At a glance
| Chemical family | A nitrosamine (N-nitroso compound) — a trace contaminant rather than a deliberate ingredient |
| CAS number | 1116-54-7 |
| Classification | IARC Group 2B — possibly carcinogenic to humans (sufficient evidence in experimental animals, inadequate evidence in humans) |
| Where you encounter it | As a trace contaminant in DEA/TEA-based personal-care products (some lotions, shampoos, soaps) that transfer onto bedding; historically also in metalworking fluids and some tobacco products |
| Sleep micro-environment relevance | Non-volatile, so it does not off-gas; it reaches bedding by contact transfer from products applied before bed. Measured product levels are low and have fallen since the 1980s |
| Activated carbon capture | Not the relevant control — NDELA is non-volatile and deposits by contact, so laundering bedding and product choice matter more than air filtration |
What it is
NDELA belongs to the nitrosamine family — the same broad chemical class as the tobacco-smoke compounds elsewhere in this Atlas. What makes it unusual among Atlas entries is that it is not really an ingredient at all. It is a by-product. It forms when an ethanolamine — diethanolamine (DEA) or triethanolamine (TEA), both used in cosmetics as emulsifiers, foaming agents and pH adjusters — encounters a nitrosating agent such as nitrite within the same product. Regulatory — U.S. FDA, Diethanolamine (Cosmetics) Put the right two things in one bottle and a little NDELA can appear on its own.
On hazard, the record is clear and worth stating plainly. The International Agency for Research on Cancer places NDELA in Group 2B — possibly carcinogenic to humans — on the basis of sufficient evidence in experimental animals and inadequate evidence in humans. Peer-reviewed — IARC Monographs Vol. 77 (2000) In animal studies it consistently produced liver tumours in rats and tumours of the nasal cavity in both rats and hamsters, and it is genotoxic, forming DNA adducts. Peer-reviewed — IARC Vol. 77 This is a compound that deserves respect.
How it relates to the bedroom
A product-transfer contaminant, not a foam ingredient
The documented route into the sleep environment is personal care. DEA- and TEA-based ingredients live in a long list of leave-on and rinse-off products — lotions, creams, shampoos, soaps — and where a nitrosating agent is also present, trace NDELA can form during manufacture or storage. Regulatory — FDA A product applied to skin or hair in the evening keeps shedding onto whatever it touches, and at night that is your pillowcase and sheets. This is exactly the pathway behind the other personal-care entries in the Atlas: the bedroom is downstream of the bathroom shelf.
It is worth correcting a tempting assumption head-on, because the chemistry invites it. DEA is also used as a crosslinker in some flexible polyurethane foams, so one might guess NDELA forms in a mattress the same way it forms in a lotion. But two things argue against treating that as fact: NDELA has not, to our knowledge, been measured emitting from mattress foam, and it is non-volatile — unlike the small molecules behind new-foam smell, it does not evaporate into bedroom air. Inferred — DEA-in-foam plus nitrosation chemistry is plausible, but unmeasured in mattresses Until someone measures it, the mattress route is an open question, not an exposure you should assume.
How much, and which way the trend points
A 2018 risk assessment measured NDELA in cosmetic products using validated LC-MS/MS, finding it from not-detected up to about 597 micrograms per kilogram, with the amount driven by how much nitrite was present and how many nitrosating agents were in the formula. Peer-reviewed — Lim et al. 2018 Those are the numbers that sound alarming in isolation. The same study then did the arithmetic that matters: at the measured levels, the calculated margin of exposure exceeded 10,000 and the estimated lifetime cancer risk came in below one in a hundred thousand — a low calculated risk — while still recommending that amines and nitrosating agents be held to levels as low as technically feasible. Peer-reviewed — Lim et al. 2018 That is ALARA stated by the authors themselves.
The longer arc is reassuring too. Regulators noticed this decades ago. The FDA flagged nitrosamine-contaminated cosmetics as potentially adulterated as far back as 1979 and, in 1996, encouraged manufacturers to remove the ingredient combinations that let NDELA form. Regulatory — FDA By the agency's own account, DEA and DEA-related ingredients are now used far less often than when the National Toxicology Program ran its animal study, and contamination levels in personal-care products have fallen markedly since the 1980s. Regulatory — FDA; IARC Vol. 77 The exposure has been shrinking for a generation.
Why it is in the Atlas anyway
The value of this entry is the pattern it illustrates: a carcinogen that never appears on an ingredient list because it is not an ingredient — it is what two permitted ingredients can quietly make together. Inferred — generalising from the DEA/TEA-plus-nitrite mechanism That is a different kind of problem from a labelled additive, and it is one you address by understanding formulation chemistry rather than by scanning for a single bad word on a bottle. Honest about the hazard, calibrated about the dose.
What the research says
- It is a genuine animal carcinogen. IARC Group 2B; consistent liver and nasal-cavity tumours in rodents; genotoxic. Peer-reviewed — IARC Vol. 77
- It forms from ordinary cosmetic ingredients. DEA/TEA plus a nitrosating agent yields NDELA; measured up to ~597 µg/kg in cosmetics. Peer-reviewed — Lim et al. 2018
- At measured levels the calculated risk is low. Lifetime cancer risk below 1 × 10⁻⁵ in the 2018 assessment. Peer-reviewed — Lim et al. 2018
- The trend is downward. Regulatory attention since the late 1970s; DEA-ingredient use and contamination both well down from the 1980s. Regulatory — FDA
What helps reduce it
Read the labels on before-bed products. The products that touch your bedding are the ones to scrutinise. DEA/TEA-containing ingredients carry recognisable names — Cocamide DEA, Lauramide DEA, Oleamide DEA, and Triethanolamine (TEA-) compounds among them — and choosing formulations without them removes the precursor entirely. Regulatory — FDA ingredient list
Launder bedding regularly. Because NDELA arrives by contact deposition rather than through the air, the residue it rides on is removed by ordinary washing. Inferred — contact-deposited residues are removed by laundering
Prefer products that document nitrosamine control. Reputable manufacturers test for and minimise nitrosamine formation; this is exactly the ALARA step the 2018 assessment called for. Peer-reviewed — Lim et al. 2018
What does NOT help
- Air purifiers and activated carbon. NDELA is non-volatile and deposits by contact, so air-cleaning devices do nothing for it. Inferred — from its non-volatility
- Chasing "nitrosamine-free" claims without substance. The meaningful signal is the absence of the DEA/TEA precursors and documented nitrosation control, not a marketing phrase. Inferred
Open research questions
- Whether DEA-crosslinked polyurethane foams shed or form any measurable NDELA in the sleep environment — currently untested. Speculation
- Real-world transfer efficiency of NDELA from skin- and hair-applied products onto bedding over a night's contact. Speculation
Citations
- IARC (2000). N-Nitrosodiethanolamine. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Vol. 77, p. 403 — overall evaluation Group 2B (possibly carcinogenic to humans); sufficient evidence in experimental animals. inchem.org — IARC Vol. 77 summary Peer-reviewed
- Lim DS, Roh TH, Kim MK, Kwon YC, Choi SM, Kwack SJ, Kim KB, Yoon S, Kim HS, Lee BM (2018). Risk assessment of N-nitrosodiethylamine (NDEA) and N-nitrosodiethanolamine (NDELA) in cosmetics. Journal of Toxicology and Environmental Health, Part A, 81(12):465–480. DOI 10.1080/15287394.2018.1460782 (PMID 29694274) Peer-reviewed
- U.S. Food and Drug Administration. Diethanolamine (Cosmetic Ingredients) — summarising the NTP 1998 animal carcinogenicity findings for DEA and DEA-related ingredients, the mechanism of nitrosamine contamination, and FDA's current position. fda.gov Regulatory
Frequently asked questions
Is NDELA something manufacturers add to products?
No. NDELA is not an ingredient anyone adds on purpose. It is a contaminant that forms when ethanolamine ingredients — diethanolamine (DEA) and triethanolamine (TEA), used as emulsifiers and foaming agents — meet a nitrosating agent such as nitrite inside the same product. That is why you will not see it on a label: it is a by-product of two otherwise-permitted ingredients reacting, not a listed component.
Is NDELA in my mattress?
There is no good evidence that it is. DEA is used as a crosslinker in some flexible polyurethane foams, so it is tempting to assume the same nitrosamine could form in a mattress — but NDELA has not been measured emitting from mattress foam, and unlike the gases behind "new-foam smell" it is non-volatile, so it does not off-gas into the air. The documented bedroom route is personal-care products that transfer onto bedding, not the foam itself. Treat the mattress route as an open question, not an established exposure.
How worried should I be about NDELA?
It is a genuine animal carcinogen — IARC Group 2B, possibly carcinogenic to humans — so it is worth taking seriously and reducing where it is easy to. But the calibrated picture is reassuring: a 2018 risk assessment of NDELA measured in cosmetics calculated a lifetime cancer risk below one in a hundred thousand at measured levels, and the DEA-based ingredients that allow it to form have become far less common since the 1980s. The honest takeaway is hazard yes, panic no.
How do I reduce NDELA exposure in the bedroom?
Focus on the products you apply before bed, since those are what transfer onto your pillow and sheets. Check leave-on lotions, shampoos and soaps for DEA/TEA-based ingredients — common names include Cocamide DEA, Lauramide DEA, Oleamide DEA, and Triethanolamine (TEA-) compounds — and prefer formulations without them. Wash bedding regularly, since contact-deposited residue comes off in the laundry. Air purifiers and carbon filters do not help here, because NDELA is non-volatile and arrives by contact, not through the air.
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.