Radon
A radioactive gas that seeps in from the ground. It causes no symptoms at all — a test is the only way to know, and testing is cheap or free.
Draft — not yet medically reviewed
Routine guidance
Here in our region
This is a regional problem, not a rare one. About half of Colorado homes and about half of Montana homes that have been tested came back above the action level, and North Dakota reports 63%.
Every state in our region has a test kit programme:
- Colorado — one free kit per household per year. If your result is above 4 and you own the home and meet income limits, the state's low-income mitigation programme may pay to fix it.
- Montana — kits for about $5
- Wyoming — free kits through the Wyoming Cancer Program
- South Dakota — a limited number of free kits
- North Dakota — free kits, usually offered in January
- Utah — low-cost kits
In Colorado, radon professionals must be state licensed — worth checking before you hire anyone. Colorado law requires sellers to disclose radon information with a warning statement, but it does not require anyone to test or to fix.
Where it comes from
Radon is a radioactive gas that forms naturally in soil and rock and seeps into buildings through foundations, crawl spaces and sump openings. You cannot see it, smell it or taste it.
Breathing it over many years raises the risk of lung cancer. That risk builds over a lifetime and shows up in adulthood — which is exactly why fixing it while your children are small is worth doing.
Any home can have it
New or old, well sealed or draughty, basement or slab — there is no type of house that is safe by default and no way to guess from the outside. Two houses next door to each other can test very differently.
The only thing that tells you is a test.
Nothing. That is the point.
Radon causes no symptoms whatsoever — no cough, no headache, nothing you would notice. Anyone who tells you they can feel it, or that a smell means radon, is mistaken.
Test, then act on the number
- Get a test kit. See the regional note above — in most of our states it is free or a few dollars.
- At 4 pCi/L or higher, EPA says fix it. Between 2 and 4, EPA says consider fixing it.
- Fixing it is ordinary building work — usually a pipe and a fan that vents gas from under the foundation. It is not a renovation.
- In Colorado, use a state-licensed radon professional.
- Do not smoke or vape indoors. Radon and tobacco smoke together are far worse than either alone.
No rush, but do ask
This is not an emergency and there is nothing to do tonight. If you have a result you are not sure how to read, or you want help finding your state's programme, ask us — that is a good use of a free consultation.
“Is radon worse for children than adults?”
Possibly, and we should be careful about how strongly we say it. ATSDR notes that children may receive higher estimated radiation doses than adults, because their lungs are smaller and they breathe faster.
What does not exist is lung-cancer data in children — the risk is a lifetime one. And a claim you may run into, that radon is worse for children because they are closer to the ground, is a simplification we would rather not repeat.
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There is no workup — and that is the point
- No biomarker of radon exposure has clinical utility. There is no screening test and no medical follow-up. If a family arrives asking what test to order, the answer is that none exists.
- The entire clinical intervention is counselling: ask whether the home has been tested, and connect the family to the state kit programme.
- Radon and tobacco smoke are multiplicative, not additive. In a smoking household this is the highest-yield thing you can say.
- Adding "has your home been tested for radon?" to a well-child environmental history takes seconds and is the only action available.
What we do and do not know in children
- No pediatric lung-cancer data exist. Risk is lifetime and manifests in adulthood.
- Leukaemia: NCI describes the evidence as not conclusive.
- A 2026 Pediatric Pulmonology review found associations between modelled radon exposure and asthma, and states plainly that relatively little is known. Treat it as a signal, not a finding.
- EPA's radon zone map is often quoted as though it were a home-level risk assessment. It dates from 1993, and EPA itself states it should not be used to decide whether an individual home needs testing. We have deliberately used state-level percentages instead.