Granite countertops and radon

Do Granite Countertops Emit Radon? (And Other Radon FAQs)

People love their granite countertops, though some now consider them too commonplace and prefer newer choices like quartz or quartzite. But there’s another reason some segue from granite. They worry that it will emit radon, a colorless, odorless radioactive gas that comes from the natural breakdown of rocks and natural stones.

So, are granite countertops a real risk? Since January is Radon Action Month, this is a good time to learn all you can about potential risks of radon in granite, and elsewhere in your home.

Here are some frequently asked questions about radon, with answers from the Environmental Protection Agency (EPA), and experts Brian Hanson, a specialist with the National Radon Program Services at Kansas State University, and Robert Emery, DrPH, vice president of safety, health, environment, and risk management at the University of Texas, Health Science Center.

What’s the key risk of radon?

It’s the leading cause of lung cancer deaths among nonsmokers in this country, claiming the lives of about 21,000 Americans a year; and, overall, it’s the second leading cause of lung cancer, the EPA says.

Why is radon a possibility with granite?

Like all rocks, granite may contain naturally occurring radioactive elements like radium, uranium and thorium. Some pieces of granite contain more of these elements than others. These radioactive elements are solids, but, over time, they decay into radon, a colorless, odorless, radioactive gas, the EPA says.

Are the levels of radon in granite countertops harmful?

Because granite isn’t very porous (compared to other porous stones like sandstone) and because large quantities of it aren’t typically used in most single-family homes, the radon isn’t likely to escape in a significant enough quantity to cause problems, says Hanson. Moreover, kitchens and bathrooms and other rooms that might contain granite are usually well ventilated, which lessens risks, he says.

Emery concurs, saying, “From published scientific literature, it seems that the amount of radon from granite countertops is miniscule. The decision whether to use it or rip it out if it’s already in a house you buy really becomes a personal decision about what products you bring into your home—similar to whether to use traditional paints or those with only no or low-VOC compounds.”

A greater risk is radon originating in soil beneath a home’s foundation and radon in well water, says Hanson.

Ok, so the risk from granite is ‘minuscule.’ But how common is radon in U.S. homes overall?

The EPA says that approximately one of every 15 homes throughout the country, whether new or old, has elevated radon levels. Radon that originates in the soil is the main cause of radon problems, the EPA says; the gas moves up from the ground and into your home through cracks and other holes and gaps in the foundation.

What is a safe versus unsafe radon level?

All houses have some level of radon. The U.S. average for indoor radon levels is 1.3 picocuries per liter (pCi/L), the EPA says. The agency recommends all homes that test at or above 4 pCi/L be mitigated to lower levels. Testing is the only way to know what level of radon your home has.

What does a radon test involve?

The test is simple when it involves measuring your home’s air. You may purchase a do-it-yourself kit by contacting your state’s radon program, buying one at a home center for about $25 (sometimes less), or through the National Radon Program Services at Kansas State University,

Testing your granite countertops for radon is typically more expensive, requiring more sophisticated equipment and the expertise of a qualified radon mitigation expert, who still may not be able to indicate the percentage of indoor radon attributable to granite. You can find a professional by accessing the American Association of Radon Scientists and Technologists’ website; testing costs between $100 and $300.

Besides concern for your family’s health, you may want to know your radon levels if you plan to sell, since most buyers want proof of low levels or will request a test.

If a home contains a high level of radon, how hard is it to fix?

The cost to mitigate soil may run $1,500, though treating well water is higher — about $2,000 or so, says Hanson. The EPA has suggestions on how to find contractors to fix your home.

If you build a home, what safeguards should you take?

Be sure a builder uses radon-resistant new construction, which involves sealing openings, cracks, and crevices in a concrete foundation and walls to prevent radon and other soil gases from entering, and installing a vent pipe from the gravel layer through the home and roof to vent away gases. If the house uses well water, filter systems can be installed, says Emery. Do not rely on geology maps indicating radon zones, which may be outdated; get a test, he says.

Advice from the EPA is much the same: Radon zone maps shouldn’t be used to determine whether a home should be tested; homes with elevated radon levels can be found throughout the country, the agency says. All homes should be tested, period.

What if you still have a problem?

The EPA offers a list of information sources. There’s also the Radon Hotline, 800-SOS-Radon (767-7236) run by Kansas State University.

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