Indoor Radon

This page has been automatically translated from English. MSDH has not reviewed this translation and is not responsible for any inaccuracies.

Radon in homes

Radon gas in homes has been identified as a national health problem. We can supply you with information on home testing kits for radon, and help you locate approved contractors for remedying radon problems. Testing is the only way to detect radon and prevent its risks to your health.

Radon in schools

Our Radon In Schools Program tested about 17% of the state-supported schools (163 of 950 schools). The initial results of this program indicated about 2.3% of the schools screened had radon concentrations of 4pCi/L or above (the EPA-recommended limit). Later testing in those schools produced no results of 4pCi/L or above. The Radon in Schools Program is now concentrating on screening all schools within the school districts that produced results of 4pCi/L or greater during the initial screening of that district.

Questions & Answers About Indoor Radon

What is radon and where does it come from?

Radon is a radioactive gas found in nature. It has no color, odor or taste and is chemically inert. Its source is natural uranium in the earth. As the uranium molecule slowly decays, it forms lead and radon gas as by-products. Being a gas, radon moves upward out of the soil and into the atmosphere. Uranium is found in most soils and in granite.

Is radon a problem in Mississippi?

Excessive radon levels have been found in all of the 50 states. In Mississippi less than three percent of the homes have radon levels in excess of the EPA recommended action level of 4 picoCuries of radon per liter of air.

How can radon damage my health?

Thousands of preventable lung cancer deaths annually in the United States are attributable to indoor residential exposure to radon. Either smoking or radon exposure can independently increase the risk of lung cancer. However, exposure to both greatly enhances that risk. (At exposures to 4 pCi of radon per liter of air, the lifetime lung cancer risk attributable to radon rises from 2 cases per thousand in non-smokers to 29 cases per thousand in smokers).

How much reliance can I put on these risk factors?

The risk factors were developed from epidemiological studies of underground miners exposed to radon. Because the studies collected data from human adult males rather than from animal subjects, they have a higher confidence level than toxicological studies.

The Surgeon General, the Environmental Protection Agency, the National Academy of Sciences, the American Medical Association, the American Lung Association and the World Health Organization have all identified indoor radon pollution as a national health problem.

How does radon get into my home?

Radon moves from uranium-bearing granite deposits in the soil to atmosphere because there is a lower concentration of radon in the atmosphere than in the soil. Your home is sited in its path, and because the house is usually warmer than the surrounding soil, the air pressure is less and soil gases, including radon, move into the home. The most common routes are:

  • spaces between basement walls and slab
  • cracks in foundations and/or walls
  • openings around sump pumps and drains
  • construction joints
  • crawl spaces
  • showers, etc. using well water with high radon concentrations

My house is new (old) so it shouldn't have a problem, right?

The age of a home is not a factor when it comes to whether excessive levels of radon are present in the dwelling.

My neighbor tested and did not find a radon problem so my home should be OK, right?

Unfortunately, that is a false assumption. Usually neither the location of the radon source or its strength (radioactivity) is known. In addition, the air spaces found in different soil types allow movement at different rates, and we seldom know what those types are 20 to 30 feet below the surface. These air spaces act as channels or dams, making it difficult to predict the radon level from one home to another, even if they are near each other. The location of ancient stream beds and of granite outcroppings (the source of much radon) also compound prediction reliability.

How do I know if my home has a radon problem?

Test for radon.

  • There are many low-cost radon test kits which may be ordered through the mail or purchased from hardware stores and other retail outlets. Be sure the kit packaging displays the phrase "Meets EPA requirements". Kits can be ordered online from the National Radon Service Program (NRSP).
  • Or, hire a radon tester qualified by the AARST-NRPP or NSRB. Visit

Does the State do radon testing?

No, the State does not compete with private industry; we provide information and advice only.

I am renting a house (apartment) and am concerned about radon. Does my landlord have to test for radon if I ask him?

No, you will have to do it yourself unless you can persuade him/her to test.

I tested my rental home (apartment) and the radon reading was high, is my landlord required to fix this problem?

No, there is no legal requirement for him/her to mitigate the radon level.

Where can we get a radon test kit?

You can purchase them from some hardware stores (be sure the kit is marked "Meets EPA Requirements"), and directly from radon test kit manufacturers through the mail for prices ranging from $10 to $45. A number of laboratories have them for sale. Kits can be ordered online from the National Radon Service Program.

How much do the radon test kits cost?

In retail outlets charcoal canisters cost about $10 to $15. Alpha track detectors which are usually used for long-term tests cost $30 or so.

Are the 'Do-It-Yourself' test kits as accurate as those used by those persons I could hire to do the testing for me?

YES, if you use a kit that meets EPA requirements and you follow the instructions on the label exactly and return it to the lab promptly as directed.

What is the difference between long and short term tests?

Short-term tests take 60 hours to complete. The house is closed for 12 hours, then the test instrument is activated or opened and left in place for 48 hours or more. Charcoal canisters are the device of choice although electronic instruments may be used. Long-term tests take more than 91 days to complete and are conducted with the house in a normal living mode. Alpha track detectors or electronic detection instruments are used.

Long-term test results give a more representative picture of the true radon levels in the home overtime as fluctuations due to changes in ambient temperature and barometric pressure are detected and factored into the final valuation.

Which floor is best for testing radon levels?

Are you wanting to test your home for a real estate transaction or are you are testing for your own purposes? The recommendations are different for the two cases. If you are testing to determine if your home has radon levels warranting action, the EPA recommends testing in the lowest living area of your home. For a real estate transaction, EPA recommends testing in the lowest area which could be modified to become a living area.

I'm closing on a house and need a radon measurement test result quickly. How do I accomplish this?

Qualified radon testers within Mississippi can be obtained online from the National Radon Proficiency Program.

Contact one of the approved operators and have them perform your testing. They will use either a continuous monitor which will permit them to give you test results at the end of the test period or some other short-term measurement device which can be read at a lab and the value reported in short order.

My family has been ill since we moved into this house and we think radon is the cause. What can we do?

The only proven health effect caused by breathing radon is the development of lung cancer after years of exposure. You may have radon problems and the only way you can know this is to test the air in your home. However, radon is not what is causing your acute symptoms.

I have a high radon reading in my home. How do I get it fixed?

The method of choice is usually sub-slab depressurization or, if you have a crawl space, sub-membrane depressurization. Contact a radon contractor to bid on the job, he will be able to tell you if your home requires a different approach. Most don't.

How much does it cost to have a home remediated (fixed)?

The cost of a sub-slab system in Mississippi is generally less than $2,000 unless aggregate or difficult foundation design problems are encountered.

Can you recommend a contractor?

A list of radon operators is available from the National Radon Proficiency Program. We recommend you call several of them and get estimates for the remediation.

Is sub-slab depressurization (the most effective technological solution) something I can do myself?

Perhaps, if you have good handy-man skills including electrical wiring skills. If you are unsure, it would be advisable to get an evaluation from an NRRP-qualified contractors before you make up your mind. A good reference can be found in your local library. It is Doug Kladder's PROTECTING YOUR HOME FROM RADON A Step-by-Step Manual for Radon Reduction. If you decide to tackle the job, call back to get a copy of the EPA instruction manual which contains all the specifications for fans, master panels, etc. We will enclose the phone numbers and addresses of several supply houses that specialize in mitigation hardware.

Could I seal and caulk only, and hope it would be enough to correct the problem?

No. While caulking and sealing is done as part of the mitigation process, the purpose is not to keep radon out but to hold conditioned air in the dwelling. Because it is impossible to seal all cracks and the task is not only time-consuming, expensive and temporary (caulk dries out over time), this procedure is not recommended as a stand-alone technique.

Should I have my water tested for radon?

If you have tested the air in your home and found a radon problem, and your water comes from a private well, you should test the water. (Call a lab-certified tester to measure radiation in water.)

Is radon a problem in drinking water supplies?

Generally, radon is not a problem with public drinking water systems because aeration releases dissolved radon to the atmosphere during the water treatment process. However, if the water supply is from a private well, radon levels could be unacceptably high. The recommendation is to test the well water if the air radon concentrations in the occupied dwelling are over 4pCi/l (the EPA suggested limit).

I am performing an Environmental Site Assessment and need to know the radon level/risk for the property at (identification). Do you have information that can help me?

Most of Mississippi is classed as EPA Zone 3, an area of low radon potential (probable indoor radon average below 4 pCi/L).

The EPA has published a map characterizing all Mississippi counties. If you identify the county, we can tell you how EPA characterized that county.

Is radon a problem in schools?

Schools are at risk from radon just as homes and businesses are. The Mississippi Radon Program has tested a number of schools over the state and have not found radon to be a major concern for schools.

Last reviewed on Jul 13, 2024 request edits
Mississippi State Department of Health 570 East Woodrow Wilson Dr Jackson, MS 39216 866‑HLTHY4U Contact and information

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