Odorless, colorless, tasteless and deadly—radon gas is the second leading cause of lung cancer and the leading environmental cause of cancer mortality, according to the U.S. Environmental Protection Agency.
The EPA has declared January to be National Radon Awareness Month in response to a World Health Organization report, which estimated radon gas caused 15,000-21,000 deaths annually in the U.S.
The EPA estimate of 20,000 deaths annually attributed to radon means it caused more deaths in the U.S. last year than drunk driving, fires or carbon monoxide poisoning.
The lifetime risk of radon-related lung cancer in someone who has never smoked is seven in 1,000 if they live in a home with radon levels of four picoCuries per liter (pCi/L). That’s the threshold at which radon reaches unsafe levels, according to the EPA and the Wisconsin Department of Health Services (WDHS). For a smoker, that risk rate increases to six in 100.
Risk is proportional to the cumulative radon exposure through time. For one year of exposure, the risk would be about 1/75th as high.
The WDHS also estimates that 40-60 percent of homes in the 54631 Zip Code exceed safe levels of radon, 4 pCi/L. The 54631 Zip Code includes the villages of Gays Mills, Mt. Sterling and Bell Center, as well as portions of Clayton, Utica, Haney and Scott Townships.
“We know we have elevated radon levels because fractured limestone allows radon gas to come up from deep within the earth,” Crawford County Public Health Nurse Gloria Wall explained. “We are especially concerned about children and others who sleep in basements (where radon levels can be higher).”
A 2009 statewide survey of the results of 115,000 radon tests done in previous years by private companies and public health officials was compiled by the state health department. The results were separated by county and zip code. That survey indicates of the 38 test results in the 54631 Zip Code, nine were between 4 pCi/L and 10 pCi/L and 18 tests exceeded 10 pCi/L.
The state survey explained that most tests were taken in basements with the windows closed and estimated a proper reading for a first floor occupant might be 40 percent of the basement test results. Nevertheless, using such a computation would mean that all of the test results over 10 pCi/L would still be at what is considered the dangerous level of over 4 pCi/L on the first floor.
Despite these test results, one hears very little about deaths caused by radon in Crawford County communities. It seems that the risk, if significant, is also a silent contributor to the disease. New homes are built by state code with special basement venting to avoid radon infiltration.
“We haven’t heard stories (in Crawford County) about people developing lung cancer from exposure to elevated levels of radon gas,” Wall acknowledged. “The statistics don’t line up with our actual experience.”
Wall was quick to point out that as public health nurses, she, Judy Powell and the rest of the staff don’t deal that much with cancer. Diagnosing and treating cancer is more of something that medical doctors do, according to Wall.
Julie Steiner, the Communications Director for Vernon Memorial Healthcare asked practitioners at the hospital in Viroqua about their experiences with radon-related disease and death and came up empty handed.
“I e-mailed all the doctors and spoke to the practitioners most likely to deal with this and no one could come forward with anything,” Steiner said. “And, as we have done our community needs assessments, radon just has not come up.”
However, the Crawford County Health Department is taking the threat seriously. Both Wall and Powell acknowledged radon gas could be a hazardous substance in homes. They urged homeowners, who suspect they might have radon present, to take the free tests and determine the radon levels in the residence.
At this month’s immunization clinic in the new Gays Mills Community Commerce Center on Wednesday, Jan. 17 from 3 to 4 p.m., Crawford County Public Health nurses will provide information on radon testing in homes, along with free radon test kits. Everyone is encouraged to attend the clinic, which is scheduled to be held in the recently completed Community Commerce Center at 16381 State Highway 131.
The North American Pooling study (Krewski et al. 2005, 2006) used by the World Health Organization in determining radon risk in the U.S. and Canada involved 3,662 cases and 4,966 controls from seven studies. Its finding suggests that 10 to 14 percent of lung cancer cases or between 15,000-21,000 people annually in the U.S. may be attributed to living with long-term radon levels of 3.2 pCi/L or greater.
Over 158,000 people die in the United States of lung cancer each year. Unofficially, 14 Crawford County residents died of lung cancer last year and there were 206 deaths in total, according to Crawford County Coroner Joe Morovits.
In the last five years, a total 60 Crawford County residents have died of lung cancer. There were 981 deaths of county residents during the last five years.
Morovits said that less than half of lung cancer deaths were in non-smokers. Many of those were listed as “origin unknown.” However, many were suspected to be from an occupational exposure. A few were suspected to be from exposure to something the residents experienced while serving in the U.S. military.
While some of the cases of unknown origin may involve long-term exposure to radon, Morovits is unable to say that radon was the certain cause of any of those deaths. The coroner did note that there was no geographic concentration of lung cancer deaths, or lung cancer deaths of unknown origin, within the county.
The phenomenon of heightened radon contamination in homes was discovered by chance in 1985 after stringent radiation testing conducted at a nuclear power plant entrance revealed that Stanley Watras, an engineer entering the plant, was contaminated by radioactive substances.
Occurring naturally as the decay product of uranium or thorium, radon is often the single largest contributor to an individual’s background radiation dose. Radon levels vary widely from location to location.
Radon can accumulate in buildings, especially in confined areas such as attics and basements. As it decays, it produces new radioactive elements called radon daughters. Radon daughters are solids that stick to surfaces such as dust particles in the air. Inhaled, these particles can stick to the airways of the lung, emitting energy bursts as it completes the decay process, damaging lung tissue and increase the risk of developing lung cancer.
Depending on how houses are built and ventilated and the subsurface rock formations of the building site, radon may accumulate in a residence. It typically seeps into the indoor environment through cracks in solid floors, construction joints, cracks in walls, gaps in suspended floors, gaps around service pipes, cavities inside walls and the water supply.
Radon levels fluctuate naturally, due to factors like changing weather conditions, so an initial test might not be an accurate assessment of a home’s average radon level. Radon levels are at a maximum during the coolest part of the day, when pressure differentials are greatest.
The EPA designated January Radon Awareness month because the winter months with houses closed to the outside offers a better chance for accurate radon testing. It is particularly conducive to the long-term test, which is based on a three-month sample accumulation in the test kit.
Short-term (three-day) test kits are available free of charge from the Crawford County Health Department. They are also available at a reasonable cost from hardware and retail stores.
After obtaining a test kit, homeowners follow instructions to properly obtain a sample. When the sample is obtained, the kit is sealed and mailed to a lab for analysis. The homeowner is then contacted with the results.
What if the test is positive for dangerous levels of radon gas?
The good news is that radon remediation is relatively inexpensive. It generally costs less than $1,000, often just hundreds of dollars, and usually involves better ventilation.
One local resident in the 54631 Zip Code detected elevated radon levels in a basement that was going to be used as a bedroom, according to Crawford County Public Health Nurse Gloria Wall. The situation was remediated by the installation of an air exchanger in the basement.
The Environmental Protection Agency generally recommends methods that prevent the entry of radon. Soil suction, for example, prevents radon from entering your home by drawing the radon from below the home and venting it through a pipe, or pipes, to the air above the home where it is quickly diluted.
The four principal ways of reducing the amount of radon accumulating in a house are:
• sub-slab depressurization (soil suction) by increasing under-floor ventilation
• improving the ventilation of the house and avoiding the transport of radon from the basement into living rooms
• installing a radon sump system in the basement
• installing a positive pressurization or positive supply ventilation system
How likely are houses to have radon problems?
It varies by location, but some areas in Crawford County produced a high percentage of positive test results for significant levels of radon gas. In addition to 54631, other Zip Codes in the county that have reported elevated levels are 54624 (DeSoto), 54626 (Eastman), and 53826 (Wauzeka).
To illustrate what that means, compare Crawford County, a high-risk county for radon exposure, to Chippewa County, where radon levels are significantly lower.
In Crawford County, the mortality rate from lung cancer is approximately 9.7 in 1,000. In Chippewa County that rate is 5.6 per 1,000. However, smoking levels tend to be higher in Crawford County than the statewide average.
According to Jennifer Maloney, with the state health department, there is a great deal we still don’t know about radon.
“Scientists are studying this, but we still don’t understand all the mechanisms of how radon moves,” Maloney explained. “You can have two houses roughly identical, side-by-side, and one will test high for radon, the other won’t.”
So, while we know that proximity to granite or fractured limestone bedrock increases your chances for higher radon levels overall, soil types, moisture levels and a host of other geologic factors can alter radon emission from the soil. Like the Crawford County Public Health nurses, Maloney recommended that everyone test their homes for radon levels.
“It’s the only way to be sure,” Maloney noted. “There’s no way to guess if you have a (radon) problem or not.”
The World Health Organization’s International Radon Project findings upon which the estimated 20,000 deaths caused by radon-related lung cancer used case-controlled studies. The project identified a number of individuals with lung cancer, as well as a group of control individuals who had not developed the disease, but were representative of the population from which the cases of lung cancer were drawn. The study collected detailed information about smoking histories and other factors that determine a person’s risk of developing lung cancer.
In order to estimate the average radon concentration to which each individual in the study had been exposed over the previous decades, measurements of the radon concentration were made both in their present home and in other homes where they had lived.
Lung cancer is the deadliest type of cancer for both men and women. Each year, more people die of lung cancer than of breast, colon, and prostate cancers combined. Often found through x-ray or computed tomography (CT) scans performed for an unrelated reason, early lung cancer may not cause any symptoms. Symptoms vary, but may include: chest pain, a cough that does not go away, coughing up blood, losing weight without effort, loss of appetite, shortness of breath and wheezing.
The only recognized prevention of lung cancer is reducing exposure to carcinogens and pollutants.
