At a glance
| Chemical family | Tobacco-derived / Third-hand Smoke |
| CAS number | 76014-81-8 |
| IARC classification | Group 1 (derived from Group 1 parent NNK) |
| Capture class | Out of scope (metabolite, not environmental) |
| Evidence strength | Strong |
| Primary audience | Third-hand smoke affected, general population |
Regulatory & certification status
Where NNAL (NNK Metabolite) 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 | No specific restriction identified. NNAL (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol, CAS 76014-81-8) does not appear on the REACH SVHC Candidate List or carry a harmonised CLP classification in Annex VI of Regulation (EC) No 1272/2008. (ECHA infocard/CL-inventory pages are bot-blocked, so this rests on the primary instruments plus the absence of any entry in search; treat as a negative finding rather than a positive clearance.) Its parent ketone NNK is the tobacco-specific nitrosamine that appears in carcinogen sources, not this alcohol metabolite. Regulatory — EUR-Lex · ECHA |
| United States | No specific restriction identified for NNAL itself. The official OEHHA Proposition 65 list contains the parent ketone NNK — "4-(N-Nitrosomethylamino)-1-(3-pyridyl)1-butanone", CAS 64091-91-4 — listed 04/01/1990 as a carcinogen with a No Significant Risk Level of 0.014 µg/day. NNAL, the alcohol metabolite (CAS 76014-81-8), is NOT separately on the list: the CAS does not appear in the December 2025 Prop 65 list and OEHHA has no NNAL chemical page. NNAL is also not the subject of any TSCA risk evaluation or action. The two compounds are frequently conflated. Regulatory — OEHHA |
| Canada | No specific restriction identified. NNAL (CAS 76014-81-8) does not appear on CEPA Schedule 1 (List of Toxic Substances); the only nitrosamine added to Schedule 1 is N-nitrosodimethylamine (NDMA), a different, non-tobacco-specific nitrosamine. No discrete Chemicals Management Plan risk-assessment action is attributable to NNAL as a standalone substance. (Schedule 1 page is bot-blocked to automated fetch; this is a negative finding from the published list, not a positive clearance.) Regulatory — Government of Canada |
| Australia | No specific restriction identified. NNAL (CAS 76014-81-8) is not identifiable as a discrete entry on the Industrial Chemicals Environmental Management Standard (IChEMS) Register, and no AICIS evaluation action is attributable to it as a standalone substance. (Negative finding from absence of any listing, not a positive clearance.) Regulatory — DCCEEW · AICIS |
| United Kingdom | No specific restriction identified. Under UK REACH and GB CLP (administered by HSE), NNAL (CAS 76014-81-8) has no identifiable GB mandatory classification or restriction. The GB mandatory classification list was inherited from the EU Annex VI table at the end of the transition period, where this metabolite carries no harmonised entry. (Negative finding from absence of any listing.) Regulatory — HSE |
| International | No international treaty restriction applies; NNAL is not a Stockholm Convention POP. On IARC: the parent compounds NNK and NNN were both classified Group 1 (carcinogenic to humans) in Monograph Vol. 89 (2007). NNAL itself was NOT excluded from that monograph — it has a dedicated section on animal carcinogenicity (3.2) and the evaluation states "there is sufficient evidence in experimental animals for the carcinogenicity of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL)." However, IARC did not assign NNAL its own overall Group classification (no standalone Group 1/2A/2B); only NNK and NNN received Group 1. Regulatory — IARC Monographs Vol. 89 |
| Certifications | CertiPUR-US: not addressed by name. Its program screens foam for substances classified carcinogenic/mutagenic/reprotoxic under GHS and for heavy metals (lead, mercury), certain flame retardants, formaldehyde, phthalates and high VOCs in the manufactured foam — it does not name NNAL or tobacco-specific nitrosamines (the by-name substance list lives in its technical guidelines, not verified to include this metabolite). OEKO-TEX Standard 100: does not list NNAL; its limit values cover a defined set of N-nitrosamines/nitrosatable substances (relevant to rubber/elastomer components), which does not include this tobacco-smoke metabolite. GREENGUARD/GREENGUARD Gold: a chemical-emissions (VOC) certification that does not screen for a non-volatile compound like NNAL. All three positions are 'not addressed' rather than confirmed pass/fail by name. Industry — CertiPUR-US · OEKO-TEX |
| The 72-hour test window | Largely missed. NNAL is a non-volatile, polar nitrosamine (MW ~209) found deposited in house dust and on surfaces in thirdhand-smoke research rather than off-gassing as a vapour, so a short ~72-hour VOC emissions chamber test would not reliably capture it; targeted LC-MS/MS of dust or surface wipes is the appropriate method. Inferred — from the compound's volatility/emission profile versus the VOC focus of short chamber tests |
What it is
NNAL — 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol, CAS 76014-81-8 — is a metabolite of NNK (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone), one of the most carcinogenic compounds in tobacco smoke. In the body, NNK is metabolized to NNAL via carbonyl reduction. NNAL is then excreted in urine, where it can be measured as a biomarker of NNK exposure.
Why it's relevant to the Atlas
NNAL is not an environmental compound that accumulates on bedding surfaces — it's a biomarker that appears in urine after a person has been exposed to NNK from their environment. NNAL is to NNK what carboxyhemoglobin is to carbon monoxide: a measurable downstream indicator of upstream exposure. It's included in the Atlas because peer-reviewed third-hand smoke research uses urinary NNAL as the gold-standard biomarker for documenting that contaminated bedding actually delivers a biologically meaningful dose of carcinogen to the sleeper. Peer-reviewed — Matt et al. 2014, Tob Control
Why it matters for sleep environments
The most compelling third-hand smoke evidence comes from biomonitoring studies showing elevated urinary NNAL in non-smokers living in formerly smoker-occupied homes — including infants — without any active smoking taking place. The chain of inference is: tobacco residues remain on surfaces (mattresses, bedding, upholstery, walls) for months to years after smoking stops → those residues continuously off-gas and transfer to skin and clothing of new occupants → NNK is absorbed → NNAL appears in urine. The presence of NNAL is the proof that the third-hand smoke pathway delivers actual exposure, not just measurable residues. Peer-reviewed
Related compounds
This is a preview of an Atlas entry under development. Last reviewed 2026-05-19. If you find a factual error, contact us.