About one in four houses in Pratt County has an undetectable killer lurking in the basement.

Radon is an odorless, tasteless and colorless gas. It is the leading cause of lung cancer among non-smokers. It is the No. 2 cause of lung cancer for smokers, said Brian Hanson, coordinator for the Kansas Radon Program through Kansas State University Extension.

Radon levels are measured in pico curries per liter of indoor air. The formula is listed as pCi/L. The lower the radon number the better. The Environmental Protection Agency recommends actively reducing radon levels that reach 4 pCi/L.

Pratt is one of 64 counties in Kansas that is in Zone One for radon levels. That means one out of every three or four houses in the county is at or above 4 pCi/L and action needs to be taken to lower the radon levels. The state average is 4.8 pCi/L.

In Kingman, Kiowa, Stafford and Barber Counties are in Zone Two with an average of two to four houses with levels above 4 pCi/L.

The safest state is Hawaii where only one in 200 houses test high for radon. The reason is Hawaiian soil is volcanic and its uranium retention is very low. Also, Hawaiian houses are open most of the year and radon disperses much faster.

Iowa has the highest level with seven out of 10 houses testing at high levels of radon. The soil retains uranium better than other states.

The first step to lower radon levels is to test the air. Kitts are available at the Pratt County Extension office for $5. The tests include all the necessary equipment and instructions.

The tests are very sensitive and have to be used immediately after they are opened. They must be mailed off immediately after use, Hanson said.

If excessive levels of radon are detected, the most common method of lowering the levels is active soil depressurization that can be applied to any foundation.

The system uses pvc pipe and a fan to create a little more vacuum than the house naturally pulls and that draws the radon out of the house through the exhaust pipe and to the open air.

Radon is a gas bi product of decaying uranium that is present in all soils worldwide.

"There's a little bit of uranium everywhere in the world," Hanson said.

The gas comes up from soil and moves upwards through houses starting in the basement where the concentration is the highest. The basement acts as a perfect bowl for where radon collects.

The radon moves upwards through the house following the natural radiant action of warm air raising though the house, through the ceiling to the upper floors and finally out through the roof, Hanson said.

As the air rises it creates a negative atmospheric pressure that draws fresh air into the house and helps pull radon up through the house.

Because of the rising action, the biggest concentration of radon is in the basement. The amount of radon depends on the amount of decay in the soil, the porosity of the soil that allows the gas to escape and the ventilation in the house, Hanson said.

Every house has a level that is unique to that individual house.

The impact of radon on the human body is based on the exposure from every house the person has lived in during their entire life.

As an inert gas, radon is odorless, colorless and tasteless so it is very hard to detect. Unfortunately, the lung cancer it causes is also one of the hardest cancers to detect, Hanson said.

Lung cancer usually occurs later in life and has the lowest five-year survivability rate of any cancer.

While radon and smoking are individually bad and cause lung cancer, combining the two makes the chances of getting lung cancer much greater.

The Kansas Department of Health and Environment estimates Kansas has 200 new cases of lung cancer every year from radon exposure according to 2009 statistics. On the average, about 21,000 people die every year in the U.S. from radon lung cancer.