Radon scam or real risk?

Radon debunked? What the miner and home studies found

WHO says an increased rate of lung cancer was first seen in uranium miners exposed to very high concentrations of radon, and that studies in Europe, North America and China have since confirmed that even low concentrations, such as those commonly found in homes, also pose health risks. Early in the debate, EPA notes, some researchers questioned whether studies of miners could be used to calculate risk in homes. Two 2005 studies, one North American and one European, each combining data from earlier residential studies, then confirmed the risks the miner studies had predicted.

EPA describes the National Academy of Sciences' BEIR VI report as the most definitive accumulation of scientific data on indoor radon, and says it confirms radon is the second leading cause of lung cancer in the U.S. and a serious public health problem. EPA's Citizen's Guide adds that we know more about radon risks than about risks from most other cancer-causing substances, because the estimates are based on studies of cancer in humans.

Radon gas hoax arguments, and where they go wrong

• "Nobody gets sick from it." True in the short term, and beside the point: EPA says the time between exposure and lung cancer may be many years.
• "It only mattered for miners." The residential studies EPA and WHO describe found risk at the levels found in homes.
• "The numbers are disputed." EPA says some scientists dispute the precise number of deaths, but all major health organizations agree radon causes thousands of preventable lung cancer deaths every year.
• "My area doesn't have it." EPA says high radon levels have been found in every state.

There is a real radon controversy, but it is narrower than the word hoax suggests. It is about how big the risk is and where to draw lines, not about whether the risk exists.

Neither line is a safety threshold. EPA says any radon exposure carries some risk, and that even levels below 4 pCi/L pose some risk; WHO assumes the dose-response relation is linear, so lung cancer risk rises in proportion to exposure. The difference between the two lines is a policy choice about where to recommend action, and the radon limits guide compares them.

Radon overblown? Putting the risk in proportion

Proportion matters in both directions. Most homes are not high: EPA estimates the average indoor level at about 1.3 pCi/L and nearly 1 in 15 U.S. homes above its action level. EPA also says not everyone exposed to elevated levels will develop lung cancer. But the risk at higher levels is real, and EPA's Citizen's Guide puts it in terms of 1,000 people exposed over a lifetime.

For people who smoke, EPA's figures are far higher: about 62 in 1,000 at 4 pCi/L. The honest summary is that radon is neither a crisis in every home nor nothing: it is a measurable, fixable risk that varies from house to house.

EPA's Home Buyer's and Seller's Guide answers the common radon myths directly. These are the ones about testing and fixing.

The granite radon myth

Granite gets outsized attention. EPA's Consumer's Guide says that in a small number of homes, building materials such as granite and certain concrete products can give off radon, but that building materials rarely cause radon problems by themselves. EPA names soil gas as the principal source of elevated radon levels in U.S. homes.

Testing is the only way to know the radon level in a specific building. A result is only as good as the test that produced it, and EPA's guidance makes a valid test straightforward to check, whether you run it yourself or hire someone. The radon testing guide covers devices in detail.

1. 1

   Use a qualified device or tester

   EPA says to use a radon measurement device from a qualified laboratory, or to hire a qualified individual. Some states issue photo ID cards; ask to see one.

2. 2

   Run it long enough

   EPA says all radon tests should be taken for a minimum of 48 hours, and some devices require longer.

3. 3

   Keep closed-house conditions

   For a short test of 2 to 4 days, windows and doors stay closed at least 12 hours before the test and throughout it, except for normal entry and exit.

4. 4

   Test the right place

   The lowest level of the home that is, or could be, used regularly.

5. 5

   Confirm before you spend

   EPA recommends a follow-up test before deciding on a fix, and a test after any fix to confirm it worked.

Closed-house conditions

EPA's Home Buyer's and Seller's Guide defines them as keeping all windows closed, keeping doors closed except for normal entry and exit, and not operating fans or other machines which bring in air from outside.

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Test	How long it runs	What it is for
Short-term test	Stays in the home from 2 to 90 days, depending on the device, and for a minimum of 48 hours.	A faster screening result. Because radon levels vary from day to day and season to season, it is less likely than a long-term test to tell you the year-round average.
Long-term test	Stays in the home for more than 90 days.	It is more likely than a short-term test to tell you the home's year-round average radon level.
Continuous monitor	Logs readings for the whole test, run as a short-term or a long-term test under the same durations in EPA guidance.	Logs a graph over time, so you can see trends and spot anomalies rather than a single number.

EPA's Consumer's Guide says to choose a radon contractor as you would anyone doing home repairs: get more than one estimate, ask for references and contact some of them. Credentials are checkable. EPA currently recognizes two national proficiency programs, the National Radon Proficiency Program (NRPP) and the National Radon Safety Board (NRSB), and many states license, certify or register radon professionals.

• Will the contractor provide references, and before and after test results from past work?
• Did the contractor inspect your home's structure before giving an estimate?
• Did the contractor review your radon measurement and whether proper testing procedures were followed?
• Does the proposal include proof of certification, liability insurance, a warning device, and testing after installation?

EPA recommends that the retest after a fix be conducted by an independent, qualified radon tester. Find credentialed measurement and mitigation providers in the radon professionals directory; in a credentialing state such as Pennsylvania, check the provider against the state's own list as well.

Not every radon treatment works equally well, and this is the real substance behind the radon treatment controversy. EPA's Consumer's Guide publishes typical reductions for each technique:

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1. 1Soil gas drawn from beneath the slab
2. 2Suction point through the slab
3. 3Vent pipe
4. 4Fan, outside the living space
5. 5Discharge above the roofline

Two findings stand out. EPA does not recommend sealing alone, because by itself sealing has not been shown to lower radon levels significantly or consistently. And opening windows is temporary: EPA says once windows, doors and vents are closed, radon concentrations most often return to previous values within about 12 hours. The radon mitigation guide explains the systems.

Soil suction

EPA's name for the radon reduction systems that draw radon from below a home through a pipe and vent it to the air above the home, where it is quickly diluted. Subslab, drain-tile, sump-hole, block-wall and submembrane suction are all forms of it.

Radon in water: where claims can mislead

EPA says to test the air first, because radon from soil is usually a much larger risk than radon from water. For a private well with a confirmed problem, EPA explains that point-of-entry treatment can remove radon before water enters the home, while point-of-use devices treat only a small portion of the water and are not effective in reducing the risk from breathing radon released from all water used in the home.

The legitimate radon market has a few pressure points where a careless or dishonest seller can take advantage. None of them requires you to judge the science; each can be checked against what EPA says a good job looks like.

If something still seems wrong, EPA's Consumer's Guide says to ask your state radon office or your county or state consumer protection office for information about the contractors. Credentials can be checked with the body that issued them; the state radon programs list says who credentials radon professionals where you live.

The surest protection against a bad job is a short list of things anyone can look at, and a test afterward. EPA's Consumer's Guide lists basic installation requirements your contractor should meet, and says to verify with your contractor that the radon mitigation standards (ASTM E2121 in particular) are properly met.

A system that passes these checks and a retest that comes back low is the proof that matters. More on each part in radon remediation systems.

Test your own home with a valid test, so the decision rests on your number rather than on anyone's claim. Then read it against EPA's guidance. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. The radon level interpreter walks a result through those bands. For context, the radon zone map and the state and county radon reports show your area's predicted potential and reported testing data, which describe an area and never your building.

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2 pCi/L

4 pCi/L

00 Bq/m³274 Bq/m³4148 Bq/m³6222 Bq/m³8296 Bq/m³10+370 Bq/m³

• Below 2 pCi/L (below 74 Bq/m³)Below both of EPA's guidance levels.
• 2 to 4 pCi/L (74 Bq/m³ to 148 Bq/m³)EPA recommends considering a fix when the level is between 2 and 4 pCi/L.
• At or above 4 pCi/L (148 Bq/m³ and up)EPA recommends fixing a home when the radon level is 4 pCi/L or higher.

EPA's Citizen's Guide is explicit that the lines are not a promise of safety: since there is no known safe level of radon, there can always be some risk, but the risk can be reduced by lowering the radon level in your home.