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Frequently Asked Questions (FAQ)

Radon is a radioactive gas. It occurs naturally in rocks, soil and water. You can’t see, smell, or taste radon. Unless you test for it, there is no way of telling how much is present indoors. Radon gas moves up through the soil and can be drawn into our homes by slight pressure differences. Once inside, radon can become trapped and build up to unsafe levels.
Is radon dangerous to human health?
Yes. Radon can cause lung cancer. Radon is thought to cause over 21,000 lung cancer deaths .This is approximately 13% of all lung cancer deaths. This means that, in Oregon, approximately 276 radon-related lung cancer deaths happen each year. Radon is the second leading cause of lung cancer death after smoking.  It is the leading cause in people who have never smoked.  
Radon gas releases particles that can get trapped in your lung passages. Those particles, called alpha particles, can break down even smaller and release tiny bursts of energy that can damage lung tissue. Alpha particles cannot pass through the skin. The damage done in your lungs by the alpha particles can lead to lung cancer over time. The length of time between being exposed to radon and the start of disease can be several years.
If you have any health concerns, it is important to speak with your health care provider.
How does lung cancer impact the health of Americans?
While the sun is the leading environmental cause of cancer (melanoma of the skin), radon is the leading environmental cause of cancer death. The National Cancer Institute found that that over 9 in 10 people diagnosed with skin cancer live at least five years after diagnosis. Unfortunetely, for lung cancer, only 1 in 6 of people diagnosed with lung cancer are still with us five years after diagosis.
Should people who smoke tobacco be especially concerned?
Yes. A person who smokes and is exposed to elevated levels of radon over time has a risk of lung cancer that is especially high. Charts on The Risk of Living with Radon, found in EPA's A Citizen's Guide to Radon, compares risks of lung cancer at various levels of radon. These are compared to risks of death from causes that may be more familiar.
Please understand these numbers are estimated averages for the American population. An individual’s risk may be higher or lower. Because of several factors that are largely unknown, it is difficult to calculate the exact increased risk of getting lung cancer due to radon for an individual. [These difficult-to-determine factors, include: precise family history of cancer; lifetime exposure to environmental cancer risks (such as smoking and second-hand smoke exposure history); and lifetime history of radon exposure from every residence past and future.]
Besides lung cancer, does radon cause any other human health effects?
Breathing radon does not cause any short-term human health symptoms such as shortness of breath, coughing, headaches, or fever. There is no conclusive evidence that children are at greater risk than adults from radon. Currently, there is also no conclusive evidence that radon exposure leads to increased risk of contracting other cancers or other diseases.
Are there some areas in Oregon that have higher radon levels than others?
Generally speaking, there are some areas that have been found to have higher radon levels.  However, you should not assume that your home will have low radon levels just because you live somewhere that is not among those areas with higher levels. It is very possible that a home in an area considered to have low risk could have unhealthy radon levels.  The opposite could also be true. Consequently, the only way to know whether your home has elevated radon levels is to test it.
How can I get an inexpensive radon test kit?
Kits can be found at hardware stores for $10-30 or online. When choosing a kit, check to see if there is an analysis fee, in addition to the test kit price. Online tests can be as accurate as kits from the hardware store. There are many online test kit options.  Below are two options for buying inexpensive kits that include shipping and analysis fees:
  • The American Lung Association (ALA) of the Mountain Pacific sells them at $15 for a  short-term (ST) kit and $38.50 for a long-term (LT) kit. You can order online or by phone at 503-718-6141.              
  • The National Radon Program Services at Kansas State University ( has short-term kits available for $15 and long-term kits available for $25 online.
I’m selling/buying a home – I need a radon test result NOW!
Currently, radon testing for real estate transactions (or any other residential purpose) is not required under Oregon law. But knowing a home’s current radon level is a good idea for the health of the people living in it.
Radon measurement (testing) companies are often hired when the results are needed quickly (like in the 10-day inspection period of a home sale).
If your radon concern is related to a real estate transaction, you may be interested in EPA’s Home Buyer's and Seller's Guide to Radon. According to the EPA, for real estate transactions, a radon test should be done in a home’s lowest living space. This is true even if the buyers don’t intend to occupy that space regularly.
A list of radon Measurement Companies companies in Oregon is on our website
How can I find a radon measurement (test) company in Oregon?
If you do not want to perform the test yourself, or you need quick test results (like for a real estate transaction), you can hire a company to test your home for radon. [For a do-it-yourself test kit, It may take several weeks for a laboratory to send back the results.]
A list of radon Measurement Companies companies in Oregon is on our website. Assuming you follow the basic instructions on a test kit that you purchased yourself, the accuracy of your results will be very close to that of a professional test result, and significantly less expensive.
Can I test my home for elevated radon myself?
Yes. Testing a home yourself, for elevated radon, is relatively straightforward. You should test at the lowest level of the structure where you spend the most time. For example, if you have a finished basement where you spend time, test the basement. However, if you only do laundry in the basement, then you should test the first floor.
It is recommended to place the test in commonly used rooms such as bedrooms and family rooms. We recommend avoiding kitchens and bathrooms because their exhaust fans may change radon or radon decay product levels in the room. These changes skew the result of a short-term test.
See Performing a Radon Test Yourself as well as tips on making sure your results are accurate.
I don't need to test because I live in a new house and I don't have a basement, right?
Not necessarily true - elevated radon levels can occur in just about any house. The only way to know is to test it.
What are the different types of radon test kits?
There are two types of radon test kits available to homeowners: short-term kits (2-90 days of measurement) and long-term kits (91 days – one year). A third type, continuous radon monitors, are usually used by radon measurement professionals.
Short-term tests are less expensive, and allow you to gain results quickly, but they only measure a small window of time. Long term tests are more reliable because they average together all of the high and low measurements over a longer period of time. This allows you to know the actual level of radon to which people in the household are exposed to over the year. However, long term testing takes at least 91 days of testing to get results.
To understand which type is right for you, we suggest you read about the advantages and disadvantages of each type of kits at Types of Radon Gas Testing.
What is a “safe” level of radon?
 It is important to know that there is no safe level of radon. [Radon levels are measured in picocuries per liter (pCi/L).] Outdoor air has radon levels from .1 to 1 pCi/L. The Environmental Protection Agency (EPA)’s action level of 4.0 pCi/L is not a health-based standard. EPA states that there isn’t a 100% “safe” amount of radon. The World Health Organization recommends that a home be mitigated when its confirmed radon level is 2.7 pCi/L or above.
Above all, the goal of radon reduction is risk reduction.
Although not required by law, radon testing is recommended to protect you and your family’s health.
The National Radon Program Services provides more information on why you should test and why 4 pCi/L is the recommended “action level” for radon.
My home has a confirmed elevated radon levels. How do I “fix” (or mitigate) it?
Reducing radon levels in your home requires technical knowledge and skill, and typically involves hiring a radon mitigation contractor. The most common approach to mitigating a radon problem is referred to as sub-slab depressurization or sub-slab suction. This technique draws radon-filled air from beneath the foundation through a pipe using a continuously running fan, and vents the radon outside. Sealing cracks and holes in the foundation makes this technique more effective.
You can see a diagram of sub-slab depresurization system here.
Which radon mitigation companies does OHA recommend?
OHA does not recommend any particular radon company or service.
A list of radon Mitigation Companies in Oregon is on our website. Companies on this list have at least one radon mitigation technician on staff who has been certified by the National Radon Proficiency Program (NRPP) or the National Radon Safety Board (NRSB). Current listings of certified mitigation technicians in Oregon can be found at their respective web sites, and
This list should be used for informational purposes only and is not intended to be an endorsement by the Oregon Health Authority of any mitigation company. The private companies listed on the webpage are provided as a convenience. The State of Oregon does not regulate, certify, endorse or sponsor their products, services or information.
These organizations are not the only sources of radon services.
What to consider when choosing a radon mitigation company?
When you’re choosing a radon mitigation company, we recommend you consider the following:
  • Get bids from several mitigation companies, and ask for (and check) their references. 
  • Ask each company's representative if they will guarantee (in a written contract ) that the radon in your home will be reduced to a certain level. Normally, a homes indoor radon can be reduced to below 4 pCi/L. Sometimes a home’s radon can be reduced to less than 2.0 pCi/L or even 1.0 pCi/L, although reductions below these levels may be dependent on the engineering of the home as well as geology of the ground underneath it. Each home is different.
  • Ask about the company's experience with mitigation of homes in your area/neighborhood. A company that understands the geologic conditions (hard, clayey soil vs. loose, sandy soil, etc.) of an area will likely design a system optimized for your house.
  • Oregon does not have state regulations that govern how companies mitigate for radon. Most mitigation companies follow technical standards/recommendations made by the EPA or the American Association of Radon Scientists & Technologists, Inc. (AARST). Many radon mitigation companies in Oregon reduce radon levels by using a method called sub-slab depressurization (see diagram on left-hand side of page).
  • Sub-slab depressurization is not the only proven method; the layout of your home and other factors may make other methods more appropriate. When interviewing a potential company, be sure to ask about which mitigation system standard they follow such as Active Depressurization Radon Mitigation Standards (ASD-RMS) for Low Rise Residential Standards - June, 2006 (toward bottom on screen).
  • Ask if they will include a short-term radon test in the price you'll pay. After the work is done, you can “test” their work yourself through a third-party – a laboratory not connected to the company that’s just done work for you.
  • Generally speaking, the cost to mitigate the average home in Oregon is $1500-2100, although this depends on a homes size, engineering, the ground beneath it, and geographic location. Price should not be the only factor in the decision. 
Can I put in my home’s radon mitigation system myself?
It is possible (and legal in Oregon) for a homeowner to put in a radon mitigation system into their home themselves, we don’t recommend it unless one has specialized radon mitigation knowledge. Radon mitigation is not just a matter of putting a hole in the ground that’s attached to a fan. Constructing an effective system requires in-depth knowledge of air-pressure differences as well as use of special equipment to test them. Those considering a DIY approach should understand that is possible, if mitigation is done incorrectly, to make one’s radon problem worse.
What about radon in well water?
Only about 1-2% of radon in the air comes from drinking water. If your drinking water coems from a surface water source, such as a river, lake, or reservoir, the majority of that radon will be released into the air before reaching your water supplier or home.

Radon is only a concern if your drinking water comes from underground, such as a private well, though not all water from underground sources contains radon. Because a home's radon, if it's elevated, is likely to come from the ground under the foundation, EPA recommends you first test your home using the directions given above. If you still want to test your well water, consider hiring a measurement company (above) or test it yourself by buying an online "radon in water test kit." The EPA has more information on this at Radon in Drinking Water.