Granite Countertops and Radon: Separating the Myths from the Evidence
Most granite countertops add little or no measurable radon to a home. Granite can contain small amounts of uranium, and some slabs do release radon, but the EPA says radon from the soil beneath a house is a far more common problem and a much larger health risk than radon from granite building materials. A handful of unusual stones have produced higher readings in lab and in-home tests, so “zero” isn’t quite accurate either. This article walks through the most common myths, what the research actually measured, how to test properly and what to do if your result comes back high.
Where the granite radon concern came from
Questions about radioactive countertops have surfaced periodically since the 1990s, but they peaked in 2008. News reports that year described homeowners who found high radiation readings near their kitchen counters, and a few people tore out their granite. Researchers at the New York State Department of Health and Rice University began measuring stones, and the stone industry funded its own studies in response.
The debate got heated partly because money was involved on every side. Some early alarm came from groups tied to competing countertop materials, while the largest reassuring study was paid for by a stone industry trade group. That history is a good reason to lean on the EPA and independent scientific organizations, which have stayed consistent since then.
What the EPA says about granite and radon
The EPA’s position has three parts. Some granite used for countertops may contribute to indoor radon in varying amounts. The agency also says the existing data aren’t enough to conclude that the types of granite commonly used in countertops are significantly raising indoor radon levels. And it recommends testing every home for radon whether or not it has granite countertops.
The EPA also notes there are too many variables to generalize about the risk in any one particular home, and that there are currently no federal regulations covering radon or radiation from countertops. In other words, the agency isn’t saying granite is a zero-radon material. It’s saying the counter is very unlikely to be what decides your home’s radon level.
Common myths about granite countertops and radon
Myth: Granite countertops are a major source of radon in homes
Radon forms when uranium in soil and rock breaks down, and it usually enters a house as soil gas pulled through cracks, gaps around pipes, sump openings and other openings in the foundation. The ground under a home is a huge source compared with a few square feet of polished stone. That’s why the American Association of Radon Scientists and Technologists (AARST) identifies the soil, sand and rock beneath a building as the primary source of indoor radon. If your home has elevated radon, the soil is almost always the reason. Our guide to what radon is explains how it gets inside.
Myth: Granite never releases any radon
This overcorrects in the other direction. A study presented by Michael Kitto of the New York State Department of Health found that most of the countertop samples he tested released a measurable amount of radon. The estimated contribution to room air ranged from under 0.1 to about 2.3 pCi/L, depending on the stone. (pCi/L, or picocuries per liter, is the unit used to measure radon in the U.S.) Preliminary results from Rice University physicist W.J. Llope, reported in 2008, found that 92 of 95 granite varieties released little or no radon, while three produced estimates between roughly 3 and 4.2 pCi/L under his test assumptions.
Those estimates came from modeling and enclosed-sample measurements. They don’t show what the same slab produces in a ventilated kitchen. They do show that granite varies a lot from stone to stone, and even across a single slab.
Myth: Industry studies proved every granite countertop is harmless
The largest single study, conducted by Environmental Health & Engineering and funded by the Marble Institute of America, ran more than 400 tests on 115 varieties of granite. It reported that no slab reached EPA’s 4 pCi/L action level in predicted indoor radon, and the highest-emitting slab was estimated to add just over 0.2 pCi/L. Average outdoor air is about 0.4 pCi/L.
The findings line up with the EPA’s general view and with most independent work. Still, the study was industry-funded, and it focused on the stones that make up most U.S. sales. It reported that the more variable stones made up a small share of the market. That supports a conclusion about typical granite. It doesn’t prove every slab in every home is a negligible source.
Myth: A Geiger counter on the counter tells you your radon risk
A Geiger counter or other handheld radiation meter detects gamma radiation coming off the stone’s surface. It doesn’t measure radon gas in the air you breathe, and radon is the health concern that matters most here. AARST’s position statement says measuring the surface of granite isn’t a reliable indicator of the radon concentration in your home, partly because emission rates vary widely across a slab. A Health Physics Society expert made a similar point, noting that gamma readings from granite don’t give homeowners useful information about health hazards, while an air test does.
The EPA describes it as extremely unlikely that gamma radiation from granite countertops would raise annual radiation doses above normal natural background levels.
Myth: If radon is high, the granite has to go
Ripping out a countertop is expensive, and it rarely addresses the real source. The EPA says that when elevated levels are found, installing a system that removes radon from the home’s air is likely a more effective step than removing granite. AARST states that no action is needed to remove granite countertops in existing homes, and that even if a counter were a concern, reducing radon throughout the home would be the more effective and cost-effective approach.
Myth: Choosing quartz or laminate means you don’t need a radon test
Engineered quartz, laminate, solid surface and butcher block countertops have received less scrutiny, and the limited testing suggests engineered quartz releases very little radon. That has nothing to do with the radon coming up from the ground. A home with no stone in it at all can still test well above 4 pCi/L. Countertop choice is a design decision, not a radon strategy.
Myth: A sealer will stop radon from your countertop
Countertop sealers are designed to resist stains and moisture. Some products have been marketed with claims about reducing radiation or radon, but we’re not aware of independent research showing that a standard countertop sealer meaningfully lowers radon in a home. Since the counter is rarely the main source anyway, a sealer isn’t a substitute for testing.
How to test a home with granite countertops
Test the same way you would in any home. The EPA recommends placing the test in the lowest level of the home that’s used or could be used as living space. EPA testing guidance also says to avoid kitchens, bathrooms, laundry rooms and hallways, because humidity and drafts can bias some test devices. For many homes, the kitchen isn’t the right spot for a standard radon test.
Keep windows and exterior doors closed, except for normal entry and exit, for at least 12 hours before and during a short-term test. Place the device about 20 inches or more off the floor, away from drafts, heat sources and exterior walls. Our article on where to place a radon test kit covers placement in more detail, and our radon test kit comparison explains the difference between short-term kits, long-term kits and continuous monitors.
If you’re curious about the countertop itself
Some homeowners want to know whether the counter is contributing anything. One informal approach is to run a second test on the same floor as the kitchen, in a nearby living area rather than right on the counter, at the same time as your standard test in the lowest lived-in level. If the upstairs result is consistently higher than the lower level, that’s unusual and worth discussing with a certified radon measurement professional. This kind of comparison can’t isolate the counter with certainty, though. Radon levels shift from day to day and room to room, and the standard test is still what should guide decisions about mitigation.
What your result means
The EPA recommends fixing a home when radon is at or above 4 pCi/L and suggests considering action between 2 and 4 pCi/L. No radon level is considered completely risk-free, and a single short-term result is a snapshot. A follow-up short-term test or a long-term test can confirm a result near the line. Our explainer on what 4.0 pCi/L actually means covers how to read a borderline number.
If you want context before you test, you can look at radon readings other homeowners have reported near you. Local results can show whether elevated radon is common in your area, but your own home can still test very differently from the house next door.
If your home tests high
For most homes with confirmed elevated radon, the standard fix is active soil depressurization. A vent pipe and fan draw radon from beneath the foundation and release it above the roofline before it can enter the living space. Sealing cracks helps the system work better, but sealing alone is usually not a dependable fix for significantly elevated radon. A post-mitigation test confirms whether the system brought levels down.
Because this approach lowers radon throughout the home, it also takes care of whatever small amount a countertop might add. Our guide to hiring a certified radon mitigator and our radon contractor checklist list the questions to ask before you sign a contract. If your result is at or above 4 pCi/L, you can connect with a certified radon mitigation professional in your area.
Frequently asked questions
Are some colors or types of granite more likely to release radon?
Researchers have found that radon release varies widely by stone, and a few less common varieties have tested higher than typical granite. Color alone isn’t a reliable guide, though, and the stone sold under a trade name can vary from quarry to quarry. No consumer test of a slab’s appearance can tell you what it will contribute to your home’s air. An air test in the home is the practical answer.
Should I worry about granite in a new home I’m buying?
The countertops shouldn’t be a deciding factor. A radon test during the inspection period is the useful step, and it should follow standard placement guidance in the lowest lived-in level. If the result is elevated, mitigation is a common negotiation point in a sale. Our article on radon and real estate transactions explains how testing usually fits into a purchase.
Is it safe to have granite fabricated or cut in my home?
Cutting and polishing stone creates dust, and crystalline silica in that dust is a recognized occupational hazard for fabricators. That’s a separate issue from radon. Most cutting happens in a shop, and installers typically do only limited on-site work. If on-site cutting is planned, ask the installer how they control dust.
Do granite floors or fireplace surrounds raise radon more than counters?
Larger areas of stone mean more surface that could release radon, so a home with extensive granite may contribute somewhat more than a single counter. The same principles apply. Soil gas usually dominates, and the way to know your level is to test the air.
Putting granite and radon in perspective
Granite countertops can release some radon, and a few stones release more than others. The evidence from the EPA, AARST and most published measurements points the same way, though: for nearly every home, the counter isn’t what determines radon exposure. The ground under the house is. Testing the air in the lowest lived-in level gives you the information that matters, and if that number is high, a mitigation system handles radon from every source at once.
Sources and further reading
- U.S. Environmental Protection Agency, Granite Countertops and Radiation (soil as the larger source, gamma radiation, testing and mitigation advice).
- U.S. Environmental Protection Agency, What about radon and radioactivity in granite countertops? (insufficient data on commonly used granite, no regulations, test all homes).
- U.S. Environmental Protection Agency, A Citizen’s Guide to Radon (action levels, test placement, no known safe level).
- American Association of Radon Scientists and Technologists, Science and Technical Committee, Position Statement: Granite Countertops and Radon Gas (2008).
- Health Physics Society, Ask the Experts: Determining health hazards from granite countertops.
- Health Physics Society, Ask the Experts: Radiation from quartz countertops.
- Kitto, M.E., New York State Department of Health, Emanation from Granite Countertops (AARST International Radon Symposium proceedings).
- Llope, W.J., “Activity concentrations and dose rates from decorative granite countertops,” Journal of Environmental Radioactivity 102(6), 2011, doi:10.1016/j.jenvrad.2011.03.012.
- Environmental Health & Engineering, Assessing Exposure to Radon and Radiation from Granite Countertops (2008), funded by the Marble Institute of America, as summarized by Stone Business.
This article is for general educational purposes and is not medical advice. Long-term radon exposure causes lung cancer, but individual risk depends on the radon level, the length of exposure and smoking history. Reducing elevated radon lowers future exposure; it does not reverse exposure already received. For help with your home, consult a certified radon measurement or mitigation professional.
