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Radon Remediation

Radon Mitigation:  When a building (or house) is found to have an elevated level of radon gas (defined by the U.S. Environmental Protection Agency as a radon result of 4.0 pCi/l or higher,) methods of reducing the levels can be applied to cure the problem.  The most common method of Radon mitigation (also known as remediation or abatement) is Active Soil Depressurization (ASD.) This method utilizes PVC piping attached to an electric suction fan.  The piping typically begins below the lowest floor of the structure's foundation (penetrating the slab of the basement or the plastic membrane of the crawl space) and extends upward to an exit point above ground level.  The inline suction fan is mounted in an inconspicuous location on the exterior or within an attic above the home.  In cases where the radon fan is installed in the attic, the discharge pipe extends out through the roof so the gas can be released outdoors.

Active (fan assisted) radon mitigation systems can reduce the radon gas entry by as much as 99%.  A qualified radon contractor (also known as a radon mitigator or radon remediation specialist) can typically install a mitigation system in a home in less than a day.  After the system is installed, the radon levels begin to drop almost immediately.  Passive radon reduction techniques (such as sealing cracks or installing pipes without an inline fan) are rarely effective at reducing radon levels.  The reason that these "passive" techniques are ineffective is because radon gas is under pressure and must escape from the ground.  It is a very inert, un-reactive gas that can be drawn up through the pours of concrete, around drains, utility penetrations, or expansion joints.  Attempting to "seal out" radon is similar to trying to keep water out of a basement by painting the walls and floor with waterproofing paint.  It may work temporarily if the problem is minor, but it wouldn't keep standing water out.  The only way to fix a water problem is to redirect the water somewhere else before it enters the home.  The same principles apply to radon correction.  Sealing cracks and openings is part of the radon mitigation process; however this is to prevent the downward draw of conditioned air from the home and to improve the pressure field extension of the system below the slab.

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 Radon gas mitigation, reduction - testing: Denver, Boulder, Colorado Springs, Milford, New Haven, Stamford, Connecticut CT, Wilmington Delaware, Indianapolis, South Bend, Fort Wayne, Bloomington, Indiana, Lexington, Louisville, Kentucky KY, Baltimore Maryland MD, Boston, Worcester, Massachusetts, Lansing, Ann Arbor, Kalamazoo, Grand Rapids, Brighton Michigan, New York, Pittsburgh, Philadelphia, Allentown, Harrisburg, Pennsylvania PA, West Virginia WV, Madison, Milwaukee, Janesville, Wisconsin

Radon Gas: Is Your Home Radioactive?

I want to discuss a subject that gets very little attention, but should be a major concern to all Americans.  Radon gas is the 6th leading cause of death overall and leading cause of lung cancer in the United States for non-smokers.  This topic is especially alarming because of two key points: 1) Radon cannot be detected by human senses [you cannot see it, smell it, or taste it.] 2) Radon problems are very common [about 10% of the homes in the United States have unacceptable levels] and the problem has been found in most areas of the country.  Radon Testing is easy, accurate, and inexpensive. 

When a home is found to have an elevated level of radon gas (defined by the EPA as a radon result of 4.0 pCi/l or above,) methods of reducing the levels can be used to fix the problem.  The most common method of Radon remediation (also known as Radon Mitigation or abatement) is Active Soil Depressurization (ASD.) This method uses PVC piping attached to an electric blower system.  The piping typically begins below the lowest floor of the home's foundation (penetrating the slab of a basement or the plastic membrane of a crawl space) and extends upward to an exit point above ground level.  The inline suction fan is mounted in an inconspicuous location in an attic or outside the home.  In cases where the radon fan is located in the attic, the exhaust pipe extends out through the roof so the gas can be released into the atmosphere.

Active (fan assisted) Radon Removal System can reduce the radon levels in a home by as much as 99%.  A qualified radon specialist (also known as a radon mitigator or radon remediation contractor) can typically install a system in a home in less than a day.  After the system is installed, the radon levels begin to drop almost immediately.  Passive radon reduction techniques (such as sealing floor cracks or installing vent pipes without inline fans) are rarely effective at reducing indoor radon levels.  The reason that these "passive" techniques are ineffective is because radon gas is pressurized and must escape from the ground.  It is an inert, un-reactive gas that can be drawn up through the pours of concrete, around utility penetrations, drains, or expansion joints.  Attempting to "seal out" radon is similar to trying to keep water out of a basement by painting the floor and walls with waterproofing paint.  It may work temporarily if the problem is minor, but it wouldn't keep standing water out.  The only way to fix a water problem is to redirect the water somewhere else before it enters the home.  The same principles apply to radon correction.  Sealing cracks and openings is part of the radon mitigation process; however this is to prevent the loss of conditioned air from the home and to improve the area of influence that the radon mitigation system has below the slab.

Radon abatement systems are very common in U.S. homes and are considered to be a home improvement.  It shouldn’t harm the resale value or aesthetics of the home, and the systems are quite efficient.  The average cost of operation is typically less than $100 per year and it usually costs less than $1,000 for installation of the entire system.  I’m sure that you would agree that this is a small price to pay to protect the health of your family. 

 

6 Mar 2020    Citizen's Guide To Radon: Radon Mitigation
 
6 Mar 2020    Iowa Radon Lung Cancer Study

The Iowa Radon Lung Cancer Study

 

 

Phase I Completed

a Field, R.W., a Lynch, C.F., b Steck, D.J., aSmith, B.J., aBrus, C.P., cNeuberger, J.S.,
aWoolson, R.F., aFisher, E.F., d Platz,C.E., d Robinson, R.A.

aCollege of Public Health
University of Iowa

b Physics Department
St. Johns University

 

c Department of Preventive Medicine
University of Kansas School of Medicine

dCollege of Medicine
University of Iowa

The Iowa Radon Lung Cancer Study was a large-scale epidemiology study initiated in 1993 and funded by the National Institute of Environmental Health Sciences (NIEHS).  The study assessed the risk posed by residential radon exposure. The 5-year study was performed in Iowa and the participants were women throughout Iowa who lived in their current home for at least 20 years.  Over a thousand Iowa women took part in the study.  Four hundred and thirteen of the participants were women who had developed lung cancer, the remaining 614 participants were controls who did not have lung cancer.  The study was limited to women, because they historically tend to spend more time at home and they have less occupational exposure to other lung carcinogens.

The epidemiologic study was performed in Iowa for several reasons. Iowa has the highest average radon concentrations in the United States.  In addition, women in Iowa tend to move less than most other states, which makes calculation of their past radon exposure easier.  Iowa was also selected because it has a quality National Cancer Institute SEER cancer registry, which helped us identify women who developed lung cancer.  Close to 60% of the basement measurements for both cases (participants with lung cancer) and controls (participants without lung cancer) exceeded the EPA's action level. Twenty-eight percent of the living areas for the controls and 33% of the living areas for the cases exceeded the EPA's action level of 4 pCi/L.

The study used the most advanced radon exposure measurement techniques ever performed in a residential radon study. Numerous yearlong radon measurements were made in each participant's home. Outdoor radon measurements were also performed in addition to estimates of work place exposure. All these measurements were linked to where the participants spent the proceeding 20 years in order to get a cumulative radon exposure. 

The major paper reporting the findings was published in volume 151 of the American Journal of Epidemiology (pages 1081-1101) in 2000. The American Journal of Epidemiology is the premier scientific journal devoted to the publication of empirical research findings and methodologic developments in the field of epidemiologic research.  Findings of the study were released to the press on May 25, 2000. 

Risk estimates for the Iowa Radon Lung Cancer Study were adjusted for age, active smoking, and education. For all lung cancer subtypes, there was a positive categorical trend (p = 0.05). Analyses restricted to the live cases and controls noted both a strong categorical (p = 0.01) and continuous trend (p = 0.03). The Iowa Radon Lung Cancer Study's estimated excess odds at 11 WLM5-19 (roughly equivalent to a 15-year exposure at an average radon exposure of 4 pCi/L) averaged 0.50 for both all cases and the live case subset. For the all-case category, large cell carcinoma exhibited a statistically significant trend for both the continuous (p = 0.04) and categorical (p = 0.03) risk estimates. However, the differences in the linear excess odds between histologic types was not statistically significant (continuous p = 0.58, categorical p = 0.65). Overall, these results suggest that cumulative radon exposure is a significant risk factor for lung cancer in women.

The Iowa Radon Lung Cancer Study had several strengths. First, independent pathologic review was performed for 96 percent of the cases. Second, the study was carried out in Iowa, which has the highest mean radon concentrations in the United States. Third, the high radon concentrations in conjunction with a strict quality assurance protocol contributed to accurate and precise radon measurements. Fourth, the IRLCS criteria requiring occupancy in the current home for at least the last 20 years eliminated the need to impute radon measurements from missing homes. Fifth, the linkage between radon measurements and retrospective participant mobility allowed for a refined exposure estimate. The IRLCS risk estimates are in general agreement with the National Research Council's predicted cancer risk associated with indoor radon exposure. Overall, the risk estimates obtained in this study suggest that cumulative radon exposure in the residential environment is significantly associated with lung cancer risk. 

 

THE IOWA and MISSOURI RESIDENTIAL RADON STUDIES

Phase II – Currently Underway

RW Field, Ph.D. a, DJ Steck, Ph.D. b, BJ Smith, Ph.D.a, CF Lynch, M.D. Ph.D.a,
JH Lubin, Ph.D.c, MA Parkhurst, Ph.D.d, MCR Alavanja, Dr. PH c

a College of Public Health
University of Iowa

b Physics Department
St. John's University

c National Cancer Institute
Rockville, MD

d Pacific Northwest National Laboratory
Richland, WA

Purpose

The specific aims of the 5-year Iowa and Missouri Residential Radon Studies (Phase-II), which initiated in 2000 are to: 1) further refine the estimated lung cancer risk posed by residential radon-222 (radon) decay product exposure using a novel glass-based retrospective radon decay product (progeny) reconstruction detector; 2) determine the shape (linear, quadratic, etc.) of the dose-response curve relating radon progeny exposure and lung cancer; 3) determine the lung cancer risk posed by radon progeny exposure for the various histologic types; and 4) examine the association between radon progeny and other lung cancer risk factors on the lung cancer incidence.  The study, using state-of-the-art methods to measure retrospective radon progeny exposure, focuses on the association between residential radon progeny exposure and lung cancer. 

Glass surfaces exposed to radon gas over an extended period of time are convenient radon progeny reservoirs that allow retrospective estimates of radon exposure.  The novel glass-based detectors measure 210Pb previously embedded in glass through residual nuclei recoil implantation following alpha decay.  Glass provides a stable matrix for the 210Pb deposit. The 22-year half-life of 210Pb means that it takes decades before the activity achieves an equilibrium value and the activity persists for years after exposure.  This predictable temporal behavior provides a long-lasting marker for past radon and radon progeny concentrations in a home.  Therefore, one can measure glass items that have been carried from home to home over long periods of time to estimate past residential radon progeny exposure.  Because the radon progeny deliver the actual radiation dose to the lung tissues, rather than the radon gas itself, better residential radon progeny dose estimates require the reconstruction of actual airborne radon progeny concentrations.  Pooling of data between two large-scale epidemiologic studies from a similar geographic area that used the glass-based detectors in addition to the contemporary radon gas detectors increases the power of the overall analyses.  We anticipate the research will significantly reduce radon (more precisely radon progeny) exposure misclassification, which will enhance our ability to address the Specific Aims above. 

Study Design

The study design has three major components: 1) field calibration and laboratory validation of the retrospective radon detectors, 2) reanalysis of the risk estimates from the Iowa Radon Lung Cancer Study incorporating radon progeny exposure estimates obtained from retrospective radon detector (RRD) measurements, rather than radon gas measurements; 3) calculation of risk estimates from a pooled analyses of retrospective radon detectors exposure results for the previous National Institutes of Environmental Health Sciences (NIEHS) funded Iowa Radon Lung Cancer Study (IRLCS) and the National Cancer Institute (NCI) funded Missouri Radon Lung Cancer Study II (MRLCS-II).

Selected Findings

Findings from the Iowa and Missouri Residential Studies have been published in over 25 peer-reviewed scientific journals.  A few examples of some of the major findings follow.

Risk Estimates for Prolonged Residential Radon Exposure Risk estimates for the Iowa Radon Lung Cancer Study using estimates of retrospective gas exposure were adjusted for age, active smoking, and education. For all lung cancer subtypes, there was a positive categorical trend (p = 0.05). Analyses restricted to the live cases and controls noted both a strong categorical (p = 0.01) and continuous trend (p = 0.03). The Iowa Radon Lung Cancer Study's estimated excess odds at 11 WLM5-19 (roughly equivalent to a 15-year exposure at an average radon exposure of 4 pCi/L) averaged 0.50 for both all cases and the live case subset. Large cell carcinoma exhibited a statistically significant trend for both the continuous (p = 0.04) and categorical (p = 0.03) risk estimates, but the differences in the linear excess odds between histologic types was not statistically significant. These results suggest that cumulative radon exposure is a significant risk factor for lung cancer in women.

Improved Residential Radon Study Methodology – The a priori defined IRLCS radon-exposure model produced higher odds ratios than those methodologies that did not link the subject's retrospective mobility with multiple, spatially diverse radon concentrations. In addition, the smallest measurement errors were noted for the IRLCS exposure model. Risk estimates based solely on basement radon measurements generally exhibited the lowest risk estimates and the greatest measurement error. The findings indicate that the power of an epidemiologic study to detect an excess risk from residential radon exposure is enhanced by linking spatially disparate radon concentrations with the subject's retrospective mobility and that previous epidemiologic investigations likely underestimated the risk posed by residential radon exposure.

State of the Art Radon and Radon Progeny Dosimetry - Radon progeny, rather than radon, deliver dose to the lungs during decade’s long exposures. The study has made advances in estimating contemporary and past radon progeny dose using passive integrating alpha detectors. Contemporary airborne radon and progeny activities are reconstructed from direct radon and surface deposited progeny measurements. Track registration material, with selected energy removing filters, detects the individual alpha emitting isotopic concentrations. These concentrations are used in a fate and transport model to calculate the available airborne dose rate. Retrospective radon progeny concentrations can be reconstructed from glass-implanted 210Po activity and the relationship between airborne and deposited activities determined from contemporary activities.  Using a regression analysis of the IRLCS retrospective detector data to identify the important environmental variables, new detector modules, as well as the old, have been calibrated in controlled exposures.  Active airborne progeny detectors are being developed and calibrated to directly sample the important environmental conditions and activities in a select group of homes to improve and validate the dose estimates.

Diet and Lung Cancer - When comparing the fifth (highest) to the first (lowest) quintile of consumption of total fat, saturated fat and cholesterol in the IRLCS, we obtained odds ratios of 2.0 (1.3-3.1), 3.0 (1.9-4.7), and 2.0 (1.3-3.0), respectively for lung cancer. However, when red meat was entered into the model along with total fat, saturated fat or cholesterol, the excess risk for the macronutrients disappeared while an odds ratio of 3.3 (1.7-7.6) was obtained for red meat. The odds ratios for red meat consumption were similar among adenocarcinoma cases, OR=3.0 (1.1-7.9) and non-adenocarcinoma cases, OR=3.2 (1.3-8.3) and among life-time nonsmokers and ex-smokers OR=2.8 (1.4-5.4), and current smokers, OR=4.9 (1.1-22.3). Yellow-green vegetables were protective with an odds ratio of 0.4 (0.2-0.7). We concluded that consumption of red meat was associated with an increased risk of lung cancer even after controlling for total fat, saturated fat, cholesterol, fruit, yellow-green vegetable consumption and smoking history, while yellow-green vegetables are associated with a decreased risk of lung cancer.

Gene Environment Interactions – Recent work with collaborators at the NCI and City of Hope (Los Angeles) have explored gene-environment interactions between residential radon, environmental tobacco smoke (ETS), and the GSTM1 null genotype. The sample series included lung cancer cases pooled from three previously completed case-control studies. Recent results show a statistically significant 3-fold increase in the interaction OR for GSTM1 null cases compared with GSTM1 present cases.  In addition, the ETS and GSTM1 interaction OR was significantly elevated over two-fold.  This is the first study to provide evidence of a radon and GSTM1 interaction in risk of lung cancer and supports the hypothesis that radon and ETS may promote neoplasia by damaging genetic pathways that include GSTM1.  These findings have just been submitted for publication.

Future Plans

Laboratory calibration of the retrospective radon progeny detector is nearing completion and field validation studies are planned for fall of 2004.  As soon as this work is complete, we will perform a reanalysis of the IRLCS data using the glass-based retrospective radon progeny data.  Next, we will pool the glass-based retrospective radon progeny data from both the IRLCS and MRLCS.  The pooled data should allow more power to examine the lung cancer risk posed by residential radon decay product exposure and determine whether the risk varies by histologic type.  We are also continuing our collaboration with European investigators pooling the findings from all the residential radon studies that have used standard radon gas measurements and plan an eventual pooling of residential radon studies that incorporated the use of the more advanced glass-based measurements.  Further collaborations are also underway with researchers at NCI and City of Hope (Los Angeles) to explore additional studies examining gene-environment interactions and lung cancer.  We have archived paraffin fixed tumor specimens from the Iowa Radon Lung Cancer Study and welcome the opportunity of additional collaborations using these materials.   We are also interested in performing future studies in Iowa, with the cooperation of the NCI SEER Iowa Cancer Registry, examining the impact of environmental causes of lung cancer in relation to energy balance in never-smoking individuals. 


Selected Peer-Reviewed Scientific Publications from the Iowa Residential Radon Study and On-going NCI-Sponsored Iowa and Missouri Residential Radon Studies

  1. Field RW, Steck DJ, Lynch CF, Brus CP, Neuberger JS, Kross BC. Residential Radon-222 Exposure and Lung Cancer: Exposure Assessment Methodology.  Journal of Exposure Analysis and Environmental Epidemiology 6(2):181-195, 1996.
  1. Field RW, Smith BJ, Brus CP, Lynch CF, Neuberger JS, Steck DJ.  Retrospective Temporal and Spatial Mobility of Adult Iowa Women, Risk Analysis: An International Journal 18(5):575-584, 1998.
  1. Fisher EF, Field RW, Smith BJ, Lynch CF, Steck DJ, Neuberger JS. Spatial Variation of Residential Radon Concentrations: The Iowa Radon Lung Cancer Study, Health Physics 75(5):506-513, 1998.
  1. Field RW, Lynch CF, Steck DJ, Fisher EF.  Dosimetry Quality Assurance: The Iowa Residential Radon Lung Cancer Study, Radiation Protection Dosimetry 78(4):295-303, 1998.
  1. Steck DJ, Field RW, and Lynch CF. Exposure to Atmospheric Radon (222Rn) in Central North America, Environmental Health Perspectives 107(2):123-127, 1999.
  1. Field RW, Lynch CF, Steck  DJ, Smith BJ, Brus CP, Neuberger JS, Woolson RF, Fisher EF, Platz CE, Robinson RA.  Iowa Radon Lung Cancer Study, Radiation Research 151:101-103, 1999.
  1. Field RW, Steck DJ, Smith BJ, Brus CP, Neuberger JS, Fisher EF, Platz CE, Robinson RA, Woolson RF, Lynch CF.  Residential Radon Gas Exposure and Lung Cancer: The Iowa Radon Lung Cancer Study, American Journal of Epidemiology 151(11):1091-1102, 2000.
  1. Field RW, Steck DJ, Smith BJ, Brus CP, Neuberger JS, Fisher EF, Lynch CF. The Iowa Radon Lung Cancer Study Phase I: Residential Radon Gas Exposure and Lung Cancer, The Science of the Total Environment 272:367-72, 2001.
  1. Steck DJ, Field RW. The Use of Track Registration Detectors To Reconstruct Contemporary and Historical Airborne Radon (222Rn) and Radon Progeny Concentrations for a Radon-Lung Cancer Epidemiologic Study, Radiation Measurements 31(1-6):401-412, 1999.
  1. Field RW, Steck DJ, Parkhurst MA, Hahaffey JA, Alavanja MCR. Intercomparison of Retrospective Radon Progeny Measurement Devices, Environmental Health Perspectives 107:905-910, 1999.
  1. Alavanja MCR, Field RW, Sinha R, Brus CP, Shavers VL, Fisher EL, Curtain J, Lynch CF. Lung Cancer Risk and Red Meat Consumption Among Iowa Women, Lung Cancer 34 (1):37 - 46, 2001.
  1. Field RW, Smith BJ, Lynch CF, Steck DJ. Intercomparison of Radon Exposure Assessment Methods: Implications for Residential Radon Risk Assessment, Journal of Exposure Analysis and Environmental Epidemiology 12(3):197-203, 2002.
  1. Steck DJ, Alavanja MCR, Field RW, Parkhurst MA, Bates DJ, Mahaffey JA. 210Po Implanted in Glass Surfaces by Long Term Exposure to Indoor Radon, Health Physics 83(2):261-271, 2002.
  1. Krewski D, Lubin J, Zielinski J, Alavanja M, Catalan V, Field RW, Klotz J, Létourneau E, Lynch C, Lyon J, Sandler D, Schoenberg J, Steck D, Stolwijk J, Weinberg C, Wilcox H A. A Combined Analysis of North American Case control Studies of Residential Radon and Lung Cancer: An Update. Radiation Research 158(6):785-790, 2002.
  1. Field RW. (Invited paper): A Review of Residential Radon Case-Control Epidemiologic studies Performed in the United States, Reviews on Environmental Health 16 (3), 2001.
  1. Field RW, Smith BJ, Platz CE, Robinson RA, Brus CP, Lynch CF. Agreement Between SEER Reported Versus Independently Reviewed Lung Cancer Morphologies: A Quality Assurance Analysis, Journal of the National Cancer Institute 96(14):1105-7, 2004.
  1. Krewski D, Lubin J, Zielinski J, Alavanja M, Catalan V, Field RW, Klotz J, Létourneau E, Lynch C, Lyon J, Sandler D, Schoenberg J, Steck D, Stolwijk J, Weinberg C, Wilcox HA.  North American Case-Control Studies of Residential Radon and Lung Cancer, Journal of Toxicology and Environmental Health, In Press.
  1. Krewski D, Lubin J, Zielinski JM, Alavanja M, Field RW, Letourneau EG, Sandler DP, Schoenberg JB, Weinberg C, Wilcox S, Catalan V. Risk of Lung Cancer in North America Associated with Residential Radon, Epidemiology, In Press.
 
4 Mar 2020    Radon and Lung Cancer: Radon Mitigation Saves Lives
 
18 Apr 2020    Radon Mitigation Denver Littletonn Colorado

Elevated radon levels have been found in most Colorado counties including Jefferson, Arapahoe, Denver, Adams, Elbert, Douglas, Boulder, Gilpin, Clear Creek, Summit, Park County, and Teller. The Surgeon General suggests that every home should be tested for radon gas.

 

 

Radon: Silent, but Deadly

Nearly every homeowner has encountered the term “radon,” either during the selling or purchasing process. Homeowners have good reason to be aware of the potential presence of radon in their home, to test radon levels, and install radon ventilation systems if the radon levels are high. Many prospective home-buyers, however, choose to forgo radon testing prior to purchasing their new home, because they are uneducated or misinformed regarding what radon is and the detrimental long-term effects it can have on the health and vitality of their families.

What is Radon?

Radon is a naturally-occurring, colorless, odorless, tasteless gas that is highly radioactive and extremely dense (nine times more dense than air!). It was discovered in 1899-1900 by two European physicists, Ernest Rutherford and Friedrich Ernst Dorn. Although there are many forms of radon, Radon-222 is the type that occurs most frequently in the environment.

Radon can be highly concentrated in groundwater and in the ground under where a building is constructed; the ingestion of this contaminated water, and the inhalation of the radon particles released from this water, are the two primary ways in which people are exposed to this radioactive substance. As radon decays, the particles attach to microscopic airborne materials, like dust, which facilitates its inhalation by humans.

Because the primary source of radon is underground, buildings that have a below-ground component (basements, lower levels, etc.) or structures that exist solely underground (tunnels, caves, mines, etc.) and have minimal fresh-air circulation, are at highest risk for elevated levels of radon and its decay products. Although the risk to habitants in a home without a finished basement is less than that to workers in an underground mine, radon, as a single atom gas, can easily penetrate paint, construction materials, and insulation, and still be a major cause of concern to families living in a radon-concentrated area.

Dangerously high levels of radon have been found in up to 8 million homes - at least 1 in 5 - throughout the United States; no area or region is untouched by the effects of radon.

Radon is a national environmental health problem. Elevated radon levels have been discovered in every state. The US EPA estimates that as many as 8 million homes throughout the country have elevated levels of radon. Current surveys in many states show that 1 home in 5 has elevated radon levels.

Health Concerns

Lung cancer is a deadly form of cancer that claims the lives of 11 to 15 percent of its victims within five years of diagnosis. The cancer cells form in the tissues of the lung, generally in the cells lining air passages. Lung cancer is categorized by two types: small cell and non-small cell lung cancer; which type is determined by the look of the cells under a microscope. According to the National Cancer Institute, in 2009, 219,440 Americans were diagnosed with lung cancer, and 159,390 died from it. For more information about lung cancer, visit the websites of the American Lung Association, American Cancer Society, and the National Cancer Institute.

Radon in our homes is the primary source of ionizing radiation to which most people are exposed. The World Health Organization (WHO) estimates that as much as 15 percent of lung-cancer worldwide is caused by radon. In the United States, the Surgeon General has indicated that, after smoking, radon is the leading cause of lung cancer, killing approximately 21,000 Americans each year. Visit the WHO International Radon Project site for more information:

there have been two studies, one in North America and one in Europe that have demonstrated unequivocally the link between exposure to radon and increased risk of lung cancer. The research showed that radon is a carcinogen that, in long-term exposure to even low levels, can cause lung cancer. Read the University of Iowa press release about the North American study at:


Individuals that smoke - or are exposed to secondhand smoke - and also live in a home with high radon levels are at extremely high risk for developing lung cancer. According to the EPA, “a person who has never smoked...who is exposed to 1.3 pCi/L [a very low level of radon] has a 2 in 1,000 chance of lung cancer; while a smoker has a 20 in 1,000 chance of dying from lung cancer.... at 8 pCi/L the risk to smokers is six times the risk to never smokers.”

Because of children’s increased respiration rate and higher rate of cell division, they may be at higher risk of negative effects from the radiation in homes containing medium- or even low-levels of radon. However, there have been no research studies to date that have proven children to be at higher risk for radon-caused lung cancer than adults.

Radon Testing and Remediation

Due to the colorless, odorless, and tasteless nature of radon, there is no way to determine whether or not radon is present in a given location - let alone the degree to which it is concentrated - without conducting a radon test. Although radon is a primary cause of cancer and other serious health issues, it typically acts slowly, over a period of years, so by the time adverse health effects are noticed in one individual, everyone in the household has had significant long-term radon exposure.

There is no level of radon determined “safe” for human exposure. The Environmental Protection Agency (EPA) recommends that a homeowner with greater than 2-4 pCi/L (pico Curies per Liter) of radon in their house should strongly consider fixing the problem.

Information About Radon Mitigation

Radon gas is found in homes all over the U.S.

Radon is an invisible and odorless radioactive gas. Elevated levels of radon have been found in homes all across the country. Any home in any state may have a radon problem: new and old homes, well-sealed and drafty homes, and homes with or without basements. Radon gas gets into all types of buildings, including office buildings and schools.

You and your family receive the greatest radiation dose in your home. That's where you spend most time - 70 to 75 percent, more for small children. The average person receives each year more radiation from radon than from all other natural or man-made sources combined. Over the years, the accumulated radiation exposure may exceed the exposure of uranium miners.

The never-ending supply of radon

Radon gas is produced during the natural disintegration of radioactive heavy metals uranium and thorium, which are dispersed throughout the Earth's crust. As the atoms of radioactive heavy metals disintegrate, they change into lighter and lighter radioactive heavy metals until they end up as stable, non-radioactive lead. But at each step of this radioactive decay chain the atom nuclei emit radiation - alpha and beta particles, or gamma rays (more energetic than x-rays).

We will never run out of uranium or thorium. Radon levels on Earth have not changed since the last Ice Age. The radioactive half-life of Uranium-238, when a half of its atoms disintegrates, is 4.5 billion years. The half-life of Thorium-232 is 14.1 billion years. Their decay chain continuously produces radium, which decays into radon isotopes Radon-222 (most common in homes) and Radon-220 (Thoron).

Radioactive decay makes life on Earth possible by heating its core. Japanese scientists have measured the antineutrinos produced by the decay of uranium and thorium deep inside the Earth. The decay generates about 19 million megawatts of heat, about half of all the heat generated inside the planet. The other half comes from gravitational and chemical sources. (NYT 7/28/05)

Radon is the heaviest known gas, nine times heavier than air. It is an aberration - the only gas in the long decay chain of heavy metal elements. Its disintegration begets a decay chain of radioactive heavy metals polonium, bismuth and lead. After 22 years, a half of Radon-222 atoms ends up as Lead-206, the final non-radioactive element.

Radon in the soil gas

Dig up the top 6 feet of an acre of land and you will find about 50 pounds of uranium. Uranium and its daughter products radium and radon are found in nearly all rocks and soils. Most contain only 1 to 3 parts per million (ppm) of uranium but some, like granites, dark shales, light-colored volcanic rocks, and sedimentary rocks with phosphate, may contain as much as 100 ppm. Thorium, which is even more common, also produces radium.

When radium atoms disintegrate into alpha particles and atoms of radon, 10 to 50 percent of the radon atoms escape from the mineral grain into the underground "soil gas," which also carries biological decay gases and moisture. In most areas of the United States, the soil gas contains between 200 and 2,000 pCi of radon per liter. As radon slowly diffuses from the ground into the ambient air, its flux varies widely but, typically, one square foot of soil emits 130 pCi of radon each hour (0.4 pCi/m2s). In the United States, the resulting outdoor radon level averages 0.45 pCi/L. But the stacks of radon mitigation systems emit undiluted soil gas with radon concentrations 2,000 times higher, averaging over 1,000 pCi/L.

As radon gas moves through underground fissures, it usually decays into solid particles after several feet. But it travels much farther in dry, permeable soils, like gravel or course sand. Radon is soluble in water and underground streams can carry it long distances. This unpredictable underground movement of radon gas explains why homes in low-radium areas also have high radon levels and why radon levels can vary several-fold between adjacent houses.

Sources of indoor radon

Radon gas naturally moves into the permeable disturbed soil and gravel bed surrounding foundations and then, into the buildings through openings and pores in concrete. Radon from soil is by far the main source of indoor radon.

Building materials like rocks, bricks, and concrete also give off radon by emanation. They produce Radon-222 and Thoron (Radon-220) but only 0.1 - 0.3 pCi/L each in a typical basement. The very short half-life of Thoron (96 seconds) reduces its typical concentration in homes to 0.3 pCi/L.

Radon is soluble in water and also gets indoors by "water migration." Water is drawn indoors by the capillary action of the pores in concrete or pushed by hydrostatic pressure (seepage). The higher temperature and lower pressure indoors release the dissolved gas. Water in sump pits and floor drains also releases radon. The typical basement or floor slab lets in 15 or 10 gallons of water and vapor each day.

If you have a private water well, radon from the water gets released into the air in your home during showering and when washing dishes or laundry. Inhalation of the radon gas released into air is much more dangerous than its ingestion with drinking water. As a rule of thumb, each 10,000 pCi/L of radon in water increases its level in indoor air by 1 pCi/L. In the U.S., the average radon concentration in surface water is 10 pCi/L but 750 pC/L in well water. However, levels exceeding 20,000 pCi/L are not uncommon. To check the level of dissolved radon, you can purchase our radon-in-water test kit.

Radon from outside air also settles in basements of homes because it is nine times heavier than air. Radon released by tailings from uranium mines was found to travel hundreds of miles and settle in homes. But more commonly, radon gas released from soil is drawn into basements over the top of the foundation, through bulkhead doors, or uncaulked basement windows above window wells. It can be even drawn into the attic underneath uncaulked siding and then sink into the house.

How buildings draw radon from the ground

The air pressure inside homes is slightly lower than in the ground (typically 0.7-1.4 psi vacuum), which draws in radon gas from several feet away. Combustion appliances, like furnaces, hot water heaters and fireplaces, as well as exhaust fans and vents reduce the indoor pressure indoor. The warm air inside buildings moves upwards like inside a stack and this "stack effect" reduces the air pressure on lower floors. Strong winds create a vacuum on the downwind side by the Bernoulli effect. When the ground is frozen or soaked by rain, the "bottled up" radon gas in the ground moves to the warm and permeable gravel and disturbed ground around the house.

The resulting pressure-driven flow (advection) draws in radon through openings or cracks and through the pores in concrete. This pressure-driven infiltration of radon is only a part of the radon inflow, or radon would be easy to mitigate by sealing all openings or simply pressurizing the basement.

Radon is also pulled in by the difference in radon concentration indoors and in the soil (diffusion). Radon tries to equalize the indoor concentration and its atoms easily penetrate through the pores in concrete. The diffusion flow through an intact concrete slab driven by the concentration gradient is several times higher than the pressure-driven advective flow. This explains why the method of pressurizing the basement does not work.

Porosity of concrete

Concrete cures by reacting with water - hydration. But almost half of the water added to the concrete mix for workability is surplus and has to evaporate. As the surplus water in newly poured concrete pushes to the surface, it leaves behind a network of capillaries (pores).

The pores constitute 12 to 18% of the concrete by volume. Their diameter is much smaller than a human hair but much larger than radon atoms or water molecules. They let in radon gas, water vapor, liquid water, and other gases.

Typical openings in basements

Any openings and cracks have to be sealed off or caulked to stop radon, as well as water vapor and soil gas. Examples:

  • Sump pits and floor drains
  • Attached crawlspaces
  • Bathroom rough-ins (gravel areas)
  • Gaps in floor-to wall joints (around floating slabs)
  • Hollow uncapped concrete blocks (use closed-cell expansion foam the top of the cores)
  • Cracks in floors or walls
  • Expansion control joints in floors (straight cuts)
  • Lolly (support) columns going through the floor
  • Gaps around service pipes

For sealing cracks in poured concrete walls, we recommend polyurethane foam injection (see our Crack Repair Kits). Cracks in slabs - route them out with a grinder and deep-fill with self-leveling polyurethane caulk available in stores, or avoid the grinding and use our Easy-Peel Crack Injection Kits. Polyurethane remains flexible for years, as the house settles and concrete continuously moves. Hydraulic cement is too rigid and will soon get loose. Caulking the surface only is inadequate - the gap fills up with radon gas which then easily by-passes the caulk through concrete. Surface caulking will soon detach as moisture degrades the concrete surface and it cannot withstand hydrostatic pressure.

Accumulation of radon inside homes

Modern houses tend to build up radon, because the building envelope is almost airtight while the foundation is "leaky" to soil gas. The soil gas infiltration ranges from less than 1% to over 20% of the total "fresh air" infiltration into homes. Opening basement windows to increase ventilation may help by removing the radon gas but it wastes energy and in some cases, can actually increase the radon level by increasing suction through the porous concrete. The best solution is sealing the concrete to ensure the foundation is more airtight than the building envelope.

The heavy radon gas accumulates in basements and on lower floors. Heating and air-conditioning, natural air movement, as well as diffusion of radon atoms through the floors and walls distribute radon throughout the house. This, in turn, draws in more radon from the ground by concentration-driven diffusion, until an equilibrium radon level is established on each floor in the house.

According to the Iowa Residential Radon - Lung Cancer Study (2000), the median first floor radon concentration in one-story homes is, on average, 60% of the basement level. But for two-story homes, the median radon levels at first and second floors are 51% and 62% of the basement level, respectively.

There is no Safe Radon Level!

Radon levels in U.S. homes

It is difficult for people to accept that their home, a place that one looks to for security, is hiding invisible danger. Yet, the average person receives a higher radiation dose from radon at home than from all other natural or man-made sources combined.

Outdoor radon levels in the U.S. range from 0.02 to 0.75 pCi/L (picoCuries per liter), averaging 0.4 pCi/L. But homes draw concentrated radon gas from the ground. Because radon is nine times heavier than air, elevated radon levels build up in basements and on lower floors. Although the U.S. Congress has set the natural radon concentration outdoors as the target level for homes, approximately two thirds of homes exceed it. A half of American homes have a radon level above 0.67 pCi/L (the median level). The average (mean) radon level in US homes is 1.25 pCi/L, or three times higher than the average level outdoors.

Nearly 8 million US homes, or 1 out of every 15, have radon levels above the EPA's 4 pCi/L "action" limit and nearly 1 out of 6 exceed the EPA's 2 pCi/L "consider action" limit. You should always try to reduce radon to a practical minimum - if you just settle for 4 pCi/L, your home will be more radioactive than 94% of US homes: 

What are "picoCuries"?

The concentration of radon gas is not measured directly but rather by the radioactivity it produces. It is expressed in picoCuries per liter of air, or "pCi/L". A Curie is a unit of radioactivity equivalent to 1 gram of radium and the prefix "pico" means a trillionth. In the metric system, radon concentration is expressed in Becquerels per cubic meter (Bq/m3). One Becquerel means one radioactive disintegration per second, and 4 pCi/L equals to 148 Bq/m3. In an average basement, 38 million atoms will undergo radioactive decay each hour.

How about all the other radiation around us?

Background radiation levels are a combination of terrestrial (radium, thorium, radon, etc.) and cosmic radiation (photons, muons, etc.) Natural radioactivity is common in the rocks and soil that make up our planet – over 60 radionuclides (radioactive elements) can be found in nature.

Sunshine is a radiation. The visible light is in the middle of its range of wavelengths. The long-wave radiation is infrared and it warms the skin. The shortest wavelength is ultraviolet radiation which causes skin cancer.

Beyond the ultraviolet radiation is a higher-frequency radiation emitted from nuclei of unstable radioactive atoms - ionizing radiation. It has enough power to knock out electrons from atoms and convert them to electrically charged ions, which can damage the large molecules of living cells. Ionizing radiation damages DNA and just one mutant cell can cause cancer. There are several types of ionizing radiation:

  • Alpha particles consist of two protons and two neutrons (like the nucleus of helium) and can pack a microscopic wallop when they collide with molecules. Because of their relatively large size, alpha particles collide readily with matter and therefore do not penetrate deep. Because they give up their energy over a relatively short distance, alpha particles can inflict more biological damage than any other radiation.
  • Beta particles are fast-moving electrons (or even the anti-matter positrons) ejected from the nuclei of atoms. Being much smaller than alpha particles, they can penetrate up to 1 to 2 centimeters of water or human flesh.
  • X-rays and gamma rays are pure energy transmitted in a wave without the movement of matter, just as light photons. But unlike light, they have great penetrating power and easily pass through the human body. Gamma rays emitted from nuclei are similar to x-rays but more energetic.

Radon decay chain offers a full menu of ionizing radiation: alpha and beta particles, and gamma rays. (Nuclear explosions emit one more radiation - neutrons.) Cosmic radiation consists of a variety of very energetic particles, including protons, muons, and neutrinos, which bombard the earth from outer space. Radioactivity is all around us and also within us.

However, two thirds of the total effective radiation dose to the average American from all natural sources comes from radon and its progeny. Radon in homes is more concentrated and far more dangerous than outdoors - the National Academy of Sciences estimates that the outdoor radon causes only 800 out of the total of 21,000 lung cancer deaths caused radon in the US each year.

Official limits on radon levels

Although radon in homes has been declared a national health problem, there are no federal or state standards. The Radon Act 51 passed by the US Congress set the natural outdoor level which averages 0.4 pCi/L as the target radon level for homes which unfortunately most homes (two thirds) exceed.

The Environment Protection Agency was given the task of developing practical guidelines. Considering the high cost of mitigation methods available to homeowners in 1980s (averaging $1,200 but up to $2,500), EPA issued its recommendations:

  • 4 pCi/L ... the "action" limit (fix your home)
  • 2 pCi/L ... the "consider action" limit (consider fixing your home)

EPA did not want to force homeowners to install costly radon mitigation systems, leaving the decision up to each homeowner. But at the same time, EPA has made it clear that the 4 pCi/L action limit is not a "safe" level and warned the public:

Any radon exposure has some risk of causing lung cancer. The lower the radon level in your home, the lower your family's risk of lung cancer.

Unlike radon levels in homes, occupational radon limits are governed by law and regulations. The Miners Safety and Health Act (MSHA) covers underground miners. Their annual exposure is limited to less than 4 WLM (Working Level Months), equivalent to 33 pCi/L during their working hours. The Occupational Safety and Health Act (OSHA) limits cumulative radon exposure in the workplace to 30 pCi/L based on 40 working hours per week. Assuming the highest radon level in modern mines, the average person receives in his home at 4 pCi/L over 12 years the same radiation dose as if he/she worked for 5 years in a uranium mine.

Action limit is not a safety limit!

"Action limit" does not imply safety. It is merely the result of a macroeconomic cost/benefit analysis for the US population at large. Shockingly, the cancer risk from radon at the "action" limit is about 1,000-times higher than the safety limits allowed for suspected carcinogens and toxins in food or drinking water.

The societal cost of mitigating all homes to a 4 pCi/L level was estimated at $44 billion but that would rise to $101 billion if the action level was set at 2 pCi/L. Most radon-attributed deaths (70%) are caused by radon levels lower than 4 pCi/L (BEIR VI, 1998). Setting the limit at 4 pCi/L benefits (but does not necessarily save) only 30% of the 21,000 people that die each year of radon-attributed lung cancer, while a lower limit of 2 pCi/L would benefit 50%. The high "action limit" reduces the number of lives saved.

And, the societal cost of lung cancer deaths caused by radon is relatively low because it kills so quickly, often within months. Its 5-year survival rate is only 10–14 percent and thus, it costs only several billion dollars per year. Spending money, for example, on an anti-smoking campaign saves more lives, even though it is unfair to non-smokers and children who may be exposed to radon gas. (Radon causes 26% of lung cancer deaths among non-smokers.)

The "action" limit is based on the average cost of a radon mitigation system in 1980s – $1,200. If the cost of radon mitigation was only $600, the action limit recommended to homeowners would have been set at 2 pCi/L.

How safe is the 4 pCi/L radon "action limit"?

People spend most of their time at home - on average 70%, but more in case of women and particularly, children. Although the 4 pCi/L level has become a benchmark for real estate transactions, it still carries considerable risks - equivalent to getting a chest x-ray or smoking 10 cigarettes each day. (EPA)

When relaxing at home, we breathe in radon. It is soluble in blood and circulates through the body and all organs. Some tends to accumulate in fatty issues. Then, almost all is harmlessly exhaled by our lungs or skin until equilibrium is established between the ambient and internal radon concentrations.

But radon decay products, radioactive solid particles, much smaller than household dust, float in the air and get trapped in our lungs, trachea, and bronchi. At 4 pCi/L each liter of air contains 70,000 radon atoms. But less than 1% of the inhaled atoms get trapped and we thus accumulate in our airways about 600,000 radioactive particles every hour. When they shoot out alpha particles, they damage the DNA of epithelial cells, causing mutations and lung cancer.

The risk to the average person of dying of radon-caused lung cancer due to a lifetime exposure to 4 pCi/L radon level at home is 2.3 percent. If there are five people in your family, the chances that someone becomes a victim of radon over 10 percent.

The most substantial epidemiological study ever on the link between residential radon and lung cancer was published the University of Iowa in 2000. This 5-year study proves that radon even at the low levels found in homes causes lung cancer and that the risk is proportional to the radon level. The study shows that the exposure of adult women to radon over 15 years at the EPA "action" level of 4 pCi/L increases the lung cancer risk by 50 percent.

NEW! Radon Systems Color-Matched to Your Home's Exterior!



Radon Remediation
/ Radon Mitigation:
  When a building (or house) is found to have an elevated level of radon gas (defined by the U.S. Environmental Protection Agency as a radon result of 4.0 pCi/l or higher,) methods of reducing the radon levels can be applied to cure the problem.  The most common method of radon mitigation (also known as radon remediation or radon gas abatement) is Active Soil Depressurization (ASD.) An ASD Radon Mitigation System utilizes PVC piping attached to an electric radon suction fan.  The piping typically begins below the lowest floor of the structure's foundation (penetrating the slab of the basement or the plastic membrane of the crawl space) and extends upward to an exit point above ground level.  The inline radon fan is mounted in an inconspicuous location on the exterior or within an attic above the home.  In cases where the radon fan is installed in the attic, the discharge pipe extends out through the roof so the radon gas can be released outdoors.  Once radon is released into the atmosphere, it is no longer hazardous.  Radon is only dangerous when trapped indoors.

Active (fan assisted) radon mitigation systems can reduce the radon gas entry by as much as 99%.  A qualified radon contractor (also known as a radon mitigator or radon remediation specialist) can typically install a radon mitigation system in a home in less than a day.  After the system is installed, the radon levels begin to drop almost immediately.  Passive radon reduction techniques (such as sealing cracks or installing pipes without an inline radon fan) are rarely effective at reducing radon levels.  The reason that these "passive" radon reduction techniques are ineffective is because radon gas is under pressure and must escape from the ground.  It is a very inert, un-reactive gas that can be drawn up through the pours of concrete, around drains, utility penetrations, or expansion joints.  Attempting to "seal out" radon is similar to trying to keep water out of a basement by painting the walls and floor with waterproofing paint.  It may work temporarily if the problem is minor, but it wouldn't keep standing water out.  The only way to fix a water problem is to redirect the water somewhere else before it enters the home.  The same principles apply to radon correction.  Sealing cracks and openings is part of the radon mitigation process; however this is to prevent the downward draw of conditioned air from the home and to improve the pressure field extension of the system below the slab, not to “seal out” the radon.

Radon is a colorless, odorless, naturally occurring, radioactive noble gas that is formed from the decay of radium. Radon gas is one of the heaviest substances that remains a gas under normal conditions and is considered to be a health hazard. The most stable isotope, Rn222 (Radon Gas), has a half-life of 3.8 days and is used in radiotherapy. While having been less studied by chemists due to its radioactivity, there are a few known compounds of this generally un-reactive element.

Radon is a significant contaminant that affects indoor air quality worldwide. Radon gas from natural sources can accumulate in buildings, especially in confined areas such as the basement. Radon can be found in some spring waters and hot springs.

According to the United States Environmental Protection Agency, radon is reportedly the second most frequent cause of lung cancer, after cigarette smoking; and radon-induced lung cancer the 6th leading cause of cancer death overall. According to the same sources, radon reportedly causes 21,000 lung cancer deaths per year in the United States.  Because of this, radon mitigation systems can be life-savers.

Indoor radon can be mitigated by sealing basement foundations, water drainage, or by sub-slab de-pressurization. In severe cases, radon mitigation can be achieved via air pipes and fans to exhaust sub-slab air to the outside. Indoor radon ventilation systems are less visible, but exterior radon systems can be more cost-effective in some cases. Modern construction that conserves energy by making homes air tight exacerbates the risks of radon exposure if radon is present in the home. Older homes with more porous construction are more likely to vent radon naturally. Ventilation systems can be combined with a heat exchanger to recover energy in the process of exchanging air with the outside.  (This is more common with commercial and industrial radon mitigation.)   Homes built on a crawl space can benefit from a radon collector installed under a radon barrier (a sheet of plastic that covers the crawl space).

The most common approaches are active soil depressurization (ASD) which utilizes a radon mitigation suction fan to pull the gas out from below the foundation of the home.  The radon fan is attached in-line with a PVC pipe system running from the foundation to the roof of the home.  Once the radon gas is discharged outdoors, it becomes diluted by the outdoor air to levels that are not hazardous.

 


 

How Radon Enters Your House

Radon is a naturally occurring radioactive gas produced by the breakdown of uranium in soil, rock, and water.  Air pressure inside your home is usually lower than pressure in the soil around your home's foundation. Because of this difference in pressure, your house acts like a vacuum, drawing radon in through foundation cracks and other openings. Radon Mitigation works by changing the pressure difference between the soil and the home.  Radon gas may also be present in well water and can be released into the air in your home when water is used for showering and other household uses. In most cases, radon entering the home through water is a small risk compared with radon entering your home from the soil. Systems are available to reduce radon entry from water sources.  In a small number of homes, the building materials (e.g., granite and certain concrete products) can give off radon, although building materials rarely cause radon problems by themselves.  In the United States, radon gas in soils is the principal source of elevated radon levels in homes.

Radon is a Cancer-causing, Radioactive Gas
Radon is estimated to cause many thousands of lung cancer deaths each year. In fact, the Surgeon General has warned that radon is the second leading cause of lung cancer in the United States.  Only smoking causes more lung cancer deaths. If you smoke and your home has high radon levels, your risk of lung cancer is especially high.  If your test shows a level of 2.7 pCi/l or above, consider installing a radon remediation system.

What Do Your Radon Test Results Mean?

Selecting a Radon Test Kit

Before you’ll know if you need a radon mitigation system, you need to conduct a test.  Since you cannot see or smell radon, special equipment is needed to detect it. When you're ready to test your home, contact your state radon office (or visit our radon testing page for information on locating qualified test kits or qualified radon testers. You can also order test kits and obtain information from a radon hotline. There are two types of radon testing devices. Passive radon testing devices do not need power to function. These include charcoal canisters, alpha-track detectors, charcoal liquid scintillation devices, and electret ion chamber detectors. Both short- and long-term passive radon devices are generally inexpensive. Active radon testing devices require power to function and usually provide hourly readings and an average result for the test period. These include continuous radon monitors and continuous working level monitors, and these tests may cost more. A state or local official can explain the differences between radon devices and recommend ones which are more appropriate for your needs and expected testing conditions. Make sure to use a radon testing device from a qualified laboratory.

Any radon exposure has some risk of causing lung cancer. The lower the radon level in your home, the lower your family's risk of lung cancer.  A radon mitigation system installed by a qualified (radon certified) contractor could save your life.  The amount of radon in the air is measured in "picocuries of radon per liter of air," or "pCi/L."  Sometimes test results are expressed in Working Levels, "WL," rather than picocuries per liter of air.  A level of 0.016 WL is usually equal to about 4 pCi/L in a typical home.  With this level, a radon abatement system would be recommended.

The U.S. Congress has set a long-term goal that indoor radon levels be no more than outdoor levels.  About 0.4 pCi/L of radon is normally found in the outside air.  EPA recommends fixing your home if the results one long-term test or the average of two short-term tests show radon levels of 4 pCi/L (or 0.016 WL) or higher.  With today's technology, radon levels in most homes can be reduced to 2 pCi/L or below.  You may also want to consider radon mitigation if the level is between 2 and 4 pCi/L.

A short-term radon test remains in your home for 2 days to 90 days, whereas a long-term test remains in your home for more than 90 days.  All radon tests should be taken for a minimum of 48 hours.  A short-term test will yield faster results, but a long-term test will give a better understanding of your home's year-round average radon level and indicate if a radon abatement or mitigation system is necessary.

The EPA recommends two categories of radon testing.  One category is for concerned homeowners or occupants whose house is not for sale; refer to EPA's A Citizen's Guide to Radon for testing guidance.  The second category is for radon testing and reduction in real estate transactions; refer to EPA's Home Buyer's and Seller's Guide to Radon, which provides guidance and answers to some common questions.

Why Hire a Radon Contractor?

EPA recommends that you have a qualified radon mitigation contractor fix your home because lowering high radon levels requires specific technical knowledge and special skills. Without the proper equipment or technical knowledge, you could actually increase your radon level or create other potential hazards and additional costs. However, if you decide to do the work yourself, get information on appropriate training courses and copies of EPA's technical guidance radon documents.

Will Any Radon Company Do?

EPA recommends that you use a state certified and/or qualified radon mitigation contractor trained to fix radon problems. You can determine a service provider's qualifications to perform radon measurements or to mitigate radon from your home in several ways.  First, check with your state radon office.  Many states require radon professionals to be licensed, certified, or registered, and to install radon mitigation systems or conduct radon testing.  Most states can provide you with a list of knowledgeable radon service providers doing business in the state.  In states that don't regulate radon services, ask the contractor if they hold a professional proficiency or certification credential, and if they follow industry consensus standards such as the American Society for Testing and Materials (ASTM) Standard Practice for Installing Radon Mitigation Systems in Existing Low-Rise Residential Buildings, E2121 (February 2003).  You can contact private proficiency programs for lists of privately-certified professionals in your area.  Such programs usually provide members with a photo-ID, which indicates their qualification(s) and the ID-card's expiration date.  For more information on private proficiency programs or contact your state radon office.

How To Select A Radon Mitigator

Get Estimates

Choose a radon contractor to fix the problem just as you would choose someone to do other home repairs. It is wise to get more than one estimate, to ask for references, and to contact some of those references to ask if they are satisfied with the radon mitigation company’s work. Also, ask your state radon office or your county/state consumer protection office for information about the radon companies.

 


Use this check-list when evaluating and comparing radon contractors and ask the following questions:

 

 

YES

NO

 

Will the contractor provide references or photographs, as well as test results of 'before' and 'after' radon levels of past radon reduction work?

Can the contractor explain what the work will involve, how long it will take to complete, and exactly how the radon mitigation system will work?

Does the contractor charge a fee for any diagnostic tests? Although many contractors give free estimates, they may charge for diagnostic tests.  These tests help determine what type of radon reduction system should be used and in some cases are necessary, especially if the contractor is unfamiliar with the type of house structure or the anticipated degree of difficulty.  See "Radon Reduction Techniques" for more on diagnostic tests.

Did the contractor inspect your home's structure before giving you an estimate for radon mitigation?

Did the contractor review the quality of your radon measurement results and determine if appropriate testing procedures were followed?

 

Compare the contractors' proposed costs for the radon system and consider what you will get for your money, taking into account: (1) a less expensive system may cost more to operate and maintain; (2) a less expensive system may have less aesthetic appeal; (3) a more expensive system may be best for your house; and, (4) the quality of the building material will affect how long the radon mitigation system lasts.

Does the radon contractor's proposal and estimate include:

 

 

YES

NO

 

Proof of state certification and/or professional proficiency or radon certification credentials?
 

Proof of liability insurance and being bonded, and having all necessary licenses to satisfy local radon remediation requirements?
 

Diagnostic testing prior to design and installation of a radon removal system?
 

Installation of a warning device to caution you if the radon mitigation system is not working correctly?
 

Testing after installation to make sure the radon reduction system works well?

A guarantee to reduce radon levels to 4 pCi/L or below, and if so, for how long?

 

The Radon Abatement Contract

Ask the contractor to prepare a contract before any radon remediation work starts. Carefully read the contract before you sign it. Make sure everything in the contract matches the original proposal. The contract should describe exactly what work will be done prior to and during the installation of the radon system, what the system consists of, and how the system will operate.  Many radon contractors provide a guarantee that they will adjust or modify the system to reach a negotiated radon level.  Carefully read the conditions of the contract describing the guarantee.  Carefully consider optional additions to your contract which may add to the initial cost of the radon removal system, but may be worth the extra expense. Typical options might include an extended warranty, a service plan, and/or improved aesthetics.

Important information that should appear in the radon abatement system contract includes:

 

The total cost of the job, including all taxes and permit fees; how much, if any, is required for a deposit; and when payment is due in full.

The time needed to complete the radon removal work.

An agreement by the contractor to obtain necessary permits and follow required building codes for radon mitigation.

A statement that the contractor carries liability insurance and is bonded and insured to protect you in case of injury to persons, or damage to property, while the radon work is done.

A guarantee that the contractor will be responsible for damage and clean-up after the job.

Details of any guarantee to reduce radon below a negotiated level.

Details of warranties or other optional features associated with the hardware components of the mitigation system.

A declaration stating whether any warranties or guarantees for the radon remediation work are transferable if you sell your home.

A description of what the contractor expects the homeowner to do (e.g., make the work area accessible) before work begins.

 

What to Look for in a Radon Reduction System

In selecting a radon reduction method for your home, you and your contractor should consider several things, including: how high your initial radon level is, the costs of installation and system operation, your house size and your foundation type.  An effective radon mitigation system can reduce your radon levels to less than 1 pCi/l.