BUNKER HILL MINING & METALLURGICAL
IDAHO
EPA ID# IDD048340921
EPA Region 10
Shoshone, Kootenai, Benewah, Spokane (WA) Counties


1st Congressional District

Other Names: Coeur d'Alene Basin
Last Update: April, 2010

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The Bunker Hill Superfund Site, located in northern Idaho and eastern Washington, was listed on the National Priority List (NPL) in 1983. It is one of the largest and most complex Superfund sites in the country. The Site includes mining-contaminated areas in the Coeur d’Alene River corridor, adjacent floodplains, downstream water bodies, tributaries, and fill areas. It also encompasses the 21-square-mile Bunker Hill “Box” located in the area surrounding the historic smelting operations.

The Bunker Hill Superfund Site is within one of the largest historical mining districts in the world. In 1883, commercial mining for lead, zinc, silver, and other metals began in the Silver Valley. Heavy metals contamination is present in soil, sediment, surface water, and groundwater from over 100 years of commercial mining, milling, smelting, and associated modes of transportation. The contamination has impacted both human health and environmental resources in many areas throughout the site. Entire communities have been built on top of old mine tailings. The principal sources of metals contamination were tailings generated from the milling of ore discharged to the South Fork Coeur d’Alene River and its tributaries or confined in large waste piles onsite; waste rock; and air emissions from smelter operations. Tailings were frequently used as fill for residential and commercial construction projects. Spillage from railroad operations added to contamination across the site.

Tailings were also transported downstream, particularly during high flow events. They were deposited as lenses of tailings or as tailings and sediment mixtures in the bed, banks, floodplains, and lateral lakes of the Coeur d’Alene River Basin and in Coeur d’Alene Lake. Some fine-grained material washed through the lake and was deposited as sediment within the Spokane River flood channel. The estimated total mass and extent of impacted materials (primarily sediments) is over 100 million tons. This is dispersed over thousands of acres. Over time, groundwater also became contaminated with metals.

Ore-processing facilities in Kellogg and Smelterville emitted contaminants into the air. Although both the lead smelter and zinc plant had recycling processes designed to minimize air-borne particulates, significant metals deposition and sulfur dioxide emissions still occurred. These emissions affected areas near the smelter and zinc plant, and greatly contributed to the denuding of surrounding hillsides. In 1981, smelter operations ended. Limited mining and milling operations continued onsite from 1988 to 1991, and small-scale mining operations continue today.

After listing on the NPL in 1983, remedial investigations (RIs) and feasibility studies (FSs) at first focused on the 21-square-mile Bunker Hill Box. Those studies mainly focused on human health risks, particularly on reducing elevated blood lead levels in children. The human health effects from heavy metals exposure have been studied extensively at the Bunker Hill Superfund Site. Childhood lead poisoning was epidemic in the 1970s, with over 75 percent of children having blood lead above 40 micrograms per deciliter (g/dL). Starting in 1996, additional human health and ecological studies were done in mining-contaminated areas outside of the Box.

The contaminants of concern are chiefly metals. Affected media are soil, sediment, surface water, and groundwater. The primary source of metals in surface water is leaching and erosion of sediments impacted by tailings. Direct exposure to metals in soil and sediments is a source of risk for human and ecological receptors, including recreational users, subsistence users, migrating waterfowl and plants. Surface water quality exceeds applicable criteria for the protection of cold water biota in portions of the South Fork Coeur d’Alene River basin by up to 200 times the criteria for dissolved cadmium and as much as 90 times the criteria for dissolved lead and zinc. The most heavily impacted areas are without aquatic life. Other areas provide only partial support for fish and other aquatic species (e.g., they are suitable for migration but not spawning and rearing).


Site Responsibility: This site is being addressed through federal, state, tribal, and potentially responsible parties' (PRP's) actions.

NPL Listing HistoryDates
Proposed Date:12/30/1982
Removed Date:
Withdrawal Date:
Final Date:09/08/1983
Deleted Date:


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Accomplishment Highlights:
-Blood lead levels in children who participate in annual testing programs are down. In 2009, more families in the Basin participated in this program after the incentive pay was raised. Efforts to increase participation rates in the testing program continue.
-To date, more than 5,500 residential properties (residential yards, commercial properties, driveways, street rights-of-way, etc), six Lower Basin recreational areas, and four mine and mill sites have been cleaned up in the site. Five recreational areas in Washington State along the Spokane River have been successfully cleaned up.
- More than two million cubic yards of contaminated material have been removed from the Coeur d'Alene river system in Smelterville Flats and side gulches.
- The Central Impoundment Area (CIA) has been capped with a protective liner and clean material.
-Trees, grasses, and shrubs are flourishing, and wildlife has returned to areas of a Hillside Revegetation Project. More than 1,000 acres of denuded hillsides have been revegetated.
-EPA has transferred about 1,800 acres of property to the State of Idaho to facilitate economic development.
- In 2008, Union Pacific Railroad transferred ownership of the railroad right-of-way to the State of Idaho and Coeur d’Alene Tribe. Cleanup of the right-of-way was completed as a removal action and was certified complete in 2005. The cleanup included conversion of the ROW into the 72-mile Trail of the Coeur d’Alenes, which is regularly used by thousands of residents and tourists.
- In 2008, EPA certified that the Upstream Mining Group (UMG) completed cleanup of contaminated residential and commercial properties within the Bunker Hill Box. In total, about 3,200 residential and commercial properties and street rights-of-way were cleaned up and 17 wells closed. Completion of the Box residential cleanup is a major milestone for the Bunker Hill Superfund site. EPA and the State of Idaho continue to work with UMG on their remaining Consent Decree obligations, such as expanding the Page repository to provide near-term capacity, and securing long-term repository space and funding for the Box Institutional Controls Program.
- Nearly 400 acreas of safe feeding habitat for wild birds and other wildlife is being created in the Lower Basin as part of an agriculture to wetland conversion project. This is the first project of its kind in the Basin, and an important step in addressing the Basin’s ecological contamination issues.
- New waste repositories are being sited and existing repositories expanded to safely contain contaminated soils from the residential cleanup and Institutional Controls Program. In 2009, a new waste repository at East Mission Flats was established and the Page Repository was expanded to provide more space for the local Institutional Controls Program.
- In 2009, a revised Coeur d'Alene Lake Management Plan was signed by the Coeur d'Alene Tribe and the State of Idaho. The plan assesses the Lake's water quality and outlines strategies to protect it.
-Local workers were hired to do yard cleanup work. In 2009 and 2010, even more local workers are are being hired as a result of $15M in American Recovery and Reinvestment Act funding received for the Bunker Hill/Coeur d'Alene Basin residential cleanup program.
-A 2009 consent decree requires the Union Pacific Railroad and the Burlington Northern Santa Fe Railway Company to clean up the former rail yard known as the Wallace Yard and its Nine Mile Creek and Canyon Creek Branch Lines. The Consent Decree was signed April 2010.
-Under a bankruptcy settlement with ASARCO Inc. that was finalized in December 2009, about $494 million will go toward cleanup in the Bunker Hill Superfund site. This is the largest Superfund settlement in EPA history. Most of the settlement funds were received for Superfund cleanup actions in mining-contaminated areas in the Coeur d'Alene Basin outside of the Bunker Hill Box.
-In 2009, over 6.5 million square feet of land was cleaned up. This was almost three times more land cleaned up compared to previous years. Much of this work was done using part of the $15 million in stimulus money through the American Recovery and Reinvestment Act.

Early Actions: In 1986, EPA removed about 8,750 cubic yards of contaminated soils from sixteen public areas in the Bunker Hill Box, such as parks and playgrounds, and disposed of contaminated soils in an on-site repository. From 1997-2001, EPA completed time critical removal actions in the Basin residential areas (residential yards and playgrounds) and at some recreational areas in the Lower Basin.

Long-Term Actions: EPA published the first Site Record of Decision (ROD) in August 1991 providing the Selected Remedy for OU1 residential soils. The second ROD for the Site was published by EPA in September 1992 addressing contamination in the non-populated OU2, as well those aspects of OU1 that were not addressed in the 1991 OU1 ROD. These two OUs then proceeded into remedial design (RD) and remedial action (RA) phases of work. Since publication of the 1992 OU2 ROD, a number of remedy changes and clarifications have been documented in two OU2 ROD amendments (September 1996 and December 2001) and two Explanations of Significant Differences or “ESDs” (January 1996 and April 1998).

EPA began the Remedial Investigation and Feasibility Study (RI/FS) for OU3 in 1998 and issued its interim thirty-year ROD to clean up mining contamination in 2002. Remedial design, remedial action, and studies to support future OU3 remedial actions were initiated in 2003. Human health cleanup actions have been prioritized for funding.

While implementing current cleanup actions and the site RODs, EPA has acknowledged that more remedial actions will need to be selected to be protective of human health and the environment and comply with applicable or relevant and appropriate requirements (ARARs). Therefore, as part of remedy implementation, EPA is reviewing the cleanup actions selected to date, considering how these actions fit into a comprehensive cleanup, and assessing what additional activities or modifications are needed. Based on this review, EPA has determined that an amendment to the existing RODs is appropriate considering new information and data that have been collected at the site. In 2010, EPA is planning to issue a ROD amendment for the Upper Basin, including the Bunker Hill Box (generally Mullan to Enaville). The ROD amendment will select actions to protect the existing human health remedy, and improve water quality for fish and other wildlife and protect recreational users at several hundred source areas (e.g., closed mine and mill sites). EPA will continue to evaluate new information about the Lower Basin to determine if additional actions would need to be selected in the future.

EPA is required to conduct Five Year Reviews at the Bunker Hill site because contamination remains in place at levels above what is permitted for unrestricted use and unlimited exposure. Five-year reviews provide an opportunity to evaluate the implementation and performance of a remedy to determine whether it remains protective of human health and the environment. EPA conducted Bunker Hill Five Year Reviews in 2000 and 2005. The next Five Year Review is scheduled to be completed in October 2010.




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