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Radon in Colorado
These maps show estimates for radon levels in indoor air in Colorado counties based on three different sources.

Figure 1 shows an EPA model that predicts high levels of radon in indoor air across the state.

Figures 2 and 3, based on results of indoor air radon tests collected from 2005-2009 and voluntarily reported to the Colorado Department of Public Health and Environment (CDPHE), also show high levels of radon across the state. Several counties had higher levels of radon on average than predicted by the EPA model, but the number of home tests was low in some of these counties. A small number of tests may not accurately represent the entire county.

Figure 4 shows counties where Colorado residents responding to the 2009 Behavioral Risk Factor Surveillance System (BRFSS) random telephone survey were less likely to report awareness of a high radon test result in their home. This finding was in contrast to test results reported to CDPHE which indicate a high percentage of high radon levels for most Colorado counties.

The chart is at the bottom of this page, Figure 5, shows the 2009 BRFSS results for the question, “Do you know what radon is?” Results indicate disparities in awareness based on age, gender, education level, income, race and ethnicity.

It is important that all Colorado residents test their homes for radon. Testing provides residents with information about radon levels in their home, and it also adds to the CDPHE radon dataset presented here to help give a better understanding of radon levels in the state.

Homeowners need to be educated about the need to test their homes for radon and about what actions are appropriate based on their radon test levels. Information should be developed for specific target audiences who currently have low awareness of radon risk.
Figure 1: EPA map of radon zones
Figure 1, from the Environmental Protection Agency (EPA), shows estimated levels of radon in indoor air in each county of the United States based on models that include many variables, such as geological data, soil characteristics and some short and long term radon testing across the country. The EPA model predicts average radon levels above the EPA action level of 4 picocuries per liter (pCi/L) for all but 12 of the 64 counties in Colorado. Four pCi/L is the radon level established by EPA for mitigation.

*Action limit for indoor radon is 4 pCi/L
Figure 1
Source: Environmental Protection Agency.
Figure 2: Average concentration of indoor radon by county, based on test results reported to CDPHE.
Figure 2 shows the average concentration of indoor air radon for each county in Colorado based on results of radon tests that are voluntarily conducted and reported to the Colorado Department of Public Health and Environment (CDPHE). When compared to the EPA model predictions, these test results show average radon levels above the EPA action level in 9 of the 12 counties that the EPA model predicted would be below the action level.

*Action limit for indoor radon is 4 pCi/L
Source: Colorado Department of Public Health Hazardous Materials and Waste Management Division (CDPHE-HMWMD) Radon Program.
Figure 3: Percent of radon tests above 4 pCi/L by county, based on test results reported to CDPHE
Figure 3 shows the percent of indoor air radon tests above the EPA action level of 4 pCi/L for each county in Colorado based on results of radon tests that are voluntarily conducted and reported to the Colorado Department of Public Health and Environment (CDPHE). The majority of counties had a high percentage of tests above the EPA action level.

*Action limit for Indoor Radon is 4 pCi/L
Source: Colorado Department of Public Health Hazardous Materials and Waste Management Division (CDPHE-HMWMD) Radon Program.
Figure 4: BRFSS survey responses – likelihood of residents to report a radon test result above 4 pCi/L compared to state average
Figure 4 shows Colorado residents’ response to questions about the level of radon in their homes as reported by the 2009 BRFSS telephone survey. The map indicates residents in 17 counties were less likely than residents in other counties to report having a radon level above 4 pCi/L. But radon test results reported to CDPHE, shown in Figure 3, indicate a high percentage of tests above 4 pCi/L in most of those 17 counties.

Over 5,300 Colorado residents were asked “Has your household air been tested for the presence of radon gas?” About 35% of them answered “yes” and were then asked “Were the radon levels in your household above 4 picocuries per liter (pCi/L)?” Of those who had tested, about 12% reported a radon test result above 4 pCi/L and 36% were not sure if their test result was above 4 pCi/L, which is the EPA action level. Radon test results reported to CDPHE, shown in Figure 6, indicate that more than 12% of tests were above the EPA action level in all but 2 of Colorado’s 64 counties.


Figure 4
*Action limit for indoor radon is 4 pCi/L
Source: Colorado 2009 Behavioral Risk Factor Surveillance System (BRFSS), Health Statistics Section, Colorado Department of Public Health and Environment.
Figure 5: Radon awareness in Colorado residents
Figure 5 shows Colorado residents’ awareness of radon as reported by the 2009 BRFSS survey results. Over 5,300 Colorado residents were asked “Do you know what radon is?” About 80% of whites participating in the survey knew what radon is, compared to less than 50% of blacks and Hispanics. Only 30% of those with less than a high school education were aware of radon risks, compared to 90% of college graduates.


Figure 5
*Action limit for indoor radon is 4 pCi/L
Source: Colorado 2009 Behavioral Risk Factor Surveillance System (BRFSS), Health Statistics Section, Colorado Department of Public Health and Environment.
Figure 6: Radon test results reported to CDPHE by county
Figure 6 shows data from over 100,000 home radon tests voluntarily conducted and reported to the CDPHE from 2005 through 2009. Some of these data are mapped in Figures 2 and 3 above. This table provides details of the number of tests that were reported in each county during this time period. State-wide, almost half of all radon tests reported to the state exceed the mitigation level. No test result was below 2 pCi/L.

About radon testing data:
All Colorado homeowners are encouraged to purchase an indoor air test kit to find out if radon levels are high, but the decision about whether to test is left up to each homeowner. Individuals can use this coupon to get a radon test kit for $15. Radon test kits are sent to laboratories for analysis. Radon laboratories send the results back to the individual, and also voluntarily provide the results to the Colorado Department of Public Health and Environment (CDPHE) along with the zip code in which the test was done.

There are some limitations to the data:
  • It doesn’t allow us to compare radon levels in different areas of the state because testing is voluntary, so some areas report more tests than others and we don’t know if results are representative of an entire county or zip code. For example, some counties report thousands of tests in a year and others report only 2 or 3. So there isn’t enough information to compare radon levels.
  • Results don’t indicate if it was a first test or a test performed after radon mitigation steps have been taken to make sure the mitigation was successful. Because this information is not included it is impossible to know how many houses are actually being tested, since one house may be tested multiple times. It is also not possible to know if lower test levels reflect radon mitigation efforts or lower levels of radon in that geographic area.
  • The only information available for all reported radon tests are year of test, test result, and the zip code in which the test was done. Because many zip codes cross county lines there is some uncertainty in assigning tests to individual counties where zip codes cross county boundaries.
Looking at radon test results by county
To estimate radon test results by county, CDPHE used Microsoft Access to create a table that contained all Colorado zip codes and the respective counties. This allowed each home radon test result to be attributed to a county.
Some duplication occurred as several zip codes cross county lines. When a zip code overlapped counties, the value for that zip code was applied to each county.
This method does not establish exact radon metrics across the state. It does provide a snapshot of radon hazards across the state, including the occurrence of radon levels well in excess of the EPA action limit.


Figure 6
Source:Environmental Programs, Colorado Department of Public Health and Environment.
What is radon?
 
Radon is a colorless, odorless, radioactive gas that forms naturally in soil. Radon is produced when uranium in the soil breaks down.
 

Why is radon a concern?
 
Radon is known to cause lung cancer and it can seep into our homes and workplaces through cracks and openings in floors and crawlspaces. When this happens, radon becomes part of the air we breathe.
 

How to test your home for radon
 

How to test your home for radon
Perform a simple, short-term test in your home. You can do it yourself and it takes 48 to 96 hours to complete. You should keep windows closed 12 hours prior to testing your house.

A coupon for $15 test kits is available on the Colorado Department of Public Health and Environment (CDPHE) website. After testing, mail the test kit to the address provided; results will be mailed to you.

If radon levels in your home are high:
  • A mitigation system should be installed if the concentration of radon is more than 4 pCi/L. These systems should include sealing cracks and openings and installing PVC piping and a fan to remove radon gas, to prevent radon from entering your home. These systems usually cost between $800 and $1,500 in the Denver metro area. In other areas of Colorado they can cost more.
  • Find a National Environmental Health Association (NEHA) certified mitigation contractor in Colorado who can install a radon mitigation system.
 

Can radon make me sick?
 
When a person is exposed to radon over many years the exposure can increase the risk of lung cancer . Radon is the second-leading cause of lung cancer in the United States; only smoking causes more lung cancer. Radon is the leading cause of lung cancer in non-smokers.

Each year, about 20,000 deaths in the United States are attributed to radon-caused lung cancer. Risk of lung cancer from radon is almost 10 times higher for smokers compared to those who have never smoked. Smoking and radon together create a greater risk of lung cancer than either one alone.
 

Who is at risk?
 
  • Everyone exposed to radon over a long period of time is at risk for lung cancer.
  • Smokers are at higher risk of lung cancer. Exposure to a combination of smoking and radon creates a greater risk than either factor alone.
  • While some studies have reported that children are at greater risk than adults for certain types of cancer from radiation, currently there is no conclusive data that their radon risk is greater than adults.
  • In Colorado we have high levels of radon in our soils. An EPA model of indoor air radon levels indicates that most of the counties in Colorado have average levels greater than 4 picocuries per liter (pCi/L), which is the level at which EPA recommends radon mitigation.
 

How can the risk be reduced?
 
Test your house for radon:
A simple test you can do yourself will tell you if you need to take action to lower radon levels in your home. A coupon for $15 test kits is available on the CDPHE website. If the concentration of radon is more than 4 pCi/L you should take action to lower the radon levels in your home.

Don’t smoke:
Exposure to a combination of smoking and radon creates a greater risk of lung cancer than exposure to just smoking or just radon alone. The risk of the two together is greater than just adding up the risk from each one; they interact to make lung cancer even more likely.
 

How is radon tracked?
 

Radon testing is not required in Colorado, so the information available is limited. There are two sources of information used by COEPHT. One provides information from indoor radon tests that are conducted by homeowners. The other is BRFSS survey data that provides information on what Colorado residents report about radon tests in their homes.

About radon testing data:
All Colorado homeowners are encouraged to purchase an indoor air test kit to find out if radon levels are high, but the decision about whether to test is left up to each homeowner. Individuals can use this coupon from Colorado Department of Public Health and Environment (CDPHE) to get a radon test kit for $15. Radon test kits are sent to laboratories for analysis. Radon laboratories send the results back to the individual, and also voluntarily provide the results to CDPHE along with the zip code in which the test was done.

There are some limitations to the data:
  • It doesn’t allow us to compare radon levels in different areas of the state because testing is completely voluntary, so some areas report more tests than others and we don’t know if results are representative of an entire county or zip code. For example, some counties report thousands of tests in a year and others report only 2 or 3. So there isn’t enough information to compare radon levels.
  • Results don’t indicate if it was a first test or a test performed after radon mitigation steps have been taken to make sure the mitigation was successful. Because this information is not included it is impossible to know how many houses are actually being tested, since one house may be tested multiple times. It is also not possible to know if lower test levels reflect radon mitigation efforts or lower levels of radon in that geographic area.
  • While some studies have reported that children are at greater risk than adults for certain types of cancer from radiation, currently there is no conclusive data that their radon risk is greater than adults.
  • The only information available for all reported radon tests are year of test, test result, and the zip code in which the test was done. Because many zip codes cross county lines it is difficult to look at this data by county.
Looking at radon test results by county
To estimate radon test results by county, CDPHE used Microsoft Access to create a table that contained all Colorado zip codes and the respective counties. This allowed each home radon test result to be attributed to a county.

Some duplication occurred as several zip codes cross county lines. When a zip code overlapped counties, the value for that zip code was applied to each county.

This method does not establish exact radon metrics across the state. It does provide a snapshot of radon hazards across the state, including the occurrence of radon levels well in excess of the EPA action limit.

About BRFSS survey:
The Behavioral Risk Factor Surveillance System (BRFSS) is an ongoing national telephone survey sponsored by CDC to monitor lifestyles, behaviors and awareness related to leading causes of illness, injury and death. In Colorado, over 1,000 adult residents complete the survey each month. In 2009 these questions about radon were included in the Colorado survey:
  • Do you know what radon is?
  • Has your household air been tested for radon?
  • Was the radon level above 4 picocuries per liter (pCi/L)?
 



Video: Radon the Invisible Killer
Source: Colorado Public Health and Environment
Running Time: (30:00)
Release Date: 01/11/2011

Video: Radon the Invisible Killer (Spanish Subtitles)
 
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