Near the town of Opportunity, this area long served as a tailings dump for the Anaconda smelters. Processed mine waste (tailings) from the smelters was mixed with water (slurried) and pumped to the site. The Waste Repository has not truly been a “pond” for many years.
Since the closure of the smelter in the 1970s, no water has been pumped to the site, leaving the tailings deposits to dry out, and creating potential dust concerns for nearby residents. The area covers approximately five square miles, with tailings deposits averaging about 20 feet deep; in the upper tiers of the repository, tailings deposits are as much as 80 feet deep.
Due to the high volumes of mine waste, in recent decades the area has been used as a repository for wastes from other regional Superfund sites. In particular, mine tailings removed from the Milltown Dam site near Missoula were transported to the BP-ARCO Waste Repository from around 2005-2009.
EPA agreed to officially change the site name from the Opportunity Ponds to the BP-ARCO Waste Repository around 2006-2007 after residents of Opportunity lobbied to remove their community name from the nearby toxic waste site. However, there is still inconsistency in how the site is referenced, even among agency personnel. For example, EPA refers to the site as a “Land Management Area,” despite its clear and agreed-upon purpose as a waste repository.
Local residents also lobbied against moving historic mine wastes from the Milltown Reservoir near Missoula to the repository, a potential environmental justice issue. EPA justified the move both by noting the large volume of contaminants already present at the repository site, and by claiming that the Milltown wastes were less-contaminated and would provide topsoil for a protective vegetative cap at the repository. Read more in the EPA Update: Focus on Opportunity Ponds (2007).
This claim, which was not thoroughly studied prior to the undertaking, turned out to be false, as vegetation has failed to grow on the Milltown wastes at the repository since the last Milltown wastes were moved to the repository in September of 2009. The Potentially Responsible Party (PRP) for the site, BP-ARCO, now must develop a new solution to prevent contaminants at the repository from spreading due to wind or water. Dust control measures are currently used at the site.
If no solution is developed by the PRP, EPA is mandated to step in and order a solution. BP-ARCO, at last notice, is studying the Milltown wastes to determine if they can be amended to allow for plant growth.
In September 2011, EPA issued an Amendment to the 1998 Anaconda Regional Water, Waste & Soils Operable Unit (OU4) Record of Decision (Sept 2011), which includes the BP-ARCO Waste Repository/Opportunity Ponds.
- Visit the website of the Arrowhead Foundation, the EPA-funded TAG group for the Anaconda area.
- Visit the website of the Opportunity Citizens Protection Association (OCPA), a grassroots community group concerned about environmental issues related to the BP-ARCO Waste Repository.
- Click here to view or download EPA Records of Decision for various Anaconda Smelter Operable Units.
- Additional information and site documents can be found on the EPA Superfund Website.
- A list of cleanup activities for the Anaconda Site can be found at the EPA Superfund Information System.
- Additional site details can be found on the EPA Superfund Information System Site Profile.
- The Clark Fork River Technical Assistance Committee (CFRTAC) also provides information and outreach in regards to the Clark Fork River Superfund sites and Operable Units.