If these chemicals were banned decades ago, why are they still in my house?

Because a ban stops supply, and dust is a reservoir that empties slowly. Measuring PCBs in California homes, Whitehead and colleagues estimated half-lives of 5 to 18 years indoors, and reported that PCBs are removed very slowly from the indoor environment. Some of it is also still arriving from outside: research on residential carpet dust concluded that outdoor sources may be significant determinants of indoor concentrations, so soil tracked in on shoes keeps topping the reservoir up.

Does finding one of these compounds in dust mean it is harming me?

No, and this is the most important limit on the page. Detection has outrun toxicology, so instruments now find compounds far below any level shown to matter. When chlordecone was measured in indoor dust and the intake from swallowing that dust was calculated, it came to under 1.5% of the acceptable daily intake. Presence is the start of a question, not the answer to it. For many compounds no inhalation benchmark has ever been published, which is what The Dose Gap counts.

Is a mattress a source of the compounds in house dust?

For most of the compounds on this page, no. Banned organochlorine pesticides, PCBs and legacy flame retardants reach a bedroom as residue in dust and soil rather than as anything a mattress emits, and saying otherwise would be selling you a product you do not need. There are real bedroom-source compounds, and they have their own pages; the honest split matters more than a scary total.

What's in your ___ · House dust

What's in your house dust — and why it is the one exposure route you can actually do something about.

Q: Should I get my house dust tested?

For almost everyone, no. There is no consumer test that covers the range of compounds discussed here at a price worth paying, and a result would rarely change what you should do. The evidence supports reducing the reservoir rather than characterising it: damp-wipe hard surfaces, vacuum with a HEPA filter, leave outdoor shoes at the door, and wash hands before eating. A randomised housing trial that included dust mitigation was associated with roughly 23% lower urinary DEHP metabolites in young children, which is a larger measured effect than any testing service can offer you.

Dust is not dirt. Indoors it is mostly shed skin, fabric fibres and soil tracked in from outside, and it is where the heavy, sticky chemistry of a home collects. Compounds that never evaporate away instead migrate out of products, bind to particles and settle. That makes dust a reservoir, and reservoirs empty slowly. It also makes dust the rare exposure route with an honest, boring, well-evidenced answer: remove the dust. Here is what the measurements actually show, tagged by how strong the evidence is, and where the numbers stop.

Founded by a 19-year firefighter who has carried other people's combustion residue home Every claim cited & tiered to the primary literature $0 affiliate — we don't sell vacuums or filters

The one thing that settles most of it

The compound matters less than the clearance rate. Whatever is in your dust arrived because it is semi-volatile: heavy enough not to blow away, light enough to leave the product it started in. Once settled it leaves on a timescale of years, not days. Whitehead and colleagues, measuring PCBs in California homes, put it plainly: "Estimated half-lives ranged from 5-18 years, indicating that PCBs are removed very slowly from the indoor environment." Peer-reviewed — Whitehead 2014

That single sentence explains most of this page. It is why a compound banned before you were born is still measurable in your living room, why the source is often a building rather than a purchase, and why the intervention is mechanical removal rather than chemistry. Read every card below with the clearance rate in mind.

Real — repeatedly measured, in most homes

Banned compounds are still there — decades later

This is the least disputed finding on the page. Dodson and colleagues, sampling homes for semi-volatile compounds, found that "Several historic use pesticides, including DDT, DDE, DDD, chlordane, and methoxychlor, were detected in the majority of homes." Peer-reviewed — Dodson 2015 Harrad's four-country survey found PCBs in domestic dust across Canada, New Zealand, the UK and the United States. Peer-reviewed — Harrad 2009

What matters: "banned" describes a supply decision, not the contents of your floor. None of these compounds is being made or sold into homes. They are residue, and residue is what dust is for.

In the Atlas: PCBs · Methoxychlor · Chlordane · DDT · Dicofol

Real — and it is mostly walked in

A lot of it comes from outside — on shoes and in soil

Indoor dust is not generated indoors alone. Studying what predicts PCB levels in residential carpet dust, DellaValle and colleagues concluded that "outdoor sources of PCBs may be significant determinants of indoor concentrations." Peer-reviewed — DellaValle 2013 For compounds with long soil lifetimes that matters for a very long time: chlordecone in French West Indies soils is projected to persist "for several decades for nitisol, centuries for ferralsol, and half a millennium for andosol." Peer-reviewed — Cabidoche 2009

What matters: the cheapest intervention on this page is a doormat and taking shoes off, because a share of the problem is transport rather than emission.

In the Atlas: Chlordecone · Polychlorinated naphthalenes

Depends — presence is not dose

Detected does not mean dangerous — and the numbers say so

This is where most coverage of house dust goes wrong, and where we would rather lose your attention than keep it dishonestly. Detection has outrun toxicology: instruments now find things at concentrations far below any level anyone has shown to matter. When Dufresne and colleagues measured chlordecone in indoor dust and then calculated what ingesting that dust actually delivers, the answer was "does not exceed 1.5 % and 0.1 %, of the acceptable" daily intake. Peer-reviewed — Dufresne 2025

What matters: a compound being in your dust is the beginning of a question, not the end of one. Ask what concentration, by what route, compared with what benchmark. For a great many compounds that benchmark does not exist for air at all, which is the finding behind The Dose Gap.

Real — and unevenly distributed

Who lives with more of it — housing, not habits

Dust burden is not evenly shared, and it is not explained by how tidy anyone is. Sampling low-income housing, Vaezafshar and colleagues reported that "Concentrations of heptachlor, lindane, chlorothalonil, and endosulfan I were 2 (chlorothalonil) to 11 (endosulfan I) times higher than those found in other studies in residential" settings. Peer-reviewed — Vaezafshar 2024

What matters: the strongest predictors here are the age and condition of the building and its pest-treatment history — things a tenant does not choose. Advice that starts with "just buy a better mattress" misses most of the variance.

In the Atlas: Endosulfan · Lindane · Heptachlor

Complicated — some of it is still arriving

Not everything in dust is legacy — the in-use additives

Most compounds on this page are residue from products that stopped being made. Some are not. Benzotriazole UV stabilisers are still manufactured at scale and still going into plastics, coatings and textiles, and a 2025 review of their environmental occurrence records "air and dust being the most contaminated media". Peer-reviewed — Ling 2025 Brominated flame retardants show the mixed picture directly: comparing UK homes across a decade, Ma and colleagues found "significant (p < 0.05) declines in concentrations of legacy BFRs, but significant increases for NBFRs over the past decade." Peer-reviewed — Ma 2024

What matters: regulation works, and it works one compound at a time. Levels of the banned thing fall while its replacement rises. That is the pattern to watch rather than any single number.

In the Atlas: UV-328 · PBDEs · Hexabromodiphenyl ether · Heptabromodiphenyl ether

Real — the one action with a measured effect

Damp-dusting and HEPA vacuuming — boring, and it works

Almost nothing in indoor-exposure research has been tested as an intervention rather than observed as a correlation. Dust removal is the exception. A randomised housing intervention that included dust mitigation was associated with roughly 23% lower urinary DEHP metabolites in young children. Peer-reviewed — Fossa 2024 Damp cloth rather than dry, because dry dusting resuspends what it lifts.

What matters: this is the whole action list. Wet-wipe hard surfaces, vacuum with a HEPA filter, leave outdoor shoes at the door, and wash hands before eating — hand-to-mouth is the dominant route for small children, who also spend the most time on the floor.

What reduces it, per compound: the Exposure Ledger

What we cannot tell you

No published study has established a dust concentration at which any of these compounds becomes harmful in a home, for most of them. The benchmarks that exist were mostly derived for eating and drinking, not for the air and dust of a bedroom. We built The Dose Gap to count exactly that absence rather than paper over it: of the compounds measured in people's bodies by national biomonitoring, most have no published inhalation reference value at all. Regulatory — derived from EPA's consolidated toxicity values

Nor can we tell you what is in your dust. There is no consumer test worth paying for that covers this range of compounds, and we do not sell one. What the evidence supports is reducing the reservoir rather than characterising it.

Frequently asked questions

Should I get my house dust tested?
For almost everyone, no. There is no consumer test that covers the range of compounds discussed here at a price worth paying, and a result would rarely change what you should do. The evidence supports reducing the reservoir rather than characterising it: damp-wipe hard surfaces, vacuum with a HEPA filter, leave outdoor shoes at the door, and wash hands before eating. A randomised housing trial that included dust mitigation was associated with roughly 23% lower urinary DEHP metabolites in young children, which is a larger measured effect than any testing service can offer you.
If these chemicals were banned decades ago, why are they still in my house?
Because a ban stops supply, and dust is a reservoir that empties slowly. Measuring PCBs in California homes, Whitehead and colleagues estimated half-lives of 5 to 18 years indoors, and reported that PCBs are removed very slowly from the indoor environment. Some of it is also still arriving from outside: research on residential carpet dust concluded that outdoor sources may be significant determinants of indoor concentrations, so soil tracked in on shoes keeps topping the reservoir up.
Does finding one of these compounds in dust mean it is harming me?
No, and this is the most important limit on the page. Detection has outrun toxicology, so instruments now find compounds far below any level shown to matter. When chlordecone was measured in indoor dust and the intake from swallowing that dust was calculated, it came to under 1.5% of the acceptable daily intake. Presence is the start of a question, not the answer to it. For many compounds no inhalation benchmark has ever been published, which is what The Dose Gap counts.
Is a mattress a source of the compounds in house dust?
For most of the compounds on this page, no. Banned organochlorine pesticides, PCBs and legacy flame retardants reach a bedroom as residue in dust and soil rather than as anything a mattress emits, and saying otherwise would be selling you a product you do not need. There are real bedroom-source compounds, and they have their own pages; the honest split matters more than a scary total.

Citations

Whitehead TP, Brown FR, Metayer C, Park JS, Does M, Dhaliwal J, Petreas MX, Buffler PA, Rappaport SM (2014). Polychlorinated Biphenyls in Residential Dust: Sources of Variability. Environmental Science & Technology. doi:10.1021/es403863m Peer-reviewed
Dodson RE, Camann DE, Morello-Frosch R, Brody JG, Rudel RA (2015). Semivolatile Organic Compounds in Homes: Strategies for Efficient and Systematic Exposure Measurement. Environmental Science & Technology. doi:10.1021/es502988r Peer-reviewed
Harrad S, Ibarra C, Robson M, Melymuk L, Zhang X, Diamond M, Douwes J (2009). Polychlorinated biphenyls in domestic dust from Canada, New Zealand, United Kingdom and United States. Chemosphere. doi:10.1016/j.chemosphere.2009.03.020 Peer-reviewed
DellaValle CT, Wheeler DC, Deziel NC, De Roos AJ, Cerhan JR, Cozen W, Severson RK, Flory AR, Locke SJ, Colt JS, Ward MH (2013). Environmental Determinants of Polychlorinated Biphenyl Concentrations in Residential Carpet Dust. Environmental Science & Technology. doi:10.1021/es401447w 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
Dufresne M, Raffy G, Guimberteau J, et al. (2025). Determination of chlordecone in indoor dust by GC/MS/MS and associated human exposure in the French West Indies. Journal of Hazardous Materials. doi:10.1016/j.jhazmat.2025.138809 Peer-reviewed
Vaezafshar S, Siegel JA, Jantunen L, et al. (2024). Widespread occurrence of pesticides in low-income housing. Journal of Exposure Science & Environmental Epidemiology. doi:10.1038/s41370-024-00665-y Peer-reviewed
Ling T, Fang Y, Zong L, Tang Z, Fan H, et al. (2025). Review of Environmental Occurrence and Toxicity of Benzotriazole Ultraviolet Stabilizers. Environment & Health. doi:10.1021/envhealth.5c00139 Peer-reviewed
Ma Y, Stubbings WA, Jin J, Cline-Cole R, Abdallah MA-E, Harrad S (2024). Impact of Legislation on Brominated Flame Retardant Concentrations in UK Indoor and Outdoor Environments. Environmental Science & Technology. doi:10.1021/acs.est.3c05286 Peer-reviewed
Fossa A, Manz K, Papandonatos G, Chen A, La Guardia M, Lanphear B, et al. (2024). A randomized controlled trial of a housing intervention to reduce endocrine disrupting chemical exposures in children. Environment International. doi:10.1016/j.envint.2024.108994 Peer-reviewed

Every figure quoted above is taken from the sentence in the source that reports it. Where a source is quoted, the wording is the author's, not ours.

Where this sits

House dust is the settled half of a story whose airborne half lives in your indoor air, and whose most concentrated few square metres are your bedroom — you spend a third of your life with your face close to a soft, warm surface that both sheds and collects. Every compound named here has a cited page in the Atlas, and the datasets behind them are open in the Exposure Ledger.

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