Though some recent studies question whether even low levels of radon are a health threat to humans, most scientists think the radioactive gas – which is found in all buildings – is still a problem.
Major health organizations, such as the Centers for Disease Control and Prevention and the American Lung Association, agree that radon causes thousands of preventable lung cancer deaths every year.
What is radon? You cannot see, taste, or smell it. It is a product of the natural decay of uranium, a radioactive element used to make nuclear energy. Uranium is found in granite, shale, and phosphate-bearing rocks. Small amounts are found throughout the earth’s crust.
Unlike other products of decay, radon is a gas that can escape from water, the ground, or even building materials. It filters through cracks in the bedrock and soil. Moving up through the ground, it invades your home and other buildings through holes and cracks. Your house traps the radon inside and the gas builds up.
Radon seeps into buildings in several ways: cracks in floors and walls, construction joints, gaps in suspended floors, openings around pipes, and sometimes through well water. Some building materials such as concrete also may be a source of radon.
From Sea to Shining Sea
Since uranium is so widespread in the earth’s crust, so is radon. It can be found all over the United States in all types of buildings – homes, offices, and schools. Radon can be a problem in old or new homes, drafty or insulated homes, those with basements or no basements.
Because you spend the most time at home, your greatest exposure is there. Radon levels vary from one home to another, even in the same neighborhood. “Hot spots” occur in such places as the Midwest and Northern Plains. But high radon levels have been found in every state.
How High Is High?
The only way to know if your home has a radon problem is to test for it. Radon is measured in units called picocuries (pCi) or one-trillionth of a curie. The curie, the unit for measuring radioactivity, is named for Marie and Pierre Curie, French physicists who first experimented with radioactivity.
Test results are designated “picocuries per liter of air” or pCi/L.
The air outside is normally about 0.4 pCi/L. Different countries have developed their own standards of safety. The United States and Sweden are extremely cautious. U.S. policy urges homeowners to reduce radon exposure if levels are 4 pCi/L or greater. Canada accepts much higher levels of radon – 20 pCi/L.
In 1988, the U.S. Congress set a long-term goal of reducing radon levels in homes to no more than the outdoor level.
Radon: A Smoking Gun?
In the sixteenth century, a Swiss physician noted a terrible breathing illness among miners in Eastern Europe. The gas percolating out of the earth and collecting in underground mines caused “miners’ disease” or “mountain sickness.” Today we know this disease as lung cancer, which causes about 150,000 deaths in the United States each year.
Everyone breathes in radon all the time, so some of our lung cells are being damaged. Some small solid bits around the radon may lodge in the bronchi, a part of the respiratory system. Here they emit radioactive alpha particles that affect the cells lining the bronchi. These particles may damage the DNA in the cell nuclei. But cells generally repair themselves unless the radiation is excessive. If cells are damaged by radiation or other irritants, they may form a cancerous tumor.
Houses with smokers are smoking guns for radon. Smoking combined with accumulated radon is an especially serious health risk.
Public health officials estimate that 10 percent of lung cancer cases may be caused by radon.
What Can Be Done?
Picture this: a young family, including their pet kitten, with lips sealed, cheeks ballooned out, holding their breath. The front cover of an Environmental Protection Agency (EPA) booklet reads, “There are two ways to protect your family from radon. First, the hard way. Holding your breath.”
The EPA estimates 6 percent of U.S. homes have high radon levels and recommends three steps to attack the problem:
1. Test your house. If the result is 4 pCi/L or higher, go to step 2.
2. Follow up with another short-term test or a long-term test. With high readings go to step 3.
3. At 4 pCi/L or higher, consider fixing your home.
Lowering radon levels requires knowledge and special skills. A contractor must take special training and pass a test. A list of qualified contractors is available from the EPA office in your state capital.
Fixing the radon level in the building usually involves sealing cracks that are entry points and then sucking the high radon gas into the outdoor air through a vacuum pump. Most homes can be fixed for about the same cost as other home repairs.
Only by testing can you be sure your home does not have too much radon.
It Only Takes a Minute
Testing for radon is easy, inexpensive, and only takes a minute, says the EPA. About 700 companies in the United States make the devices.
Kits are available through the mail and at hardware or other retail stores. Look for “Meets EPA Requirements” to be sure the test is reliable, and carefully follow all directions.
The kit should be placed at the lowest lived-in level and in a room that is used regularly such as a living room, playroom, den, or bedroom – not in a kitchen or bathroom. Once you have finished the test, reseal the package and send it to the lab designated in the kit. It takes about two weeks to get the results.
You may call your regional EPA office, state radon office, or 1-800-SOS-RADON for more information. They can advise you about different types of testing devices.