If you know the house has been treated with chlordane/heptachlor or aldrin/dieldrin.
If t he house was treated for termites between 1950 and 1990.
If you see drill holds around the basement floor. (This type of application results in the highest levels)
If you are refinishing your basement as a living space. (We have found that chlordane levels in basements can be up to 8 times higher than those in ground level rooms)
If you are experiencing symptoms in you current home: