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How long before you get sick from radon?

By Radon411 Editorial TeamUpdated How we research

Short answer

Radon does not make you feel sick. Its known harm is lung cancer, which CDC says takes many years to develop, and EPA says the time between exposure and the onset of the disease may be many years. The risk grows with the level, the time spent in the home and smoking, so lowering it helps whenever you start.

Next step: a test is the only way to know your home's level. How to test your home

CDC explains what happens: when you breathe in radon, radioactive particles from the decay of radon gas can get trapped in your lungs. It takes many years for lung cancer to develop, CDC says, and most people don't have symptoms until lung cancer is advanced. WHO says no other cancer risks or other health effects have been established to date.

EPA's 2003 Assessment of Risks from Radon in Homes gives a sense of the timing. The risk models it uses, from the National Academy of Sciences' BEIR VI report, incorporate a 5-year minimum latency period, and EPA estimates the average age for radon-induced lung cancer deaths at about 65, compared with 72 for all lung cancer deaths.

What to do next: test your home now rather than waiting for a sign, and fix it if the result calls for it. The Citizen's Guide says you will reduce your risk of lung cancer when you reduce radon levels, even if you've lived with a radon problem for a long time.

What radon does in the body

The Citizen's Guide says radon gas decays into radioactive particles that can get trapped in your lungs when you breathe, and that as they break down further, these particles release small bursts of energy, which can damage lung tissue and lead to lung cancer over the course of your lifetime. It adds that not everyone exposed to elevated levels of radon will develop lung cancer.

What to know about timing
Point in timeDetail
While you are exposedRadon is a gas with no immediate health symptoms (2005 Surgeon General's advisory)
The first yearsThe BEIR VI risk models EPA uses incorporate a 5-year minimum latency period (EPA 2003 assessment)
Many years laterIt takes many years for lung cancer to develop; the time between exposure and onset may be many years
Age at deathAbout 65 on average for radon-induced lung cancer deaths, against 72 for all lung cancer deaths (EPA 2003 assessment)
Years of life lost17 years on average for radon-related cases, against 12 for lung cancer deaths generally (EPA 2003 assessment)

What sets the risk

The Citizen's Guide says your chances of getting lung cancer from radon depend mostly on how much radon is in your home, the amount of time you spend in your home, and whether you are a smoker or have ever smoked. WHO says the risk of lung cancer increases by about 16% per 100 increase in long time average radon concentration, and that smokers are estimated to be 25 times more at risk from radon than non-smokers.

Bar chart of EPA's radon risk estimates for people who smoked and people who never smoked: out of 1,000 people exposed over a lifetime, about how many could get lung cancer at 20, 10, 8, 4, 2, 1.3 and 0.4 pCi/L, from about 260 smokers at 20 pCi/L to about 3 at 0.4 pCi/L, with EPA's advice at each level.
Read this figure as text

EPA estimate, lifetime exposure

  • Out of 1,000 people who smoked
  • Out of 1,000 people who never smoked
About how many people out of 1,000 exposed over a lifetime could get lung cancer, by radon level
Radon levelCould get lung cancer, per 1,000What to do
20 pCi/L740 Bq/m³Smoked: About 260Never smoked: About 36Fix your home
10 pCi/L370 Bq/m³Smoked: About 150Never smoked: About 18Fix your home
8 pCi/L300 Bq/m³Smoked: About 120Never smoked: About 15Fix your home
4 pCi/L150 Bq/m³Smoked: About 62Never smoked: About 7Fix your home
2 pCi/L75 Bq/m³Smoked: About 32Never smoked: About 4Consider fixing between 2 and 4 pCi/L
1.3 pCi/L50 Bq/m³Smoked: About 20Never smoked: About 2Average indoor radon level
0.4 pCi/L15 Bq/m³Smoked: About 3Never smoked: No figure givenAverage outdoor radon level
  • Smoked: If you are a former smoker, your risk may be lower.
  • Never smoked: If you are a former smoker, your risk may be higher.
  • Reducing radon levels below 2 pCi/L (75 Bq/m3) is difficult.
  • Lifetime risk of lung cancer deaths, as EPA estimates it.
EPA's lifetime risk chart: out of 1,000 people exposed over a lifetime, about how many could get lung cancer at each level.

It is not too late to lower it

Time matters in the other direction too. EPA's 2003 assessment estimates that about one-fourth of the radon-related lung cancers could be averted by reducing radon concentrations in homes that exceed EPA's recommended 4 . CDC says reducing radon inside your home or building will always help reduce your risk of lung cancer, even when the level in your home is less than 4 pCi/L.

Questions about radon and getting sick

Can radon make you sick right away?

No. The 2005 Surgeon General's advisory described radon as a gas with no immediate health symptoms. Its known effect is lung cancer, years later.

Does radon cause headaches, coughing or tiredness?

WHO says no other cancer risks or other health effects have been established to date beyond lung cancer. See what are the symptoms of radon in your home.

How much radon exposure is dangerous?

EPA says there is no known safe level of exposure to radon. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. EPA recommends considering a fix when the level is between 2 and 4 pCi/L.

Are children at greater risk from radon?

CDC says there is not enough data to show whether children have a higher risk of developing lung cancer from radon exposure than adults, but that children may have higher doses of radon than adults even when exposed to the same radon levels for the same amount of time.

I have lived with radon for years. Should I still fix it?

Yes. The Citizen's Guide says you will reduce your risk of lung cancer when you reduce radon levels, even if you've lived with a radon problem for a long time.

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