Granite countertops have been a popular choice for kitchens and bathrooms for decades thanks to their durability and style. However, some homeowners have concerns about the potential for radon emission from these natural stone surfaces.
The short answer is no, granite countertops do not generally emit enough radon gas to be a concern. But there are steps you can take to reduce your risk. In this comprehensive guide, we’ll explore the facts behind granite countertops and radon, helping you understand the risks and make informed decisions for your home.
What Is Radon and Why Is It Concerning?
Radon is a colorless, odorless, and tasteless radioactive gas that occurs naturally in the environment. It’s produced by the breakdown of uranium in soil, rock, and water. Radon becomes a health concern when it accumulates in enclosed spaces, such as homes, where it can be inhaled over long periods.
The primary health risk associated with radon exposure is an increased chance of developing lung cancer. According to the Environmental Protection Agency (EPA), radon is the second leading cause of lung cancer in the U.S., responsible for about 21,000 lung cancer deaths each year.
In the late 2000s, media reports began to highlight the potential radon risks of granite, suggesting that some granite countertops could emit dangerous levels of radon.
The reports cited instances where some granite countertops were found to emit radon at levels exceeding the EPA’s safety limit of 4 picocuries per liter of air. This sparked a debate within the scientific community and the stone industry about the actual risks posed by granite countertops.
Pro Tip: Bill Long, director of the EPA’s Center on Radon and Air Toxics, underscores the danger: “It’s a radioactive gas, and it causes lung cancer.” Long recommends “testing every couple of years, and after a major renovation,” noting that leaky ducts, kitchen vent hoods, and fireplaces—anything that decreases the air pressure inside a home—can draw more radon in.
What TOH Found: As This Old House Magazine reported in its investigation of the granite-radon scare, some granite countertops were indeed found to give off trace amounts of radon, with reporters citing a few kitchens with radon levels as high as 25 times the EPA’s safety limit. Granite is mined from the earth, where radium and naturally occurring radioactive materials are not uncommon—and certain regions have higher levels of radioactivity than others.
Scientific Research on Granite and Radon Emissions
Some studies have found that certain types of granite can give off low levels of radon. Research conducted by geologists and environmental scientists has shown that granite, a natural stone, can contain trace amounts of uranium and other radioactive elements. These elements can decay over time, potentially releasing radon gas.
However, it’s important to note that the amount of radon emitted by most granite countertops is typically very low and not considered a significant health risk compared to other sources of radon in homes.
The majority of scientific research suggests that granite countertops do not pose a significant radon risk in homes. A comprehensive study by the Marble Institute of America found that the average radon emissions from granite countertops were well below the EPA’s action level for indoor air.
“Very few granite countertops pose a real threat,” says Bill Brodhead, president of WPB Enterprises, a Pennsylvania radon mitigation company. The EPA also concluded that there isn’t enough evidence to suggest granite countertops are a significant source of radon after reviewing test data submitted by manufacturers.
Comparing Radon Levels: Granite vs. Other Sources
Comparing radon emissions from granite countertops to other sources can help put the risk in perspective.
Natural Ground Radon
The primary source of radon in most homes is the ground beneath the house. Radon naturally occurs in soil and rock and can seep into homes through cracks in foundations, floors, and walls. This ground-based radon is typically the most significant contributor to indoor radon levels.
Building Materials and Radon
While granite countertops have been a focus of concern, other building materials can also contribute to indoor radon levels. Concrete, brick, and gypsum board can contain small amounts of naturally occurring radioactive materials. However, like granite, these materials generally do not release radon in amounts that pose a significant health risk.
Factors Affecting Radon Emissions in Granite
The potential for radon emissions can vary depending on the type and origin of the granite. Granites from different quarries around the world have varying compositions of minerals and trace elements. Some types of granite may contain higher levels of uranium and other radioactive elements, potentially leading to higher radon emissions.
The size and thickness of a granite slab can influence its potential radon emissions. Larger and thicker slabs may have a greater volume of stone, which could theoretically contain more radioactive elements. However, the surface area exposed to the air also influences how much radon can be released into the environment.
Why Origin Matters: Granite is mined from the earth, where radium and naturally occurring radioactive materials are not uncommon. As TOH Magazine has reported, certain regions have higher levels of radioactivity than others, and scientists have worked for years to determine where they are. This means that two slabs of granite from different quarries — even if they look similar — can have very different radioactive profiles.
Testing for Radon in Your Home
Testing for radon is an essential step in protecting your health. Home radon testing kits are readily available and provide an affordable way to check radon levels in your home. These kits typically cost around $146, according to Angi, and can be found at hardware stores or online. They usually involve placing a small device in your home for a specified period and then sending it to a lab for analysis.
For more accurate and comprehensive results, homeowners can opt for professional radon testing, which costs about $715, per Angi. Certified radon measurement professionals use sophisticated equipment to provide detailed analysis of radon levels throughout the home. This option is recommended if initial DIY tests show elevated radon levels or if you’re buying or selling a home.
Pro Tip: As Ross, a radon specialist featured on Ask This Old House, explains: “The only way to test is actually to monitor. You can’t detect it with your nose. It’s invisible. It’s odorless.” This is why proactive testing is so important — radon can enter through the slab, foundation walls, water pipes, or a sump-pump basin without any visible or olfactory signs.
How TOH Tests for Radon: On a recent Ask This Old House project, homeowner Vincent used a continuous radon monitor over three months to track levels in his home. The data revealed a three-month average of 12.7 picocuries per liter — about three times the EPA’s recommended action level of 4 picocuries per liter. As radon specialist Ross explained on the project, continuous monitors like these let you “see what the radon levels are over time,” giving a much clearer picture than a single snapshot test.
According to TOH Magazine’s indoor air quality coverage, few home air-quality monitors actually track radon — most focus on CO2 as a general indicator. The magazine recommends that if an at-home radon test kit reveals high levels, “a dedicated mitigation system that vents the gas outside should be installed.” For homeowners considering professional testing, keep in mind that costs can vary significantly by region and home size.
Radon Mitigation Strategies for Homeowners
There are several effective strategies for reducing radon levels in homes.
One of the most effective ways to reduce radon levels in a home is to improve ventilation. This can involve installing ventilation systems that draw radon-tainted air from beneath the house and blow it outside. Proper ventilation not only helps with radon but can also improve indoor air quality.
Sealing Cracks and Gaps
Sealing cracks and gaps in your home’s foundation, walls, and floors can help prevent radon from leaking inside. This technique is often used in conjunction with other mitigation techniques, as sealing alone is not typically sufficient to significantly reduce radon levels.
Sub-Slab Depressurization
Sub-slab depressurization systems can be highly effective in reducing radon levels in homes. These systems use pipes and fans to draw radon from beneath the slab and vent it outside. This method is often recommended for homes with high radon levels and provides a long-term solution to radon mitigation.
Pro Tip: Ross, a certified radon mitigation specialist featured on This Old House, advises that the age of your home can significantly affect how easy or difficult a sub-slab system is to install: “With an older house like this, we probably have compacted dirt and soil underneath our slab. In a new house, we’d have a nice gravel base. So when we put that fan down in a new home, it’s usually pretty easy to create that suction throughout the entire concrete slab because you have a gravel base that allows all that radon gas to move.” For older homes, the team recommends using diagnostic pressure testing across multiple points to ensure adequate suction before finalizing the system design.
How It Works in Practice: During a TOH project, radon mitigation specialist Ross explained the process: “We’re gonna take a white PVC pipe, we’re gonna drill a hole in the slab, stick a pipe down through it. We’re then gonna bring that pipe up, bring it out through the side of the building, through the rim joist, and bring it up the side of the building. We’re gonna put a fan on it so that it’s active, meaning it’s operational. And that’s gonna create a suction underneath the slab.” Before installing the system, the team drilled 1-inch test holes in four corners of the basement and used theatrical fog to visually confirm airflow pathways beneath the slab — proving that negative pressure from a Shop-Vac at the main suction point could draw air from all four corners back to the extraction point.
Alternatives to Granite Countertops
Exploring alternatives to granite countertops can address concerns about radon emissions.
Quartz Countertops
Quartz countertops are a popular alternative to granite. They are engineered stone products made from ground quartz mixed with resins and pigments. Quartz countertops do not emit radon and offer a similar durability and look as granite.
Other Natural Stone Options
Other natural stone options such as marble, soapstone, and slate can be alternatives to granite. While these materials may contain trace amounts of radioactive elements, their potential for radon emissions is generally considered negligible.
Solid Surface Countertops
Solid-surface countertops, such as those made from acrylic or polyester resins, do not emit radon. They are also durable and come in a variety of colors and patterns, making them an attractive option for homeowners.
Why Quartz Stands Out: Engineered quartz countertops are made from a factory mix of roughly 93 percent quartz granules held together with a resin binder. As TOH has noted, the material is nonporous, stain resistant, unfazed by heat, and unaffected by everyday acids like coffee, citrus, and vinegar. It’s also hard as steel — drag a key across a quartz-based engineered countertop and a film of metal is left behind, not a scratch on the surface.
Our Conclusion
While concerns about radon emissions from granite countertops have been raised, scientific evidence suggests that the risk is minimal for most homeowners. The primary source of radon in homes is typically the ground beneath the structure, not countertops or other building materials.
If you’re concerned about radon in your home, the best course of action is to conduct a comprehensive radon test of your entire living space. This will give you a clear picture of your home’s radon levels and help you determine if any mitigation steps are necessary. Remember, maintaining good indoor air quality involves considering multiple factors, and granite countertops are just one small piece of the puzzle.
