Kathi Hooper, Director, Lincoln County Environmental Health Department Allan Payne, RGp, M.S., Doney, Crowley, Payne, Bloomquist, P.C.

Transcription

1 August 3, 2012 Mr. Nick Raines Asbestos Resource Program Manager Lincoln County Environmental Health 418 Mineral Avenue Libby, MT RE: Activity-Based Evaluation Report, August 3, 2012 Asbestos Resource Program Lincoln County, Montana Dear Mr. Raines: Enclosed please find the Activity-Based Evaluation Report, dated August 3, 2012, which was prepared by Trihydro Corporation (Trihydro) for the City-County Board of Health of Lincoln County, Montana (Board of Health). The report was prepared in general accordance with Task 2 Review of Available Activity-Based Exposure Levels, as described by Exhibit A of the March 2012 contract between Lincoln County and Trihydro. The report summarizes available toxicological and activity-based sampling findings, draft and final, that characterize exposures to Libby Amphibole asbestos. The report also provides considerations for risk and exposure reduction in the development of the Asbestos Resource Program being developed by the Board of Health. Trihydro appreciates the opportunity to assist the Board of Health with this important project. Please contact the undersigned at (406) if you have questions regarding this report. Sincerely, Trihydro Corporation Sarah J. Seitz Geologist/Engineer Tom Smith, P.E., P.G. Project Manager 20Z Enclosures cc: Kathi Hooper, Director, Lincoln County Environmental Health Department Allan Payne, RGp, M.S., Doney, Crowley, Payne, Bloomquist, P.C. H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABEReport-FINAL_LTR.docx

2 ACTIVITY-BASED EXPOSURE LEVELS REPORT ASBESTOS RESOURCE PROGRAM LINCOLN COUNTY, MONTANA August 3, 2012 Project #: 20Z SUBMITTED BY: Trihydro Corporation 2707 Broadwater Avenue, Helena, MT 59601

3 Table of Contents EXECUTIVE SUMMARY... i 1.0 INTRODUCTION Site Description Report Limitations LIBBY AMPHIBOLE (LA) ASBESTOS EXPOSURE AND RISK REVIEW Toxicity of Libby Amphibole Asbestos Libby Amphibole Asbestos Geology and Occurrence Libby Amphibole Asbestos Exposure Pathways Libby Amphibole Asbestos Noncarcinogenic Response Libby Amphibole Asbestos Carcinogenic Response Activity-Based Sampling (ABS) Activity-Based Sampling at Operable Units Former Export Plant and Current Riverfront Park Complex (OU1) Former Screening Plant and Surrounding Area (OU2) Former Vermiculite Mine Facility and Surrounding Area (OU3) Libby and Surrounding Area (OU4) Former Stimson Lumber Mill (OU5) BNSF Railway Properties and Right-of-WayS (OU6) Troy and Surrounding Area (OU7) U.S., Montana, and Secondary Highways in the Vicinity (OU8) Pending Activity-Based Sampling Scenarios Air Monitoring Activities Ambient Air Monitoring in Libby Ambient Air Monitoring in Troy Air Monitoring in Schools Risk Assessment TOXICITY AND EXPOSURE SYNOPSIS Toxicity Synopsis Activity-Based Exposure Synopsis Ambient Exposure Synopsis Risk Assessment Synopsis H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx

4 Table of Contents (cont.) 4.0 RISK REDUCTION CONSIDERATIONS REFERENCES H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx

5 List of Tables 2-1. Status Summary and Available Results for Activity-Based Sampling Scenarios H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx

6 List of Figures 1. USEPA Libby Asbestos NPL Site Operable Units, April 2012 H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx

7 List of Appendices A. REFERENCES 1. CDM PREPARED FOR UNITED STATES ENVIRONMENTAL PROTECTION AGENCY. FINAL REMEDIAL INVESTIGATION REPORT, OPERABLE UNIT 1 FORMER EXPORT PLANT, LIBBY ASBESTOS SITE, LIBBY, MONTANA. AUGUST 3, (CDM-USEPA 2009A) 2. CDM PREPARED FOR UNITED STATES ENVIRONMENTAL PROTECTION AGENCY. FINAL REMEDIAL INVESTIGATION REPORT, OPERABLE UNIT 2 FORMER SCREENING PLANT AND SURROUNDING PROPERTIES, LIBBY ASBESTOS SITE, LIBBY, MONTANA. AUGUST 24, (CDM-USEPA 2009B) 3. CDM PREPARED FOR UNITED STATES ENVIRONMENTAL PROTECTION AGENCY. SAMPLING AND ANALYSIS PLAN, SUPPLEMENTAL ACTIVITY-BASED SAMPLING, LIBBY ASBESTOS SITE, OPERABLE UNIT 4. JUNE 18, (CDM-USEPA 2010) 4. CDM SMITH MEMORANDUM: OU5 WOOD CHIP ACTIVITY-BASE SAMPLING SUMMARY, LIBBY ASBESTOS SITE, LIBBY, MONTANA. JANUARY 9, (CDM SMITH 2012) 5. HDR ENGINEERING INC. AND SYRACUSE RESEARCH CORPORATION PREPARED FOR UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REMEDIAL INVESTIGATION REPORT FOR OPERABLE UNIT 5, LIBBY ASBESTOS NATIONAL PRIORITIES LIST SITE, LIBBY, MONTANA. SEPTEMBER (HDR- SYRACUSE-USEPA 2010) 6. HDR ENGINEERING INC. AND SYRACUSE RESEARCH CORPORATION PREPARED FOR UNITED STATES ENVIRONMENTAL PROTECTION AGENCY. DRAFT REMEDIAL INVESTIGATION REPORT, OPERABLE UNIT 8, LOCAL AND STATE HIGHWAYS IN LIBBY AND TROY, LIBBY ASBESTOS NATIONAL PRIORITIES LIST SITE, LIBBY, MONTANA. APRIL, (HDR-SYRACUSE-USEPA 2012) H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx

8 List of Appendices (cont.) 7. TETRA TECH PREPARED FOR MONTANA DEPARTMENT OF ENVIRONMENTAL QUALITY. DRAFT FINAL REMEDIAL INVESTIGATION REPORT, OPERABLE UNIT 7 OF THE LIBBY ASBESTOS SITE, TROY, MONTANA. DECEMBER, (TETRA TECH MDEQ 2010) 8. TETRA TECH PREPARED FOR MONTANA DEPARTMENT OF ENVIRONMENTAL QUALITY. DRAFT FINAL REMEDIAL INVESTIGATION REPORT ADDENDUM, 2010 FOR OPERABLE UNIT 7 OF THE LIBBY ASBESTOS SITE, TROY, MONTANA. FEBRUARY, (TETRA TECH-MDEQ 2012) 9. TRIHYDRO CORPORATION LAND USE RESTRICTIONS REPORT, ASBESTOS RESOURCE PROGRAM FOR LIBBY AMPHIBOLE, CITY OF LIBBY, CITY OF TROY, AND LINCOLN COUNTY, MONTANA. JUNE 27, (TRIHYDRO 2012) 10. UNITED STATES ENVIRONMENTAL PROTECTION AGENCY FIBROUS AMPHIBOLE CONTAMINATION IN SOIL AND DUST AT MULTIPLE LOCATIONS IN LIBBY POSES AN IMMINENT AND SUBSTANTIAL ENDANGERMENT TO PUBLIC HEALTH: AN ADDENDUM TO MY MEMORANDUM OF MAY 10, (USEPA 2000) 11. UNITED STATES ENVIRONMENTAL PROTECTION AGENCY FINAL SUMMARY OF OUTDOOR AMBIENT AIR MONITORING FOR ASBESTOS AT THE LIBBY ASBESTOS SITE, LIBBY, MONTANA, OCTOBER 2006 TO JUNE FEBRUARY 9, (USEPA 2009) 12. UNITED STATES ENVIRONMENTAL PROTECTION AGENCY FINAL ACTIVITY- BASED SAMPLING SUMMARY REPORT, OPERABLE UNIT 4, LIBBY, MONTANA, SUPERFUND SITE. JUNE 2, (USEPA 2010A) 13. UNITED STATES ENVIRONMENTAL PROTECTION AGENCY PUBLIC SCHOOLS ASBESTOS SAMPLING SUMMARY REPORT, LIBBY, MONTANA, SUPERFUND SITE. JULY 2, (USEPA 2010B) H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx

9 List of Appendices (cont.) 14. UNITED STATES ENVIRONMENTAL PROTECTION AGENCY INITIAL SCREENING LEVEL HUMAN HEALTH RISK ASSESSMENT FOR EXPOSURE TO ASBESTOS, OPERABLE UNIT 3, LIBBY ASBESTOS SUPERFUND SITE, LIBBY, MONTANA. JANUARY 23, (USEPA 2011A) 15. UNITED STATES ENVIRONMENTAL PROTECTION AGENCY EXTERNAL REVIEW DRAFT TOXICOLOGICAL REVIEW OF LIBBY AMPHIBOLE ASBESTOS, IN SUPPORT OF SUMMARY INFORMATION ON THE INTEGRATED RISK INFORMATION SYSTEM (IRIS). AUGUST, (USEPA 2011B) 16. UNITED STATES ENVIRONMENTAL PROTECTION AGENCY AMBIENT AIR SAMPLING RESULTS FOR OPERABLE UNIT 4, LIBBY ASBESTOS SITE, LIBBY, MONTANA 2010 TO (USEPA 2012A) 17. UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 8 SUPERFUND LIBBY ASBESTOS: ABCS OF ASBESTOS. (USEPA 2012B) H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx

10 Acronyms ABS ARP ATV BDL Blvd BNSF cc CERCLA MDEQ IC IUR IRIS LA LHRs MDT MT NPL OU O&M PCME PLM-VE RfC ROW Activity-Based Sampling Asbestos Resource Program All Terrain Vehicle Below Detection Limits Boulevard Burlington Northern Santa Fe Railway Cubic Centimeter Comprehensive Environmental Response, Compensation, and Liability Act Montana Department of Environmental Quality Institutional Controls Inhalation Unit Risk Integrated Risk Information System Libby Amphibole Local Health Regulations Montana Department of Transportation Montana National Priority List Operable Units Operations and Maintenance Phase Contrast Microscopy Equivalent Polarized Light Microscopy Visual area Estimation Reference Concentration Right of Way H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx

11 Acronyms (cont.) s/cc SAB TEM USEPA USFS vs. LA Asbestos Structures per Cubic Centimeter Scientific Advisory Board Transmission Electron Microscope United States Environmental Protection Agency United States Forest Service Versus H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx

12 EXECUTIVE SUMMARY The Libby Asbestos Site (Site) was established as a United States Environmental Protection Agency (USEPA) Superfund site in 1999 due to asbestos-related human health concerns associated with the mining and processing of vermiculite ore that contained asbestos from the Kootenai River Valley geologic deposits. Since the establishment of the Site, asbestos fibers from the Libby Amphibole (LA) asbestos ore deposit have been shown to be prevalent throughout the Libby and Troy, Montana areas. Asbestos has been found in the soil and air, as well as building insulation and related products. The USEPA has established eight different operable units to evaluate the extent of asbestos contamination and determine appropriate remedial activities in order to protect human health and the environment. This report is prepared on behalf of the City/County Board of Health for Lincoln County, Montana (Board of Health) to support human health decisions affecting the Kootenai River Valley citizens. Summaries are provided regarding LA asbestos exposure and risk data, as reported in the USEPA Site documents through June The exposure and risk concerns that could be relevant to the initial development of the Board of Health s Asbestos Resource Program (ARP) are also provided. The scope of this report is limited by the fact that the USEPA s activity-based sampling efforts are ongoing, and the LA asbestos toxicity factor and risk assessment calculations have not yet been finalized. Based on the review of available exposure and risk data, the following considerations are provided to address potential exposure and human health risks associated with LA asbestos at the Site: Request information from the USEPA regarding the pending Site risk assessment and the comparative exposure analysis, which will have implications for the Board of Health s understanding of risk for the communities located within the Site. The request could include, but is not limited to, the following issues: Site Risk Assessment - The rationale for using the data from the ABS, ambient air monitoring, and the nature and extent studies in the risk calculations. - The process used to evaluate cumulative risk. - The anticipated actions to monitor and review risk (activity-based and cumulative) during and after remedy implementation. Comparative Exposure Analysis - The scope of work for expanding the comparative ambient air analysis in Eureka, Helena, and Whitefish. H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx i

13 - The rationale for using Eureka, Helena, and Whitefish, versus other communities that may not be downwind of the Site. - Methodologies used to compare and contrast the carcinogenic and non-carcinogenic toxicity data for LA asbestos and non-la asbestos. - The implications of the comparative exposure analysis on the characterization of risk at the Site. Revise existing or develop new land use restrictions to address LA asbestos exposure activities associated with higher potential exposures and risks such as the following: Expand the building permit program, promote U-Dig program, and provide residents with resources to understand potential exposures associated with excavations. Expand air pollution/dust control ordinances to incorporate paved road cover or dust control measures for potentially higher risk areas (e.g., City of Troy roads, alleys, and parking areas; recreational access around the mine site; and recreational paths/sidewalks). Create licensing or certification programs for workers who are at greater risk for exposure, such as: outdoor construction workers near or at the former Stimson Lumber Mill area; landscaping companies that mow, disturb surficial soils, or excavate deeper soils; and outdoor jobs that require all-terrain-vehicle (ATV) use on trails around the Kootenai River Valley. Develop public resources and outreach programs to promote awareness of potential exposure and risks associated with higher LA asbestos exposure activities such as the following: Heavy machinery operators. Gardening/landscaping-related businesses, garden material suppliers, and local residents to increase exposure awareness (i.e. seasonal effects, materials selection, testing, etc.) with gardening and landscaping activities. Recreational users of paved and off-road trail systems. Recreational users in or around Zonolite Mountain, also known as the mine site, or other natural vermiculite deposit outcrops. Develop public resources and outreach programs for potentially sensitive populations, such as young children and immune-compromised individuals, to promote life-long LA asbestos exposure awareness and prevention. The Board of Health may utilize the exposure and risk summaries and the associated considerations included in this report in developing local health regulations, resources, and outreach programs for the ARP. The results of the pending ii H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx

14 ARP outreach survey may also be utilized to identify potential data gaps and public perceptions that may warrant revisions or additions to these considerations. H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx iii

15 1.0 INTRODUCTION The City-County Board of Health for Lincoln County, Montana (Board of Health) is developing an Asbestos Resource Program (ARP) to help reduce human health exposure and risks associated with asbestos within the Libby Asbestos Site (Site) and the surrounding area. The ARP may include Local Health Regulations (LHRs), public resources, and outreach efforts. The Board of Health intends to use the ARP as an interim measure until the United States Environmental Protection Agency (USEPA) has completed a cumulative risk assessment, and implemented final remedies for the operable units (OUs) at the Site. At that time, the Board of Health may consider a longer-term program to address exposure to residual LA asbestos and other forms of asbestos in general. In addition, the USEPA may use the ARP as part of the interim and/or final institutional controls (ICs) for the Site. The Board of Health is evaluating current land use restrictions and available human health risk data as part of developing the LHRs, resources, and outreach efforts that will be a part of the ARP. The report summarizing current land use restrictions was completed and submitted to the Board of Heath in June 2012 (Trihydro 2012). This Activity- Based Exposure Report summarizes documents prepared by or on behalf of the USEPA and the Montana Department of Environmental Quality (MDEQ) as part of the Superfund process for the Site. Section 1 of this report provides a general description of the Site and the limitations of this report. Section 2 describes the toxicity of LA asbestos, the results of activity-based sampling efforts, air monitoring data, and the status of EPA s risk assessment. Section 3 summarizes the exposures that have been identified and the associated risks. Section 4 identifies potential options and considerations for addressing the risks posed LA asbestos exposure in the area. Section 5 identifies the references used to prepare this report. 1.1 SITE DESCRIPTION Vermiculite in the Rainy Creek complex was mined near Libby, Montana from the 1920 s to The vermiculite was primarily used as insulation in homes, an agricultural soil conditioner, packaging material, and in the manufacturing of wallboard. The Rainy Creek complex vermiculite contains LA asbestos, which is a combination of amphibole asbestos fibrous minerals. Over 6-million tons of vermiculite were mined from the Rainy Creek complex, processed, and shipped off site to over 200 facilities nationwide (USEPA 2011b). Human health studies in the 1980 s and 1990 s identified adverse conditions for workers associated with vermiculite mining and processing activities. Asbestos-related diseases were observed in both the worker and community populations around Libby, Montana. As a result of local health concerns, the USEPA began investigating former mining communities near Libby in The investigation included collection of air, soil, dust, and insulation samples H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx 1-1

16 from homes and businesses to assess the levels of asbestos contamination. As a result of the USEPA s initial investigation, as well as reports of adverse health effects, the Site was added to the USEPA National Priorities List (NPL) in 2002 as the Libby Asbestos Site (USEPA 2000). The primary constituent of concern for the Site is the asbestos found in the Rainy Creek vermiculite deposits. Asbestos is a naturally occurring mineral that can be divided into two main categories: serpentine and amphibole. Although not all vermiculite contains asbestos fibers, mineralogical studies of the Site have discovered that several types of amphibole asbestos are present in the Rainey Creek complex vermiculite deposit. The USEPA refers to the mixture of amphibole asbestos types in the vermiculite as Libby Amphibole (LA) asbestos. The USEPA has reported LA asbestos to be a unique and relatively uncommon form of asbestos that is likely more toxic than other forms of asbestos (USEPA 2012b). In general, asbestos exposure in humans may have both non-carcinogenic (i.e., non-cancerous) and carcinogenic (i.e., cancerous) health effects. Carcinogenic effects include lung cancer and mesothelioma, while non-carcinogenic effects include asbestosis and pleural anomalies (USEPA 2012b). The most common route of exposure for asbestos is inhalation, but asbestos can also be ingested. A toxicity study specific to LA asbestos has been drafted by the USEPA and is in scientific review at this time (USEPA 2011b). The Site has been divided into eight operable units (OUs). Individual OUs are described in Section 3.0 of this document and delineated on Figure 1. The OUs of most concern for the Board of Health include OU4 and OU7. OU4 includes the City of Libby, Montana and the surrounding area. OU7 includes the City of Troy, Montana and the surrounding area. Since 2002, over 3,500 properties in Libby and Troy have been evaluated for the presence of asbestos. Remedial action has been completed at over 1,700 residential and commercial properties as of the first quarter of The USEPA is continuing the process of investigating properties in Libby to identity, and where appropriate, remove LA asbestos. The MDEQ is conducting a similar investigation and removal program in Troy. Both the USEPA and the MDEQ are working toward final remedies for all eight OUs at the Site. 1.2 REPORT LIMITATIONS This Activity-Based Exposure Report provides a review of various Site documents in various stages of completion. This includes USEPA s draft Toxicological Review for Libby Amphibole Asbestos (USEPA 2011b), which is currently in an external draft review process. The USEPA s risk assessment for the majority of the OUs, which will be based on 1-2 H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx

17 the toxicological review of LA asbestos, has not yet been published. Additionally, previous risk screening levels presented in the USEPA remedial investigations will need to be revisited after toxicity factors specific to LA asbestos and new activity-based exposure scenarios are finalized. Therefore, the information and considerations provided in this report are limited, and may need to be reviewed and revised once the USEPA finalizes the toxicological review and the risk assessment for the Site. H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx 1-3

18 2.0 LIBBY AMPHIBOLE (LA) ASBESTOS EXPOSURE AND RISK REVIEW This section summarizes the results of the four main exposure and risk components evaluated for LA asbestos: LA asbestos toxicity; activity-based sampling (ABS) efforts; ambient air monitoring activities; and the Site risk assessment. 2.1 TOXICITY OF LIBBY AMPHIBOLE ASBESTOS As part of the assessment of risk for the Libby Asbestos Site, the USEPA conducted a review of information regarding the toxicity specific to LA asbestos, the results of which are published in the External Review Draft of the USEPA s Toxicological Review for Libby Amphibole Asbestos (USEPA 2011b). The draft toxicological report is a tool that can be referenced for the basis of LA asbestos mineralogy, exposure potential, exposure pathways, fiber analysis/transport, types of asbestos-related health effects, availability of epidemiological and toxicological studies, and LA asbestos carcinogenic and noncarcinogenic toxicity factors that will be used in the upcoming risk assessment. The draft toxicological report also defines the underlying assumptions and limitations of risk analysis. As of July 2012, this document was in external draft review by an independent Scientific Advisory Board (SAB) selected to review and comment on the technical accuracy and scientific policy implications of the document. Assumptions, limitations, and data interpretations could change during the review process, which would result in changes to the proposed toxicity values. However, USEPA representatives have commented, as recently as the June 2012 Libby Asbestos Site Operation & Maintenance (O&M) status meeting, that they do not anticipate drastic changes to the underlying background mineralogy, geology, exposure potential, or exposure pathway information. According to Libby Asbestos Site O&M June 2012 status updates, the USEPA expects to receive all comments and recommendations from the SAB on the draft LA asbestos toxicological report by the fall of At that time, the USEPA will review the recommendations and comments, and pursue finalizing the toxicological review in The LA asbestos toxicological review being prepared by the USEPA defines the underlying basis for both carcinogenic and non-carcinogenic evaluations. While the USEPA s report is not final, the toxicological review provides a framework for characterizing the toxicology, identifying critical exposure pathways, and understanding human health effects associated with LA asbestos exposures. Once the report is finalized, the toxicological review will also provide the basis for completing a risk assessment for the Site. The following subsections summarize pertinent exposure and risk information from the toxicological review (USEPA 2011b) that may be considered during the development of the ARP. H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx 2-1

19 2.1.1 LIBBY AMPHIBOLE ASBESTOS GEOLOGY AND OCCURRENCE LA asbestos is a collection of minerals included in the large vermiculite deposit at Zonolite Mountain, which is approximately 6 miles northeast of Libby, Montana. The vermiculite deposit originates in the Rainy Creek complex geologic unit as an igneous intrusion into the complex (USEPA 2011b). From the 1920 s until 1990, the vermiculite deposit was mined for commercial uses, including building insulation, packing material, agriculture soil conditioners, and in the manufacturing of wallboard. LA asbestos is a fibrous silicate mineral consisting primarily of three types of amphibole minerals: winchite, tremolite, and richterite. The USEPA performed a more in-depth analysis of the fiber characteristics of LA asbestos, which concluded that the asbestos fibers within the vermiculite ore deposit at Zonolite Mountain were similar to the asbestos fibers identified by air sampling in Libby. The occurrence of LA asbestos beyond the ore deposit is attributed to both human and environmental processes LIBBY AMPHIBOLE ASBESTOS EXPOSURE PATHWAYS LA asbestos exposure exists across the Site and the surrounding communities. Former and current residents in Libby, Troy, and the Kootenai River Valley in Montana have been, and may still be, exposed to LA asbestos from a variety of activities. During active mining operations, many community members worked at the mine or processing areas. Vermiculite and waste rock from the deposit may have been transported off-site to residential and recreational areas, either intentionally as soil amendment or insulation, or unintentionally on vehicles or clothing. LA asbestos may also have dispersed by natural mechanisms such as wind and surface water transport. LA asbestos minerals are fibrous and their main route of exposure is inhalation. The inhalation of fibers is largely dependent on the availability and concentration of LA asbestos in the breathing zone, the aerodynamic characteristics of the fibers, and the anatomy of the individual. The LA asbestos fibers are transported throughout the respiratory tract including the tracheal and alveolar regions. Inhalation of LA asbestos can result in serious non-carcinogenic and carcinogenic health effects. Ingestion of asbestos is another potential route of exposure, although it is generally considered to be secondary to inhalation. Exposure can occur through ingestion of expelled lung clearance material, as well as ingestion of soils and water containing LA asbestos fibers. There is no research on ingestion of LA asbestos to determine human health effects, and there is limited research on the health effects from ingestion of other types of asbestos fibers. Dermal exposure to LA asbestos is not considered a significant pathway for exposure based on the available data. 2-2 H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx

20 2.1.3 LIBBY AMPHIBOLE ASBESTOS NONCARCINOGENIC RESPONSE The USEPA derived a draft inhalation reference concentration (RfC) for non-carcinogenic (i.e., non-cancerous) effects associated with LA asbestos, which are based on health effects from a study in Marysville, Ohio (USEPA 2011b). Between 1959 and 1980, the O.M. Scott facility in Marysville, Ohio received and processed vermiculite ore mined from the Site. Because sampling confirmed similarities in the asbestos fibers at the Marysville facility and the Site, the USEPA considers the non-carcinogenic RfC for LA asbestos exposure derived for the Marysville facility applicable to potential LA asbestos exposure. The RfC derived for LA asbestos is the first RfC designated for an asbestos fiber by the USEPA. An RfC is defined by the USEPA as an estimate (with uncertainty spanning perhaps an order of magnitude) of a continuous inhalation exposure to the human population (including sensitive subgroups) that is likely to be without appreciable risk of deleterious effects during a lifetime (USEPA 2011b). An RfC considers non-carcinogenic toxic effects in the respiratory system, as well as effects peripheral to the respiratory system. The reported draft LA asbestos RfC is 1.96E-3 fibers/cc, which is still under final review by the SAB and the USEPA, and is based on continuous exposure (i.e., 24 hours/day and 365 days/year) for 60 years. The draft RfC for LA asbestos can be utilized in inhalation hazard calculations to determine a non-carcinogenic risk hazard based on exposure and concentration parameters. The RfC is intended to protect against non-carcinogenic health effects from LA asbestos exposure including: Pleural abnormalities (pleural lining thickening) in the lungs Asbestosis Reduced lung function or respiratory symptoms Increased morbidity and mortality Human health studies indicate that non-carcinogenic mortality for LA asbestos exposure is greater than cancer mortality for LA asbestos exposure in Libby, Montana. However, an association between exposure of LA asbestos with carcinogenic mesothelioma and lung cancer has also been reported (USEPA 2011b). The USEPA asserts that certain criteria could make a population more susceptible to health effects from LA asbestos exposure (USEPA 2011b). Limited studies have been performed on early life exposure to LA asbestos, which may lead to increased risk of asbestos-related disease later in life. Due to the longer latency period of some asbestos-related diseases following initial exposure, adverse health effects may be more likely to be evident later in life. This could imply that early-life exposure to LA asbestos (i.e., as a child) may increase the probability of adverse effects later in H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx 2-3

21 life. However, the potential contributing factors, both environmental and physical, have not been studied sufficiently to effectively determine susceptible populations for LA asbestos exposure LIBBY AMPHIBOLE ASBESTOS CARCINOGENIC RESPONSE The USEPA also derived a draft inhalation unit risk (IUR) for LA asbestos, which is defined as the upper-bound on the estimate of carcinogenic (cancer) risk estimated to result from a continuous exposure to a constituent of concern at a concentration of 1 µg/m 3 in air. In the case of LA asbestos fibers, the IUR is presented as excess cancers per fibers/cc for continuous lifetime exposure. The USEPA draft IUR for combined mesothelioma and lung cancer for LA asbestos is 0.17 (fibers/cc) -1, which is still under final review by the SAB and USEPA. The IUR may be interpreted as a 17% increase in the lifetime risk of dying from mesothelioma or lung cancer with each 1 LA asbestos fiber/cc increase in continuous lifetime exposure (USEPA 2011b). The draft IUR can be utilized in inhalation risk calculations to determine a combined mesothelioma and lung cancer risk for specific concentrations and exposure parameters. 2.2 ACTIVITY-BASED SAMPLING (ABS) Activity-based sampling is the protocol the USEPA is using at the Site to assess the concentration of LA asbestos during a specific activity or task in a specific OU. A variety of ABS activities have been completed, and additional ABS activities are pending. The ABS data may be utilized to identify and prioritize activities that pose a risk to the community so that appropriate LHRs, public resources, and outreach efforts can be implemented as part of the ARP. Replication of ABS activities after implementation of the ARP could also be used to evaluate the effectiveness of components of the ARP. This Activity-Based Exposure Levels report reviews the status and findings of ABS that are pertinent to the current human health risk at the Site for all OUs within Lincoln County. Following is a list of the OUs where ABS was examined and presented herein: OU1 Former Export Plant (currently the Riverfront Park Complex) OU2 Former Screening Plant and Surrounding Area OU3 Former Vermiculite Mining Site and Surrounding Area OU4 Libby and Surrounding area OU5 Former Stimson Lumber Mill OU6 Burlington Northern Santa Fe Railway Property and Right-of-Way (ROW) 2-4 H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx

22 OU7 Troy and Surrounding area OU8 Highway, Secondary Highways, and ROWs in the Vicinity of the Site In general, the ABS protocol is performed by fitting personal air monitors (low and high volume) on a representative person who is performing a given ABS activity for a specified period of time (CDM-USEPA 2010). The air monitors collect particulates and fibers in the breathing zone of the sampler. The air sampling cartridges are then analyzed to determine the exposure concentration for the activity during the time interval. For asbestos, the concentrations are presented as LA asbestos structures per cubic centimeter of air (s/cc). There are multiple sources of variability inherent in these measurements, which should be considered when interpreting ABS data results. The sources of variability include the activity, the location, the surroundings activities, as well as the LA asbestos concentrations in soil and air at the time of sampling (i.e. ambient air concentrations) (USEPA 2010a). Visual assessments of the amount of vermiculite in the soil were completed in the ABS areas. In some cases, soil samples from outdoor sources, and/or dust samples from indoor sources were collected and analyzed to determine if there is a correlation between source concentration and the activity-based exposure concentration. Primarily, air monitoring samples were analyzed for LA Asbestos using transmission electron microscopy (TEM) combined with phase contrast microscopy equivalent (PCME). TEM is a more precise analytical method for asbestos fibers, but PCME is an analytical method that can be utilized more quickly to count fibers that are likely to be asbestos based on the shape and size (CDM-USEPA 2010). Soil samples have been analyzed primarily with polarized light microscopy and visual area estimation (PLM-VE), but a smaller subset of soil samples have been analyzed with fluidized bed separation followed by TEM analysis. In addition to ABS results, some of the Site investigations derived a screening level risk estimate of the activity summarized for each activity or groups of activities (CDM-USEPA 2009a, CDM-USEPA 2009b, HDR-Syracuse- USEPA 2012, USEPA 2010a). These initial screening level risk estimates are omitted from this report because they are not specific to LA asbestos, and were derived before the USEPA s draft toxicological report was available ACTIVITY-BASED SAMPLING AT OPERABLE UNITS The following sections describe the ABS scenarios considered or evaluated for each of the eight OUs at the Site (Figure 1). Table 2-1 summarizes ABS scenarios by operable unit, status of sampling, and results. H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx 2-5

23 FORMER EXPORT PLANT AND CURRENT RIVERFRONT PARK COMPLEX (OU1) OU1 encompasses the Former Export Plant on the south side of the Kootenai River and north of downtown Libby. OU1 was historically used while the vermiculite mine was operational as a distribution and storage area for vermiculite prior to shipment. The property is currently owned by the City of Libby. The USEPA has almost completed the selected remedy for this area and is in the process of converting OU1 into a city park called the Riverfront Park. In addition to being a public recreation space and public access to the Kootenai River, OU1 also houses the David Thompson Search and Rescue center. In 2007, pre-remedy ABS activities were conducted to assess the LA asbestos concentrations in indoor air at the existing David Thompson Search and Rescue center. Sampling was also conducted to assess the LA asbestos concentrations for outdoor workers involved in brush hogging activities (prior to remedy selection and implementation). The concentrations for the indoor activities prior to remediation ranged from below detection limit (BDL) to 7E-2 s/cc. The concentrations for outdoor workers at the site ranged from 3.8E-3 to 7.2E-2 s/cc for wetted brush hogging activities (CDM-USEPA 2009a). During the 2007 sampling, corresponding indoor dust, ambient air, and outdoor soil samples were also collected. The indoor dust sample concentrations ranged from BDL to 75 s/cc. Ambient outdoor air concentrations ranged from BDL to 1.6E-4 s/cc. Outdoor surface soil concentrations ranged from BDL to <1% LA asbestos (CDM-USEPA 2009a). Partially completed in 2011 and continuing in 2012, proposed remedies at OU1 included soil removal and placement of clean cover soils. The USEPA intends to conduct sampling for indoor and outdoor ABS scenarios for post-remedy evaluation of OU1 later in 2012 or during FORMER SCREENING PLANT AND SURROUNDING AREA (OU2) OU2 is the former screening plant at the base of OU3, next to Highway 37. From 1975 to 1990, the screening plant sorted vermiculite from the mine, and then transported the sorted material across the Kootenai River for loading and transport onto rail cars. Following termination of mining operations, the largest parcel of OU2 was converted to a retail nursery, which operated from 1993 until In 1999, the USEPA started extensive investigation and removal activities throughout OU2 (CDM-USEPA 2009b). The property is now privately owned, and no commercial or businesses are maintained on the property. 2-6 H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx

24 Extensive remediation and soil capping activities were already completed for OU2 prior to the USEPA starting ABS activities; therefore, no ABS scenarios were performed during the remedial investigation. The USEPA reports that the capped areas have no completed exposure pathways of concern (CDM-USEPA 2009b). However, the USEPA is planning on performing post-remedy ABS activities in 2012 to evaluate the effectiveness of the remedy along the highway right-of-way and along the Kootenai River, which includes a bank fishing ABS scenario right at OU2 and a river-use ABS scenario on Zonolite Island near OU2 and OU3. The USEPA is also performing ecological risk sampling activities along the Kootenai River near the Rainy Creek outfall FORMER VERMICULITE MINE FACILITY AND SURROUNDING AREA (OU3) OU3 includes the area of the former vermiculite mine owned by the Kootenai Development Corporation, a subsidiary of the former owner W.R. Grace & Co. This OU also includes the surrounding area owned by Plum Creek Timber Company. The majority of OU3 is a steep forested mountain area that includes the Rainy Creek drainage and Rainy Creek Road. OU3 was the main source area for vermiculite mining activities. The lands are currently unused or utilized for recreational purposes, and wood product/timber harvesting near the boundaries of OU3. According to the Initial Screening Level Human Health Risk Assessment for Exposure to Asbestos, Operable Unit 3 (USEPA 2011a), the majority of the property is expected to remain inaccessible to recreational uses by the current owner. Therefore, the ABS activities focused primarily on recreational areas near the edges of the property and along Rainy Creek. The following ABS scenarios were evaluated for the OU3 Initial Screening Level Human Health Risk Assessment Report (USEPA 2011a): Recreational Riding ATV Walking/hiking Camping or clearing an area of duff for campsite Wood gathering/ firewood harvesting Smoke inhalation from campfire Occupational Driving through area United States Forest Service (USFS) trail/maintenance operations USFS fire-fighting operations (ground and pilot/air based) H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx 2-7

25 The results of the individual ABS activities are available in the electronic database associated with the referenced report; however, the report table summarizing the ABS concentrations was not located in the referenced report. In addition to the completed ABS activities described above, the following ABS scenarios for OU3 are under consideration or included in proposed sampling efforts: Commercial logging Ground fire-fighting activities Recreational hunting Recreational fishing OU3 ABS results and risk assessment calculations will be separate from the general site risk assessment, and are scheduled to be completed in 2013 following completion of ABS scenarios and available LA toxicity data LIBBY AND SURROUNDING AREA (OU4) In 2010 the USEPA released the Final Activity-Based Sampling Summary Report for Operable Unit 4 (USEPA 2010a), which reports the ABS findings that were completed for the City of Libby and surrounding area in OU4. This report focused on outdoor ABS results for raking, mowing, and digging, and indoor ABS results for passive and active behaviors. Generally, the outdoor sampling took place over a 2-hour time interval. The USEPA also looked at differentiating the seasonal effects by sampling in the spring and during drier summer months. For indoor activities the USEPA focused on passive or active activities over an 8-hour time interval. Passive indoor activities included reading a book, watching TV, and working at a desk. For active indoor activities, the USEPA looked for activities of movement within a building, including walking, sitting on upholstered furniture, sweeping, and vacuuming. These indoor ABS scenarios were examined in the summer, fall, winter, and spring to account for seasonal effects. The following ABS activities were examined as part of the ABS report for OU4: Indoor Active dusting, sweeping, and moving throughout the building Passive working at desk, sitting, and reading Outdoor Yard/gardening mowing, raking, digging, gardening, and landscaping with bark/cover 2-8 H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx

26 Driving a car Bicycling (adult) on paved and unpaved surfaces Child tricycle riding on an unpaved driveway and riding in a carrier behind an adult on paved roads/paths Child digging in an unpaved driveway Outdoor ABS results were reported in the ABS report for OU4 (USEPA 2010a), and are summarized below: 62 different properties in Libby were investigated. High variability in ABS concentrations of the outdoor air samples was observed, ranging from <0.001 s/cc (nondetect) to >20 s/cc. Mowing and digging activities appeared to have similar ABS concentrations. In general, raking activities exhibited lower ABS concentration values than mowing/digging. Summer activities yielded higher general air concentrations than spring activities, which may be attributed to higher soil moisture in spring. In most cases, the higher air sample results correlated with increased LA asbestos concentrations in the soil. In general, analytical analysis of soil samples using PLM-VE, and visual vermiculite observations resulted in similar air-soil correlation. Indoor ABS results were reported in the ABS report for OU4 (USEPA 2010a), and are summarized below: 80 different post-cleanup properties in summer, fall, winter, and spring were investigated. Both passive and active sampling was examined at all locations and all seasonal changes. Indoor air levels ranged from BDL (<0.0003) s/cc (non-detect) to approximately 0.01 s/cc. Higher concentrations were generally associated with active versus passive activities. The USEPA suggested that indoor air dust may be a contributing factor; however, due to very few dust samples with measurable detections there was no statistically significant relationship. Indoor air results were generally lowest in winter and highest in summer for both passive and active ABS scenarios. H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx 2-9

27 There was a weak correlation between indoor air concentrations and outdoor soil samples on the property, which may suggest that outdoor soil concentrations may be one factor that contributes to indoor air contamination. Where no outdoor soil clean-up was required, the indoor air had lower LA asbestos as compared to areas that required soil clean-up or had already been cleaned up. Following the submittal of the OU4 ABS summary report (USEPA2010a), additional ABS activities were conducted in 2010 and 2011 (CDM-USEPA 2010). The results of the most recent sampling event have not been published. The 2010 and 2011 sampling events included the following: Outdoor Yard/gardening landscaping with bark/cover Yard/gardening mechanical Driving a car Bicycling (child and adult) Walking outdoors Child tricycle riding on unpaved driveway Child digging in an unpaved driveway The USEPA expanded its ABS program in OU4 during the summer of 2010 to include the following outdoor ABS activities: adult yard work (raking, mowing, and digging); adult garden work (digging with a trowel); child playing on unpaved driveways; driving on roads (paved and unpaved); and riding bicycles on paved and unpaved trails/roads (CDM-USEPA 2010). The focus of the expanded sampling effort in OU4 was to examine a property as a whole exposure unit, and determine if similar use areas, such as driveways, resulted in similar sample ABS results. The expanded sampling effort in OU4 was also designed to compare ABS results for post-remedy properties with ABS results for those properties that still required clean-up (i.e., pre-remedy). Neither carcinogenic risk nor noncarcinogenic hazard calculations for the referenced OU4 ABS scenarios have been published at the time of this report. The USEPA continues to expand their ABS efforts through 2012/2013. As part of that expansion, the USEPA is examining occupational ambient air quality results for the following occupational activities in OU4: Occupational Ambient Air Monitoring Fire department air monitoring at structure (OU4) and wildland areas (OU4/OU3) 2-10 H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx

28 Teaching indoor ambient air monitoring at Libby Schools (see Section of this report) Office work (USEPA info center) indoor ambient air monitoring USFS indoor work indoor ambient air monitoring Outdoor construction work outdoor air monitoring During July 2012 Site project update meetings in Libby, the USEPA outlined several additional ABS scenarios for OU4. The USEPA is planning to complete all ABS activities for OU4 in the second half of 2012 or early One additional scenario within OU4 includes commercial logging ABS scenarios for the Flower Creek area, which is just south of the Town of Libby. Another ABS scenario will look at the exposures associated with cleaning ash from a wood stove after burning low, medium, and high-level asbestos contaminated wood. Additional ABS activities will use previously collected indoor samples for use in determining a trade-person ABS scenario for a worker entering the home and performing basic maintenance FORMER STIMSON LUMBER MILL (OU5) OU5 is property within the town of Libby that includes the area of the former Stimson Lumber Mill site. The property is currently owned by the Lincoln County Port Authority. Historically the site was a lumber facility, but is being redeveloped for multiple industrial and recreational uses. In 2007 and 2008, the USEPA performed several recreational and occupational ABS studies including the following ABS scenarios (HDR-Syracuse-USEPA 2010): Occupational Indoor work scenario for various office and industrial buildings Outdoor work near/loading wood chip/waste bark pile Recreational Adult and child biking scenarios near paved path at Libby Creek Walking/hiking scenario near Libby Creek Motocross riding and observation ABS activities were conducted under drier seasonal conditions from September to October. Corresponding dust, soil, and/or waste bark LA asbestos samples were also collected in the vicinity of ABS activities. H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx 2-11

29 Report findings for OU5 ABS and risk calculations are summarized as follows (HDR-Syracuse-USEPA 2010): Occupational Vacant buildings had no detectable LA asbestos concentrations/fibers. The mean sample results for occupied buildings detected LA asbestos with concentrations ranging from 9.8E- 05 s/cc to 1.4E-02 s/cc. LA asbestos was detected in seven of eight outdoor work areas and ranged from BDL to 6.3E-3 s/cc. Recreational ABS results for riding in the motocross park were BDL for LA asbestos fibers. ABS results for adult and child bicycle riding had similar mean concentrations, with adult concentrations at 9.5E-05 s/cc, and child concentrations at 1.4E-04 s/cc. Bicycling on paved and non-paved areas was only evaluated for an adult ABS scenario due to fact that the unpaved portions of the trail are steep and narrow in sections and unlikely to be used by a child. An additional evaluation of wood-chip related activities was conducted in August 2011 (CDM-Smith 2012), and included the following scenarios: Spreading of wood chips using a shovel and manual labor Raking the wood chips Digging into the wood chips/cover with a hand trowel Corresponding wood chip sampling for LA asbestos also coincided with the ABS event. The ABS results were BDL for all samples, and only one of 15 wood chip samples had one LA asbestos fiber present, which corresponded to a concentration of 2.3E-05 s/cc BNSF RAILWAY PROPERTIES AND RIGHT-OF-WAYS (OU6) OU6 includes the BNSF Railway properties that extend throughout the Libby Asbestos Superfund OUs, and the ROWs located to the eastern edge of OU4 and the western edge of OU7 (Figure 1). Historically, the railroads were the primary method of transporting vermiculite from the Kootenai River Valley. As of the date of this report, investigation of OU6 has not been completed. The USEPA is working with BNSF to facilitate a schedule for investigation of OU6, which is expected to be completed by BNSF under the oversight of the USEPA H:\Projects\LincolnCtyHealthDpt\ProjectDocuments\MT\LibbyInstitutionalControls\Reports\02_ABE_Report\Final\1_Text\201208_ABE-Report-FINAL_RPT.docx