RECORD OF DECISION AMENDMENT COMMUNITY SOILS OPERABLE UNIT Anaconda Smelter National Priorities List Site Anaconda, Montana SEPTEMBER 2013 U.S. Environmental Protection Agency and Montana Department of Environmental Quality Part I - Declaration Site Name and Location Anaconda Company Smelter Superfund Site (the Site), Anaconda-Deer Lodge County (ADLC), Montana 59711. EPA ID: MTD093291656. SSID: 0818. Community Soils Operable Unit (Community Soils OU). Statement of Basis and Purpose This document amends the 1996 record of decision (ROD) (EPA 1996) for the remedial action to clean up mining-related contamination at the Community Soils OU. The amended remedy 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, to the extent practicable, the National Oil and Hazardous Substance Pollution Contingency Plan (NCP). This document is issued by the EPA Region 8, the lead agency, and the Montana Department of Environment Quality (DEQ), the supporting agency. Both the EPA and DEQ concur on the selected remedy presented herein. This ROD amendment is based on the administrative record for the Site and will become part of the administrative record per the NCP, Section 300.825(a)(2). The administrative record (on microfilm) and copies of key documents are available for public review at the joint Deer Lodge County/Arrowhead Foundation Superfund document Repository at 118 East Seventh Street in Anaconda. The complete written administrative record is maintained at the EPA-Montana Office, 10 West 15th Street, Suite 3200, in Helena, Montana and can be viewed during normal business hours. Assessment of the Site The Site is located in the Deer Lodge Valley in southwestern Montana, in and around the city of Anaconda. Milling and smelting activities conducted for nearly 100 years resulted in the contamination of soils, surface water, and ground water, primarily through airborne emissions and disposal practices from smelting operations. The primary contaminants of concern are arsenic, cadmium, copper, lead, and zinc. The remedial action selected in this ROD amendment is necessary to protect public health or welfare or the environment from actual or threatened releases of hazardous substances at the Site. Description of the ROD Amendment The ROD amendment changes only those provisions of the 1996 Community Soils OU ROD which deal with residential soils. Remedial decisions for commercial/industrial properties and active railroad beds remain unchanged. The amended remedy differs from the 1996 ROD with the addition of a cleanup level for lead in soils and cleanup levels for arsenic and lead in accessible interior dust, as well as the expansion of the I-1 Community So ils Operable Unit ROD Am endment • Declaration institutional controls as implemented through the Community Protective Measures Program (CPMP) to provide for a health education program. All other components of the 1996 ROD remain unchanged. Changes are due primarily to concentrations of lead in residential soils being significantly higher than those originally reported in the remedial investigation/feasibility study (Rl/FS). Additionally, there is also a better understanding of the site conceptual model based on the large amount of remedial action and other sample data collected since 1996. Although smelter emissions remain the primary source of contamination, it is now clear that some properties contain other sources of contamination (such as imported waste material). Statutory Determinations The selected remedy meets the mandates of CERCLA §121 and the NCP/ It is protective of human health and the environment, 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. However, contaminated soils present at the Community Soils OU do not represent a principal threat, and treatment would be significantly more expensive due to the very large quantities of materials impacted. Although they are present in large volumes, the soils within the Community Soils OU are low in toxicity and can be reliably contained. Because this amended remedy will continue to result in mining contaminants remaining on site above levels that allow for unlimited use and unrestricted exposure, statutory five-year reviews have been initiated at the Site and will continue to ensure that remedies remain protective of human health and the environment. The five-year reviews will continue to focus on areas where waste has been left in place or where remaining concentrations do not allow for unlimited use of the property. Authorizing Signatures This 2013 ROD Amendment documents the se lected remedy for the Anaconda Smelter Community Soils OU. This remedy was selected by EPA with concurrence of the State of Montana. Date: Martin Hestmark Assistant Regional Administrator, Ecosystems Protection and Remediation U.S. Environmental Protection Agency, Region 8 I 1-2 Community Soils Operable Un it ROD Amendment • Declaration Date: Tracy -Manning, Direc.tor Montana Department of Environ I 1-3 Record of Decision Amendment Table of Contents Part I - Declaration ............................................................................................................................................................I-1 Site Name and Location ....................................................................................................................................................I-1 Statement of Basis and Purpose ...................................................................................................................................I-1 Assessment of the Site ......................................................................................................................................................I-1 Description of the ROD Amendment ...........................................................................................................................I-1 Statutory Determinations ...............................................................................................................................................I-2 Authorizing Signatures ....................................................................................................................................................I-2 Part II- Decision Summary ............................................................................................................................................ II-1 1.0 Introduction ................................................................................................................................................................ II-1 1.1 Site Description .......................................................................................................................................................... II-1 1.2 Community Participation ....................................................................................................................................... II-3 2.0 Site History and Enforcement Activities .......................................................................................................... II -4 2.1 Site History ................................................................................................................................................................... II-4 2.2 Implementation of the 1996 ROD ...................................................................................................................... II-5 2.2.1 2002 to 2005 – Remedial Design/Remedial Action ....................................................................... II-6 2.2.2 2006 – Five Year Review ............................................................................................................................ II-7 2.2.3 2007 – Data Collection ................................................................................................................................ II-7 2.2.4 2008 - Data Interpretation and Analysis Report ............................................................................. II-8 2.2.5 2010 - FYR ........................................................................................................................................................ II-9 3.0 Basis for Amendment .............................................................................................................................................. II-9 4.0 Development of Remedial Alternatives ......................................................................................................... II-11 4.1 Summary of Site Risks ........................................................................................................................................... II-11 4.2 Remediation Goals .................................................................................................................................................. II-11 4.3 ARARs ........................................................................................................................................................................... II-12 4.4 Area of Concern .......................................................................................................................................................