I only learned about this when buying a house and the inspector asking if I wanted to pay to have the test done. It came back positive and I disclosed the results to the seller, and in my state it requires them to mitigate before selling. My second house already had a system installed, but we also sleep on a second floor. I have always wondered how good the mitigation is; is Canada behind on public safety of this issue? Are Radon-related cancers on par in states with more regulation/mitigation?