Radon is a gas that can move from the ground into your home.

The U.S. Environmental Protection Agency estimates that radon causes about 21,000 lung cancer deaths in the United States each year.

According to the National Institute of Health radon exposure is the second leading cause of lung cancer after active smoking and the leading cause among non-smokers.

The colorless and odorless radioactive gas is released from the normal decay of uranium, thorium, and radium in rocks and soil.

Everyone breathes in radon every day, but usually at very low levels.

However, people who inhale high levels of radon are at an increased risk of developing lung cancer.

Radon levels can be higher in homes that are well insulated or tightly sealed.

About 1 in 15 U.S. homes is estimated to have radon levels at or above this EPA action level.

Basement and first floors typically have the highest radon levels because of their closeness to the ground.

It typically moves up through the ground and into the home through cracks in floors, walls and foundations as well as being released from building materials or from well water.

Usually, the air pressure in homes and buildings is lower than the pressure outside in the soil around or underneath the foundation.

The pressure difference creates suction and radon comes through cracks due to that suction.

According to the National Cancer Institute, testing is the only way to know if a person’s home has elevated radon levels.