Radon in the yard and garden
High risk for your yardIARC Group 1; 21,000 US deaths/year; ~1 in 15 US homes exceed EPA action level 4 pCi/L.
What is radon?
Also known as: Alphatron, Radium emanation, Niton, Niton /Radon-222/.
- IUPAC name
- radon
- CAS number
- 10043-92-2
- Molecular formula
- Rn
- Molecular weight
- 222.01758 g/mol
- SMILES
- [Rn]
- PubChem CID
- 24857
Risk for people, pets,
High riskIARC Group 1; 21,000 US deaths/year; ~1 in 15 US homes exceed EPA action level 4 pCi/L.
Regulatory consensus
4 regulatory and scientific bodies have classified Radon. The classifications differ — that's the data.
| Agency | Year | Classification | Notes |
|---|---|---|---|
| IARC | 2012 | Group 1 (carcinogenic to humans) | Lung cancer; decay products Ra-222; Monograph 100D |
| US EPA | 2003 | Known to be a human carcinogen | 2nd leading cause of lung cancer in US; 21,000 deaths/year |
| EPA CTX / NTP RoC | — | Known Human Carcinogen | |
| EPA CTX / IARC | — | Group 1 - Carcinogenic to humans |
Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.
Where your yard encounter radon
-
Indoor Air/Building Environments
— Basements and lower levels of homes, Crawl spaces and foundations, Poorly ventilated residential buildings, Commercial buildings with inadequate ventilation
Radon accumulates in enclosed spaces; enters through cracks in foundations, soil contact areas. ~1 in 15 US homes exceed EPA action level of 4 pCi/L
-
Drinking Water
— Groundwater-fed wells and municipal supplies, Private well water systems, Water from radon-rich geological areas
EPA has set drinking water standard of 300 pCi/L; radon dissolves in water from underground sources
-
Occupational Settings
— Underground mines and quarries, Uranium mines, Radon spas and health facilities
Workers in underground/below-ground occupations experience elevated radon exposure
-
Geological/Environmental
— Soil in areas with uranium and radium deposits, Granite bedrock regions, Shale formations
Radon naturally occurs from radioactive decay in soil and rock; geographically variable concentrations
Safer alternatives
Lower-risk approaches that achieve a similar outcome to Radon:
-
NSF-certified activated carbon filtration
Trade-offs: Does not remove all contaminants. Requires filter replacement.Relative cost: 2-5×
Frequently asked questions
Is radon safe for your yard?
IARC Group 1; 21,000 US deaths/year; ~1 in 15 US homes exceed EPA action level 4 pCi/L.
What products contain radon?
Radon appears in: Basements and lower levels of homes (Indoor air/Building environments); Crawl spaces and foundations (Indoor air/Building environments); Groundwater-fed wells and municipal supplies (Drinking water); Private well water systems (Drinking water); Underground mines and quarries (Occupational settings).
Why do regulators disagree about radon?
Radon has been classified by 4 agencies including IARC, US EPA, EPA CTX / NTP RoC, EPA CTX / IARC, with differing conclusions. Regulators apply different standards of evidence (animal data weighting, exposure-pattern assumptions, epidemiological power thresholds), which is why two scientific bodies can review the same data and reach different conclusions. See the regulatory consensus table on this page for the full picture.
See Radon in the outdoor app
Look up products containing radon, compare to alternatives, and explore the full data record.
Open in outdoor View raw API dataSources (2)
- IARC Monographs Volume 100D: Radiation — Radon-222 and its Decay Products (2012) — regulatory
- US EPA: A Citizen's Guide to Radon (2003) — regulatory
Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →