3. ROD - Former Export Plant OU 1 - May 2010.pdf

RECORD OF DECISION

FOR

LIBBY ASBESTOS SUPERFUND SITE

THE FORMER EXPORT PLANT

OPERABLE UNIT 1

LINCOLN COUNTY, MONTANA

May 2010

LIBBY ASBESTOS SUPERFUND SITE

THE FORMER EXPORT PLANT

Part 1 Declaration

D-1

Site Name and Location The Libby Asbestos Superfund Site (Libby site) (Comprehensive Environmental Response, Compensation, and Liability Information System [CERCLIS] # MT0009083840) is located in and around the Town of Libby, Montana. Libby is the county seat of Lincoln County and is in the northwest corner of Montana, about 35 miles east of Idaho and 65 miles south of Canada (Exhibit 1-1). Operable Unit 1 (OU1), also known as the former Export Plant, is one of eight OUs at the site and is located in town at the intersection of Highway 37 and the Kootenai River.

Statement of Basis and Purpose This decision document presents the selected remedy for OU1. The remedy selected in this ROD was chosen in accordance with the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) of 1980, as amended by the Superfund Amendments and Reauthorization Act of 1986 and the National Oil and Hazardous Substance Pollution Contingency Plan (NCP). The decision is based on the administrative record file for OU1 of the site. This document is issued by the EPA Region 8, the lead agency, and the Montana Department of Environmental Quality (MDEQ). Both EPA and MDEQ concur on the selected remedy presented herein.

The remedial action selected in this ROD is necessary to protect public health and welfare and the environment from actual or threatened releases of hazardous substances at the site. It will reduce the public health risks by blocking contaminant pathways to the available receptors. However, the selected remedy must be reevaluated when the site-wide risk assessment is completed. An ecological risk assessment is being developed at the mine site, OU3. Once that work is complete, EPA will build upon information gathered during the risk assessment for OU3 to identify potential pathways and receptors to evaluate ecological risk at OU1.

Assessment of Site The response action selected in this ROD is necessary to protect the public health and welfare and the environment from actual or threatened releases of hazardous substances into the environment.

Description of Selected Remedy The majority of the OU has already been remediated through past removal actions.

The selected remedy will eliminate the remaining exposure pathway to the Libby amphibole asbestos (LA) contamination present at the OU by a combination of containment (with soil covers) and removal (excavation and disposal). Institutional controls (ICs) with monitoring and statutory reviews (five-year reviews and other) will provide assurance that the integrity of the remedy will be protected.

EPA will also conduct a review to evaluate effectiveness of the remedy, as soon as sufficient new information concerning toxicity factors is available. If unacceptable

D-2 exposures are identified, EPA will take action as necessary to ensure that the soil-to-air pathway is broken. Actions may include additional excavation, improving covers, and/or strengthening ICs. When the site-wide risk assessment is completed, the ICs will be revisited to determine whether any modification is needed.

Statutory Determinations The selected remedy meets the mandates of CERCLA §121 and the National Contingency Plan. The remedy is protective of human health and the environment. It complies with all federal and state requirements that are applicable or relevant and appropriate to the remedial action, is cost effective, and utilizes permanent solutions and alternative treatment technologies to the maximum extent practicable.

The remedy does not satisfy the statutory preference for treatment as a principal element of the remedy (this preference is triggered by the presence of a principal threat waste). Treatment of LA is not viable at OU1 for several reasons:

High relative cost. Thermo-chemical treatment of asbestos wastes is significantly more expensive than off-site disposal. Because the wastes must be shipped to an off-site treatment facility in another state, treated, and then shipped back to the site for disposal, transportation costs are also disproportionately high. Treatment of LA-contaminated soil increases the remedy costs by over 600% without adding significantly to protectiveness.

Lack of irreversibility data. In addition to the cost issues related to treatment, the treatment technology is relatively new, so extensive data are not available to confirm long-term irreversibility of the treatment process.

Ongoing need for monitoring and five-year reviews. Subsurface waste material will remain at depth at the site, so the treatment of the small amounts of remaining near surface LA would not negate the need for ongoing monitoring and five-year reviews. Thus no efficiencies or savings are gained regarding treatment in terms of long-term protectiveness.

As noted above, a statutory review will be conducted within 5 years after initiation of remedial action to ensure that the remedy is, or will be, protective of human health and the environment.

Future Public Comment When the site-wide risk assessment is complete, the agencies will re-evaluate the remedy in accordance with the review requirements at CERCLA Section 121(c). This determination will be published and an opportunity for public comment will be provided. Similar opportunities for public comment will be provided at the time of the subsequent five-year reviews.

D-3

ROD Data Certification Checklist Once a quantitative site-wide risk assessment is completed and a cleanup level is established, the ROD for this OU will be modified, as appropriate. If modified, the ROD will include this new information and will incorporate all necessary remedial actions, modifications of the institutional controls, and modifications to operation and maintenance plans in order to properly manage the residual contamination in a manner that will protect human health and the environment. The following information is included in the decision summary section (Part 2) of this ROD.

Additional information can be found in the administrative record file for this site.

Contaminants of concern and their respective concentrations

Risks represented by the contaminants of concern

How source materials constituting principal threats are addressed

Current and reasonably anticipated future land use assumptions used in the risk assessment

Potential land use that will be available at the Site as a result of the selected remedy

Estimated capital, annual operation and maintenance (O&M), and total present worth costs, discount rate, and the number of years over which the remedy cost estimates are projected

Key factors that led to selecting the remedy

Cleanup criteria for levels of concern and the basis for those levels are typically included in a ROD. However, a site-wide risk assessment has not yet been completed.

Although an OU-specific human health risk assessment was conducted for OU1, it did not include LA-specific toxicity values. In the absence of established quantitative, risk-based cleanup levels, EPA is removing and/or capping all visible vermiculite and any detectable LA thereby breaking complete exposure pathways and reducing future potential risk for LA exposure. Exceptions include those circumstances where vermiculite is otherwise well-contained. If LA source materials are encountered during excavation activities, removal will continue until the source material is removed (to a maximum of 3 feet). If contamination continues below 3 feet, a visible barrier marking the extent of excavation will be placed before backfilling. Once sufficient data are obtained to establish the LA-specific toxicity values, the site-wide risk assessment will be conducted.

D-1

LIBBY ASBESTOS SUPERFUND SITE

THE FORMER EXPORT PLANT

Part 2

Decision Summary i

Table of Contents

Part 1 Declaration

Part 2 Decision Summary

Section 1 Introduction ................................................................................................. 1-1 Site Name and Location ........................................................................................... 1-1

1.1 Key Features of the Libby Site and OU1 ................................................... 1-1

1.1.1 Site OUs ........................................................................................... 1-1

1.1.2 Site Contamination ........................................................................ 1-3

1.2 ROD Format .................................................................................................. 1-4

Section 2 Site History and Response Activities ..................................................... 2-1

2.1 Site Background and History ..................................................................... 2-1

2.1.1 Former Export Plant (Area 1) ....................................................... 2-2

2.1.2 Riverside Park (Area 2) ................................................................. 2-3

2.1.3 Embankments (Area 3) .................................................................. 2-4

2.2 Response Activities ...................................................................................... 2-4

2.2.1 Site-Wide EPA Activities .............................................................. 2-5

2.2.1.1 Activities Conducted Prior to NPL-Listing ................. 2-5

2.2.1.2 Activities Conducted After NPL Listing ..................... 2-5

2.2.2 OU-Specific Response Activities .................................................. 2-6

2.2.2.1 Area 1 Investigation and Removal Activities ............. 2-6

2.2.2.2 Area 2 Investigation and Removal Activities ........... 2-11

2.2.2.3 Area 3 Investigation Activities .................................... 2-12

2.2.2.4 Other OU1 Investigation Activities ............................ 2-12

2.3 Summary of Data Sources and Quality Assurance/ Quality Control 2-13

Section 3 Highlights of Community Participation ................................................ 3-1

3.1 Conducted Interviews and Prepared the CIP .......................................... 3-2

3.2 Established a Local Information Center and an Information

Repository ..................................................................................................... 3-2

3.3 Established an On-site CI Team ................................................................. 3-2

3.4 Provided Support to the Real Estate Community ................................... 3-2

3.5 Provided Education to Stakeholders via Classes and Workshops ........ 3-3

3.6 Provided Support to the TAG and CAG .................................................. 3-3

3.7 Developed a Site Mailing List and Prepared and Distributed Multiple

Fact Sheets ..................................................................................................... 3-3

3.8 Published Advertisements .......................................................................... 3-3

3.9 Developed and Distributed Informational Brochures, Written

Materials, and a Website ............................................................................. 3-4 ii

3.10 Held Public Meetings and Availability Sessions and Updated Commissioners ............................................................................................. 3-4

3.11 Implemented Targeted Informational Campaigns.................................. 3-4

3.12 Issued Proposed Plans, Held a Public Hearing, and Developed

Responsiveness Summaries and RODs ..................................................... 3-4

Section 4 Scope and Role of Operable Unit ............................................................ 4-1

Section 5 Summary of Site Characteristics ............................................................. 5-1

5.1 Site Overview ............................................................................................... 5-1

5.1.1 Surface Features and Size ............................................................. 5-1

5.1.2 Climate............................................................................................. 5-1

5.1.3 Areas of Archeological or Historical Importance ...................... 5-2

5.1.4 Geology ........................................................................................... 5-2

5.1.5 Soil .................................................................................................... 5-3

5.1.6 Surface Water Hydrology ............................................................. 5-3

5.1.7 Hydrogeology ................................................................................. 5-3

5.2 Conceptual Site Model ................................................................................ 5-4

5.2.1 Source Materials ............................................................................. 5-5

5.2.2 Affected Media ............................................................................... 5-5

5.2.3 Migration Routes and Exposure Pathways ................................ 5-5

5.2.4 Populations of Concern ................................................................. 5-6

Section 6 Current and Potential Future Land and Resource Uses ...................... 6-1

6.1 Land Use ........................................................................................................ 6-1

6.2 Groundwater Use ......................................................................................... 6-2

6.3 Surface Water Use ........................................................................................ 6-2

Section 7 Summary of Site Risks .............................................................................. 7-1

7.1 Exposure Assessment .................................................................................. 7-2

7.1.1 Conceptual Site Model .................................................................. 7-2

7.1.2 Exposure Routes ............................................................................. 7-2

7.1.3 Exposure Pathways ....................................................................... 7-2

7.2 Toxicity Assessment .................................................................................... 7-5

7.2.1 Non-Cancer Effects ........................................................................ 7-5

7.2.1.1 Asbestosis ......................................................................... 7-5

7.2.1.2 Pleural Abnormalities .................................................... 7-5

7.2.1.3 Observations of Asbestos-Related Non-Cancer

Diseases in People Exposed to LA .............................................. 7-6

7.2.2 Cancer Effects ................................................................................. 7-6

7.2.2.1 Lung Cancer .................................................................... 7-6

7.2.2.2 Mesothelioma .................................................................. 7-7

7.2.2.3 Other Cancers .................................................................. 7-7 iii

7.2.2.4 Observations of Asbestos-Related Cancer Cases in

Workers in Libby ........................................................................... 7-7

7.2.3 Toxicity Values ............................................................................... 7-7

7.3 Quantification of Exposure Risk ................................................................ 7-7

7.3.1 Evaluation of Risks from Breathing Ambient Outdoor Air ..... 7-7

7.3.2 Evaluation of Risks from Indoor Exposure ................................ 7-8

7.3.3 Evaluation of Risks from Disturbing Outdoor Soil ................... 7-8

7.3.3.1 Air Concentrations under Current Site Conditions ... 7-8

7.3.3.2 Consideration of Future Site Conditions ..................... 7-9

7.4 Summary of Human Health Risk .............................................................. 7-9

7.5 Ecological Risk ............................................................................................ 7-10

7.6 Basis of Action ............................................................................................ 7-10

Section 8 Remedial Action Objectives and Remedial Goals .............................. 8-1

8.1 Remedial Action Objectives ........................................................................ 8-1

Section 9 Description of Alternatives ...................................................................... 9-1

9.1.1 Alternative 1: No Action ............................................................... 9-2

9.1.2 Alternative 2: Institutional/Engineered Controls with

Monitoring ...................................................................................... 9-2

9.1.3 Alternative 3a: In-Place Containment of Contaminated Soil, and ICs with Monitoring ............................................................... 9-3

9.1.4 Alternative 3b: In-Place Containment of Contaminated Soil, Partial Removal of Contaminated Soil for Utility Corridors, Offsite Disposal at the Former Libby Vermiculite Mine, and ICs with Monitoring ...................................................................... 9-4

9.1.5 Alternative 4a: Partial Removal of Contaminated Soil, Offsite Disposal at the Former Libby Vermiculite Mine, and ICs with Monitoring ...................................................................................... 9-4

9.1.6 Alternative 4b: Partial Removal of Contaminated Soil, Additional Removal for Utility Corridors, Offsite Disposal at the Former Libby Vermiculite Mine, and ICs with Monitoring9-5

9.1.7 Alternative 5a: Partial Removal of Contaminated Soil, Offsite Thermo-Chemical Treatment and Reuse of Treated Material, and ICs with Monitoring ............................................................... 9-5

9.1.8 Alternative 5b: Partial Removal of Contaminated Soil, Additional Removal for Utility Corridors, Offsite Thermo- Chemical Treatment and Reuse of Treated Material, and ICs with Monitoring ............................................................................. 9-6

9.2 Common Elements and Distinguishing Features of Each Alternative . 9-7

9.2.1 In-Place Containment of Contaminated Soil with Covers ....... 9-7

9.2.2 Contaminant Removal (Excavation) ........................................... 9-7

9.2.3 Off-Site Disposal ............................................................................ 9-8

9.2.4 Off-Site Treatment Technology .................................................... 9-8 iv

9.2.5 ICs with Monitoring ...................................................................... 9-8

9.2.6 Engineering Controls ..................................................................... 9-8

9.2.7 Five-Year Reviews ......................................................................... 9-8

Section 10 Comparative Analysis of Alternatives ............................................... 10-1

10.1 Threshold Criteria ...................................................................................... 10-1

10.1.1 Overall Protection of Human Health and the Environment.. 10-1

10.1.2 Compliance with ARARs ............................................................ 10-2

10.2 Balancing Criteria ....................................................................................... 10-5

10.2.1 Long-Term Effectiveness and Permanence .............................. 10-5

10.2.2 Reduction of Toxicity, Mobility, or Volume through

Treatment ...................................................................................... 10-5

10.2.3 Short-Term Effectiveness ............................................................ 10-6

10.2.4 Implementability .......................................................................... 10-7

10.2.5 Cost ................................................................................................ 10-7

10.3 Modifying Criteria ..................................................................................... 10-8

10.3.1 State Acceptance ........................................................................... 10-8

10.3.2 Public Acceptance ........................................................................ 10-8

10.3.3 Modifications Made as a Result of Comment .......................... 10-9

Section 11 Principal Threat Wastes ........................................................................ 11-1

Section 12 Selected Remedy .................................................................................... 12-1

12.1 Short Description of the Selected Remedy ............................................. 12-1

12.2 Rationale for the Selected Remedy .......................................................... 12-2

12.3 Detailed Description of the Selected Remedy ........................................ 12-2

12.3.1 Containment and Removal ......................................................... 12-3

12.3.2 ICs ................................................................................................... 12-3

12.3.3 Operations and Maintenance ..................................................... 12-4

12.4 Estimated Cost of the Selected Remedy .................................................. 12-5

12.5 Expected Outcomes of the Selected Remedy ......................................... 12-5

12.6 Performance Standards ............................................................................. 12-5

Section 13 Statutory Determinations ..................................................................... 13-1

13.1 Protection of Human Health and the Environment .............................. 13-1

13.2 Compliance with ARARs .......................................................................... 13-1

13.2.1 Contaminant Sources ................................................................... 13-2

13.2.2 Surface Water ................................................................................ 13-2

13.2.3 Other ARARs ................................................................................ 13-2

13.3 Cost Effectiveness ...................................................................................... 13-3

13.4 Utilization of Permanent Solutions and Alternative Treatment (or

Resource Recovery) Technologies to the Maximum Extent Practicable ................................................................................................... 13-3

13.5 Preference for Treatment as a Principal Element .................................. 13-4 v

13.6 Five-Year Reviews ...................................................................................... 13-4

Section 14 Documentation of Significant Changes ............................................. 14-1

Section 15 References ................................................................................................ 15-1

Part 3 Responsiveness Summary

List of Exhibits Exhibit 1-1 ............................................................................................................ Site Location Map Exhibit 1-2 ...................................................................................................... OUs at The Libby Site Exhibit 1-3 ................................... Post-Removal LA Results Representing Current Status of OU1 Exhibit 1-4 .............................................................. The Superfund Process – The Road to the ROD Exhibit 2-1 .............................................................. History of Mining Activities Relevant to OU1 Exhibit 2-2 ............................................................................................................. OU1 Site Layout Exhibit 2-3 ...................................................... Response and Mining/Industrial Activities at OU1 Exhibit 2-4 ................................................................. Summary of Investigation Activities at OU1 Exhibit 2-5 ........................................................... Summary of Response Action Removals at OU1 Exhibit 5-1 .......................................... Summary of Current Status of Exposure Pathways at OU1 Exhibit 7-1 ............................................................. CSM for Current and Future Land Use at OU1 Exhibit 9-1 ......................... Technologies and Process Options Used in Site Remedial Alternatives Exhibit 10-1 ...................................................... Summary of Comparative Analysis of Alternatives Exhibit 12-1 ............................................................... Cost Estimate Summary for Selected Remedy Exhibit 13-1 ....................................... Evaluation of Compliance with ARARs for Selected Remedy

Appendix A Summary of Compliance with Federal and State Applicable or Relevant and

Appropriate Requirements vi

Acronyms ABS .......................................................................................................... activity based sampling ACM ................................................................................................ asbestos containing material ARAR ..................................................... applicable or relevant and appropriate requirement BMP ................................................................................................... best management practices BNSF ............................................................................................. Burlington Northern Santa Fe bgs ............................................................................................................... below ground surface CAG ............................................................................................... Community Advisory Group CDM ................................................................................. CDM Federal Programs Corporation CERCLA ....... Comprehensive Environmental Response, Compensation, and Liability Act CERCLIS ............. Comprehensive Environmental Response, Compensation, and Liability

Information System CI ........................................................................................................... Community Involvement CIC ................................................................................. Community Involvement Coordinator CIP ............................................................................................... Community Involvement Plan CSM ............................................................................................................ conceptual site model CTE ..................................................................................................... central tendency exposure CSS ................................................................................................ Contaminant Screening Study cy ................................................................................................................................... cubic yards DQO ............................................................................................................. data quality objective EPA ............................................................... United States Environmental Protection Agency ERS ....................................................................................... Environmental Resource Specialist FS ........................................................................................................................... feasibility study Grace ................................................................................................... W.R. Grace and Company HEPA ............................................................................................. high efficiency particulate air Libby site .................................................................................... Libby Asbestos Superfund Site LA ........................................................................................................ Libby amphibole asbestos MDEQ ........................................................... Montana Department of Environmental Quality MDT .............................................................................Montana Department of Transportation NCP ...................... National Oil and Hazardous Substances Pollution & Contingency Plan ND ................................................................................................................................... non-detect NPL ............................................................................................................National Priorities List O&M ................................................................................................. operation and maintenance OU ............................................................................................................................ Operable Unit PLM ................................................................................................... polarized light microscopy PLM-VE ....................................... polarized light microscopy visual area estimation method PV ............................................................................................................................... present value QA/QC ................................................................................. quality assurance/quality control RAO ....................................................................................................... remedial action objective RA .......................................................................................................................... remedial action RG ............................................................................................................................. remedial goal vii

RME ........................................................................................... reasonable maximum exposure RI ................................................................................................................ remedial investigation ROD ................................................................................................................... record of decision s/cc ............................................................................................. structures per cubic centimeter s/cm2 ........................................................................................ structures per square centimeter TAG .................................................................................................. Technical Assistance Group TEM ...................................................................................... transmission electron microscopy UAO ............................................................................................ unilateral administrative order °F ...................................................................................................................... degrees Fahrenheit < .......................................................................................................................................... less than % ........................................................................................................................................... percent viii

1-1

Section 1 Introduction

Site Name and Location The Libby site (CERCLIS # MT0009083840) is located in and around the Town of Libby, Montana.

Libby is the county seat of Lincoln County and is in the northwest corner of Montana, about 35 miles east of Idaho and 65 miles south of Canada (Exhibit 1-1). The town lies in a picturesque valley carved by the Kootenai River and framed by the Cabinet Mountains to the south. The community's assets include clean water, beautiful scenery, and recreational opportunities such as fishing, hiking, hunting, boating and skiing. OU1, also known as the former Export Plant, is located in town near the intersection of Highway 37 and the Kootenai River.

1.1 Key Features of the Libby Site and OU1

1.1.1 Site OUs

To facilitate a multi-phase approach to remediation of the Libby site, eight separate OUs have been established. These OUs are shown on Exhibit 1-2 and include:

OU1. The former Export Plant is situated on the south side of the Kootenai River, just north of the downtown area of the City of Libby, Montana. OU1 includes the embankments of Montana Highway 37, the former Export Plant, and Riverside Park. The property is bounded by the Kootenai River on the north, Highway 37 on the east, the BNSF railroad thoroughfare on the south, and State of Montana property on the west.

OU2. OU2 includes areas impacted by contamination released from the former Screening Plant. These areas include the former Screening Plant (Subarea 1), the Flyway property (Subarea 2), a privately-owned property (Subarea 3), and the Rainy Creek Road Frontage and Highway 37 right-of-way adjacent to Rainy Creek Road (Subarea 4).

Exhibit 1-1. Site Location Map

Section 1 Introduction

1-2

Exhibit 1-2 OUs at the Libby Site

1-3

OU3. The mine OU includes the former vermiculite mine and the geographic area (including ponds) surrounding the former vermiculite mine that has been impacted by releases from the mine, including Rainy Creek and the Kootenai River. Rainy Creek Road is also included in OU3. The geographic area of OU3 is based primarily upon the extent of contamination associated with releases from the former vermiculite mine.

OU4. OU4 is defined as residential, commercial, industrial (not associated with former W.R. Grace Company [Grace] operations), and public properties, including schools and parks in and around the City of Libby, or those that have received material from the mine not associated with Grace operations. OU4 includes only those properties not included in other OUs.

OU5. OU5 includes all properties that were part of the former Stimson Lumber Mill and that are now owned and managed by the Kootenai Business Park Industrial Authority.

OU6. The rail yard owned and operated by Burlington Northern Santa Fe (BNSF) is defined geographically by the BNSF property boundaries and extent of contamination associated with BNSF rail operation. Railroad transportation corridors are also included in this OU and have not been geographically defined.

OU7. The Troy OU includes all residential, commercial, and public properties in and around the Town of Troy, approximately 20 miles west of downtown Libby.

OU8. OU8 is comprised of the US and Montana State highways and secondary highways that lie within the boundaries of OU4 and OU7.

1.1.2 Site Contamination

OU1 was historically owned and used by Grace for stockpiling, staging, and distributing vermiculite and vermiculite concentrate to vermiculite processing areas and insulation distributors outside of Libby. The vermiculite deposit that was mined by Grace contains a distinct form of naturally-occurring amphibole asbestos that is comprised of a range of mineral types and morphologies. In various past reports, this form of amphibole asbestos has been termed interchangeably by the EPA as Libby amphibole asbestos or Libby asbestos (LA). The term LA refers generally to amphibole materials that originated in the Libby vermiculite deposit, have the ability to form durable, long, and thin structures that are generally respirable, can reasonably be expected to cause disease, and hence are considered the contaminant of concern at the site.

Because vermiculite mined from Libby has been found to be contaminated with LA, which is known to cause human health effects, the United States Environmental Protection Agency (EPA) initiated an emergency response action in November 1999 to

1-4 address questions and concerns raised by citizens of Libby regarding possible ongoing exposures to asbestos fibers as a result of historical mining, processing, and exportation of asbestos-containing vermiculite.

OU1 is divided into three areas (Area 1, Area 2, and Area 3), each of which are described and shown in maps in Section 2. Numerous investigations were conducted at the site and are summarized in Section 2.2. Based on those investigations, contamination is known to be present in the following media:

Indoor air

Indoor dust

Outdoor air (both ambient and near disturbed soil)

Soil

Exposure to the contamination has been mitigated by various interim removal actions (see Section 2.2.2) conducted in Areas 1 and 2 primarily to remove accessible source areas. Concentrations of LA remaining are shown in Exhibit 1-3.

Exhibit 1-3. Post-Removal LA Results Representing Current Status of OU1

Media Total

Number of Samples Collected

Total Number of Samples with Detections of LA

Percentage of Samples with LA Observed

Range of LA Results

Indoor Air 22 18 81.8 ND to 0.0699 s/cc

Indoor Dust 9 2 22.2 ND to 75 s/cm2

Outdoor Ambient Air* 143 32 22.4 ND to 0.00016 s/cc

Outdoor Air Near Disturbed Soil 8 6 75.0 ND to 0.0715 s/cc

Surface Soil 73 16 21.9 ND to <1%

ND – non-detect; s/cc – structures per cubic centimeter; s/cm2 – structures per square centimeter;* Original table from OU1 RI Report (EPA 2009a)

1.2 ROD Format

This record of decision (ROD) is the final decision document at the end of a detailed investigation and evaluation of conditions at OU1 (Exhibit 1-4). Since the selected remedy will leave waste in place, the remedy will be evaluated at least every five years to ensure that the remedy remains protective. When the site-wide risk assessment

1-5

Exhibit 1-4. The Superfund Process – The Road to the ROD is complete, the agencies will re-evaluate the remedy in accordance with the review requirements at CERCLA Section 121(c).

If unacceptable exposures are identified, EPA will take action as necessary to ensure that the soil-to-air pathway is broken. Actions may include additional excavation, improving covers, and/or strengthening ICs. It is anticipated that current research efforts will result in data that will contribute to the development of LA-specific toxicity values.

When those toxicity values are available , EPA will reevaluate this remedy to ensure continued protectiveness.

Once the remedy has been implemented and performance standards have been met, there will be an opportunity to delete this OU from the National Priorities List (NPL).

Institutional controls (ICs) and operation and maintenance (O&M) will continue.

Deletion from the NPL does not preclude any additional response actions to ensure protectiveness of the remedy.

EPA’s detailed investigation and evaluation of conditions at OU1 included performance of a remedial investigation/feasibility study (RI/FS) for OU1 and the completion of numerous removal actions to address significant human health risks during completion of the RI and FS. The RI report for OU1 includes a comprehensive description of the nature and extent of contamination and a description of past investigative and removal actions at the site, as well as the risk assessment. The FS report for OU1 uses information from the RI to perform a systematic analysis to determine the need for, and scope of, any required remedial action. The steps leading up to the ROD also included numerous opportunities for public involvement, including preparation of a proposed plan (mailed to all Libby residents on September 7, 2009), a public meeting, and a 120-day public comment period.

1-6

This ROD documents EPA’s selected remedy for OU1. The next step in the Superfund process at OU1 will be completion of a remedial design followed by implementation of a remedial action (RA) based on the selected remedy documented in this ROD.

This ROD is organized into the following sections:

Section 1 – Introduction. Provides a very brief introduction to the ROD.

Section 2 – Site History and Response Activities. Provides a brief history of the site, OU1, and EPA’s activities.

Section 3 – Highlights of Community Participation. Describes the range of community outreach activities conducted site wide and at OU1.

Section 4 – Scope and Role of OU1. Describes how the actions taken at OU1 fit into the overall scope of the Libby site.

Section 5 – Summary of Site Characteristics. Contains an overview of the site, conceptual site model (CSM), and a summary of the results of the RI.

Section 6 – Current and Potential Future Land and Resource Uses. Describes land use and how resource use will be addressed in a site wide ROD.

Section 7 - Summary of Site Risks. Discusses the human health risk assessment for OU1, including risk estimates.

Section 8 - Remedial Action Objectives and Remedial Goals. Discusses the goals and objectives developed by EPA to protect human health and the environment at the Libby site in general and OU1 in particular.

Section 9 - Description of Alternatives. Describes the remedial alternatives developed and evaluated in the FS, including a description of remedy components, common elements and distinguishing features, and expected outcomes.

Section 10 - Comparative Analysis of Alternatives. Presents a summary of the remedial alternatives that were retained for detailed analysis against the two threshold criteria and five balancing criteria in the FS.

Section 11 - Principal Threat Wastes. Identifies the principal threat waste at OU1 and discusses how the selected remedy will prevent exposure to it.

Section 12 – Selected Remedy. Provides a detailed description of the selected remedy, including its components, cost, expected outcomes, performance standards, and compliance with EPA’s environmental justice mandate.

1-7

Section 13 –Statutory Determinations. Describes how the selected remedy is protective of human health and the environment, complies with or appropriately waives applicable or relevant and appropriate requirements (ARARs), is cost effective, and utilizes permanent solutions and alternative treatment technologies or resource recovery technologies to the maximum extent practicable.

Section 14 – Documentation of Significant Changes. Confirms that no significant changes were made to the Preferred Remedy that was outlined in the proposed plan prior to its becoming the selected remedy described in this ROD.

Section 15 – References. Provides a list of references cited in the ROD.

2-1

Section 2 Site History and Response Activities

2.1 Site Background and History

Numerous hard rock mines have operated in the Libby area since the 1880s, but the dominant impact to human health and the environment in Libby has been from vermiculite mining and processing. Prospectors first located vermiculite deposits in the early 1900s on Rainy Creek northeast of Libby. Edward Alley, a local rancher, was also a prospector and explored the old gold mining tunnels and digs in the area.

Reportedly, while exploring tunnels in the area, he stuck his miner's candle into the wall to chip away some ore samples. When he retrieved his candle, he noticed that the vermiculite around the candle had expanded, or “popped,” and turned golden in color.

In 1919 (Exhibit 2-1), Alley bought the Rainy Creek claims and started the vermiculite mining operation called the “Zonolite Company.” While others thought the material was useless, he experimented with it and discovered it had good insulating qualities.

Over time, vermiculite became a product used in insulation, feed additives, fertilizer/soil amendments, construction materials, absorbents, and packing materials. Many people used vermiculite products for insulation in their houses in and around the Libby site and soil additives in their gardens. In 1963, Grace bought the mine and associated processing facilities and operated them until 1990.

Operations at the mine included blast and drag-line mining and milling of the ore.

Dry milling was done through 1985, and wet milling was done from 1985 until closure in 1990. After milling, concentrated ore was transported down Rainy Creek Road by truck to a screening facility (known today as the former Screening Plant) adjacent to Highway 37, at the confluence of Rainy Creek and the Kootenai River. Here the ore was size-sorted and transported by rail or truck to processing facilities in Libby and nationwide. At the processing plants, the ore was expanded or “exfoliated” by rapid

Exhibit 2-1. History of Mining Activities Relevant to OU1

Section 2 Site History and Response Activities

2-2 heating, then exported to market via truck or rail. Historic maps show the location of the “Zonolite Company” processing operation at the edge of the lumber mill, near present day Libby City Hall. This older processing plant was taken off line and demolished sometime in the early 1950s. The other processing plant (known today as the former Export Plant – OU1), was located near downtown Libby near the Kootenai River and Highway 37. Expansion operations at the site ceased sometime prior to 1981, although existing site buildings were still used to bag and export milled ore until 1990.

After operations ceased, Grace completed reclamation of the vermiculite mine.

Reclamation included demolition of existing facilities and standard land recontouring and revegetation. The former Screening Plant was sold and converted into a nursery and was used for that purpose until 2000. Over the course of Grace’s operation in Libby, invoices indicate shipment of nearly 10 billion pounds of vermiculite from Libby to processing centers and other locations. Most of this was shipped and used within the United States. Nearly all of this material ended up in a variety of commercial products that were marketed and sold to millions of consumers.

2.1.1 Former Export Plant (Area 1)

From the early 1960s to approximately 1990, the Export Plant was used by Grace for stockpiling and distributing vermiculite concentrate to Grace expansion plants and customers throughout the United States (Exhibit 2-2). Ownership was transferred to the City of Libby in the mid-1990s.

Throughout its history, portions of the site were leased to various parties for both commercial and non-commercial enterprises. From approximately 1977 to 1997, organized youth baseball events (games and practices) were held at ball fields, which were centrally located in Area 1. Between approximately 1987 and 2000, the Millwork West Company, a retail lumberyard and building material supplier, leased the northwestern portion of Area 1. Buildings and equipment owned by Millwork West were removed and/or demolished as part of the removal activities conducted by Grace in 2001 and 2002.

Other commercial and industrial uses of the site also occurred in the past that utilized infrastructure at the site. These other commercial/industrial uses reportedly included a metal scrap dealer and a larch tree gum manufacturer. The infrastructure that supported these businesses included industrial power supply, a railroad spur, and truck scales. This infrastructure was removed during the removal activities conducted at this site.

Area 1 is approximately 12 acres in size. It is currently owned by the City of Libby and is undeveloped, with the exception of a small area used by David Thompson Search and Rescue. In 2004, the search and rescue organization constructed a building containing an office and a five-bay garage on the northwest portion of the site on the

2-3

Exhibit 2-2. OU1 Site Layout south side of City Service Road. The garage is used for storing search and rescue equipment and vehicles. Several other agencies, including local and state law enforcement, also hold meetings in the main office. Access to Area 1 has been restricted by construction fencing and EPA has provided guidance to the city regarding the use of caution when conducting any activities at the site that disturb soil.

2.1.2 Riverside Park (Area 2)

Area 2, Riverside Park, is approximately 4.7 acres in size. It is also currently owned by the City of Libby and serves a variety of recreational visitors. The main features of the park include two boat ramps, two pavilions, picnic tables, and a pumphouse. The newer of the two boat ramps is used by recreational boaters and commercial fishing outfitters; the older ramp is not commonly used due to swift current at its approach.

The pumphouse contains a pump that draws non-potable water from the Kootenai River. The pump was installed jointly by the City of Libby and Lincoln County in 1999 to provide a backup water source to local fire departments. The pumphouse is accessed by city personnel in order to perform maintenance on the pump. The pump is connected to an external water spigot, which is used by the city to draw water for street sweeping and other maintenance operations, and other workers (such as employees of local fill pits and contractors working on EPA’s removal program) to

2-4 draw water primarily for use in dust suppression equipment. Access to Area 2 is unrestricted.

2.1.3 Embankments (Area 3)

Area 3 is less than 1 acre in size. It is owned and maintained by the Montana Department of Transportation (MDT). MDT currently performs only periodic maintenance of these embankments as needed. The types of maintenance activities conducted by MDT include application of herbicides, replacement of guardrails and guardrail posts, and replacement and maintenance of roadside light posts. Access to these areas is unrestricted.

2.2 Response Activities

In response to local concern and news articles about asbestos-contaminated vermiculite, EPA sent an Emergency Response Team to Libby, Montana in late November 1999 (Exhibit 2- 3). EPA's first priority was to assess the current risk to public health from asbestos-contaminated vermiculite in Libby. EPA then began taking necessary actions to reduce that risk.

In December 1999, EPA collected nearly 700 samples from air, soil, dust and insulation at homes and businesses. Indoor air sample results were released in January - first to property owners and then to the media and general public. EPA also moved immediately to locate areas in and near Libby that were likely to have high levels of contamination such as two former vermiculite processing facilities.

Exhibit 2-3. Response and Mining/Industrial Activities at OU1

2-5

EPA also looked at general asbestos exposures in the community and at health effects seen in people who had little or no association with the vermiculite mine in Libby.

EPA worked closely with local, state and federal agencies to understand how people might come into contact with asbestos-contaminated vermiculite and what can…