The Information here is directly from the EPA
Radon is a cancer-causing, radioactive gas.
You can't see radon. And you can't smell it or taste it. But it may be a problem in your home. Radon is estimated to cause many thousands of deaths each year. That's because when you breathe air containing radon, you can get lung cancer. In fact, the Surgeon General has warned that radon is the second leading cause of lung cancer in the United States today. Only smoking causes more lung cancer deaths. If you smoke and your home has high radon levels, your risk of lung cancer is especially high.
Radon can be found all over the U.S.
Radon comes from the natural (radioactive) breakdown of uranium in soil, rock and water and gets into the air you breathe. Radon can be found all over the U.S. It can get into any type of building — homes, offices, and schools — and result in a high indoor radon level. But you and your family are most likely to get your greatest exposure at home, where you spend most of your time.
You should test for radon.
Testing is the only way to know if you and your family are at risk from radon. EPA and the Surgeon General recommend testing all homes below the third floor for radon. EPA also recommends testing in schools. Testing is inexpensive and easy — it should only take a few minutes of your time. Millions of Americans have already tested their homes for radon.
You can fix a radon problem.
Radon reduction systems work and they are not too costly. Some radon reduction systems can reduce radon levels in your home by up to 99%. Even very high levels can be reduced to acceptable levels.
How Does Radon Get Into Your Home?
Any home may have a radon problem. Radon is a radioactive gas. It comes from the natural decay of uranium that is found in nearly all soils. It typically moves up through the ground to the air above and into your home through cracks and other holes in the foundation. Your home traps radon inside, where it can build up. Any home may have a radon problem. This means new and old homes, well-sealed and drafty homes, and homes with or without basements.
Radon from soil gas is the main cause of radon problems. Sometimes radon enters the home through well water. In a small number of homes, the building materials can give off radon, too. However, building materials rarely cause radon problems by themselves.
RADON GETS IN THROUGH:
Cracks in solid floors
Cracks in walls
Gaps in suspended floors
Gaps around service pipes
Cavities inside walls
The water supply
Nearly 1 out of every 15 homes in the U.S. is estimated to have elevated radon levels. Elevated levels of radon gas have been found in homes in your state. Contact your state radon office for general information about radon in your area. While radon problems may be more common in some areas, any home may have a problem. The only way to know about your home is to test.