Radon is a cancer causing radioactive gas. It is produced naturally by the breakdown of uranium in soil, rock and water. It has no taste or smell. It gets into homes and buildings from beneath their foundations and then travels upwards. Radon can enter the foundation through cracks or holes in concrete floors, walls, construction joints, sump pumps and loose-fitting pipes. If radon is present in well water it can be released into the air of a home when water is used for showering or other household uses.
Radon gas usually exists at very low levels outdoors. However, in areas without proper ventilation, such as underground mines, radon can accumulate to levels that substantially increase the risk of lung cancer. New Hampshire has some of the highest levels of radon in the country because of the bedrock geology.
Everyone breathes radon in the air every day, usually at very low levels. However, people who inhale high levels of radon are at an increased risk for developing lung cancer. Radon is the leading cause of lung cancer among nonsmokers and the second leading cause of lung cancer death. For smokers the risk of lung cancer is significant due to the synergistic effects of radon and smoking. Many New Hampshire residents are unaware of their increased risk of lung cancer due to elevated radon levels in their homes.
Long-term exposure to radon gas in the home leads to an estimated 100 lung cancer and related deaths in New Hampshire residents each year. Although testing for radon is inexpensive and can help prevent these lung cancer deaths many New Hampshire homes remain untested, and, as the Granite state, many are likely to have elevated radon levels. Risk of elevated radon varies by town and within a town. Of the approximately 25,000 New Hampshire homes that were tested through the State radon program, more than 30 percent exhibited radon concentrations that exceeded the action level of 4.0. (NH Dept of Health & Human Services - Environmental Health Tracking)
Testing is the only way to know if a home or building has elevated radon levels. The U.S. Environmental Protection Agency (EPA) recommends taking action to reduce radon in homes that have a radon level at or above 4 picocuries per liter (pCi/L). See EPA Find a Radon Test Kit.