The Bunker Hill Superfund Site is primarily located in Idaho’s Panhandle, extending from the Idaho-Montana border into portions of eastern Washington. It covers over 1,500 square miles, making it one of the most complex Superfund Sites in the United States (US). The US Environmental Protection Agency (EPA) listed the Site on the national priorities list in 1983 due to high levels of metal contamination in the environment and elevated blood lead levels discovered in local children. A map of the Bunker Hill Superfund Site is available here.
The area, aptly named the “Silver Valley”, has a rich mining history dating back to the 1880’s. As common for the time, mining and milling operations discharged waste, or tailings, into the South Fork of the Coeur d’Alene River and its tributaries. In addition, the Bunker Hill Company operated a primary lead smelter in Kellogg, Idaho beginning in 1917. In 1969, Gulf Resources acquired operation of the mine, mill and smelting complex, operating the lead smelter until its closing in 1981. It is estimated that more than 60 million tons of metal-contaminated tailings were discharged directly into rivers and waterways from 1880 to 1968. Additionally, over 100 million tons of mine waste, including 2.4 billion pounds of lead, was dispersed over thousands of acres. Because of these historic mining operations, there is over 15,000 acres in the Lower Coeur d’Alene Basin with lead concentrations that are acutely toxic to waterfowl. Decades of atmospheric emissions from the smelter further increased levels of lead and other heavy metals in residential soils throughout much of the Site.
The Bunker Hill Company produced one-third of the nation’s lead, half of the silver, and over one quarter of the zinc during this period. The Bunker Hill Company was once the largest employer in the State of Idaho, making the Silver Valley one of the most prosperous mining communities in the US. Unfortunately, the lead smelter was also responsible for the worst childhood blood lead poisoning event in US history. On September 3rd, 1973, the smelter’s baghouse, the primary filtration system for Bunker Hill’s lead smelter, caught fire. This incident had dire consequences for Silver Valley residents. Following the fire, increasing metals prices led Gulf Resources, the current operating company, to run the smelter without a properly functioning filtration system. During this period, the lead smelter emitted up to 160 tons of particulate emissions per month, containing 50-70% lead. Prior to the destruction of the baghouse, particulate emissions ranged from 10-20% lead. Excessive smelter emissions containing high-lead particulates continued until August of 1974 when emergency response actions began. Learn more about the history of the Bunker Hill Baghouse Fire and its effects.
As a result of the high-lead particulate emissions from the smelter that impacted surrounding communities, dozens of local children were diagnosed with acute lead poisoning in 1974. The US Centers for Disease Control and Prevention (CDC), Idaho Department of Health and Welfare (IDHW), and Panhandle Health District (PHD) initiated a blood lead screening campaign for area children. The agencies found that 99% of the children had a blood lead level greater than 40 micrograms per deciliter (µg/dL). For comparison, the CDC’s current reference level for children is 3.5 µg/dL. The highest recorded blood lead level of 164 µg/dL belonged to a child. Children living within one mile of the smelter had an average blood lead level of 67.4 µg/dL. These were some of the highest levels ever recorded in US history. Learn more about blood lead trends in children who have participated in PHD’s Lead Health Intervention Program (LHIP).
Tragedy struck the Silver Valley again on August 25, 1981, when Gulf Resources announced they would shut down Bunker Hill operations by the end of the year. Declining silver prices, aging infrastructure, and looming financial obligations from years of environmental degradation had taken their toll. The local communities not only lost 2,400 jobs in a matter of months but were faced with one of the largest environmental clean-ups ever undertaken.
Since EPA listed the Bunker Hill Superfund Site on the National Priorities List in 1983, EPA and Idaho Department of Environmental Quality (DEQ) have installed protective barriers on over 7,000 residential and commercial properties in the Silver Valley, provided $54 million in funding for local jurisdictions to repair or replace roads (which act as a barrier to contamination), and completed actions that protect barriers from flooding. These actions, in combination, prevent exposure to remaining contamination and provide a safe and clean environment in community areas. The Institutional Controls Program (ICP), which provides long term protection of remediation barriers and remedies, is considered a model for other large Superfund sites.
Contaminated soil can still be encountered throughout the Coeur d’Alene Basin outside of residential communities. Historic mine sites, floodplains, and the banks of the Coeur d’Alene River and its tributaries still contain lead and other heavy metals. Many of these areas are popular recreational sites. Contaminated material tracked home from un-remediated areas can result in elevated lead levels in house dust, creating an additional exposure source. In addition, the community faces the same lead exposure issues that can be found throughout the US; lead-based paint, lead in drinking water, lead contaminated dust, and exposure from occupational sources can all increase the risk of elevated blood lead levels.
Protection of human health remains the highest priority for ongoing cleanup actions at the Site. Due to the combined efforts of EPA, DEQ, IDHW, PHD, and the local communities, blood lead levels have dropped from their average of over 40 µg/dL in the 1970’s to below 3.5 µg/dL, the national level of concern. PHD’s Lead Health Intervention Program (LHIP) provides free blood lead screening and follow-up services year-round, environmental assessments, public health education, prenatal blood lead screenings, counseling, education in local schools to include hand washing and play clean education for K-3rd grade students, and physician awareness programs in and around the Site.
Cleanup activities are ongoing for mine and mill sites, areas where people recreate, and many other places due to the continued presence of harmful metal contamination. View images of cleanup activities.
EPA and DEQ partner to implement the cleanup. Together, they address local concerns and the state’s goals and priorities. DEQ’s Kellogg Superfund Project Office serves the Silver Valley and Coeur d’Alene Basin communities by assisting the public, property owners, and local governments with questions about ongoing activities within the Superfund Site.
Annual project plans, reports, and updates are provided to the community through the Basin Environmental Improvement Project Commission (BEIPC), a commission of three counties, two states, the federal government, and the Coeur d’Alene Tribe.
The following will provide more information on the history and cleanup of the Bunker Hill Superfund Site:
