Established in 1998, the Anaconda Regional Water, Waste & Soils (ARWWS) Operable Unit (OU) is the largest and most diverse Operable Unit in the Anaconda Smelter NPL site. As a result, the OU was separated into fifteen Remedial Design Units (RDUs) and two Expansion Areas based upon factors such as location, source and type of contamination, and remedial needs. Click here for more information about the ARWWS OU.
The West Galen Expansion Area was added to the Anaconda Regional Waters, Wastes & Soils (ARWWS) Operable Unit (OU) following sampling and investigation activities that identified smelter-related impacts in the area north of Anaconda. The identified area encompasses 34 parcels. Soils in the area were generally impacted by smelter fallout from the Upper and Lower Works as well as – to a lesser degree – by the Washoe Smelters, which were in operation between 1884 and 1980.
Remedial action began in 2006 in the West Galen Expansion Area, addressing a total of 224 acres. This acreage was separated into two work areas: Work Area A (South), consisting of 104 acres near the Anaconda Sewage Lagoons; and Work Area B (North), consisting of 120 acres near the intersection of Galen Road and Antelope Springs Road. Construction activities were completed in April of 2007 and included the installment of a protective vegetative cover. In 2011, after four years of evaluation, seven of the 34 parcels within the West Galen Expansion Area were submitted to the EPA for consideration to move into the 5-year review phase.
To make this decision, the EPA uses the Land Reclamation Evaluation System (LRES); a decision-making tool designed to evaluate the conditions of an Operable Unit or subarea and select the appropriate level of reclamation using a scientific approach. The quantitative scores produced by the LRES program are used to determine if the actions outlined in remedial decision documents have been satisfied for an Operable Unit or subarea. The 5-year review phase includes long-term monitoring and maintenance of an Operable Unit or subarea (Remedial Design Unit or Expansion Area).
Visit the Superfund Library, located on the Arrowhead Foundation’s website, to review documents and research regarding the Anaconda Smelter NPL site. Additional information can also be found on the EPA’s website.