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One local family learned that radon levels can be quite high, yet leave no signs. After watching a news program about a woman who developed lung cancer due to radon exposure the local family, who lives in the Heatherwood Addition east of Paynesville, tested their own home. They discovered a radon concentration more than three times the highest acceptable level in their basement.

At least one neighbor had levels more than four times the acceptable level. Another home between St. Martin and Albany also tested extremely high.

Finding high levels of radon in the Paynesville area doesn't surprise Kathy Norlein, a research scientist for the Minnesota Department of Health. But homeowners shouldn't panic just because a neighbor's home tested high for radon, she added. Because radon levels depend on a variety of factors - how the home is sealed, the depth of the basement or crawl space, the home's ventilation system, and the type of soil under each home - radon levels may be less than at a neighbor's house.

Methods for lowering high radon levels - a leading cause of lung caner - include: (A) putting a layer of gravel under a new house to allow radon to move away; (B) putting plastic over bare soil to block vapors; (C) sealing and caulking all cracks and pores in the concrete; (D) installing a vent pipe to allow radon to escape; (E) providing electrical service for a fan to pull radon out of the home.

Radon is a naturally occurring gas, the result of decaying minerals - including uranium and radium - in the soil. Because central Minnesota is rich in these minerals, homes in Stearns, Meeker, and Kandiyohi counties are at a particularly high risk of developing high radon levels, said Norlein. In fact, the rates of radon concentration in central and southern Minnesota are among the highest in the country, according the the U.S. Environmental Protection Agency. In addition to having more naturally occurring radon, central Minnesota homes are prone to high levels because they tend to be sealed tight during the winter months, according to Norlein.

Radon can seep into homes through unsealed sump pumps, floor to wall joints, exposed soil, loose fitting pipe penetrations, unsealed tops of block walls, or cracks and pores in unsealed basements or slabs. Because radon is heavier than air, it tends to accumulate under a home and in the home's lowest levels. Forced air heating or air conditioning systems create a vacuum that can pull radon out of the ground and circulate it throughout the home.

Radon exposure is the second highest cause of lung cancer, with as much as 12 percent of all lung cancer cases in the United States caused by long-term radon exposure, according to the Environmental Protection Agency. One study estimated that radon caused 21,000 lung cancer deaths each year. For non-smokers, radon is the number one cause of lung cancer.

According to the Minnesota Department of Health, a person who never smoked exposed to 4pCi/L of radon over an extended period (20 years) had a seven out of 1,000 chance of developing lung cancer. At 10pCi/L the chance of developing lung cancer rose to 18 out of 1,000, and at 20pCi/L the risk rose to 36 out of 1,000. The risk for smokers exposed to radon was significantly higher.

Radon levels in the Heatherwood homes were 10.4pCi/L and 12.6pCi/L. The home near St. Martin tested at more than 16pCi/L. The Minnesota Department of Health estimated that one out of three homes in the state has enough radon to pose a health risk over time. Everyone should test their homes for radon, said Norlein. The good news is that radon contamination is easy to detect and easy to eliminate, she added.

Radon tests are done either short- or long-term. The short-term test involves leaving a test kit in the lowest occupied part of the home,where levels tend to be highest because radon is heavier than air, said Norlein. Basements are the primary entrance point for radon, and levels tend to be higher in basements than in upper levels because upper levels also tend to contain more fresh air to dilute the radon, said Norlein. Homeowners who use their basements as bedrooms or family rooms need to be especially diligent about testing.

A radon test is left in place for three days, then sent to a laboratory for analysis, which is usually done within a couple of weeks.

If the short test indicates high radon levels - more than 4pCi/L - then a long-term test is warranted. Long-term tests can be purchased as a home kit or can be done by a radon professional.

A long-term test is usually done for 90 days to a year, ideally through a warm and a cool season, said Norlein. The long-term test is a truer indicator of actual radon exposure levels, which can be higher in the winter and lower during warmer months when the home may not be closed.

Homeowners with a concentration of more than 4pCi/L on the long-term test should consider making changes to their homes to lower the levels.

Test kits are available in hardware stores and through the Minnesota Department of Health, which has a limited number of low-cost short-term tests for $5 including laboratory analysis. These tests can be ordered online through a link at www.health.state.mn.us.The Department of Health's website also offers information on how to fix a radon problem and a list of radon professionals statewide.

Kits purchased elsewhere range in price and may not include the price of laboratory analysis, so consumers should be careful when purchasing kits, said Norlein.

Homes need to be retested if any major changes are made to the home or how it is used, including finishing a basement, changing heating or air conditioning, or building an addition, according to Norlein.

Reducing or eliminating radon levels can be as simple as sealing the concrete in basements, slabs, and crawl spaces, or installing a vapor barrier to any bare dirt under a home. Fixing a radon problem could also include installing a ventilation system to pull radon out of the ground around the home.

Most area homes are already well-sealed, but little attention is usually paid to sump pumps, which are a common area for radon to enter a home, said Norlein. In many cases, sealing the sump hole and installing a vent pipe with a fan in the tiled drainage area around the home can allow radon to return to safe levels.

Homebuilders should consider installing a ventilation system in all new homes, said Norlien. According to the Department of Health, to include a radon ventilation system in new construction only cost a few hundred dollars, where adding a system later could cost several thousand dollars.