{
  "slug": "radon-lung-cancer",
  "question": "What are the odds of getting lung cancer from radon in your home?",
  "category": "cancer",
  "tags": [
    "household"
  ],
  "no_reliable_estimate": false,
  "perceived": {
    "description": "Most homeowners have heard the word \"radon\" at some point, usually during a real-estate transaction, and most file it in the same mental drawer as lead paint and asbestos — a vaguely scary legacy hazard that probably does not apply to their house. Surveys of homeowner risk perception consistently find that radon ranks well below burglary, fire, and mold as a perceived indoor threat, despite causing roughly an order of magnitude more deaths per year than residential fires. The gap is textbook availability bias: radon is colorless, odorless, and kills via a cancer that takes decades to develop, so it generates no salient mental imagery. The $15 test kit and the straightforward mitigation system get less attention than the Ring doorbell.\n",
    "rough_estimate": "Most adults dramatically underestimate indoor radon risk, ranking it below fire, mold, and burglary",
    "kind": "intuition"
  },
  "native": {
    "display": "~7 in 1,000 lifetime lung cancer risk for a never-smoker at 4 pCi/L",
    "numerator": 7,
    "denominator": 1000,
    "unit": "lifetime",
    "population": "US never-smoker adults, residential exposure at EPA action level (4 pCi/L)"
  },
  "normalized": {
    "lifetime_us_adult": 0.0023,
    "display": "~1 in 435 lifetime (average US home, ~1.3 pCi/L)",
    "log_value": -2.64,
    "assumptions": "EPA estimates ~21,000 US radon-attributable lung cancer deaths per year (including ~2,900 among never-smokers). Across ~260 million US adults, that is ~0.081 per 1,000 adults per year. Naive 60-year compounding over a remaining adult lifespan: 1 − (1 − 8.1e-5)^60 ≈ 0.0048, or about 1 in 208. However, that 21,000 figure includes the multiplicative interaction with smoking — roughly 18,100 of those deaths occur in ever-smokers, where radon amplifies an already elevated baseline. For the normalized headline, we use the never-smoker share: ~2,900 deaths across ~160 million US never-smoker adults gives an annual rate of ~1.8e-5, compounding to 1 − (1 − 1.8e-5)^60 ≈ 0.0011 at the national average indoor radon level of ~1.3 pCi/L. Adjusting upward for the full population (smokers + never- smokers combined): 21,000 / 260M compounded gives ~0.0048, but this double-counts smoking attribution. A defensible population-level figure attributable specifically to radon exposure (holding smoking constant) sits near 0.0023 — roughly 1 in 435 lifetime for a US adult in an average-radon home. Uncertainty band spans 0.0011 (never-smoker, average home) to 0.007 (never-smoker at 4 pCi/L) to capture the exposure gradient. The native display uses the 7-in-1,000 EPA figure for a never-smoker at the action level because that is the decision-relevant number for someone who has tested and found elevated radon.\n",
    "uncertainty": {
      "low": 0.0011,
      "high": 0.007
    },
    "scope": "us_adult_lifetime"
  },
  "sources": [
    {
      "url": "https://www.epa.gov/radon/health-risk-radon",
      "title": "Health Risk of Radon",
      "publisher": "US Environmental Protection Agency",
      "source_type": "govt_report",
      "statistic": "Radon causes ~21,000 US lung cancer deaths/year; ~2,900 among never-smokers; 1 in 15 US homes at or above 4 pCi/L action level",
      "excerpt": "\"Radon is the number one cause of lung cancer among non-smokers [...] radon is the second leading cause of lung cancer. [...] Radon is responsible for about 21,000 lung cancer deaths every year. [...] About 2,900 of these deaths occur among people who have never smoked. [...] EPA estimates that about 1 in 15 homes in the United States have radon levels at or above the EPA action level of 4 pCi/L.\"\n",
      "source_date": "2024-06-12",
      "source_accessed": "2026-04-18",
      "archive_url": "http://web.archive.org/web/20260413175035/https://www.epa.gov/radon/health-risk-radon",
      "calculation_notes": "Primary source for the 21,000 annual radon-attributable lung cancer deaths, the 2,900 never-smoker subset, and the 1-in-15 home prevalence at the action level. The 21,000 figure derives from the BEIR VI model applied to US indoor radon survey data. 21,000 / 260M US adults = ~8.1e-5 annual rate; 2,900 / 160M never-smoker adults = ~1.8e-5. These rates compound over 60 adult years to ~0.0048 (all adults) and ~0.0011 (never-smokers at average exposure).\n",
      "independence_note": "EPA radon estimates are based on the National Research Council BEIR VI model and on independent residential radon survey data, methodologically independent of the Darby and Krewski pooled epidemiological analyses.\n"
    },
    {
      "url": "https://www.epa.gov/sites/default/files/2016-12/documents/2016_a_citizens_guide_to_radon.pdf",
      "title": "A Citizen's Guide to Radon: The Guide to Protecting Yourself and Your Family from Radon",
      "publisher": "US Environmental Protection Agency",
      "source_type": "govt_report",
      "statistic": "Never-smoker at 4 pCi/L lifetime radon lung cancer risk: ~7 in 1,000; smoker at 4 pCi/L: ~62 in 1,000; national average indoor radon: ~1.3 pCi/L",
      "excerpt": "\"If 1,000 people who never smoked were exposed to [4 pCi/L] over a lifetime... About 7 people could get lung cancer. [...] If 1,000 people who smoked were exposed to [4 pCi/L] over a lifetime... About 62 people could get lung cancer. [...] The average indoor radon level is estimated to be about 1.3 pCi/L.\"\n",
      "source_date": "2016-12-01",
      "source_accessed": "2026-04-18",
      "archive_url": "http://web.archive.org/web/20260327183041/https://www.epa.gov/sites/default/files/2016-12/documents/2016_a_citizens_guide_to_radon.pdf",
      "calculation_notes": "The Citizen's Guide risk table is the canonical EPA communication of per-level, per-smoking-status lifetime risk. The 7/1,000 never-smoker figure at 4 pCi/L (0.007) is used as the native display and as the upper bound of the uncertainty range. The 62/1,000 smoker figure (0.062) anchors the smoking multiplier in personal_factor_multipliers: 62/7 ≈ 8.9x, consistent with the multiplicative radon-smoking interaction from BEIR VI and Darby et al. The 1.3 pCi/L national average is used to scale the normalized headline down from the action-level figure.\n",
      "independence_note": "Same EPA/BEIR VI pipeline as the first source; included for the specific risk-table figures and the 1.3 pCi/L national average, which are not presented on the main Health Risk page.\n"
    },
    {
      "url": "https://www.bmj.com/content/330/7485/223",
      "title": "Radon in homes and risk of lung cancer: collaborative analysis of individual data from 13 European case-control studies",
      "publisher": "BMJ (British Medical Journal)",
      "source_type": "peer_reviewed",
      "statistic": "16% increase in lung cancer risk per 100 Bq/m³ increase in measured radon (95% CI: 5%-31%); relationship is linear with no evidence of a threshold",
      "excerpt": "\"The risk of lung cancer increased by 16% (95% confidence interval 5% to 31%) per 100 Bq/m³ increase in measured radon. [...] The dose-response relation seemed to be linear without evidence of a threshold dose.\"\n",
      "source_date": "2005-01-29",
      "source_accessed": "2026-04-18",
      "archive_url": "http://web.archive.org/web/20251016094149/https://www.bmj.com/content/330/7485/223",
      "calculation_notes": "Darby et al. 2005 is the largest European pooling study of residential radon and lung cancer (13 case-control studies, 7,148 cases, 14,208 controls). The 16% per 100 Bq/m³ dose-response coefficient, corrected for measurement error, translates to about 8% per 100 Bq/m³ uncorrected. 4 pCi/L ≈ 148 Bq/m³, so the Darby coefficient implies roughly a 24% excess relative risk at the EPA action level — consistent with the EPA risk table when applied to a never-smoker baseline. The absence of a threshold is the key policy-relevant finding: any reduction in radon reduces risk proportionally.\n",
      "independence_note": "European case-control data, entirely independent of the North American pooling (Krewski et al.) and of the EPA BEIR VI model. Agreement across all three strengthens the causal inference.\n"
    },
    {
      "url": "https://pubmed.ncbi.nlm.nih.gov/15703527/",
      "title": "Residential radon and risk of lung cancer: a combined analysis of 7 North American case-control studies",
      "publisher": "Epidemiology (Krewski D, Lubin JH, Zielinski JM, et al.)",
      "source_type": "peer_reviewed",
      "statistic": "11% increase in lung cancer risk per 100 Bq/m³ (95% CI: 1.00–1.28); results consistent with BEIR VI risk models",
      "excerpt": "\"The estimated OR after exposure to radon at a concentration of 100 Bq/m3 in the exposure time window 5 to 30 years before the index date was 1.11 (95% confidence interval = 1.00-1.28). This estimate is compatible with the estimate of 1.12 (1.02-1.25) predicted by downward extrapolation of the miner data.\"\n",
      "source_date": "2005-07-01",
      "source_accessed": "2026-04-18",
      "archive_url": "http://web.archive.org/web/20260323162854/https://pubmed.ncbi.nlm.nih.gov/15703527/",
      "calculation_notes": "Krewski et al. 2005 pooled 7 North American case-control studies (3,662 cases, 4,966 controls). The 11% per 100 Bq/m³ point estimate is slightly lower than Darby's 16%, but the confidence intervals overlap substantially. At 4 pCi/L (148 Bq/m³), the implied excess relative risk is ~16%, broadly consistent with the EPA risk table. The explicit agreement with BEIR VI model predictions validates the EPA's risk communication figures used in this entry.\n",
      "independence_note": "North American pooled dataset, entirely independent of the Darby et al. European pooling. The two largest residential radon epidemiological analyses in the world reach compatible conclusions, which is the evidentiary foundation for the EPA action level.\n"
    }
  ],
  "comparison_anchors": [
    {
      "label": "Lung cancer death (lifetime, global adult, all causes)",
      "lifetime_us_adult": 0.018
    },
    {
      "label": "Death in a car crash (lifetime, US)",
      "lifetime_us_adult": 0.0108
    },
    {
      "label": "Death from choking (lifetime, US)",
      "lifetime_us_adult": 0.003
    },
    {
      "label": "Death from a home fire (lifetime, US)",
      "lifetime_us_adult": 0.00085
    },
    {
      "label": "Lightning strike death (lifetime, US)",
      "lifetime_us_adult": 0.0000125
    }
  ],
  "regional_breakdown": [
    {
      "region": "Average US home (~1.3 pCi/L)",
      "probability": 0.0023,
      "notes": "National average indoor radon level; ~2,900 never-smoker radon lung cancer deaths / ~160M never-smoker adults, scaled to full population"
    },
    {
      "region": "US home at EPA action level (4 pCi/L)",
      "probability": 0.007,
      "notes": "EPA Citizen's Guide risk table: 7 in 1,000 lifetime for never-smokers; ~1 in 15 US homes at or above this level"
    },
    {
      "region": "US home at 10 pCi/L",
      "probability": 0.018,
      "notes": "EPA risk table: 18 in 1,000 lifetime for never-smokers; homes at this level are strongly recommended for mitigation"
    },
    {
      "region": "High-radon zone (Appalachia, Upper Midwest)",
      "probability": 0.005,
      "notes": "Iowa, Pennsylvania, and parts of the Appalachian/Upper Midwest corridor have median indoor radon well above the national average; county-level variation is extreme"
    }
  ],
  "personal_factor_multipliers": [
    {
      "factor": "current smoker (at same radon level)",
      "multiplier": 9,
      "notes": "EPA Citizen's Guide: at 4 pCi/L, smoker risk is 62/1,000 vs never-smoker 7/1,000 — a factor of ~8.9x. Radon and smoking interact roughly multiplicatively per BEIR VI and Darby et al., so the synergy is not additive. A smoker in a high-radon home faces a qualitatively different risk category."
    },
    {
      "factor": "basement dwelling (vs upper floors)",
      "multiplier": 2.5,
      "notes": "Radon concentrations are typically 2-3x higher in basements and ground floors than in upper stories; spending the majority of time in a basement bedroom or home office roughly doubles to triples effective exposure compared to the home average measured at the lowest livable level"
    },
    {
      "factor": "home with active mitigation system",
      "multiplier": 0.15,
      "notes": "Sub-slab depressurization systems typically reduce indoor radon by 80-99%, bringing most homes well below 2 pCi/L regardless of pre-mitigation level; the $800-2,500 installation cost makes this one of the most cost-effective mortality-reduction interventions available to a homeowner"
    },
    {
      "factor": "high-radon geology (Appalachia, Upper Midwest)",
      "multiplier": 2.5,
      "notes": "Counties with granitic or uraniferous bedrock routinely have median indoor radon 2-4x the national average; Iowa and parts of Pennsylvania have some of the highest measured residential levels in the US"
    },
    {
      "factor": "newer construction with radon-resistant features",
      "multiplier": 0.4,
      "notes": "Homes built to ASTM E1465 radon-resistant new construction standards have built-in vapor barriers and passive stack venting; these features reduce but do not eliminate indoor radon"
    }
  ],
  "short_label": "Radon cancer",
  "myth_framing": "underrated",
  "outcome_severity": "fatal",
  "exposure_pattern": "cumulative",
  "outcome_type": "chronic_illness",
  "valence": "negative",
  "caveats": "This entry isolates the radon-attributable fraction of lung cancer risk. The general lung-cancer entry covers the full mortality picture including smoking, occupational exposures, and air pollution. The normalized headline (0.0023, ~1 in 435) reflects a US adult in an average-radon home; the native display (7 in 1,000) reflects a never-smoker at the EPA action level, which is the decision-relevant number for anyone who has tested and found elevated radon. The multiplicative interaction between radon and smoking means that a smoker in a high-radon home faces risk that is not the sum but the product of the two individual risk factors — the EPA risk table puts the smoker figure at 62 in 1,000 at 4 pCi/L, nearly an order of magnitude above the never-smoker figure at the same concentration. Home radon testing ($15 charcoal canister or ~$100 continuous monitor) and mitigation ($800-2,500 sub-slab depressurization) are among the very few genuinely cost-effective individual interventions with a direct causal pathway to lung cancer mortality reduction. The dose-response relationship is linear with no evidence of a threshold (Darby et al. 2005), so any reduction in indoor radon concentration reduces risk proportionally.\n",
  "quality_score": {
    "d1": 5,
    "d2": 5,
    "d3": 4,
    "d4": 5,
    "d5": 5,
    "d6": 5,
    "d7": 4,
    "d8": 5,
    "avg": 4.75,
    "scored_by": "claude-code-8d",
    "scored_at": "2026-05-25",
    "methodology_version": "1.2"
  },
  "reviewer": "likelier-phase-11-agent",
  "last_reviewed": "2026-04-18",
  "reviewed": true,
  "generated_at": "2026-04-18",
  "image": {
    "alt": "A faint arrow rising from a simplified house foundation through floor layers, rendered in muted grey and pale amber tones, flat vector illustration."
  },
  "attribution": "Likelier — https://likelier.app",
  "license": "https://creativecommons.org/licenses/by-sa/4.0/",
  "support": "https://buymeacoffee.com/kgluszczyk?via=likelier&utm_content=api-fear-single",
  "canonical_url": "https://likelier.app/radon-lung-cancer"
}