January is National Radon Action Month – Part 1

What is radon? Radon is a naturally occurring radioactive gas. It is formed from the radioactive decay of radium which is found in at least trace amounts in almost every type of soil or rock in the U.S.

January is National Radon Action month and for good reason.  Radon, which is a tasteless, colorless and odorless gas, is classified as a Class A carcinogen. This means it is known to cause cancer in humans. In fact, it is the second leading cause of lung cancer behind smoking. Approximately 21,000 deaths are caused by lung cancer each year in the U.S.

What is radon?  Radon is a naturally occurring radioactive gas. It is formed from the radioactive decay of radium which is found in at least trace amounts in almost every type of soil or rock in the U.S.

Radon can enter any building (home, school, business, church, etc.) through openings in the structure’s foundation floor or walls. This can occur any place where the foundation comes in contact with the soil. Because it is a gas, it can travel through soil and tends to move from areas of higher pressure to areas with lower pressure. In most cases, the soil is at higher pressure than the building’s foundation. As radon gas moves along the foundation, it can be forced into the building through any openings, including sump pumps, crawlspaces, cracks in the foundation, spaces around plumbing or wiring, floor/wall joints, hollow block walls, etc.

While much less likely, radon can also enter a building through the groundwater supply. As a gas, radon can dissolve in groundwater. As the groundwater enters the building, the dissolved gas is released from the water. The EPA recommends that any buildings using private wells be tested if the radon level in the building’s air has tested above the 4 pCi/l level. Remember, however, the majority of radon risk comes from inhalation not ingestion. 

Any structure regardless of its age, foundation type or energy efficiency can have a radon problem. It’s not based on the building’s age but the amount of radon in the soil.  While any building can have entry points for radon, the home is likely to be the most significant source of radon exposure simply based on the amount of time spent there.

The only way to know if there is radon in a building is to have it tested. There are no physical signs to warn occupants that there is danger.  Because there can be a wide range of levels in any given area and can vary greatly from building to building, each building must be tested separately. Do not rely on test results from your neighbor to determine if your home has a problem.

There is NO safe radon level. It is believed that there is some risk associated with any exposure. As a general rule, the higher the radon level and the longer the exposure, the greater the risk. And if you are a smoker, that increases the risk. While the federal government is working to reduce levels down to below 2 picocuries per liter (pCi/l) in homes, the current guidelines for action are set at 4 pCi/l which is easily achievable with reasonable effort over time. A picocurie is a measurement of radioactivity.

One in four Michigan homes is anticipated to have a radon problem. In some areas of the state this could rise to 40-50 percent of homes with problems.

Radon tests are available at your county health department or they can be purchased at local hardware stores, home improvement stores, or on the internet. The EPA suggests starting with a short-term test.  If the results are above 4pCi/l, then follow up with either a second short-term test or a long-term test.  If the long term test results are above the recommended level, you might want to consider calling a professional to determine the necessary steps to reduce radon exposure. Use professionals certified by the National Radon Proficiency Program or the National Radon Safety Board.   

The Michigan Department of Environment Quality has a number of resources on radon at:


If you would like to see Michigan Radon Levels by County:


Part Two will discuss radon testing and the Michigan Radon Program.

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