Hazardous Materials and Waste Management Division
Radiation Program
Frequently asked questions about radon
Question:
What is radon and where does it come from?
Answer:
Radon is a radioactive gas found in nature. It has no color, odor or taste
and is chemically inert. It's source is uranium. As the uranium molecule decays to form
stable lead, a process taking many, many years, it changes from one radioactive element to
another in a sequence known as the Uranium Decay Cycle. Partway through this cycle, the
element radium becomes radon which as a gas moves up through the soil to atmosphere.
Uranium is found in most soils and in granite.
Question: Is radon a problem in
Colorado?
Answer: Excessive
radon levels have been found in all of the 50 states. In Colorado between one-third and
one -half of the homes have radon levels in excess of the EPA recommended action level of
4 picoCuries (pCi) of radon per liter of air.
Question: How can radon damage my
health?
Answer: 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).
Question: How much reliance can I
put on these risk factors?
Answer: 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 is applied to 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.
Question: How does radon get into
my home?
Answer: 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
Question: My house is new (old)
so it shouldn't have a problem, right?
Answer: The age of a
home is not a factor when it comes to whether excessive levels of radon are present in the
dwelling.
Question: My neighbor tested and
did not find a radon problem so my home should be OK, right?
Answer:
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 where they act as channels or dams, predicting a radon
level in one home on the basis of a tested level in a home 75 to 200 or so feet away
becomes radon guessing. The location of ancient stream beds (channel) and of granite out
cropping (the source) also compound prediction reliability.
Question: How do I know if my
home has a radon problem?
Answer: Test for
radon.
-
There are many kinds of low
cost "do it yourself" 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" or
-
Hire a qualified radon
tester. Lists of qualified measurement testers may be obtained from the
Radiation Program of the Hazardous Materials and Waste Management Division 303-692-3300 or
800-846-3986.
Question: Does the State do radon
testing?
Answer: No, the State
does not compete with private industry; we provide information and advice only.
Question: I am renting a house
(apartment) and am concerned about radon. Does my landlord have to test for radon if I ask
him?
Answer: No, you will
have to do it yourself unless you can persuade him/her to test.
Question: I tested my rental home
(apartment) and the radon reading was high, is my landlord required to "fix"
this problem?
Answer: No, there is
no legal requirement for him/her to mitigate the radon level.
Question: Where can we get a
radon test kit?
Answer: You can
purchase them from some hardware stores (be sure the kit is marked "Meets EPA
Requirements"), and directly from radon
measurement laboratories through the mail for prices ranging from $10 to $45. Several
laboratories in Colorado have them for sale. The Division can send you a list of
labs or we can
send you a coupon so you can order a
short term charcoal test kit for $7.00 from the National
Safety Council. You may also order a long
term test kit for $20.00 using the available coupon. Call the Radiation Program at 303-692-3300 or
800-846-3986.
Question: How much do the radon test kits cost?
Answer: In retail
outlets charcoal canisters cost about $25.00, alpha track detectors, which are usually used
for long-term tests, cost $30.00 or so.
Question: Are the 'Do-It-Yourself' test kits as
accurate as those used by those persons I could hire to do the testing for me?
Answer: 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.
Question: What is the difference between long-
and short-term tests?
Answer: 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 over time as
fluctuations due to changes in ambient temperature and barometric pressure are detected
and factored into the final valuation.
Question: Which floor is best for testing radon
levels?
Answer: 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 mitigation, 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.
Question: I'm closing on a house and need a
radon measurement test result quickly. How do I accomplish this?
Answer: A list of National Environmental Health
Association (NEHA) listed radon measurement contractors is available on this website or can be faxed
on request by calling the Radiation Program at 303-692-3300 or
800-846-3986. These contractors 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.
Question: My family has been ill since we moved
into this house and we think radon is the cause, what can we do?
Answer: 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.
Question: I have a high radon reading in my
home. How do I get it fixed?
Answer: The method of
choice is usually sub-slab (or if you have a crawl space, sub-membrane) depressurization.
Contact a National Environmental Health Association (NEHA) listed radon contractor to bid on the job. He/she will be able to tell you if
your home requires a different approach. Most don't.
Question: How much does it cost to have a home
remediated (fixed)?
Answer: The cost of a
sub-slab system in Colorado is generally less than $1000 unless aggregate or difficult
foundation design problems are encountered.
Question: Can you recommend a contractor?
Answer: The Division can supply
you with a list of National
Environmental Health Association (NEHA) listed radon mitigation contractors
that have passed the National Radon Contractor Proficiency
Examination. We recommend you call
several of them and get estimates for the remediation.
Question: Is sub-slab depressurization
(the most
effective technological solution) something I can do myself?
Answer: 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 one of the National
Environmental Health Association (NEHA) listed contractors before you
make up your mind. Look for Doug
Kladder's "Protecting Your Home From Radon - A Step-by-Step Manual for Radon
Reduction" at your local library. If
you decide to tackle the job, contact the Radiation Program at 303-692-3300 or
800-846-3986 to get a copy of the EPA instruction manual which
contains all the specifications for fans, master panels, etc. Phone
numbers and addresses of several supply houses that specialize in mitigation
hardware will be included.
Question: Could I seal and caulk only, and hope
it would be enough to correct the problem?
Answer: 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. It is impossible to seal
all cracks and the task is time-consuming, expensive and temporary (dries out
over time), so this procedure is not recommended as a stand-alone technique.
Question: Should I have my water tested for
radon?
Answer: 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. (Look in the yellow pages for a lab certified to measure radiation in water.)
Question: Is radon a problem in drinking water
supplies?
Answer: Generally,
radon is not a problem with public drinking water systems because during the water
treatment process aeration releases dissolved radon to the atmosphere. 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 4 pCi/l.
Question: I am performing an Environmental Site
Assessment and need to know the radon level/risk for this property. Do
you have information that can help me?
Answer: Most of
Colorado is classed as EPA Zone 1, an area of high radon potential (probable indoor radon
average above 4 pCi/L). The EPA has published a map
characterizing all Colorado counties. If you identify the county, the
Division can tell you how EPA
characterized that county. There are also some older
data which, although incomplete, may prove helpful. This is the Colorado Geological
Survey (CGS) Open-File Report 91-4
Results of the 1987-88 EPA Supported Radon Study in Colorado. This is available from the
Colorado Geological Survey at (303) 866-2611.
Question: Is radon a problem in schools?
Answer: Schools are
at risk from radon just as homes are. Colorado statute requires all schools to have tested
for radon, and to maintain records of the test results for disclosure on request. The
regulation does not require schools that find a problem to mitigate according to a
mandated schedule. It is up to the District and its constituents to address mitigation
issues. About fifty percent of the schools that were found to have a problem have
mitigated.
Further information on radon
in schools can be found in the EPA Radon
Publication Radon in Schools
.
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