Radon is an important issue here in Minnesota. The EPA estimates that at least 1 in 5 homes have levels greater than the "Action Level" of 4 pCi/L.
There are a few different ways to mitigate radon. The most cost effective method involves cutting a hole in the basement (floor) slab and inserting a PVC vent pipe into the ground. This PVC pipe would then extend up through the house and attic and has a power fan that draws air through the pipe. This draws the radon with it and expels it out of the house.
Here are some Radon contractors.
Quality Radon Services
Brad Nyberg
BradRadonMan@aol.com
612-521-3580
The Radon Guys
info@radonnet.com
763-416-6768
www.RadonFixed.com
Mateffy Engineering
Leslie H. Mateffy III
651-636-6166
les@mateffyeng.com
http://www.mateffyeng.com/services_radon.html