Radon gas occurs naturally.
It is present in nearly all soil and rock; you can't see, smell or taste it - but it's there.
Radon forms when uranium breaks down to radium, which in turn breaks down to form radon. As radon decays, it releases radioactive byproducts that are inhaled. Radon is the second-leading cause of lung cancer after smoking -- and the number one reason why non-smokers die of lung cancer. It's estimated to be responsible for over 21,000 deaths annually in the United States.
Radon enters a home through cracks in walls, basement floors, foundations and other openings. Once inside, radon can become trapped and build up to unsafe levels, especially in areas below ground-level. Nationwide it's estimated that 1 in every 15 homes has elevated radon levels. In the Portland / Vancouver area that number can skyrocket to 1 in 4 homes.
North and Northeast Portland homeowners have the Great Missoula floods to blame for their radon-rich soil.
The floods from the last ice age 13,000 to 15,000 years ago swept in to the area when ice dams in western Montana burst. Glacial Lake Missoula immediately released an astounding 520 cubic miles of water swamping Portland and the Willamette Valley to a depth of 300 to 400 feet and leaving behind layers of radon-generating sediments.
Radon levels can vary sharply from one house to the next, so testing is the only sure way to know the amount of radon in your home.
When the radon concentration in a living area of a home exceeds 4 pCi/liter (picocuries per liter), it is recommended that measures be taken to lower the concentration.
Accurate test kits are available at home improvement stores or online for under $20 each (3 for $40). Testing is easy. Simply open the test and hang it at normal breathing level for 3-7 days. Then return the test by mail for immediate processing and results.
Fixing a radon problem costs $800 to $2,500 and involves sealing cracks in walls, basement floors, foundations and possibly installing additional ventilation. Radon repairs should be done by a qualified radon repair specialist.