Radon-related lung cancer kills an alarming 21,000 people each year, a tragedy multiplied by the fact that significant exposure to the gas can be easily remedied. The scope of the work depends on the level of gas and the style of your house, but it's pretty simple and not overly expensive.
According to the Environmental Protection Agency, radon is found in every state. It's a naturally occurring radioactive gas produced by the breakdown of uranium in soil, rock, and water. Because the air pressure inside a house is typically lower than the pressure in the soil around its foundation, radon is drawn into the home through cracks in the foundation and other openings.
Radon levels are measured in picocuries per liter, or pCi/L. Levels of 4 pCi/L or higher are considered hazardous. Radon levels less than 4 pCi/L still pose a risk and in many cases can be reduced, although it is difficult to reduce levels below 2 pCi/L.
The EPA estimates that a radon removal system costs about $1,200 for an average house. The system is usually comprised of one or more PVC pipes that run from the radon-emitting soil beneath a home up through the roof. An in-line fan draws air through the system so that it doesn't leach into living spaces. Once installed, a follow-up radon test is done. Even in houses with extremely high radon levels, you can expect a drop to levels considered safe.