What is radon?

Radon is a radioactive gas that is formed naturally from the radioactive decay of uranium in rocks and soil. The chemical symbol for radon is Rn. It can remain in the soil, move to the soil surface and enter the air, or enter groundwater. It is more common in some areas of the country than others. 

Radon is colorless, odorless, and tasteless, but extremely toxic. When cooled below the freezing point, radon becomes phosphorescent, in yellow and orange-red tones. 

Radon was previously used to treat cancer, arthritis, diabetes, and ulcers. It is currently used to predict earthquakes, study atmospheric transport, and explore for petroleum and uranium. It is also used to initiate and influence chemical reactions, in the study of surface reactions, and as a tracer in leak detection.

You can be exposed to radon through breathing or swallowing it, either as a gas or as particles of radon that attach to dust. You can be exposed to very low levels of radon in outdoor air. 

If you live in an area where the amount of uranium and radium in rocks is high, you can be exposed to higher levels of radon indoors and in underground work areas such as mines. If radon is in the rocks and soil around a building, cracks in the building's basement or foundation can allow radon to move into the building. You can also be exposed to radon by drinking water obtained from wells that contain radon. 

You can be exposed to higher levels of radon at work if you are a uranium miner, a hard rock miner, or work in tunnels, power stations, public baths, or spas.

Radon is listed as a human carcinogen in the Twelfth Report on Carcinogens published by the National Toxicology Program because it causes lung cancer. Exposure to high levels of radon can cause other lung diseases such as emphysema and thickening of lung tissues. Simultaneous exposure to radon and cigarette smoking can increase the incidence of lung cancer and lung disease.

For poisoning emergencies or questions about possible poisons, please contact your local poison control center at 1-800-222-1222.

This description is based on the information found in the Web links listed with this topic.

Locations where Radon may be found: more neighborhoods >>
City	Farm	Town
Drinking Water Factory Homes Hospital Indoor Air Offices and Stores School	Drinking Water Homes Hydraulic Fracturing Indoor Air	Drinking Water Factory Homes Indoor Air Mining Offices and Stores School
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US Border Regions	Port	US Southwest
Drinking Water Homes Indoor Air Maquiladora Tienda	Drinking Water Homes Indoor Air Offices and Stores	Abandoned Mines Drinking Water Homes Hydraulic Fracturing Indoor Air Mining Oil and Gas Fields Uranium Tailings Water Wells

Last Updated: February 12, 2013