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Learn about radon
What radon is, where it comes from, how it gets indoors and what it does to health.
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What this topic covers
Start here if radon is new to you. These guides cover what the gas is, where it comes from, how it gets into a building, what the evidence says about health, and the element itself.
“Radon is a colorless, odorless, tasteless and invisible gas produced by the decay of naturally occurring uranium in soil and water.”
EPA “Exposure to radon is the second leading cause of lung cancer after smoking.”
EPA
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Guides and pages in Learn
11 to read, the one to start with first.
Short answers
Questions in Learn
The 6 most asked of 34, each with its short answer.
Where does radon come from?
Radon comes from uranium, which is present naturally in nearly all rock, soil and water and decays into radium and then into radon gas.
Read the full answerWhat causes radon in a house?
Radon in a house comes from uranium breaking down in the soil and rock beneath it.
Read the full answerWhat houses are most at risk for radon?
Any house can have high radon: EPA says new and old homes, well-sealed and drafty homes, and homes with or without basements can all have a problem.
Read the full answerWhat state is highest in radon?
There is no official ranking of states by measured radon, and the CDC testing figures the site holds are county figures.
Read the full answerHow long before you get sick from radon?
Radon does not make you feel sick.
Read the full answerWhere is radon found?
Radon is found in rock, soil and groundwater across the country, because it forms wherever uranium in the ground breaks down.
Read the full answer