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For more than a century, Black Rock has been a landmark on Lake Pend Oreille. What appears to be mysterious and natural is actually toxic. The metals contamination does not impact the water quality of the lake.

The Historic Smelter area was developed in 1904 and operated sporadically from 1907 to 1909. In 1922, the plant was dismantled and all salvageable materials were scrapped. All that remains today are a crumbling foundation, brick piles, ore and waste piles, and a slag heap known as Black Rock.

In its short operational history, the smelter’s impact was lasting. Because of this activity, the soil contains a high level of lead and other metals.


How bad is it?

A 2012 study revealed that the soil contained heavy metals (primarily lead) at concentrations exceeding EPA Residential Screening Levels (RSLs).


The Facts:

  • In 2012, a study of the area revealed the need for cleanup of contaminated soils in the two-mile trail corridor.
  • In FY 2019, the City applied for and received a Brownfields Multipurpose grant for $800,000 in hazardous substances funding to address much-needed brownfield planning, assessment, and cleanup activities within the Historic Smelter Area.
  • These funds will be used to conduct environmental site assessments, develop an area-wide plan, and clean up the Historic Smelter Area. This area sits along the undeveloped Pend d’Oreille Bay Trail with concrete abutments and a large slag heap — known as “Black Rock” on the lake’s edge.
  • Cleanup will address lead and other heavy metals contamination from past operations at the Panhandle Smelting and Refining Company.
    • Lead levels in surface soils were found as high as 19,200 mg/kg.
    • Arsenic levels in surface soils were found as high as 946 mg/kg. (The CDC says natural levels of arsenic soils usually range from 1 to 40 mg/kg)
    • Samples were taken between 6 and 24 inches below ground surface found lead and arsenic levels increased to 77,100 mg/kg and 1,960 mg/kg, respectively.
    • Also, the slag pile (“Black Rock”) is visibly eroding. It is a source of continuing contamination at the site with lead and arsenic concentrations as high as 20,500 mg/kg and 125 mg/kg, respectively.


The Front Yard Project Overview
  1. Details
  2. Benefits
  3. Background
  4. Brownfields Cleanup
  5. Frequently Asked
  6. Questions and Inquiries

If you’d like to stay informed and/or provide feedback on this project, you can do so here.

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