional Controls

The 2007 FYR indicated that formal groundwater use restrictions through the DWRi had not been implemented at the Site. Questar provides semi-annual reports on groundwater quality at the Site to the DWRi, led by the State Engineer. The DWRi informed EPA that they did not have the authority to restrict groundwater use. However, DWRi could notify EPA and UDEQ if an application for groundwater use is made within the Site and then EPA and UDEQ could take action to assure that groundwater is not used inappropriately. It was determined that this DWRi notification could act as an institutional control for

29

groundwater at the Site. The DWRi implemented a formal process in February 2008 to send a warning email notification to Utah Department of Environmental Quality (UDEQ) - Division of Environmental Response and Remediation (DERR) and EPA whenever there is an application to divert water from the Site.

EPA, UDEQ and Questar signed an environmental covenant containing land use and groundwater restrictions, and requiring nofification of building demolition, vapor intrusion risk assessment and mitigation associated with new building construction and recorded it with the Salt Lake County Recorder's office on January 14, 2009. The institutional control impacted five property parcels at the Site (Table 7, Figure 3).

Table 7: Properties Included in 2009 Environmental Covenant

Owner Parcel Identiflcation number Total Parcel Acreage Questar infocomm Inc 1513351003 7.36 Questar Infocomm Inc 1513351004 3.51 Questar Infocomm Inc 1513351006 0.70 Questar Infocomm Inc 1513351007 2.97 Questar Infocomm Inc 1513351008 0.02

Table 8 summarizes the institutional controls associated with areas of interest at the Site.

Table 8: Institutional Control (IC) Summary Table

Media ICs

Needed

ICs Called for in the Decision

Documents

IC Objective

Instrument in Place

Groundwater Yes Yes Restrict installation of groundwater wells.

The State Engineer's office implemented a formal process in February 2008 to send a warning email notification to UDEQ-DERR and EPA whenever there is an application to divert water from the Site. Environmental covenant filed January 14, 2009, provides for land use and groundwater restrictions for a portion of the Site.

Soil Yes Yes

Prohibit any activity that may disturb the integrity of the engineering controls, assess risks associated with potential vapor intrusion for new buildings, and limit fiiture uses to industrial land uses.

Environmental covenant filed January 14, 2009, for a portion of the Site.

The environmental covenant filed in 2009 only affects the portion of the Site with properties currently owned by Questar (Figure 3). Plume maps provided by Questar in April 2012 indicate that groundwater contaminant plumes containing DCE, TCE and vinyl chloride impact property parcels that are not included in the covenant (Appendix F). However, these properties are covered by the DWRi notification IC. Table 9 includes

30

property parcel identification information for parcels noted in Figure 3. Multiple site properties do not have institutional controls fulfilling the objectives related to assessing risks related to vapor intrusion. In particular, the property affected by the construction of the FNSTEL warehouse in late 2007 (parcel 1513301001) does not currently have any institutional controls related assessing risks associated with potential vapor intrusion for new buildings.

Table 9: Property Parcel Identification in Institutional Control Base Map

Owner Parcel Identification number Total Parcel Acreage Instel West Properties 1513301001 18.6 Rio Grande Land Company

1513302001 0.52

No information available 1513351001 No information available Questar Infocomm Inc 1513351003 7.36 Questar Infocomm Inc 1513351004 3.51 Questar Infocomm Inc 1513351006 0.70 Questar Infocomm Inc 1513351007 2.97 Questar Infocomm Inc 1513351008 0.02 No information available 1513351012 No infonnation available No information available 1513501013 No information available No information available 1513501110 No information available No information available 1513501111 No information available No information available 1513501112 No information available No information available 1513501113 No information available No information available 1513501114 No information available The D&RGW RR Co 1513501115 1.31 No information available 1513501116 No information available No information available 1513501117 No information available

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Figure 3: Institutional Control Base Map

0 100 200 400 I Feel

Legend

11231 Parcel boundaries V / A Properties included in the and parcel number 2009 environmental covenant

i) sl<eo O NORTH

Wasatch Chemical Co. (Lot 6) Salt Lake City, Salt Lake County, Utah

Disclaimer: This map aiid any boundary lines within the map are approximate and subject to change. The map is not a survey. The map is for informational purposes only r^arding EPA's response actions at the Site, and is not intended for any olher purpose.

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6.4 Data Review

Groundwater

The 1991 ROD identified five indicator COCs for remediation and long-term monitoring in site groundwater: PCE, TCE, 1,1-DCE, PCP and 2,4-D. Monitoring for 2,4-D was discontinued in 2004 after the COC had not been detected in several rounds of sampling. Vinyl chloride, which was not included as an indicator COC in the 1991 ROD, has been detected in several rounds of groundwater sampling. Concentrations of vinyl chloride are now routinely monitored. Isomers for 1,2-DCE have been routinely monitored since 2009 to aid in evaluation of the MNA pilot study; cis-l,2-DCE and trans-1,2-DCE are common breakdown products of TCE and PCE. The pump-and-treat groundwater remedy operated at the Site from 1995 to 2003, when EPA transitioned the groundwater remedy to MNA. EPA is evaluafing the effectiveness of MNA before issuing a final decision regarding whether or not to reinstate the pump-and-treat remedy or evaluate other remedial alternatives.

During the current FYR period, groundwater monitoring was performed semi-annually at 15 wells screened in the shallow aquifer. A sixteenth well, MW-30, was drilled in 2011 and will be part of the routine semi-armual sampling program These wells are used to monitor natural attenuation of contaminants and also to assess the potential for migration of groundwater contaminafion. In October 2011, remedial contractors drilled four new groundwater monitoring wells: a shallow aquifer well (MW-30) and three deeper aquifer wells (MW-31D, MW-32D and MW-33D) to assess the potential presence of DNAPL in the deeper aquifer. November 2011 sampling performed in association with the October 2011 drilling event detected contaminant concentrations above the MCL for one or more COC in nine of the 16 shallow groundwater monitoring wells: ES-01, EX-02, EX-04, EX-05, EX-07, EX-08, EX-11, MW-20 and MW-30 (Appendix F; Table F-1).

Well EX-02 continues to exhibit the most elevated concentrations of TCE and highly elevated concentrafions of vinyl chloride, with concentrations two orders of magnitude above the MCL for all sampling events in the current FYR period except for November 2011. November 2011 sampling results for EX-02 indicated a TCE concentration of 74 Hg/1 (the MCL is 5 ig/l) and a vinyl chloride concentrafion of 68 n-g/l (the MCL is 2 [ig/l). In addifion to achievement of MCLs, the 1991 ROD selected a secondary goal of a 50 percent reduction of contaminant concentrations relative to the 1995 baseline. EX-02 is the only well that has not achieved this reduction in TCE concentrations.

The most elevated concentrations of vinyl chloride were detected in EX-11. Values of vinyl chloride fluctuated, ranging from a high of 920 i^g/l in April 2008 to a low of 230 ^g/l in April 2011 (the MCL is 2 |ag/l; Figure 4). Fluctuations of cis-1,2-DCE (Figure 4), TCE and 1,1-DCE in EX-11 (Figure 5) are also present and exhibit higher concentrations in the spring sampling events. Similar spiking of contaminant concentrations in the spring sampling events was noted for PCE, TCE, vinyl chloride and PCP in ES-01 (Figure 6) and for vinyl chloride in EX-02 (Figure 7). While there has been some variance in both

33

TCE and cis-1,2-DCE in EX-02 over time, TCE concentrations appear to be declining while cis-1,2-DCE, a breakdown product of TCE, concentrations are beginning to rise (Figure 7). The possibility of seasonal fluctuations in groundwater concentrafions may require further investigation and should be considered in the scope and evaluation of the interim pilot study currently underway at the Site.

In the deeper aquifer groundwater sampling late in 2011, exceedances of the MCLs for TCE and PCE were detected in MW-33D (Table 10). All three wells will continue to be monitored for site contaminants during the on-going investigation.

Figure 4: Concentrations of Cis-1,2-DCE and Vinyl Chloride in Well EX-11, October 2007 to November 2011

1,400

1,200

•2 1,000

c

= o

= = o

O

800

600

400

200

•Cis-1,2-DCE

•Vinyl Chloride

0 Oct-06 Feb-08 Jul-09 Nov-10

Sampling Date

Apr-12

34

Figure 5: Concentrations of TCE and 1,1-DCE in Well EX-11, October 2007 to November 2011

90 1

Iso

•TCE

•1,1-DCE

Oct-06 Feb-08 Jul-09 Nov-10 Sampling Date

Apr-12

Figure 6: Concentrations of PCE, TCE, Vinyl Chloride and PCP in Well ES-01, October 2007 to November 2011

•PCE

•TCE

Vinyl Chloride

• PCP

Oct-06 Feb-08 Jul-09

Sampling Date

Nov-10 Apr-

35

Figure 7: Concentrations of TCE, Cis-1,2-DCE and Vinyl Chloride in Well EX-02, October 2007 to November 2011

250

2 200

^ 150

e o ^ 100

50

0

•TCE

•Cis-1,2-DCE

•Vinyl Chloride

Oct-06 Feb-08 Jul-09 Nov-10

Sampling Date

Apr-12

Table 10: 2011 Deep Aquifer Groundwater Monitoring Well Results

COC MCL (ng/i)

Well (Sample Date)

COC MCL (ng/i) IVIW-31D

(12/20/2011) MW-32D

(12/20/2011) MW-33D

(12/28/2011)

PCE 5 <1 <l 46 TCE 5 1 1 31 J 1,1-DCE 7 <l <I <1 Cis-1,2-DCE 70 <1 1 4.7 Trans-1,2-DCE 100 <1 <1 1 Vinyl chloride 2 <1 <l <1 I'CI' 1 <0.5 0.5 <0.5 Notes: J: Data estimated due to associated quality control daa. Bold; Detected concentration is equal to or exceeds MCL.

Soil

The 1991 ROD selected landfarming and ISV to address soil contamination at the Site. EPA certified completion of landfarming activities in 1995 and completion of ISV activities in 1996. Al l known soils and wastes containing contaminants above action levels selected in the ROD were successfully and permanently treated. No additional monitoring of soil contamination was required.

36

In accordance with the 2011 Final Groundwater Monitoring Well Installation and Sampling Plan, soils excavated during the drilling of groundwater wells must be tested and contaminant concentrations compared with the EPA Regional Screening Levels for Industrial Use. During October 2011, remedial contractors detected additional shallow soil contamination during drilling activities associated with the groundwater monitoring program. Soil sampling detected VOCs and PCP during drilling of two of the four new groundwater monitoring wells: MW-30 and MW-33D (Table 11). Cis-1,2-DCE and a trace amount of TCE were detected in soils at MW-30. Significant dilutions were required for analysis of soil samples from MW-33, but several VOCs were detected, including concentrations of TCE and PCE exceeding soil performance standards for the Site. Further investigation is necessary to delineate the extent of this recently identified area of soil contamination. In addition, sampling analysis methods for soil samples taken from MW-31D and MW-32D did not permit comparison of concentrations with the screening levels because the minimum detection limit exceeded the screening levels. Future analysis should utilize methodology that permits a low enough minimum detection limit to allow comparison with screening levels. Remedial actions may be required to address soil contamination at levels above performance standards for the Site.

37

Table 11: 2011 Soil Sampling Results

Contaminants

Well MW-30 iVIW-31D MW-32D MW-33D MW-33D MW-33D

Contaminants

Sample Depth (ft)

17.5 25.5 21.5 3.5 15.5 38

Contaminants EPA Regional Screening Level for

Industrial Soil (mg/kg)

(mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg) (mg/kg)

Contaminants to be sampled per the EPA-approved work plan

1,1-DCE 1,100 <4.7 <6.5 <6.8 <6,400 D <5.6 <5.4

Cis-1,2-DCE 2,000 10 <6.5 <6.8 37,000 D 420 1.6 T

Trans-1,2-DCE 690 <4.7 <6.5 <6.8 <6,400 D 1.4 T <5.4

PCE 110 <4.7 <6.5 <6.8 3,100,000 D 4,500 D 8,000 D

PCP 2.7 <12 <14 <14 1,200 D 95 <13

TCE 6.4 1.1 T <6.5 <6.8 78,000 D 12 1.7 T

Vinyl chloride 1.7 <4.7 <6.5 <6.8 <6,400D <5.6 <5.4

Additional sampling for A4W-33D 1,1,1-Trichloroethane 38,000 NA NA NA 4,000 T <5.6 <5.4 2-Butanone (MEK) 200,000 NA NA NA < 13,000 D <l 1 7.7 T

Acetone 630,000 NA NA NA < 13,000 D <11 32

Benzene 5.4 NA NA NA <6,400 D 1.3 T 1.7T

Carbon disulfide 3,700 NA NA NA <6,400D <5.6 2.7 T

Chloroform 1.5 NA •NA NA <6,400 D 2.6 T <5.4

Ethylbenzene 27 NA NA NA 1,400,000 D 2,400 D 2,600 D

M/P-Xylenes 2,500 NA NA NA 12,000,000 D 7,400 D 10,000 D

0-Xylene 3,000 NA NA NA 4,000,000 D 3,100 D 4,100 D

Toluene 45,000 NA NA NA 610,000 D I,100D 1,500 D

Notes: NA: Not Applicable T; Trace concentration detected below reporting limit D: Sample diluted mg/kg: milligrams per kilogram Bold: Denotes value that meets or exceeds the EPA Regional Screening Le\el for Industrial Soil. Instances where the detection level was not low enough to permit comparison with the screening level have also been marked h bold.

6.5 Site Inspection

The site inspecfion was performed on March 20, 2012, by the following participants: Sam Garcia and Peggy Linn of EPA Region 8; Tony Howes of UDEQ; Paul L. Drake and Gordon Murdock of Questar; Susan L. Eyzaguirre, Stacey Arens and Jesse A. Stewart of MWH; and Treat Suomi and Eric Marsh of Skeo Solutions. The completed site inspection checklist is available in Appendix D. General conditions were noted and photographed (Appendix E).

38

Site inspection participants met in the groundwater treatment system building and discussed the current activities at the Site, the remedy, the status of the recommendations from the 2007 FYR and the site inspecfion components. The participants then inspected sampling ports inside the building, which are used to collect groundwater samples from extraction wells. The participants also inspected the two large holding tanks adjacent to the building where water is discharged and lefl: to evaporate following sampling events and monthly exercising of the pumps. The participants then walked around the Site, viewing the area of vitrified soil, monitoring wells and general site conditions. Site participants inspected monitoring wells on the east side of the railroad tracks as well as those at the northern end of the Site, at the steel warehouse. Site participants also viewed an industrial ditch along the western edge of the Site. Several industrial businesses are operating on site.

Eric Marsh and Treat Suomi of Skeo Solutions inspected site monitoring wells. All wells were locked and in good condition. Site inspection participants from Questar and MWH were interviewed after the site tour.

EPA CIC Peggy Linn, UDEQ CIC Coordinator Dave Allison and Skeo Solutions staff drove to the Salt Lake City and County Building to interview District 2 Council representative Kyle LaMalfa.

EPA and Skeo Solutions staff returned to the Site to interview business owners.

6.6 Interviews

During the FYR process, interviews were conducted with parties impacted by the Site, including the current landowoiers, and regulatory agencies involved in site activities or aware of the Site. The purpose of the interviews was to document the perceived status of the Site and any perceived problems or successes with the phases of the remedy implemented to date. Interviews are summarized below and complete interviews are included in Appendix C.

PRP: Paul Drake, Senior Environmental Health & Safety Coordinator for Questar Gas Company, explained that the remedial action is protecting the environment and personnel. Apart from environmental covenants, he is not aware of any effects the Site has had on the surrounding community. Similarly, he is not aware of any complaints from residents since implementation of the cleanup. Recently, he has been in touch with on-site businesses discussing vapor intrusion monitoring with them. The businesses, he explained, have been supportive of this.

Mr. Drake believes that the groundwater pump-and-treat system has reached the limits of its effectiveness. It is now time to move past a memo with EPA focused on MNA testing and implement a ROD Amendment that fiiUy supports MNA.

Overall, Mr. Drake feels that the remedy process is going slower than he would like. In addition, he would like to see better communication with EPA. Recent communication

39

difficulties may have been due in part to turnover in EPA project managers. A communication plan was included as part of a work strategy recently submitted to EPA.

Remedial Contractor: Regarding their overall impressions of the project, representatives for MWH, Questar's remedial contractor, explained that the original groundwater pump-and-treat remedy achieved all that it could in terms of removing contaminant mass. However, they now feel it is time to move forward with an alternative remedy to capture the remaining one percent of contamination in groundwater. They explained that they have looked at other potential remedies and feel that MNA will be the best approach moving forward.

Regarding O&M, MWH representatives explained that the monitoring well manager checks the wells on a monthly basis. Site inspections are also conducted monthly. They added that there have been no significant changes in O&M requirements since the shutdown of the pump-and-treat system in 2003. The representatives also noted that since sampling of new deeper wells showed contamination in October 2011, MWH has conducted additional investigations. These investigations have not affected protectiveness. Moreover, restrictions are in place to restrict digging and MWH representatives have not identified any signs of digging.

Regarding unexpected O&M difficulties or costs, MWH representafives explained that they were considering a new, long-term sampling plan; this would be something that might be more efficient and save on costs. The current sampling protocol has been in effect since 1996.

MWn representatives feel that communication with EPA could be enhanced, with more regular communicafion and less emphasis on written communication. They included some ideas in the work strategy recently submitted to EPA. They added that with the new soil contamination and vapor intrusion investigations, there is an opportunity to be more collaborative with EPA.

On-site Business: An operations manager for FNSTEL Steel West explained that the environmental contamination issues were located toward the southem portion of the Site and in the north-central portion of the Site, where INSTEL Steel West had recently constructed a warehouse. FNSTEL uses the city's water supply and does not have a private well on site. Overall, the manager has a favorable impression of the project. He did not believe the Site had had any effects on the surrounding community. He explained that about four years ago when he started working at FNSTEL there had been problems with break-ins on FNSTEL's property. Since his company enacted security measures, these problems have stopped. The manager also explained that the only time EPA needed to get in touch with him was during EPA site inspections. The best way to do this is via phone.

Local Govemment Official: Salt Lake City Council Member Kyle LaMalfa was not aware of the Site until it was brought to his attention as part of the site inspection. He was not aware of any state laws or local regulations that might affect the protectiveness of the

40

Site's remedy. However, he explained that the Site falls within an area the City is addressing through the West Salt Lake Master Plan and EPA should make planners aware of the Site. In terms of communications, the council member prefers to have an annual face-to-face meeting with EPA and UDEQ about this and other similar sites in his district. In terms of communicafing with the surrounding community about the Site, the council member recommends communicating through a community newspaper (westviewmedia.org) that is mailed to all households in his district.

EPA RPM: Sam Garcia is EPA's RPM for the Site. Mr. Garcia is not aware of any negative effects, complaints, inquiries or community concerns about the Site. Mr. Garcia feels informed about site activities and is comfortable with the status of the institutional controls. Mr. Garcia believes the maintenance and reuse of the Site to be consistent with neighboring properties. Mr. Garcia expressed that EPA, the State and the PRP are addressing recently discovered soil and groundwater contamination and that soil and groundwater sampling should be completed prior to evaluating any long-term groundwater remedies.

7.0 Technical Assessment

7.1 Question A: Is the remedy functioning as intended by the decision documents?

The review of documents, ARARs, risk assumptions, institufional controls and the site inspecfion indicate that portions of the remedy may not be functioning as intended by site decision documents.

Excavation and landfarming of hydrocarbon-contaminated soils was completed in 1994. Contaminated soils, sludges and debris were placed in the on-site concrete evaporation pond. Residual soils from the landfarm remediation were placed on top of the consolidated material in the evaporation pond. A clean soil cap was placed over the treatment zone, and a clean soil berm was placed around the concrete evaporation pond. ISV was completed and verification samples of the vitrified material showed the ISV process effectively reduced chemical concentrations below the risk-based acfion levels established for the Site in 1996. EPA and UDEQ determined that remedial activities had attained performance standards for soils, sludges and dioxin removal wastes and issued the Construction Completion Report for the soils remedy in January 1996.

Groundwater extraction and treatment was implemented in ^995 and subsequently halted in 2003 . A groundwater study was implemented to evaluate possible alternative remedies for groundwater. In 2010, Questar submitted a draft FFS to EPA to identify goals, objectives and remediation altemafives as a result of the pilot studies. EPA is working with Questar to idenfify additional data necessary to fully review outstanding FFS issues. EPA is evaluating the effectiveness of MNA before issuing a final decision regarding whether or not to reinstate the pump-and-treat remedy or evaluate other remedial altematives.

41

In October 2011, remedial contractors detected additional shallow soil contamination during drilling activities associated with the groundwater monitoring program. Soil sampling detected VOCs and PCP in soil samples collected from two of the four new groundwater monitoring wells, including concentrations of TCE and PCE exceeding soil performance standards for the Site. Further investigation is necessary to delineate the extent of this recently identified area of soil contamination. Remedial actions may be needed to address soil contamination at levels above performance standards for the Site.

Both land use restrictions and groundwater institutional controls are required as part of the selected remedy. DWRi, led by the State Engineer, implemented a formal process in Febmary 2008 to send a waming email notification to UDEQ-DERR and EPA whenever there is an application to divert water from the Site. An environmental covenant containing land use and groundwater restrictions, and requiring notification of building demolition, vapor intmsion risk assessment and mitigation associated with new building constmction is in place for a portion of the Site. Multiple site properties do not have institutional controls fulfilling the objective to assess risks related to vapor intmsion. In order to prevent construction from occurring without proper notification and consideration of the remedy, as occurred on the FNSTEL property in 2007, additional institutional controls are needed. In particular, the property affected by the construction of the FNSTEL warehouse in late 2007 (parcel 1513301001) does not currently have any institutional controls related assessing risks associated with potential vapor intmsion for new buildings. In order to ensure long-term protectiveness, EPA will evaluate the need for institutional controls on the remaining properties at the Site.

7.2 Question B: Are the exposure assumptions, toxicity data, cleanup levels and RAOs used at the time of remedy selection still valid?

No. Several changes have occurred related to the toxicity review for COCs at the Site.

For soils, sludges and dioxin removal wastes, the remedial goal is treatment so that the level of contaminants remaining in these materials does not pose an unacceptable risk to human health or the environment. Since no federal or state chemical-specific ARARs exist for soils and sludges, action levels were determined through a site-specific risk analysis. Action levels for soils, sludges and dioxin removal wastes were selected to achieve a 10" carcinogenic risk for an industrial use scenario and a 10' carcinogenic risk for a residential use scenario. Changes in the oral reference dose used in the site-specific risk analysis have occurred for dioxins. EPA will work to evaluate how these changes affect risk estimates at the Site.

EPA's dioxin reassessment has been developed and undergone review over many years with the participafion of scientific experts in EPA and other federal agencies, as well as scientific experts in the private sector and academia. The Agency followed current guidelines and incorporated the latest data and physiological/biochemical research into the assessment. EPA has released a final reassessment resulting in a non-cancer dioxin toxicity number (IIUS Reference Dose, or RfD). The cancer toxicity number is expected to follow as soon as possible. The RfD is the recommended value for use in developing

42

site-specific cleanup levels, as well as in re-evaluation of sites previously investigated or cleaned up under Superfund. The dioxin toxicity reassessment for the Site is expected to take 36 months.

In addition to the release of EPA's non-cancer toxicity value for dioxin, there have been changes to the cancer slope factors and oral reference doses for PCE and TCE. EPA will work to evaluate how these changes affect risk estimates at the Site.

Questar conducted initial vapor intmsion data collection and analysis in early 2012. However, EPA has determined that additional sampling and analysis are necessary to determine protectiveness related to vapor intmsion.

7.3 Question C: Has any other information come to light that could call into question the protectiveness of the remedy?

Yes. Vinyl chloride, which was not included as an indicator COC in the 1991 ROD, has been detected in several rounds of groundwater sampling. Vinyl chloride concentrations are now routinely monitored at the Site as part of current work plans. Exceedances of vinyl chloride MCLs occurred throughout the FYR period; multiple samples contained vinyl chloride concentrations as high as two orders of magnitude above the MCL. Vinyl chloride should be included as a COC.

7.4 Technical Assessment Summary

The review of documents, ARARs, risk assumptions, institutional controls and the site inspection indicate that portions of the remedy may not be functioning as intended by site decision documents.

The soil remedy that included excavation and landfarming of hydrocarbon-contaminated soils, consolidation of materials, placement of a clean soil cap, and treatment of staged soils, sludges and dioxin removal wastes by thermal destmction of contaminants through ISV was completed. Verification samples of the vitrified material showed the remedy was effective in reducing chemical concentrations below the risk-based action levels established for the Site in 1996.

Remedial contractors recently detected additional shallow soil contamination during drilling activities associated with the groundwater monitoring program. Soil sampling detected VOCs and PCP in soil samples collected from two of the four new groundwater monitoring wells, including concentrations of TCE and PCE that exceed the soil performance standards for the Site. Further investigation is necessary to delineate the extent of this recently identified area of soil contamination and remedial actions may be needed to address soil contamination at levels above performance standards for the Site.

Groundwater extraction and treatment was implemented and subsequently halted to evaluate possible alternative remedies for groundwater. EPA is working with the Site's PRPs to identify additional data necessary to fully review outstanding issues with the

43

draft FFS. EPA is evaluating the effectiveness of MNA before issuing a final decision regarding whether or not to reinstate the pump-and-treat remedy or evaluate other remedial altematives.

DWRi implemented a formal notification process that acts as a groundwater institufional control at the Site. In addifion, an environmental covenant containing land use and groundwater restrictions, and requiring notification of building demolition, vapor intmsion risk assessment and mitigation associated with new building constmction is in place for a portion of the Site. Some areas of the Site do not have institutional controls fulfilling the objective to assess risks related to vapor intmsion. In order to ensure long-term protectiveness, EPA will evaluate the need for institutional controls on the remaining properties at the Site.

Several changes related to the toxicity for COCs at the Site have occurred. First, there have been changes in cancer slope factors and oral reference doses for PCE and TCE. EPA will work to evaluate how these changes affect risk estimates at the Site. In addition, EPA has released a final revision to the non-cancer dioxin toxicity number. The cancer toxicity number is expected to follow shortly. EPA is working to re-evaluate the risk associated with dioxins in site soil to determine the impacts on protectiveness.

Initial vapor intmsion data collecfion and analysis occurred in early 2012. EPA has determined that additional sampling and analysis are necessary to evaluate the potential risk from vapor intmsion.

Exceedances of the vinyl chloride MCL occurred throughout the FYR period; multiple samples contained vinyl chloride concentrations as high as two orders of magnitude above the MCL. Current work plans regard vinyl chloride, a degradation product of TCE and PCE, as a COC. When decision documents are developed to address sitewide groundwater, vinyl chloride should be included as a COC.

44

8.0 Issues

Table 12 summarizes the current site issues.

Table 12: Current Site Issues

Issue Affects Current Protectiveness

(Yes or No)

Affects Future Protectiveness (Yes or No)

The selected remedy is not currently in operation. MNA is in the process of evaluation.

No Yes

Land use and groundwater institutional controls are only in place for a portion of the Site.

No Yes

Dioxin toxicity values have changed. No Yes Additional sampling and analysis is required to evaluate the potential risk fi-om vapor intrusion.

No Yes

Changes in cancer slope factors and oral reference doses have occurred for PCE and TCE.

No Yes

VOCs and PCP were detected in soil samples collected during installation of two new groundwater monitoring wells, including concentrations of TCE and PCE that exceed soil performance standards for the Site.

No Yes

Vinyl chloride exceeded MCLs throughout the FYR period. Although current work plans regard vinyl chloride as a COC, vinyl chloride is not listed as a COC in EPA's decision documents.

No Yes

9.0 Recommendations and Follow-up Actions

Table 13 provides recommendations to address the current site issues.

Table 13: Recommendations to Address Current Site Issues

Issue Recommendations / Follow-Up Actions

Party Responsible

Oversight Agency

Milestone Date

Affects Protectiveness?

(Yes or No) Issue Recommendations / Follow-Up Actions

Party Responsible

Oversight Agency

Milestone Date

Current Future

The selected remedy is not currently in operation. MNA is in the process of evaluation.

Evaluate the effectiveness of MNA and issue a final decision regarding whether or not to reinstate the pump-and-treat remedy or evaluate other remedial altematives.

EPA EPA 09/29/2013 No Yes

45

Issue Recommendations / Follow-Up Actions

Party Responsible

Oversight Agency

Milestone Date

Affects Protectiveness?

(Yes or No) Some areas of the Site do not have institutional controls fulfilling the objective to assess risks related to vapor intrusion.

Evaluate the need for institutional controls on additional portions of the Site.


Dioxin toxicity values have changed.

Re-evaluate the risk associated with dioxins in site soil.


Additional sampling and analysis is required to evaluate the potential risk from vapor intrusion.

Collect necessary data and evaluate how sampling results affect risk estimates.

PRP/EPA EPA 03/31/2014 No Yes

Changes in cancer slope factors and oral reference doses have occurred for PCE and TCE.

Evaluate how changes in toxicity factors affect risk estimates.


VOCs and PCP were detected in soil samples collected during installation of two new groundwater monitoring wells, including concentrations of TCE and PCE that exceed soil performance standards for the Site.

Delineate the extent of the newly identified area of soil contamination and determine if remedial actions are needed to address soil contamination present at levels above performance standards for the Site.

PRP/EPA EPA 03/31/2014 No Yes

Vinyl chloride exceeded MCLs throughout the FYR period. Although current work plans regard vinyl chloride as a COC, vinyl chloride is not listed as a COC in EPA's decision documents.

If decision documents are developed to address sitewide groundwater, vinyl chloride should be included as a COC.


10.0 Protectiveness Statements

A protectiveness determination of the remedy cannot be made at this time until fiarther information is obtained. This will require additional sampling and analysis to fully determine the potential for vapor intmsion at the Site and a dioxin toxicity reassessment at the Site. It is expected that these actions will take approximately 36 months to complete. At that time, a

46

protectiveness determination will be made. The remedy at the Site has resulted in the excavation and landfarming of hydrocarbon-contaminated soils, consolidation of materials, placement of a clean soil cap, and treatment by ISV to reduce chemical concentrations below risk-based action levels established for the Site in 1996; implementation of land use and groundwater institufional controls for a portion of the Site; and an evaluation of the effectiveness of the remediation of groundwater.

11.0 Next Review

The Site requires ongoing statutory FYRs as long as waste is left on site that does not allow for unrestricted use and unlimited exposure. The next FYR will be due within five years of the signature/approval date of this FYR.

47

Appendix A: List of Documents Reviewed

Constmction Completion Report Groundwater Extraction and Treatment System. Wasatch Chemical Site. Prepared by Montgomery Watson for Interstate Land Corporation. August 1997.

Constmction Completion Report Remedial Action/ Remedial Design - Soils. Wasatch Chemical Site, Salt Lake City, Utah. Prepared by Harding Lawson Associates for Entrada Industries, Inc. January 15, 1996. ^

Draft Operations and Maintenance Manual, Wasatch Chemical Site, Salt Lake City, Utah. Prepared by Montgomery Watson for Interstate Land, Inc. June 1997.

EPA Record of Decision: Wasatch Chemical Co. (Lot 6). Prepared by EPA. March 1991.

Explanation of Significant Differences, Wasatch Chemical Co. (Lot 6) Superfund Site. Prepared by EPA. November 1995.

Final Design Report, Groundwater Remediation, Remedial Design/Remedial Action (RD/RA), Wasatch Chemical Site, Salt Lake City, Utah. Prepared by Harding Lawson Associates for Entrada Industries, Inc. June 13, 1994.

Final Wasatch Chemical Site Groundwater Monitoring Plan. Prepared by Montgomery Watson. August 1996.

Five-Year Review Summary Report, Wasatch Chemical Co. (Lot 6) Superfund Site, Salt Lake City, Utah. Prepared by EPA, October 1997.

Five-Year Review Summary Report for the Wasatch Chemical Co. (Lot 6) Superfund Site. Prepared by EPA, September 2002.

Five-Year Review Summary Report for the Wasatch Chemical Co. (Lot 6) Superfund Site. Prepared by EPA, September 2007.

Groundwater Flow and Coritaminant Transport Modeling Report. Prepared by MWH Americas, Inc. for Questar InfoComm, Inc. October 2009.

Groundwater Monitoring Plan, Remedial Design/Remedial Action (RD/RA), Wasatch Chemical Site, Sah Lake City, Utah. Prepared by Harding Lawson Associates for Entrada Industries, Inc. June 13, 1994.

Monitoring Plan for Natural Attenuation at Wasatch Chemical. Prepared by MWH Americas, Inc. for Questar InfoComm, Inc. November 14, 2002.

Remedial Investigation Report, Wasatch Chemical Site, Salt Lake City, Utah. Volumes I-VII. Prepared by Harding Lawson Associates. March 30, 1990.

A-1

Technical Memorandum for the Wellfield Operation Modification Wasatch Chemical Site, Salt Lake City, Utah. Prepared by MWH for Interstate Land, Inc.

Wasatch Chemical Site Progress Report No. 87. Prepared by MWH. May 30, 2007..

Wasatch Chemical Site Progress Report No. 88. Prepared by MWH. January 17, 2008.

Wasatch Chemical Site Progress Report No. 89. Prepared by MWH. July 18, 2008.





Wasatch Chemical Site Progress Report No. 94 (Material on CD for,Record). Prepared by MWH. January 2011.

Wasatch Chemical S ite Progress Report No. 95. Prepared by MWH. July 27, 201


A-2

Appendix B: Press Notice

EPA Five-Year Review Planned for the Wasatch Chemical Co. Superfund Site w

'Ihe IJ s Kmmwnmgnfcil Pmhw-hnn Agpnpy (PPA)_ in coopeiztiaa nidi tiis Utah Depaitment of Environmailal QualiAy, is '^mAiriii^ TiMitili Ffw-VaaTTtt Ltuui of die TMBPAJI actions pef&ini£d under die Sm»ufiiiid luu^jm fbr flie Wasatch fTicmirql Co. (Lot 6) SLpafimd Site in Salt Lake City, UtalL The innpose of die Hv^Year Retiew is to ensme diat die sekctad cleamqi acliims e £ f e ^ protect human healdi and die aiiironmenL The Fiire-Year Review is sdiedided to be cnmplripd by SQitember 28,2012.

The IS-aiTO site is located at 1987 Soodi 700 West in Sah I^Qty.Begiiimiig in die 19^ l IMt/ i T g j g t i - T i O i jTTTi ra l P « T m p g n y pTT%Airwj p g g h ' i i j p t t i p A i r i J i w ; a n d -iTjTinin: r l i p m i r a l j i m A i r K rm gfh»

resubiQg in the ^Hiiii jiiiinarimi of soils and giuuudvratcj. Ihunaiy cfntzmmants of ccmcennnchide hsbicides, pesticides, 'jifrrir?, and semi-TOlatile and inJatile argaiiic compoimds. EPA propased die site & j Usting on die Natioml Pnonties list (NFL) in 19S7; it vcas finaUisd on the HFL in 199

Cleaiiiq> activities isdnded escavation of t*tmt mrwatoA soils and lonmral of dnzms of baszdous TnjfMmT< fimTTi tTip cite Cuiieiit opsation jiM^ iim I iiumw^ actiklhes mdude uuudwdtHr mooitDnng ^od aisuring conqiliznce nidiinstitntioaal controls. Once grotmdnatacleamip >als have been met, EPA will delete the site fiom die NFL. EPA canqdeted the site's most tecent Five-Year Sevier in Sottemba-2007. Since naste remains on site, EPA will canlimie to rmAnt^ Fire-Year Reviews to ensme diat the lemetfy nsnamspiutecb\'e of hnman i pjltf tfw* put iniinBiuiTf

EPA invites ccmmimitjr paiticqtation in the Five-Year Review process: Commmiity mmyiim JOB escoQiaged to contact EPA staff widi any in&niBtion diat may he^ EPA make its deLmuiination regaiding die protectrveness and efliicliveuBss of the pFmeitips at the site. Additional siteinfimnatimiis a -ailaUe at: Utah Department of Enviromnental Quality 195 Noidi 1 »S0 West, Salt Lake City, Utah 84114 Phnne- 801-5364100 Fax: 801-53fr«601

Or visit the EPA nvbsite at: htlp://wTvw.fiM.gov/rggoiiy8iiperfiind/at/wasatch/indeiJiliiil

Qiustisiu? FUase Contoet:

Peggy Linn fJtTmrm^nT^y Tnun luMi Hiiil C o O l d i s S t O r

Envmmmental Protectum Agcsicy, Region 8 303-312-6622 EnudL Kmi-peegviflieiia.gpv

Sam Garcia Remedial Fhiject Mana^ EnvironmeDtai Prutectum Agoicy, Region 8 303-312-6247 Ematl: rairia omOonaPtyi/

Dare ADisan ^jiTnimmT4yTTIT¥I1 mi i t u i i i CoOsdl l i a to r

Utah Department of Enviromnental Qaahty 801-536-4479 Fjwaril- da l l [email protected] lV

Toiq-Howes Project ManagET TTtali r>ap»¥ tmMi t « f P m i i m m i m n f a l Q a a h t y

801-536-4283 Pjfiaril- tiioBresfShrtah-gov

B-1

Appendix C: Interview Forms

Wasatch Chemical Co. (Lot 6) Superfund Five-Year Review Interview Site Form Site Name: Wasatch Chemical Co. (Lot 6) EPA ID No.: UTD000716399 Interviewer Name: Peggy Linn Affiliation: U.S. EPA Region 8 Subject Name: Ray Woodard Affiliation: INSTEL Steel West Subject Contact Information: 801-433-9263 / rav.woodard(a),instelsteel.com Time: 2:30 pm Date: 3/20/2012 Interview Location: Instel Steel Office

Interview Format (circle one): Cjn^Pers it) Phone Mail Other:

Interview Category: Resident ^usinesse^

1. Are you aware of the former environmental issues at the Site and the cleanup activities that have taken place to date?

Somewhat. The main problem is the property over there (toward the south) and in the area where the new building was constructed (toward the east).

2. What is your overall impression of the project; including cleanup, maintenance, and reuse activities (as appropriate)?

Overall, pretty good.

3. WTiat have been the effects of this Site on the surrounding community, if any?

None that 1 am aware of.

4. Have there been any problems with unusual or unexpected activities at the Site, such as emergency response, vandalism or trespassing?

The first year 1 started - four years ago, there were five break-ins on our property. But we took several steps to stop this, such as installation of security cameras, and these problems have stopped.

5. Has EPA kept involved parties and surrounding neighbors informed of activities at the Site? How can EPA best provide site-related information in the fiiture?

I only need to be informed when EPA is here - like today, or when a well is being drilled. I prefer to be informed by email or phone. Phone is the best way to get a hold of me.

6. Do you own a private well in addition to or instead of accessing city/municipal water supplies? If so, for what purpose(s) is your private well used?

We use chy water only. We do not have a well.

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7. Do you have any comments, suggestions or recommendations regarding any aspects of the project?

No everything seems to be good.

C-2

Site Name: Wasatch Chemical Co. (Lot 6) EPA ID No.: UTD000716399 Interviewer Name: Peggy Linn Affiliation: U.S. EPA Region 8 Subject Name: Paul L. Drake Affiliation: Questar Gas Company Subject Contact Information: 801-324-3427 / Paul.Drake(a).Ouestar.com Time: 11:30 am Date: 3/20/2012 Interview Location: Wasatch Groundwater Treatment System Building

Interview Format (circle one): ( Tn Person Phone Mail Other:

Interview Category: Potentially Responsible Parties (PRPs)

1. What is your overall impression of the remedial activities at the Site?

The remedial acfion is protecting the envirormient and personnel. We are moving into a dynamic period. Recently lots of things have changed. We're moving but not quite as quick as I would like. Not sure how long it should take, but it's going slow.

2. What have been the effects of this Site on the surrounding community, if any?

1 don't think there's been much impact, except for the environmental covenants.

3. What is your assessment of the current performance of the remedy in place at the Site?

We reached the maximum improvement possible with the pump-and-treat system. We need to move off the memo focused on testing MNA and move to a ROD amendment supporting MNA and we think that the evidence supports that.

4. Are you aware of any complaints or inquiries regarding environmental issues or the remedial action from residents since implementation of the cleanup?

Not aware of any. Within the past few weeks we've been discussing vapor intrusion monitoring with the businesses located on the Site. They have been supportive of this. These businesses include Instel, Kepko and Peterson.

5. Do you feel well-informed regarding the Site's activities and remedial progress? If not, how might EPA convey site-related information in the future?

I think so. The process is slower than what I'm accustomed to. In the work strategy we've suggested a communication plan. But I don't know what to expect. But the process is thorough. But maybe the process is thorough by nature.

6. Do you have any comments, suggestions or recommendations regarding the management or operation of the Site's remedy?

There has been considerable turnover in EPA project managers. The current RPM is the third RPM in two years. Would be helpfial to have some consistency there.

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Site Name: Wasatch Chemical Co. (Lot 6) EPA ID No.: UTD000716399 Interviewer Name: Peggy Linn Affiliation: U.S. EPA Region 8 Subject Name: Kyle LaMalfa Affiliation: Salt Lake City Council,

District 2 Subject Contact Information: 801-535-7781 / kvle.lamalfa(a),slcgov.com Time: 1:00 pm ET Date: 3/20/2012 Interview Location: City & Council Building

Interview Format (circle one): (jnPers^^ Phone Mail Other: Interview Category: Local Government

1. Are you aware of the former envirormiental issues at the Site and the cleanup activities that have taken place to date?

Not until now.


I have only been in office for two months, but I have lived in the community for ten years. I haven't heard of this site. In terms of communicating with me, one-on-one face-to-face meetings once per year. Would like to talk about all Superfund sites, brownfields and chemical areas in my district. My district extends north-south from 21 South and the North Temple, and east-west from Interstate 15 and the city limits - basically between 201 and Interstate 80.

In terms of communicating with the community, there is a community newspaper that goes out to about 20,000 - to every household in Carlton (District 1) and my neighborhoods. Westviewmedia.org. The paper is about eight pages. They might be interested in doing a story.

3. Have there been any problems with unusual or unexpected activities at the Site, such as emergency response, vandalism or trespassing?

I don't know that there are any problems there, but it's in an area that is not in that great of shape. I recommend you contact Van Turner, the former council member for this district for 12 years.

4. Are you aware of any changes to state laws or local regulations that might affect the protectiveness of the Site's remedy?

No

5. Are you aware of any changes in projected land use(s) at the Site?

There's a master plan that the city is putting together that encompasses the area that includes the Site - the West Salt Lake Master Plan. Making them aware of this would be good.

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6. Do you have any comments, suggestions or recommendations regarding the project?

I would like to do sit downs and review the Superfund sites and chemical areas in Salt Lake. Also, I am the chair of the RDA and we've set aside some money to do some cleanup in the North Temple area.

C-5

Site Name: Wasatch Chemical Co. (Lot 6) EPA ID No.: UTD000716399 Interviewer Name: Peggy Linn Affiliation: U.S. EPA Region 4 Subject Name: Jesse A. Stewart, Susan Affiliation: MWH Americas, Inc.

L. Eyzaguirre, and Stacey Arens

Subject Contact Information: 801-617-3294 / [email protected] Time: 11:45 am Date: 3/20/2012 Interview Location: Wasatch Groundwater Treatment System Building

Interview Format (circle one): CTn Person^ Phone Mail Other: Interview Category: Remedial Contractor


The original remedy did all that it could - now we've had time to look at MNA and collect some evidence that supports MNA. We hope to move forward with an alternative remedy that would complete the groundwater cleanup.


The pump-and-treat remedy has removed about as much contaminant mass as it could. Now we're studying MNA. We also previously tried modifications and best practices to optimize the pump-and-treat remedy, including bioremediation. Bioremediation of groundwater contamination showed limited success because it is clay in the subsurface and the bioremediation radius of influence is quite small. We've looked at numerous other alternative remedies and determined that implementation of these alternative remedies at this site would be difficult, marginally effecfive and extremely expensive. We're trying address the remaining one percent of contamination in groundwater. We've been collecting good data since the pump-and-treat system has been shut off.

3. What are the findings from the monitoring data? What are the key trends in contaminant levels that are being documented over time at the Site?

See the natural attenuation memo as well as progress report #96. Pump-and-treat worked really well. Enhanced bioremediation worked but only in a localized area. There's been a lot of success. We're almost there, but this last bit is the hardest bit.

The ORPs (oxygen reduction potential) at the site are negative, and pH is in a good range for MNA. The presence of vinyl chloride around the site is a good sign, indicating degradation of other contaminants. Vinyl chloride is a daughter product of the original contaminants. This suggests you have the right conditions and there is a lot of evidence that natural attenuation will work.

4. Is there a continuous on-site O&M presence? If so, please describe staff responsibilities and activities. Alternatively, please describe staff responsibilities and the frequency of site inspections and activities if there is not a continuous on-site O&M presence.

C-6

The monitoring well manager with Questar checks the wells on a monthly basis. Site inspections are also conducted monthly.

5. Have there been any significant changes in site O&M requirements, maintenance schedules or sampling routines since start-up or in the last five years? If so, do they affect the protectiveness or effectiveness of the remedy? Please describe changes and impacts.

Nothing really from the shutdown of the pump-and-treat system, prior to the last FYR. In the last five years there has not been anything except the new deeper wells showing contamination in October 2011. This led to more investigation and is also leading us to additional soil investigation. No concerns regarding protectiveness. For shallow soil contamination we have restrictions on digging and there haven't been any signs of digging. We're looking into further defining the extent of soil contamination.

6. Have there been unexpected O&M difficulties or cost's at the Site since start-up or in the last five years? If so, please provide details.

No. However, we're looking into writing a new long-term sampling plan; something that might be more efficient and save on costs. We're currently following the same sampling protocol we've been following since 1996.

7. Have there been opportunifies to optimize O&M activities or sampling efforts? Please describe changes and any resulting or desired cost savings or improved efficiencies.

NA


The last few years of RPM turnover at EPA have created periods of time with a lack of communications. The project could potentially benefit from more regular communication instead of only written communication. We have included some ideas in the work strategy. With the new soil contamination and the vapor intrusion investigation there is an opportunity to be more collaborative. Our goal is to sit down together, have an on-board meeting, and this will help reduce the time of getting actions agreed to. With some of the dynamic strategies, it helps improve the review cycle and increase the speed of getting to the final goal.

9. Do you have any comments, suggestions or recommendations regarding O&M acfivities and schedules at the Site?

NA

C-7

Site Name: Wasatch Chemical Co. (Lot 6) EPA ID No.: UTD000716399 Interviewer Name: Treat Suomi Affiliation: Skeo Solutions Subject Name: Sam Garcia Affiliation: EPA Subject Contact Information: (303) 312-6247; garcia.sam(a),epa.gov Time: NA Date: NA Interview Location: NA

Interview Format (circle one): In Person Phone Mail Cother: EmjiL) Interview Category: EPA Remedial Project Manager


Regarding the overall cleanup, the upcoming soil and groundwater sampling event should be completed before evaluating any long-term groundwater remedies. The maintenance and reuse of the Wasatch Chemical Co. site appears to be consistent with neighboring properties.

2. What have been the effects of this Site on the surrounding community, if any?

I am not aware of any negative effects on the surrounding community.

3. Are you aware of any complaints or inquiries regarding site-related environmental issues or remedial activities since the implementation of the cleanup?

I am not aware of any complaints or inquiries.


Other than the need to characterize some recently discovered soil and groundwater contamination plus evaluating and implementing a long-term groundwater solution, the rest of the remedy appears to function as designed.

5. Are you comfortable with the status of the institufional controls at the Site? If not, what are the associated outstanding issues?

Yes

6. Are you aware of any community concems regarding the Site or the operation and management of its remedy? If so, please provide details.

I am not aware of any concems.

C-8

7. Do you feel well-informed regarding the Site's activities and remedial progress? If not, how might EPA convey site-related information in the fijture.

Yes, I feel informed.

8. Do you have any comments, suggesfions or recommendations regarding the management or operation of the Site's remedy?

The PRP, State, and EPA are in the process of addressing some recently discovered soil and groundwater issues and will be followed by evaluating a long-term solution to sitewide contaminated groundwater.

C-9

Appendix D: Site Inspection Checklist

FIVE-YEAR REVIEW SITE INSPECTION CHECKLIST

I. SITE INFORMATION

Site Name: Wasatch Cheinical Company (Lot 6) Date of Inspection: 03/20/12

Location and Region: Salt Lake City, UT, Region 8 EPA ID: UTD0007I6399

Agency, Office or Company Leading the Five-Year Review: EPA Region 8 Weather/Temperature: Sunny/ 40° F

Remedy Includes: (Check all that apply) ^ Landfill cover/containment • Monitored natural attenuation ^ Access controls O Groundwater containment ^ Institutional controls • Vertical barrier walls

Groundwater pump and treatment • Surface water collection and treatment ^ Other: The remedy does not include MNA, but is currently in the process of evaluation .

Attachments: [ 3 Inspection team roster attached n Site map attached

IL INTERVIEWS (check all that apply)

I. O & M Site Manager Paul L. Drake Senior Environmental & Safety Name Coordinator, Ouestar

Title Interviewed | ^ at site f"] at office f") by phone Phone: 801-324-3427 Problems, suggestions O Report attached:

03/20/12 Date

2. O&M Staff Jesse A Stewart. Name Susan L. Eyzaguirre Name Stacey Arens Name

Principal Geoloeist/Proiect Manager. MWH Title Senior Engineer Title Senior Chemical Engineer Title

03/20/12 Date

Interviewed ^ at site f l a t office f l bv phone Phone: 801-617-3294 Problems/suggestions O Report attached:

D-I

3. Local Regulatory Authorities and Response Agencies (i.e., state and tribal offices, emergency response office, police department, office of public health or environmental health, zoning office, recorder of deeds, or other city and county offices). Fill in all that apply.

Agency Saih Lake City Council Contact Kyle LaMalfa

Name Problems/suggestions O Report attached:

Agency Contact Name

Problems/suggestions • Report attached:

Council. D. 2 Title

03/20/12 Date

801-535-7781 Phone No.

Title Date Phone No.

Agency Contact

Name Title Problems/suggestions • Report attached:

Agency, Contact

Date Phone No.

Name Title Problems/suggestions • Report attached:

Agency. Contact

Date Phone No.

Name Title Problems/suggestions Q Report attached:

Date Phone No.

Other Interviews (optional) O Report attached:

Ray Woodard, Operations Manager, Instel Steel West

III. ON-SITE DOCUMENTS AND RECORDS VERIFIED (check all that apply)

O&M Documents

lEI O&M manual

n As-built drawings

n Maintenance logs

Remarks:

^ Readily available

• Readily available

r~l Readily available

^ Up to date

• Up to date

• Up to date

• N/A

13 N/A

KIN/A

2. Site-Specific Health and Safety Plan ^ Readily available • Up to date • N/A

n Contingency plan/emergency response plan O Readily available • Up to date • N/A

Remarks:

3. O&M and OSHA Training Records ^ Readily available • Up to date • N/A

Remarks:

D-2

4. Permits and Service Agreements

• Air discharge permit • Readily available • Up to date S N / A

• Effluent discharge • Readily available • Up to date lElN/A

• Waste disposal, POTW • Readily available • Up to date ^ N / A

n Other permits: • Readily available • Up to date ^ N / A

Remarks: NPDES permit has expired but is not currently reauired because the pump-and-treat system was shut down in January 2003. If the pump-and-treat system is re-started, the NPDES permit would need to be renewed.

5. Gas Generation Records

Remarks:

• Readily available • Up to date IEIN/A

6. Settlement Monument Records

Remarks:

• Readily available • Up to date KIN/A

7. Groundwater Monitoring Records

Remarks:

^ Readily available ^ Up to date • N/A

8. Leachate Extraction Records

Remarks:

• Readily available • Up to date 13 N/A

9. Discharge Compliance Records

[~~| Air • Readily available • Up to date lEI N/A

• Water (effluent) • Readily available • Up to date lEI N/A

Remarks:

10. Daily Access/Security Logs

Remarks:

• Readily available • Up to date S N / A

IV. O&M COSTS

1. O&M Organization

• State in-house

^ PRP in-house

• Contractor for state

S Contractor for PRP

• Federal facility in-house • Contractor for Federal facility

n

D-3

2. O&M Cost Records

• Readily available • Up to date

• Funding mechanism/agreement in place ^ Unavailable

Original O&M cost estimate: • Breakdown attached

From: mm/dd/yyyy

Date

From: mm/dd/yyvy

Date

From: mm/dd/yyyy

Date

From: mm/dd/yyyy

Date

From: mm/dd/ww

Date

Total annual cost by year for review period if available

To: mm/dd/ww

Date Total cost

To: mm/dd/yyyy

Date

To: mm/dd/yyyy

Date

To: mm/dd/yyyy

Date

To: mm/dd/yyyy

Date

Total cost

Total cost

Total cost

• Breakdown attached

I I Breakdown attached

• Breakdown attached



Total cost

3. Unanticipated or Unusually High O&M Costs during Review Period

Describe costs and reasons:

V. ACCESS AND INSTITUTIONAL CONTROLS ^ Applicable • N/A

A. Fencing

1. Fencing Damaged • Location shown .on site map • Gates secured • N/A

Remarks: Fencing surrounding the Site appeared to be in good condition.

B. Other Access Restrictions

1. Signs and Other Security Measures

Remarks:

• Location shown on site map N/A

C. Institutional Controls (ICs)

D-4

Implementation and Enforcement

Site conditions imply ICs not properly implemented • Yes No • N/A

Site conditions imply ICs not being fully enforced • Yes 13 No • N / A

Type of monitoring (e.g.. self-reporting, drive by): Site inspections

Frequency: Monthly

Responsible party/agency: Ouestar

Contact Paul L. Drake Operations Manager. Ouestar

03/20/12 801-324-3427

Name Title Date Phone no.

Reporting is up to date • Yes • No ^ N / A

Reports are verified by the lead agency • Yes • No ^ N/A

Specific requirements in deed or decision documents have been met ^ Yes • No • N/A

Violations have been reported • Yes • No S N/A

Other problems or suggestions: • Report attached

Institutional controls are only in place at a portion of the Site properties. Evaluation of the need for • institutional controls at additional site properties is needed.

2. Adequacy • ICs are adequate 3 ICs are inadequate • N/A

Remarks: Institutional controls currently in place are adequate for those properties. However, institutional controls are inadequate for all properties at the Site.

D. General

I. Vandalism/Trespassing • Location shown on site map

Remarks:

No vandalism evident

Land Use Changes On Site • N/A

Remarks: A large steel warehouse was constructed on site in 2007.

Land Use Changes Off Site • N/A

Remarks: No recent nearby off-site development was apparent.

VL GENERAL SITE CONDITIONS

A. Roads Applicable • N/A

I. Roads Damaged

Remarks:

• Location shown on site map ^ Roads adequate • N/A

B. Other Site Conditions

Remarks:

VIL LANDFILL COVERS I Applicable • N/A

A. Landfill Surface

D-5

^ Settlement not evident

Depth:

Settlement (low spots) • Location shown on site map

Arial extent: Approximately 125' X 125'

Remarks: Vitrified soil/sludge/debris is located on site in a former concrete-lined evaporation pond. The residual soils fi-om the landfarm remediation were placed on top of the consolidated material in the evaporation pond. A clean soil cap was placed over the treatment zone, and a clean soil berm was placed around the concrete evaporation pond.

2. Cracks

Lengths: _

Remarks:.

• Location shown on site map

Widths:

^ Cracking not evident

Depths:

3. Erosion

Arial extent:

• Location shown on site map • Erosion not evident

Depth:

Remarks: Small shards of vitrified materials are located at various points on top of the clean soil cap.

Holes

Arial extent:

Remarks:

• Location shown on site map ^ Holes not evident

Depth:

Vegetative Cover

^ No signs of stress

Remarks: •

^ Grass ^ Cover properly established

• Trees/shrubs (indicate size and locations on a diagram)

Alternative Cover (e.g., armored rock, concrete)

Remarks:

N/A

7. Bulges

Arial extent:

Remarks:

• Location shown on site map 3 Bulges not evident

Height:

8. Wet Areas/Water Damage

• Wet areas

• Ponding

• Seeps

• Sott subgrade

Remarks:

^ Wet areas/water damage not evident

• Location shown on site map Arial extent:




Slope Instability • Slides

^ No evidence of slope instability

Arial extent:

Remarks: °


B. Benches • Applicable N/A

(Horizontally constructed mounds of earth placed across a steep landfill side slope to interrupt the slope in order to slow down the velocity of surface runoff and intercept and convey the runoff to a lined channel.)

D-6

1. Flows Bypass Bench

Remarks:

1 1 Location shown on site map • N/A or okay

2. Bench Breached

Remarks:

1 1 Location shown on site map • N/A or okay

3. Bench Overtopped

Remarks:

• Location shown on site map • N/A or okay

C. Letdown Channels • Applicable 3 N/A

(Channel lined with erosion control mats, riprap, grout bags or gabions that descend down the steep side slope of the cover and will allow the runoff water collected by the benches to move off of the landfill cover without creating erosion gullies.)

1. Settlement (Low spots) • Location shown on site map

Arial extent:

Remarks:

• No evidence of settlement

Depth:

2. Material Degradation • Location shown on site map

Material type:

Remarks:

• No evidence of degradation

Arial extent:

3. Erosion

Arial extent:

Remarks:

• Location shown on site map • No evidence of erosion

Depth:

4. Undercutting

Arial extent:

Remarks:

• Location shown on site map r~l No evidence of undercutting

Depth:

5. Obstructions Type:


Size:

Remarks:

• No obstructions

Arial extent:

6. Excessive Vegetative Growth Type:

• No evidence of excessive growth

• Vegetation in channels does not obstruct flow


Remarks:

D. Cover Penetrations • Applicable ^ N/A

D-7

I. Gas Vents • Active • Passive

• Properly secured/locked • Functioning • Routinely sampled • Good condition

• Evidence of leakage at penetration • Needs maintenance • N/A

Remarks:

2. Gas Monitoring Probes

• Properly secured/locked • Functioning 1 1 Routinely sampled • Good condition

• Evidence of leakage at penetration 1 1 Needs maintenance • N/A

Remarks:

3. Monitoring Wells (within surface area of landfill)


1 1 Evidence of leakage at penetration • Needs maintenance • N/A

Remarks:

4. Extraction Wells Leachate

1 1 Properly secured/locked • Functioning • Routinely sampled n Good condition

• Evidence of leakage at penetration • Needs maintenance • N/A

Remarks:

5. Settlement Monuments • Located

Remarks:

1 1 Routinely surveyed • N/A

E. Gas Collection and Treatment • Applicable ^ N / A

1. Gas Treatment Facilities

1 1 Flaring • Thermal destruction 1 1 Collection for reuse

1 1 Good condition • Needs maintenance

Remarks:

2. Gas Collection Wells, Manifolds and Piping

1 1 Good condition • Needs maintenance

Remarks:

3. Gas Monitoring Facilities (e.g., gas monitoring of adjacent homes or buildings)

• Good condition • Needs maintenance • N/A

Remarks:

F. Cover Drainage Layer • Applicable ^ N / A

1. Outlet Pipes Inspected • Functioning • N/A

Remarks:

2. Outlet Rock Inspected • Functioning

Remarks:

• N/A

G. Detention/Sedimentation Ponds • Applicable ^ N / A

D-8

1. Siltation Area extent:

I I Siltation not evident

Remarks:

Depth: • N/A

2. Erosion Area extent:

r~l Erosion not evident

Remarks:

Depth:

3. Outlet Works

Remarks:

• Functioning • N/A

4. Dam

Remarks:

• Functioning • N/A

H. Retaining Walls Applicable • N/A

1. Deformations • Location shown on site map ^ Deformation not evident

Horizontal displacement: Vertical displacement:

Rotational displacement:

Remarks: This is in reference to the clean soil berm placed around the concrete evaporation pond where the contaminated soil, sediment and debris was vitrified. No deformation of the berms was evident.

2. Degradation • Location shown on site map • Degradation not evident

Remarks: This is in reference to the clean soil berm placed around the concrete evaporation pond where the contaminated soil, sediment and debris was vitrified. No degradation of the berms was evident.

I. Perimeter Ditches/Off-Site Discharge ^ Applicable • N/A

1. Siltation

Area extent:

I I Location shown on site map ^ Siltation not evident

Depth:

Remarks: A drainage ditch (700 West Ditch) is located along the western edge of the Site. The drainage ditch connects to other industrial drainage ways, with ultimate discharge to the Great Salt Lake. Sometimes the ditch is a receiving ditch: in other instances it is a contributing ditch.

2. Vegetative Growth • Location shown on site map • N/A

^ Vegetation does not impede flow ^

Area extent: Type: Various grasses and shrubs.

Remarks:

3. Erosion • Location shown on site map ^ Erosion not evident

Area extent: Depth:

Remarks:

4. Discharge Structure ^ Functioning • N/A

Remarks:

VIIL VERTICAL BARRIER WALLS •Applicable | 3 N/A

D-9

1. Settlement • Location shown on site map • Settlement not evident

Area extent: Depth:

Remarks:

2. Performance Monitoring Type of monitoring:

• Performance not monitored

Frequency: • Evidence of breaching

Head differential:

Remarks:

IX. GROUNDWATER/SURFACE WATER REMEDIES ^Applicable • N/A

A. Groundwater Extraction Wells, Pumps and Pipelines ^ Applicable • N/A

1. Pumps, Wellhead Plumbing and Electrical

^ Good condition • All required wells properly operating • Needs maintenance • N/A

Remarks: Pumps are used to collect groundwater samples fi'om extraction wells located throughout the Site. The pumps are regularly exercised as part of ongoing sampling.

2. Extraction Systein Pipelines, Valves, Valve Boxes and Other Appurtenances

^ Good condition • Needs maintenance

Remarks:

3. Spare Parts and Equipment ,

^ Readily available • Good condition • Requires upgrade • Needs to be provided

Remarks:

B. Surface Water Collection Structures, Pumps and Pipelines • Applicable ^ N/A

1. Collection Structures, Pumps and Electrical

• Good condition • Needs maintenance

Remarks:

2. Surface Water Collection System Pipelines, Valves, Valve Boxes and Other Appurtenances

I I Good condition • Needs maintenance

Remarks:

3. Spare Parts and Equipment

• Readily available • Good condition • Requires upgrade • Needs to be provided

Remarks:

C. Treatment System ^ Applicable • N/A

D-IO

1. Treatment Train (check components that apply)

• Metals removal • Oil/water separation • Bioremediation

• Air stripping • Carbon adsorbers

• Filters:

• Additive (e.g., chelation agent, flocculent):

• Others:

• Good condition • Needs maintenance

^ Sampling ports properly marked and fiinctional

• Sampling/maintenance log displayed and up to date

I I Equipment properly identified

I I Quantity of groundwater treated annually:

• Quantity of surface water treated annually:

Remarks: The pump-and-treat system has been shut down since January 2003. However, sampling ports are used to collect samples fi'om extraction wells located throughout the Site. The pumps are exercised monthly.

2. Electrical Enclosures and Panels (properly rated and functional)

• N/A ^ Good condition • Needs maintenance

Remarks:

3. Tanks, Vaults, Storage Vessels

I I N/A ^ Good condition • Proper secondary containment • Needs maintenance

Remarks: Water collected from groundwater monitoring and the regular exercising of the pumps is discharged to two holding tanks located adjacent to the Wasatch groundwater treatment system building. The collected water ultimately evaporates.

4. Discharge Structure and Appurtenances

• N/A ^ Good condition • Needs maintenance

Remarks:

5. Treatment Building(s)

• N/A ^ Good condition (esp. roof and doorways) • Needs repair

• Chemicals and equipment properly stored

Remarks: A general facility inspection is conducted monthly.

6. Monitoring Wells (pump and treatment remedy)


• All required wells located • Needs maintenance • N/A

Remarks: See Section E below.

D. Monitoring Data

D-11

I. Monitoring Data

^ Is routinely submitted on time 13 Is of acceptable quality

2. Monitoring Data Suggests:

• Groundwater plume is effectively contained • Contaminant concentrations are declining

E. Monitored Natural Attenuation 1. Monitoring Wells (natural attenuation remedy)

^ Properly secured/locked ^ Functioning ^ Routinely sampled ^ Good condition

r~l All required wells located • Needs maintenance • N/A

Remarks: A few wells are missing labels.

X. OTHER REMEDIES If there are remedies applied at the site and not covered above, attach an inspection sheet describing the physical nature and condition of any facility associated with the remedy. An example would be soil vapor extraction.

XI. O V E R A L L OBSERVATIONS A. Implementation of the Remedy

Describe issues and observations relating to whether the remedy is effective and functioning as designed. Begin with a brief statement of what the remedy is designed to accomplish (e.g., to contain contaminant plume, minimize infiltration and gas emissions). No deficiencies related to the remedy were identified during the site inspection. However, prior to the site inspection, Questar had briefed EPA on recently identified issues. These include recent data indicating that vinyl chloride in MW-30 is above the MCL. uncertainty regarding the western boundary of the vinyl chloride plume, newly identified soil contamination near MW-33D, and the possibility of vapor intrusion into various buildings located on site. Questar and EPA are currently working to address these issues.

In addition, Questar is working with EPA on a FFS to examine the possibility of formally changing the current remedy for groundwater fi'om pump-and-treat remedy to MNA.

B. Adequacy of O & M Describe issues and observations related to the implementation and scope of O&M procedures. In particular, discuss their relationship to the current and long-term protectiveness of the remedy. O&M to service the pumps necessary for groundwater monitoring appears sufficient.

Early Indicators of Potential Remedy Problems Describe issues and observations such as unexpected changes in the cost or scope of Q&M or a high frequency of unscheduled repairs that suggest that the protectiveness of the remedy may be compromised in the future. See above.

D. Opportunities for Optimization Describe possible opportunities for optimization in monitoring tasks or the operation of the remedy. See above.

Site Inspection Team: Jesse A. Stewart, MWH Sam Garcia, EPA Region 8 Treat Suomi, Skeo Solutions Peggy Lirm, EPA Region 8 Eric Marsh, Skeo Solutions. Tony Howes, UDEQ Paul L. Drake, Questar Gordon Murdock, Questar Susan L. Eyzaguirre, MWH Stacey Arens, MWH

D-12

Appendix E: Photographs from Site Inspection Visit

Wasatch groundwater treatment system building facing east

Sampling ports used for periodic groundwater sampling located inside the Wasatch groundwater treatment system building

E-1

Tanks (facing north) located adjacent to the Wasatch groundwater treatment system building. Water collected from sampling ports located inside the treatment building is ultimately discharged to these tanks. The collected water is

left to evaporate.

Recently constructed monitoring well (MW-3 ID) (facing west) located directly south of the Instel Steel West office

E-2

Recently constructed monitoring well (MW-3ID)

Recently constructed monitoring well (MW-3ID)

E-3

Recently constructed monitoring well (MW-30) located directly west of the Wasatch groundwater treatment system building

Recently constructed monitoring well (MW-33D) (facing south) located on the eastern edge of the Site next to the Peterson Plumbing Supply building. Herbicide and pesticide manufacturing previously took place in this area.

Recently, contamination was identified in subsurface soil in this area.

E-4

Vitrified soil area (facing southwest) located in the central-eastern portion of the Site. After vitrifying the soil, the vitrified material was capped with soil and surrounded by a clean soil berm.

Vitrified material located on top of the soil cap in the vitrified soil area.

E-5

he 700 West Ditch (facing north), a drainage ditch, located along the western edge of the Site

Instel Steel West warehouse (facing southeast), constructed in 2007, located in the northwest portion of the Site

E-6

Instel Steel West shipping and receiving building (facing south), located on the western edge of the Site just west of the Instel Steel West warehouse and north of the Instel Steel West parking lot

Instel Steel West offices (facing east), located on the western edge of the Site and south of the Instel Steel West parking lot

E-7

Offices of KEPCO-t- (facing west), an architectural cladding systems contractor, located south on the southwestern edge of the Site and northwest of the Peterson Plumbing Supply building

Peterson Plumbing Supply building (facing southeast), located on the eastern edge of the Site southeast of the KEPCO-*- offices

E-8

Appendix F: Data Review Supporting Data and Figures

Table F-1: Shallow Aquifer Groundwater Monitoring Results, October 2007 to November 2011

Well

COC (MCL jig/l) PCE

(5 Hg/I) TCE

(5 g/l) 1,1-DCE (7 Mg/1)

Cis-1,2-DCE

(70 Mg/1)

Trans-1,2-DCE (100 Mg/1)

Vinyl chloride (2 Mg/1)

PCP (1 Mg/1)

Well Sampling

Date

PCE (5 Hg/I)

TCE (5 g/l)

1,1-DCE (7 Mg/1)

Cis-1,2-DCE

(70 Mg/1)



PCP (1 Mg/1)

ES-01

10/29/2007 1.4 2 < 1 - ~ 2.4 0.1 T

ES-01

4/28/2008 13 62 D 6.1 - ~ 85 D 16 D

ES-01

10/14/2008 1.2 2.4 < 1 ~ ~ 1.6 <0.5

ES-01 4/7/2009 70 D ISO D 10 J - ~ 75 D 42TDJ

ES-01 1 1/3/2009 0.4 1.7 D < 1 0.81 T 0.5 T 0.7 D 0.5 D ES-01 4/26/2010 14 47 6.7 78 0.77 T 30 J 26 D

ES-01

10/26/2010 0.2 T 0.4 T < 1 0.45 T <1 0.4 T <0.5

ES-01

4/11/2011 4.7 19 2.6 48 0.6 T 18 8.6 D

ES-01

11/9/2011 0.3 T 2.3 < 1 1.4 0.39 T 1.2 <0.5

EX-02

10/30/2007 0.6 T 120 D 11 ~ - 170 D 1.5

EX-02

4/30/2008 ~ ~ ~ - . - 1

EX-02

5/13/2008 1 200 D 12 ~ ~ 180 D 2

EX-02

10/14/2008 1 140 D 12 ~ - 180 D 11 D

EX-02 7/4/2009 0.8 T 140 0 13 ~ - 220 D 8 D

EX-02 11/3/2009 0.5 T 99 D 7.9 73 D 7.6 140 D 7.9 D

EX-02

4/26/2010 0.9 T 130 D 9.6 94 11 210 D 6.7 D

EX-02

10/26/2010 0.4 T 110 D 9 100 D 11 llOD 7.9 D

EX-02

4/13/2011 0.4 T 120 D 8.6 84 11 210 D 3.5 D

EX-02

11/9/2011 0.2 T 74 7.2 HOD 8.8 68 7.7 D

EX-04

10/30/2007 <I 52 D 14 - ~ 0.7 T <0.5

EX-04

4/30/2008 <I 85 D 14 - -- 0.9 T <0.5

EX-04

10/14/2008 <I 83 D 13 - ~ 0.9 T <0.5

EX-04 4/6/2009 <1 54 D 11 - ~ 1.6 <0.5

EX-04 11/2/2009 <1 58 D 12 110 D 20 1.9 <0.5 EX-04 4/26/2010 <1 48 12 150 D 20 1.9 <0.5

EX-04

10/26/2010 <I 55 17 180 D 29 2.9 <0.5

EX-04

4/14/2011 <I 29 12 180 D 20 2.3 <0.5

EX-04

11/10/2011 <I 15 6.6 84 9.8 0.74 T <0.5

EX-05

10/30/2007 < I 0.5 T 17 - ~ 9.3 ,< 0.5

EX-05

4/29/2008 < I 0.4 T 10 ~ ~ 44 D <0.5

EX-05

10/14/2008 < 1 0.4 13 ~ ~ 40 <0.5

EX-05 4/7/2009 < 1 0.4 T 12 - ~ 47 <0.5

EX-05 11/2/2009 < I 0.4 T 8.5 150 D 170 D 27 <0.5 EX-05 4/26/2010 < 1 0.4 T 5.8 140 0 130 D 20 <0.5

EX-05

10/26/2010^ < 1 0.5 T 9.9 170 D 170 D 16 <0.5

EX-05

4/13/2011 < 1 0.4 T 9 HOD 150 D 17 <0.5

EX-05

11/9/2011 < 1 0.4 T 8.6 140 D 150 D 12 <0.5

F-1

Well

COC (MCL Mg/1) PCE

(5 Mg/1) TCE

(5 Mg/1) 1,1-DCE (7 Mg/1)

Cis-1,2-DCE

(70 Mg/1)



PCP (1 Mg/1)

Well Sampling

Date

PCE (5 Mg/1)

TCE (5 Mg/1)

1,1-DCE (7 Mg/1)

Cis-1,2-DCE

(70 Mg/1)



PCP (1 Mg/1)

EX-07

10/30/2007 < I 2.1 0.4 T ~ - 4.2 O.I T

EX-07

4/30/2008 < 1 5 0.8 T ~ - 8.9 0.2 T

EX-07

10/13/2008 < I 5 1.6 ~ - 29 <0.5

EX-07 4/7/2009 < 1 3 0.8 T ~ ~ 10 O.I T

EX-07 11/3/2009 < 1 1.2 0.3 T 6 1.4 3.6 <0.5 EX-07 4/26/2010 < I 2 < I 3.6 0.62 T 1.4 <0.5

EX-07

10/26/2010 < 1 1.5 0.3 T 8.3 4 4.1 <0.5

EX-07

4/14/2011 0.5 T 2.4 0.3 T 4 0.5 T 1.4 <0.5

EX-07

11/10/2011 - < 1 I.I 0.4 T 10 5 5.3 <0.5

EX-08

10/30/2007 0.4 T 1.6 < 1 ~ - 1.9 1.1

EX-08

5/13/2008 < I 0.2 T < 1 - < I 1.2

EX-08

10/15/2008 < I 0.2 T < 1 - ~ < 1 1.4

EX-08 4/7/2009 0.8 T 4.7 T 0.9 T ~ ~ 11 1.0

EX-08 11/4/2009 < I 0.4 T < 1 0.94 T <1 0.4 T 2.7 D EX-08 4/27/2010 < 1 0.3 T < 1 <1 <I < 1 1.8

EX-08

10/25/2010 < I •0.4 T < 1 <I <1 < 1 3.4 D

EX-08

4/12/2011 < I 0.3 T < 1 <I <1 < 1 1.2

EX-08

U/10/201! < 1 0.3 T < 1 0.83 T <1 0.9 T 2.9 D

EX-09

10/30/2007, < 1 0.6 T 1.8 - ~ 1.2 T <0.5

EX-09

4/30/2008 < 1 < I 0.6 T - ~ < 1 <0.5

EX-09

10/13/2008 < 1 0.4 T 1.8 ~ ~ < I <0.5

EX-09

4/7/2009 < 1 0.3 T 2.0 ~ - < 1 <0.5 EX-09 11/3/2009 < 1 0.3 T 1.6 19 5.8 < 1 <0.5 EX-09

4/27/2010 < 1 0.3 T 2.8 35 10 < 1 <0.5 EX-09

10/27/2010 < I 0.3 T 1.7 26 8.2 < 1 <0.5

EX-09

4/14/2011 < I 0.2 T 1.2 17 5.6 < 1 <0.5

EX-09

I I/I0/2011 < 1 0.2 T 1.2 15 5.3 < 1 <0.5

EX-11

10/30/2007 <1 4.3 0.7 T - ~ 480 D <0.5

EX-11

4/30/2008 1.2 64 D 18 - ~ 920 D <0.5

EX-11

10/14/2008 <1 3.8 l.I ~ - 520 D <0.5

EX-11 4/8/2009 <1 83 D 23 ~ - 560 D <0.5

EX-11 11/3/2009 <1 2.5 3.4 300 D 78 D 840 D <0.5 EX-11 4/26/2010 <1 35 20 1,300 D 100 550 D <0.5

EX-11

10/27/2010 <1 2.3 4.1 420 D 87 790 DJ <0.5

EX-11

4/11/2011 1.7 26 15 740 D 81 230 D <0.5

EX-11

11/9/2011 <1 2 1.2 97 54 240 D <0.5

F-2

Well

COC (MCL Mg/i) PCE

(5 Mg/1) TCE

(5 Mg/1) 1,1-DCE (7 Mg/1)

Cis-1,2-DCE

(70 Mg/1)



PCP (1 Mg/1)

Well Sampling

Date

PCE (5 Mg/1)

TCE (5 Mg/1)

1,1-DCE (7 Mg/1)

Cis-1,2-DCE

(70 Mg/1)



PCP (1 Mg/1)

MW-06

10/31/2007 < 1 0.2 T < 1 - ~ < 1 -

MW-06

4/29/2008 < 1 < 1 < I ~ ~ < I ~

MW-06

10/15/2008 < 1 0.6 T < I ~ ~ < I ~

MW-06 4/8/2009 < 1 < I 0.4 T ~ ~ 0.2 T -

MW-06 11/4/2009 < 1 < 1 < 1 0.86 T <I < 1 ~ MW-06 4/27/2010 < 1 < I 0.9 T 5.3 0.65 T < 1 ~

MW-06

10/25/2010 < 1 < 1 0.7 T 4.5 0.61 T 0.3 T ~

MW-06

' 4/13/2011 < 1 < 1 3.5 21 3.2 1.5

MW-06

II/I0/2011 < 1 < 1 3 18 2.8 1 T ~

MW-20

10/30/2007 < 1 1.4 0.6 T ~ ~ 0.7 T ~

MW-20

4/30/2008 0.3 T 4.9 3.4 - . ~ 3.3 <0.5

MW-20

10/14/2008 < 1 2.6 2 - ~ 3.1 -

MW-20 4/7/2009 < 1 5.5 3 - ~ 3.0 0.1 T

MW-20 11/3/2009 < 1 1.2 1.5 20 10 3.3 <0.5 MW-20 4/26/2010 < 1 2.3 2.3 34 17 3.8 <0.5

MW-20

10/27/2010 < 1 1 0.8 T 14 10 3.2 ~

MW-20

4/14/2011 < 1 3.4 2 26 21 8.1 ~

MW-20

11/10/2011 < 1 I T I T 15 13 2.4 ~

MW-23

10/31/2007 < 1 < 1 < 1 - ~ < 1 -

MW-23

4/29/2008 < 1 < 1 < 1 - - < 1 ~

MW-23

10/15/2008 < 1 < 1 < 1 ~ ~ < 1 ~

MW-23 4/8/2009 < 1 < 1 < 1 ~ ~ < 1 ~

MW-23 11/4/2009 < 1 < 1 < 1 <I . <1 < 1 ~ MW-23 4/27/2010 < 1 < 1 < 1 <I <1 < 1 ~

MW-23

10/26/2010 < 1 < 1 < 1 <1 <1 < 1 ~

MW-23

4/13/2011 < 1 < 1 < 1 <1 <1 < 1

MW-23

11/10/2011 < 1 < 1 < 1 <1 <l < 1 -

MW-24A

10/31/2007 < 1 < 1 < 1 ~ ~ < 1 ~

MW-24A

4/29/2008 < 1 < 1 < 1 ~ < 1 ~

MW-24A

10/15/2008 < 1 < 1 < 1 - - < 1 ~

MW-24A 4/8/2009 < 1 < 1 < 1 ~ ~ < 1 -

MW-24A 11/4/2009 < 1 < 1 < 1 <1 <I < 1 ~ MW-24A 4/28/2010 < I < 1 < 1 <1 <1 < 1 -

MW-24A

10/25/2010 < 1 < 1 < 1 <I <I < 1 -

MW-24A

4/13/2011 < 1 < 1 < 1 <1 <I < 1 ~

MW-24A

11/11/2011 < 1 < 1 < 1 <1 <1 < 1 ~

F-3

Well

COC (MCL Mg/1) PCE

(5 Mg/1) TCE

(5 Mg/1) 1,1-DCE (7 Mg/1)

Cis-1,2-DCE

(70 Mg/1)



PCP (1 Mg/1)

Well Sampling

Date

PCE (5 Mg/1)

TCE (5 Mg/1)

1,1-DCE (7 Mg/1)

Cis-1,2-DCE

(70 Mg/1)



PCP (1 Mg/1)

MW-25

10/31/2007 < 1 < I < 1 - ~ < 1 ~

MW-25

4/29/2008 < 1 < 1 < 1 - ~ < 1 ~

MW-25

10/15/2008 < 1 < 1 < I - ~ < 1 ~

MW-25 4/8/2009 < 1 < I < 1 ~ ~ < 1 ~

MW-25 11/4/2009 < 1 < I < 1 <I <1 < 1 ~ MW-25 4/28/2010 < 1 < I < 1 <1 <1 < 1 -

MW-25

10/25/2010 < 1 < 1 < 1 <1 <1 < 1 -

MW-25

4/12/2011 < I < 1 < 1 <1 <1 < 1 ~

MW-25

11/11/2011 < 1 < 1 < 1 <1 <1 < 1 -

MW-30 11/10/2011 < 1 0.59 T 5.8 64 1.6 14 <0.5

MW-30 12/21/2011 < 1 0.7 T 9 75 1.9 25 <0.5

PZ-01

10/31/2007 < 1 < 1 < 1 ~ - < I ~

PZ-01

4/29/2008 < 1 < 1 < 1 - ~ < 1 -

PZ-01

10/15/2008 < 1 < 1 < 1 - ~ < 1 -

PZ-01 4/8/2009 < 1 < 1 < 1 - ~ < 1 -

PZ-01 11/4/2009 < 1 < 1 < I <1 <1 < 1 -PZ-01 4/28/2010 < 1 < 1 < 1 <1 <I < 1 -

PZ-01

10/25/2010 < 1 < 1 < 1 <I <1 < 1 ~

PZ-01

4/13/2011 < 1 < 1 < 1 <1 <1 < 1 ~

PZ-01

11/10/2011 < 1 < 1 < 1 <1 <1 < 1 ~

PZ-03

10/31/2007 < 1 < 1 < 1 - ~ < 1 ~

PZ-03

4/29/2008 < 1 < 1 < 1 - - < 1 ~

PZ-03

10/15/2008 < 1 < I < 1 ~ - < 1 -

PZ-03 4/8/2009 < 1 < 1 < 1 ~ ~ < 1 ~

PZ-03 11/4/2009 < 1 < 1 < 1 <1 <1 < 1 ~ PZ-03 4/28/2010 < 1 < 1 < 1 <1 <I < 1 ~

PZ-03

10/25/2010 < 1 < 1 < 1 <1 <1 < 1 -

PZ-03

4/12/2011 < 1 < 1 < 1 <1 <1 < 1 ~

PZ-03

I I/I 1/2011 < 1 < 1 < 1 <1 <1 < 1 ~ Notes: D. Sample dilution required for analysis; reported values reflect the dilution, J: Data estimated due to associated quality control daa. T: Analyte was positively identified but the reported concentration is estimated; reported concentration is less than the reporting limit, but greater than the method detection limit. Bold: Detected concentration is equal to or exceeds MCL. -; Contaminant was not analyzed for.

F-4

Figure F-1: Shallow Aquifer Groundwater Plumes Reported by PRP in April 2012

F-5