At a glance
| Chemical family | Organochlorine insecticide (fully chlorinated cage ketone, C10Cl10O) |
| CAS number | 143-50-0 |
| Also known as | Kepone (US trade name), Curlone (France), GC-1189; EC 205-601-3 |
| Classification | IARC Group 2B, possibly carcinogenic to humans (Volume 20, Supplement 7, 1987); NTP reasonably anticipated to be a human carcinogen; Stockholm Convention Annex A with no specific exemptions; EU harmonised classification Carc. 2, Acute Tox. 3, Aquatic Chronic 1 |
| Where you encounter it | Contaminated soil in Guadeloupe and Martinique, where it was applied against the banana root borer, and the James River corridor near Hopewell, Virginia after the 1975 manufacturing disaster. Diet is the dominant route: local root vegetables, freshwater fish, backyard poultry and eggs |
| Sleep micro-environment relevance | Low, and only in the contaminated regions. Vapour pressure 2.25 × 10−7 mm Hg at 25 °C, so there is no off-gassing route from any product. Indoor dust in Martinique homes and schools carried <16 to 247 ng/g, modelled at up to 1.5% of the acceptable daily intake in children |
Regulatory & certification status
| European Union | Banned. Chlordecone (CAS 143-50-0, EC 205-601-3) is listed in Annex I Part A of Regulation (EU) 2019/1021, the POPs Regulation, with the exemption column blank. Manufacture, placing on the market and use are prohibited. Annex I is a genuine ban, unlike the REACH Candidate List, which only identifies a substance. Regulatory — EU authority |
| European Union — classification | Harmonised classification under CLP Annex VI, index number 606-019-00-6, entry source 32008R1272: Carc. 2 (H351), Acute Tox. 3 (H311), Acute Tox. 3 (H301), Aquatic Acute 1 (H400), Aquatic Chronic 1 (H410). Signal word Danger. A classification describes the hazard; it does not by itself restrict anything. The Annex I listing is what does the restricting here. Regulatory — EU authority |
| United States | NTP lists Kepone (chlordecone) as reasonably anticipated to be a human carcinogen, first listed in the Second Annual Report on Carcinogens in 1981. California Proposition 65: listed for cancer on 1 January 1988 and for developmental toxicity on 1 January 1989, no-significant-risk level 0.04 µg/day. RCRA hazardous waste code U142; CERCLA reportable quantity 1 lb. FDA action levels 0.3–0.4 ppm in fish and crabmeat. NIOSH recommended exposure limit 0.001 mg/m³, treated as a potential occupational carcinogen. Agency sources disagree on the end date: the POPRC risk profile says manufacture was discontinued in the USA in 1976, the NTP profile says use ended in 1978. Both follow the 1975 Hopewell, Virginia disaster. Regulatory — US authority |
| Canada | Not listed in the Prohibition of Certain Toxic Substances Regulations, 2025 (SOR/2025-270). Several sibling organochlorines in this Atlas are; chlordecone is not, and a full-text search of that regulation returns no hit for chlordecone, Kepone or 143-50-0. Control runs instead through CEPA Schedule 3, the Export Control List: SOR/2012-164 added “Chlordecone (Chemical Abstracts Service [CAS] registry number 143-50-0)” as item 12 of Part 1, and the accompanying statement says of that Part that use of these substances is prohibited in Canada. Regulatory — Canada authority |
| United Kingdom | Regulation (EU) 2019/1021 is assimilated in Great Britain. The legislation.gov.uk text of Annex I Part A carries the row for chlordecone, 143-50-0, 205-601-3, with no specific exemption, matching the EU entry. Northern Ireland's position under the Windsor Framework was not checked for this page. Regulatory |
| Australia | Australia is a Party to the Stockholm Convention, so the Annex A elimination obligation applies. No Australian domestic instrument was verified for this page: the DCCEEW National Implementation Plan and the AICIS banned-or-restricted chemical pages could not be retrieved. Treat any APVMA or AICIS status as unchecked rather than absent. Inferred |
| International | Stockholm Convention Annex A, elimination, added in 2009 at the fourth Conference of the Parties by decision SC-4/12 with no specific exemptions. The Convention's own table records Production: None and Use: None. IARC Group 2B, possibly carcinogenic to humans, evaluated in Monographs Volume 20 and carried through Supplement 7 in 1987, and not re-evaluated since. Regulatory — International authority |
What it is
Chlordecone is a fully chlorinated cage ketone, C10Cl10O, introduced commercially in 1958 as Kepone. It was used against the banana root borer, fly larvae, apple scab, Colorado potato beetle and wireworm. In France it was marketed as Curlone, and in Guadeloupe and Martinique it was applied to banana plantations from 1972 until 1993. It has no flame-retardant, plasticiser or foam-chemistry role, which is what separates it from most of the compounds in this Atlas.
Its defining property is that it does not break down. The POPRC risk profile prepared for the Stockholm Convention states that chlordecone is not expected to hydrolyse or biodegrade in aerobic aquatic environments or in soil, that direct photodegradation is not significant, and that the compound is considered highly persistent. Regulatory Cabidoche and colleagues modelled how long the French West Indies soil reservoir will last and concluded that pollution is bound to last for several decades in nitisol, centuries in ferralsol and half a millennium in andosol. Peer-reviewed The reservoir does not go away, so neither does the tracking-in.
The United States stopped it after the 1975 Hopewell, Virginia manufacturing disaster, which contaminated the James River. Sources disagree on the exact end date, and the honest answer is to give both: the POPRC risk profile says manufacture was discontinued in the USA in 1976, while the NTP Report on Carcinogens says use ended in 1978.
Where it shows up in a bedroom
Not from anything you sleep on. Chlordecone was never a mattress, pillow, textile, foam or adhesive input, and the NTP substance profile records a vapour pressure of 2.25 × 10−7 mm Hg at 25 °C. Regulatory At that vapour pressure there is effectively no gas phase, which rules out off-gassing as a mechanism.
What can happen is soil transfer. Chlordecone binds strongly to organic matter in soil, sediment and dust, so contaminated outdoor soil carried in on shoes, feet, pets and clothing settles indoors as house dust. In Guadeloupe and Martinique that soil is contaminated for centuries. Elsewhere it is not, and a reader in Toronto, Manchester or Sydney has no established route to this compound.
What the research says
The indoor-dust question has one dataset. Dufresne and colleagues sampled homes and schools in Martinique and reported that concentrations of chlordecone in indoor dust varied from below 16 to 247 ng/g, and that exposure through indoor dust ingestion does not exceed 1.5% of the acceptable daily intake in children and 0.1% in adults. Peer-reviewed Dust is a real route and a small one. Diet, meaning local root vegetables, freshwater fish, backyard poultry and eggs, dominates by roughly two orders of magnitude.
The health evidence that drives the regulation comes from the population, not from bedrooms. In a case-control study in Guadeloupe, Multigner and colleagues found a significant increase in the risk of prostate cancer with increasing plasma chlordecone concentration, with an odds ratio of 1.77 (95% CI 1.21 to 2.58) for the highest tertile of values above the limit of detection. Peer-reviewed In the TIMOUN mother-child cohort, Oulhote and colleagues reported that a twofold increase in 7-year chlordecone concentrations was associated with a decrease of 0.67 point (95% CI −1.13 to −0.22) on Full-Scale IQ and an increase of 0.04 SD on externalizing problems. Peer-reviewed Those associations sit at general-population blood levels in Guadeloupe, not at occupational ones.
IARC placed chlordecone in Group 2B, possibly carcinogenic to humans, in Monographs Volume 20 carried through Supplement 7, with 1987 as the year of evaluation. Regulatory That evaluation predates both of the studies above and has not been revisited.
What helps
- Take shoes off at the door, and keep a coarse mat at every entrance. Tracked-in soil is the only established route into house dust for this compound, so interrupting transfer at the threshold acts on the actual mechanism. No trial has tested shoe removal specifically for chlordecone; this follows from the transport pathway described in the POPRC risk profile and the Martinique dust study. Inferred
- Vacuum with a sealed HEPA machine and damp-wipe rather than dry-dust. Chlordecone in a home is bound to settled dust particles. Removing the dust removes the compound. This works on the carrier, not on a gas phase. No trial has tested cleaning method against chlordecone specifically. Inferred
- Wash children's hands before meals. The Dufresne study models the exposure as hand-to-mouth ingestion of dust, and children carry the higher modelled fraction of the acceptable daily intake, 1.5% against 0.1% in adults. Peer-reviewed
- In Guadeloupe and Martinique, follow the local dietary guidance on garden produce, freshwater fish and backyard eggs. Diet is the dominant route by a wide margin. A household that fixes its dust and ignores its food has addressed the small half of the problem. Inferred
What does not help
- Air purifiers, carbon filters or ventilation aimed at chlordecone. At 2.25 × 10−7 mm Hg there is essentially no gas phase to capture. A HEPA unit may pull down resuspended dust, a modest side benefit, but nothing about this compound responds to air treatment the way a VOC does.
- Airing out a new mattress, or buying a low-VOC or emissions-tested one. Useful for other compounds in this Atlas. Irrelevant to this one, which has never been a bedding input and does not off-gas.
- Looking for a “chlordecone-free” product claim. Manufacture, placing on the market and use are prohibited in the EU under Annex I Part A of Regulation (EU) 2019/1021, use is prohibited in Canada under Part 1 of the CEPA Export Control List, and US production ended in the 1970s. A product sold today does not contain it, so the label would say nothing.
- Detox protocols, sauna programmes and chelation. Nothing in the verified literature reviewed for this page supports any of them for chlordecone. Body burden is a matter for a clinician, not a consumer product.
Open research questions
- There is one indoor-dust dataset for chlordecone in the world, from homes and schools in Martinique, published in 2025. Its own authors describe it as exploratory and say it cannot be generalised to the whole French West Indies population.
- No bedroom-specific sampling exists. Nobody has measured bed dust or mattress dust separately from floor dust for this compound.
- No measured indoor air concentration for chlordecone has been published anywhere, and no inhalation reference value exists. That combination, measured in people but with no air benchmark and no sleeping-environment measurement, is exactly the pattern the Dose Gap tracks.
- Hopewell, Virginia and the James River are the largest chlordecone release in US history, and no one appears to have sampled house dust in nearby homes. That is an unmeasured gap, not evidence of clean houses.
- Australia's domestic position could not be verified for this page. Someone needs to open an Australian primary instrument before anything beyond the Stockholm Annex A obligation is stated.
The exposure ledger for Chlordecone (Kepone)
One chemical, several public questions, answered from independent datasets and joined here — the environment it shows up in, the body burden it carries, how it is regulated, and what actually reduces it.
Detection and body-burden figures are occurrence data, not a personal measurement or a health diagnosis. Part of the Embr Exposure Ledger — an open, cross-dataset chemical join (download the data), reusable with attribution.
Where you meet Chlordecone across your home
The same compound turns up in more than one place you live. Here's where it shows up in Embr — each links to the full breakdown for that part of your home.
Citations
- Dufresne M, Raffy G, Guimberteau J, Bonvallot N, Lecorgne A, Surget E, Boullanger C, Multigner L, Ramalho O, Glorennec P, Le Bot B (2025). Determination of chlordecone in indoor dust by GC/MS/MS and associated human exposure in the French West Indies. Journal of Hazardous Materials, vol. 495. DOI: 10.1016/j.jhazmat.2025.138809 Peer-reviewed
- Cabidoche YM, Achard R, Cattan P, Clermont-Dauphin C, Massat F, Sansoulet J (2009). Long-term pollution by chlordecone of tropical volcanic soils in the French West Indies: a simple leaching model accounts for current residue. Environmental Pollution. DOI: 10.1016/j.envpol.2008.12.015 Peer-reviewed
- Multigner L, Ndong JR, Giusti A, Romana M, Delacroix-Maillard H, Cordier S, Jégou B, Thomé JP, Blanchet P (2010). Chlordecone exposure and risk of prostate cancer. Journal of Clinical Oncology. DOI: 10.1200/JCO.2009.27.2153 Peer-reviewed
- Oulhote Y, Rouget F, Michineau L, Monfort C, Desrochers-Couture M, Thomé JP, Kadhel P, Multigner L, Cordier S, Muckle G (2023). Prenatal and childhood chlordecone exposure, cognitive abilities and problem behaviors in 7-year-old children: the TIMOUN mother-child cohort in Guadeloupe. Environmental Health. DOI: 10.1186/s12940-023-00970-3 Peer-reviewed
- Persistent Organic Pollutants Review Committee, Stockholm Convention (2006). Risk profile on Chlordecone (UNEP/POPS/POPRC.2/17/Add.2). United Nations Environment Programme. Source Regulatory
- National Toxicology Program, U.S. Department of Health and Human Services (2021). Report on Carcinogens, Fifteenth Edition — Kepone (chlordecone) substance profile. Source Regulatory
- International Agency for Research on Cancer (1987). Agents Classified by the IARC Monographs (classification list, alphabetical order). Source Regulatory
- Secretariat of the Stockholm Convention (2009). The New POPs under the Stockholm Convention — Chlordecone listing (decision SC-4/12). Source Regulatory
- Government of Canada (2012). SOR/2012-164 — chlordecone (CAS 143-50-0) added as item 12 of Part 1 of the Export Control List, CEPA Schedule 3. Canada Gazette Part II, Vol. 146 No. 19, 12 September 2012. Source Regulatory
- European Union. Regulation (EU) 2019/1021 on persistent organic pollutants, Annex I Part A (consolidated text 02019R1021). Source Regulatory
Frequently asked questions
Can chlordecone off-gas from a mattress?
No. Chlordecone was never a mattress, foam, textile or adhesive input, and its vapour pressure is 2.25 × 10−7 mm Hg at 25 °C (NTP Report on Carcinogens, 15th edition). At that vapour pressure there is essentially no gas phase, so there is no mechanism by which any bedding product emits it. The only route indoors is contaminated soil carried in on shoes, pets and clothing and settling as house dust.
Has chlordecone actually been measured in house dust?
Once. Dufresne and colleagues (Journal of Hazardous Materials, 2025) measured chlordecone in indoor dust from homes and schools in Martinique at concentrations from below 16 to 247 ng/g, and calculated that dust ingestion accounts for at most 1.5% of the acceptable daily intake in children and 0.1% in adults. No bedroom-specific or bed-dust sampling exists anywhere, and no measured indoor air concentration has been published.
Should I worry about chlordecone if I do not live in the French West Indies?
Almost certainly not. The contaminated-soil reservoir that feeds indoor dust is concentrated in Guadeloupe and Martinique, where chlordecone was applied to banana plantations, plus the James River and Hopewell, Virginia legacy of the 1975 US manufacturing disaster. A reader outside those areas has no established route of exposure. Nobody has sampled house dust near Hopewell, so that particular gap is unmeasured rather than clean.
Is chlordecone banned?
In the European Union, yes. Chlordecone is listed in Annex I Part A of Regulation (EU) 2019/1021 with the exemption column blank, so manufacture, placing on the market and use are prohibited. The Stockholm Convention added it to Annex A in 2009 by decision SC-4/12 with no specific exemptions. Canada does not list it in the Prohibition of Certain Toxic Substances Regulations, 2025; its control runs instead through Part 1 of the CEPA Export Control List, added by SOR/2012-164, and Canada states that use of Part 1 substances is prohibited.
Related compounds
Embr is a sleep environment company researching and addressing the chemistry of the bedroom. Research and product development in progress.
Last reviewed 2026-07-25. If you find a factual error, contact us.