At a glance
| Chemical family | Epoxide (oxirane) — a small reactive cyclic ether; an industrial feedstock and sterilant |
| CAS number | 75-21-8 |
| Classification | IARC Group 1 (carcinogenic to humans), Monograph Volume 100F; NTP — known to be a human carcinogen; EPA — carcinogenic to humans; subject of EPA's 2024 emission standards for commercial sterilizers |
| Where you encounter it | Chemical manufacturing (feedstock for ethylene glycol, glycol ethers, surfactants, and polyether polyols); medical-device and spice sterilization; community air near commercial sterilization facilities |
| Sleep micro-environment relevance | Upstream foam chemistry — used to make and 'cap' the polyols that react with isocyanates to form polyurethane; not a documented emission from finished mattress foam |
| Activated carbon capture | Limited — a very small, volatile, water-reactive gas; not a primary capture target relative to larger compounds |
Regulatory & certification status
Where Ethylene Oxide stands across the major regulatory systems and the certifications a bedroom product might carry. Each row links to the governing instrument; where a jurisdiction has no specific measure, that is stated plainly rather than left blank.
| European Union | Ethylene oxide (oxirane, Index 603-023-00-X) carries a harmonised CLP classification under Annex VI to Regulation (EC) No 1272/2008: carcinogen (Carc. 1B), germ-cell mutagen (Muta. 1B) and reproductive toxicant (Repr. 1B), alongside Flam. Gas 1 / Press. Gas and acute-toxicity/STOT hazards. It is not on the REACH SVHC Candidate List or the Annex XIV Authorisation List; its use as a sterilant/biocide is instead controlled under the Biocidal Products Regulation, and no Annex XVII consumer restriction specific to ethylene oxide was confirmed. Regulatory — EUR-Lex · CCOHS |
| United States | EPA regulates ethylene oxide principally under FIFRA as an antimicrobial sterilant pesticide (medical-device, spice and equipment sterilisation), and its IRIS assessment characterises it as carcinogenic to humans by the inhalation route. Under California Proposition 65 it is listed for cancer (1 Jul 1987), female reproductive toxicity (27 Feb 1987), and developmental and male reproductive toxicity (both 7 Aug 2009). Regulatory — US EPA · US EPA IRIS |
| Canada | Ethylene oxide is on the CEPA Schedule 1 List of Toxic Substances. Following a Priority Substances List assessment that concluded it is 'toxic' under section 64 (a danger to human life or health, though without harmful environmental effects), it was recommended for addition to Schedule 1 in 2002 and is now listed. A federal risk-management strategy addresses its release, principally from sterilisation and chemical manufacturing. Regulatory — Government of Canada |
| Australia | Ethylene oxide (oxirane) has been assessed by the Australian industrial-chemicals regulator under the IMAP framework (now AICIS), which identifies it as a carcinogen. It is a listed reportable substance on the National Pollutant Inventory. A specific IChEMS environmental schedule could not be confirmed against the official register. Regulatory — AICIS IMAP · DCCEEW |
| United Kingdom | Great Britain assimilated the EU harmonised classification in force on 31 December 2020 into the GB Mandatory Classification and Labelling (GB MCL) list under GB CLP, so ethylene oxide retains its Carc. 1B / Muta. 1B / Repr. 1B classification in GB. HSE administers GB CLP and UK REACH; no GB-specific divergence for this substance was identified. Regulatory — HSE |
| International | The IARC Monographs classify ethylene oxide in Group 1 (carcinogenic to humans); it is a direct-acting alkylating agent acting by a genotoxic mechanism, evaluated in Volume 100F (and earlier in Supplement 7 and Volumes 60 and 97). No Stockholm or Minamata Convention listing applies. Regulatory — IARC · IARC Monograph Vol. 100F |
| Certifications | CertiPUR-US: not named — its 2025 prohibited-substances list targets flame retardants, certain ozone-depleting and chlorinated solvents, heavy metals, phthalates and a formaldehyde emissions limit, but does not list ethylene oxide, which is a sterilant residue rather than a foam ingredient. OEKO-TEX: the ECO PASSPORT / STANDARD 100 restricted-substance framework governs intentionally-added process chemicals, but a specific ethylene oxide residue limit was not confirmed in the public standard. GREENGUARD/GREENGUARD Gold: a low-VOC emissions certification (UL 2818 / CDPH Section 01350) that screens broad VOC totals rather than certifying against ethylene oxide by name. Industry — CertiPUR-US · OEKO-TEX |
| The 72-hour test window | Detectable in principle. Ethylene oxide is an extremely volatile gas (boiling point ~10.7 degrees C), so it behaves as a VOC and a short chamber test could capture it if present — but in finished bedding it appears as a sterilisation residue that dissipates quickly, not as a foam off-gassing component, so absence in a 72-hour test does not imply it was never used. Inferred — from the compound's volatility/emission profile versus the VOC focus of short chamber tests |
What it is
Ethylene oxide is the simplest epoxide: a two-carbon ring closed by an oxygen, under ring strain that makes it extraordinarily reactive. That reactivity is the source of both its usefulness and its danger. As a gas, it penetrates and kills microorganisms by damaging their DNA, which makes it the dominant sterilant for heat-sensitive medical equipment. The very same DNA-damaging chemistry makes it carcinogenic to the humans exposed to it.
IARC classifies ethylene oxide as Group 1 — carcinogenic to humans — one of the relatively few chemicals at the top of the classification scale, with the strongest human evidence for lymphoid cancers and breast cancer. Regulatory — IARC Monograph 100F The U.S. National Toxicology Program lists it as a known human carcinogen, and EPA's assessment likewise classifies it as carcinogenic. Regulatory — NTP, EPA
Industrially, ethylene oxide is overwhelmingly an intermediate: more than 97% of production goes into making other chemicals — ethylene glycol (antifreeze) is the largest single use, alongside glycol ethers, surfactants, and polyether polyols. In foam chemistry it is used to build and 'cap' polyols, converting their secondary hydroxyl groups into the more reactive primary ones that perform well in polyurethane. Regulatory — ATSDR
How it relates to the bedroom
Upstream foam chemistry, not a mattress emission
Ethylene oxide's foam connection is real but indirect: it helps make the polyol half of polyurethane. By the time a polyol reaches the foam reaction — and certainly by the time the foam is cured in a mattress — the ethylene oxide has been consumed. A finished polyurethane mattress is not a documented ethylene-oxide source. This is the opposite of the amine catalysts, which can stay emissive in the finished product. Inferred — ethylene oxide is consumed upstream in polyol manufacture; finished foam is not a characterised source
Where the real exposure is: occupational and community air
The documented ethylene-oxide exposures are occupational (chemical plants and sterilization facilities) and community — the air around commercial sterilizers. In March 2024 the EPA finalized tighter emission standards for ethylene-oxide commercial sterilizers, projecting more than a 90% reduction in emissions specifically to lower the elevated cancer risk for people living near these facilities. Regulatory — EPA 2024 NESHAP That is where the large, documented exposures happen.
One recent measurement complicates the tidy version of that story, and honesty means putting it on the table. In a controlled climate-chamber study of typical daycare activities, ethylene oxide emitted from new mattresses under warm, humid conditions reached concentrations above the 10−5 lifetime cancer-risk threshold for young children, alongside styrene and tetrachloroethylene traced to other sources. Peer-reviewed — Zheng et al. 2024, Sci Total Environ This is one small study of a handful of mattresses, and it does not overturn the picture: the exposures that dominate ethylene-oxide risk are still occupational and community air near sterilizers. But it is a real, peer-reviewed detection of the gas coming off a new mattress under body-like heat and humidity, which sits in tension with treating a mattress as a non-source, and it is worth watching rather than waving away.
Sterilized-product residue
Ethylene oxide is widely used to sterilize medical devices and some consumer goods and spices, and sterilized items can carry trace residual gas that dissipates with aeration — which is why residue limits exist for sterilized products. For typical bedroom items this is a minor pathway, but it is the one consumer route worth naming. Regulatory
What the research says
A known human carcinogen
The Group 1 classification is among the strongest IARC assigns: convincing human evidence, a clear genotoxic mechanism, and consistency with the animal data. Regulatory — IARC Monograph 100F The cancers most associated with ethylene oxide exposure are lymphohaematopoietic (lymphoid) and breast cancer, observed in occupationally exposed cohorts.
Why the bedroom story is honest-by-subtraction
It would be easy to weaponize "Group 1 carcinogen in foam chemistry." We won't. The truthful account is that ethylene oxide is a serious carcinogen whose exposures are occupational and community, and whose foam role is upstream and consumed. Including it makes the foam-chemistry picture complete; implying your mattress emits it would be false. Inferred
What helps reduce exposure
This is not a mattress-controllable exposure. The meaningful ethylene-oxide reductions are regulatory and occupational — the EPA's sterilizer emission standards, and workplace controls in plants and sterilization facilities. We say this plainly because the honest answer is not a consumer product tweak.
Aerate ethylene-oxide-sterilized items per their instructions. For the minor residue pathway, following aeration guidance on sterilized products is the relevant step.
General ventilation helps with indoor air broadly, but ethylene oxide specifically is not a finished-mattress emission to filter.
What does NOT help
- Treating your mattress as an ethylene-oxide source. It is not one; the exposures that matter are occupational and near sterilizers.
- Activated-carbon filtration as a fix. Ethylene oxide is a tiny, reactive gas and not a primary capture target; more importantly, it is not emitting from your bed to capture.
- Conflating ethylene oxide with the foam's amine catalysts. Those can off-gas from finished foam; ethylene oxide does not.
Open research questions
- Whether any consumer textiles or bedding items are ethylene-oxide sterilized at a scale that produces measurable residue in the sleep environment. Speculation
- The completeness of ethylene-oxide consumption in polyol manufacture and whether any trace persists into finished foam. Speculation
The Embr Exposure Ledger: Ethylene oxide
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.
Citations
- IARC Monographs Volume 100F. Ethylene oxide — Group 1 (carcinogenic to humans). Regulatory
- NTP. 15th Report on Carcinogens — Ethylene oxide (known to be a human carcinogen). Regulatory
- EPA. IRIS — Ethylene oxide; 2024 NESHAP for ethylene oxide commercial sterilizers. Regulatory
- ATSDR. Toxicological Profile for Ethylene Oxide (2022). Regulatory
- Zheng H, Csemezová J, Loomans M, Walker S, Gauvin F, Zeiler W. (2024). Species profile of volatile organic compounds emission and health risk assessment from typical indoor events in daycare centers. Science of the Total Environment 918:170734. doi.org/10.1016/j.scitotenv.2024.170734 Peer-reviewed
Frequently asked questions
What is ethylene oxide and why is it concerning?
Ethylene oxide is a small, highly reactive gas. IARC classifies it as Group 1 — carcinogenic to humans — and the U.S. National Toxicology Program lists it as a known human carcinogen, with the strongest evidence for lymphoid cancers and breast cancer. The same DNA-damaging reactivity that makes it an effective sterilizing gas is what makes it carcinogenic. Regulatory
How is ethylene oxide connected to mattress foam?
Ethylene oxide is a feedstock in polyether-polyol chemistry — the polyol half of polyurethane. It is used to 'cap' polyols (converting secondary hydroxyl groups to more reactive primary ones) used in foam. So it is upstream foam chemistry, consumed in making the polyol; it is not a residue that sits in a finished mattress in any significant amount.
Where does real ethylene oxide exposure happen?
The documented exposures are occupational (chemical plants, sterilization facilities), community air near commercial sterilizers, and residues on ethylene-oxide-sterilized products such as some medical devices. The EPA finalized stronger emission standards for commercial sterilizers in 2024 specifically to cut community cancer risk. A cured polyurethane mattress is not a major documented ethylene-oxide source, though a 2024 climate-chamber study did detect the gas emitting from new mattresses under warm, humid conditions.
Is ethylene oxide used to sterilize consumer products?
Yes — it is widely used to sterilize heat-sensitive medical equipment and some consumer goods and spices. Sterilized items can carry trace residual ethylene oxide that dissipates with aeration. For most bedroom items this is not a significant pathway, but it is the reason ethylene oxide residue limits exist for sterilized products.
Should I worry about ethylene oxide from my mattress?
No — the mattress itself is not a meaningful ethylene-oxide source. We include ethylene oxide because it is part of the upstream foam-chemistry story (polyol feedstock) and because it is a Group 1 carcinogen worth understanding. The exposures that matter are occupational and community air near sterilizers, not your bed.
Related compounds
Embr is a sleep environment company researching and addressing the chemistry of the bedroom. Research and product development in progress.
Last reviewed 2026-06-27. If you find a factual error, contact us.