Groundwater contamination (click on image to make it larger)

WHAT'S HAPPENING NOW?

Kaiser Mead National Priorities List (NPL) Site Groundwater Cleanup

On May 9, 2019, we finalized a workplan to address groundwater contamination left behind by smelter operations.

• Final plan
• State Environmental Policy Act determination and checklist
• Response to comments

What's the plan?
The proposed workplan would create a "pump and treat" system to remove cyanide and fluoride contamination in groundwater left behind by Kaiser’s waste handling practices from the 1940s to the late 1970s.

Under the proposal, we would:

• Design, install and operate a system to capture groundwater.
• Treat it to remove contamination.
• Maintain a system where treated water filters back into the ground, recharging the aquifer.

Design of the system and possibly some construction activities will take place in 2019, with completion of construction and start-up happening in 2020.

BACKGROUND

The Kaiser Aluminum Company produced aluminum at the Mead site for more than 50 years. Waste handling practices used from the 1940s to the late 1970s led to cyanide and fluoride contamination in part of the Spokane-Rathdrum Prairie Aquifer and the Little Spokane River. The groundwater plume is 145 feet below ground, 800 – 1500 feet wide, and travels approximately 2.5 miles to the Little Spokane River. It then discharges into a series of springs

A number of activities have already taken place to address the problem.

• In the late 1970s, Kaiser provided alternate water supplies for property owners whose wells were contaminated. The county put restrictions on new wells in the area.
• Wastes remaining on site were covered with an asphalt cap to keep rain and snow from leaching more contamination into groundwater.
• Investigation of other potential sources of contamination

While these steps have helped control the risk posed by the site, groundwater monitoring shows that levels of contamination in the groundwater have not declined as quickly as expected. Even though no one is drinking the groundwater, and there is no immediate risk to people, we believe more should be done.

ADDITIONAL RESOURCES

• Acronyms used by the Toxics Cleanup Program
• Cleanup Process: Major Steps & Definitions
• Data Submittal Requirements for All Cleanup Sites
• Toxics Cleanup publications