Since Burke, Mullan and Wallace were settled more than a century ago, it's been common practice for residents to unwittingly pollute their own homes.
Living in communities that revolved around the Hercules, Hummingbird, Morning and other mines, miners and their families used what was close at hand to build their homes and yards.
Flood plains were raised with dirt and waste rock from mine or mill operations. Foundations were placed on fill material that came from any nearby pile without regard for how contaminated it might be with heavy metals.
Even now some homeowners unknowingly transport polluted dirt to their homes to build a driveway, plant a garden patch or fill in a swampy area.