Use the Department of Ecology's Cleanup Site Search: https://fortress.wa.gov/ecy/gsp/SiteSearchPage.aspx. It may be easier to find sites by searching city, county, or zip code.
For almost 100 years, the Asarco Company operated a copper smelter in Tacoma. Air pollution from the smelter settled on the surface soil over more than 1,000 square miles of the Puget Sound basin. Arsenic, lead, and other heavy metals are still in the soil as a result of this pollution. The area of contamination is known as the Tacoma Smelter Plume. The plume includes area in Thurston, Pierce and King County.
To see if your project is within the Tacoma Smelter Plume area, visit https://fortress.wa.gov/ecy/smeltersearch/. This interactive map displays potential arsenic levels across the plume area. After you enter your address, the map will zoom to the area and show the predicted arsenic concentration. It also provides contact information and a list of services available in your area.
More information, useful links, and contact information can be found at: http://www.ecy.wa.gov/programs/tcp/sites_brochure/tacoma_smelter/2011/ts-hp.htm.