At a glance
| Chemical family | A synthetic phenolic antioxidant preservative; the close sibling of BHT |
| CAS number | 25013-16-5 |
| Classification | IARC Group 2B (possibly carcinogenic) and California Prop 65 — based on rodent forestomach tumors widely judged not human-relevant; non-mutagenic. Contested weak endocrine activity |
| Where you encounter it | Cosmetics (lipstick, eye shadow, lotions, makeup) and many foods (E320: fats/oils, snacks, baked goods) |
| Sleep micro-environment relevance | A leave-on cosmetic preservative that transfers from skin and lips onto bedding; also a dietary exposure |
| Activated carbon capture | Not the lever — label-reading and product choice address it |
Regulatory & certification status
Where BHA (Butylated Hydroxyanisole) 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 REACH SVHC Candidate List or Authorisation List (Annex XIV) entry, no restriction (Annex XVII) entry, and no harmonised CLP classification (Annex VI) was identified for BHA (CAS 25013-16-5); it remains a permitted EU food additive (E320). The active EU step is the SCCS scientific advice SCCS/1682/25 (final version adopted 26 March 2026; preliminary 30 October 2025), assessing BHA in light of potential endocrine-disrupting properties, which concluded dermal cosmetic use up to 0.07% in leave-on and rinse-off products is safe. That advice is scoped to dermal exposure only (it does not cover oral-care or inhalation use) and is advisory — not a binding restriction. The absence of a Candidate-List/CLP entry is inferred from these lists not naming BHA rather than from a positive confirmation, so this remains partial. Regulatory — SCCS scientific advice on · SCCS/1682/25 final opinion |
| United States | Listed under California Proposition 65 as a carcinogen since 1 January 1990 (CAS 25013-16-5), via the authoritative-bodies mechanism on the basis of the IARC classification (OEHHA endpoint: cancer). Federally, BHA is a long-standing FDA-permitted food antioxidant: FDA lists it as GRAS for antioxidant use with the limitation that total antioxidant content not exceed a small fraction of the food's fat or oil, so it is governed under the FFDCA food-additive/GRAS framework rather than TSCA. In February 2026 the FDA opened a post-market safety re-assessment via a Request for Information (Federal Register, published 11 February 2026; Docket FDA-2026-N-0302; comments due 13 April 2026) — an information-gathering inquiry, not a finalized restriction or ban. Regulatory — OEHHA Proposition 65 · OEHHA |
| Canada | Assessed under the CEPA 1999 Chemicals Management Plan Challenge (CAS 25013-16-5). The final screening assessment concluded that BHA does NOT meet the criteria in section 64 of CEPA 1999, and that it did not meet the ecological categorization criteria for persistence, bioaccumulation or inherent toxicity to aquatic organisms. BHA is therefore not on CEPA Schedule 1 (List of Toxic Substances). Regulatory — Government of Canada |
| Australia | BHA is listed on the Australian Inventory of Industrial Chemicals and was evaluated by AICIS in an Evaluation statement (EVA00029, 14 January 2022) covering BHA and related antioxidants. That statement found the evidence that BHA is endocrine-active inconclusive and judged current environmental concentrations to be below levels of concern, concluding identified risks can be managed within existing frameworks. No specific industrial-use restriction or mandatory hazard classification was identified from that statement. Regulatory — AICIS |
| United Kingdom | Post-Brexit, Great Britain inherited the pre-2021 EU position under UK REACH and GB CLP (administered by HSE). No GB-specific UK REACH restriction and no entry in the GB Mandatory Classification and Labelling list were identified for BHA (CAS 25013-16-5). This is an absence-of-entry finding from the general HSE framework rather than a BHA-specific confirmation, so it remains partial. Regulatory — HSE |
| International | The IARC Monographs classify butylated hydroxyanisole as Group 2B, possibly carcinogenic to humans (evaluated in Volume 40, 1986; classification confirmed in Supplement 7, 1987), based on sufficient evidence in experimental animals — benign and malignant forestomach tumours in rats and hamsters at high dietary doses — with no human carcinogenicity data available at the time. Regulatory — IARC · IARC Monographs Vol. 40 / |
| Certifications | CertiPUR-US: does not name BHA; its published criteria prohibit specified flame retardants (PBDEs, TDCPP/TCEP), heavy metals (e.g., mercury, lead), formaldehyde, regulated phthalates, and ozone depleters (CFCs), and cap total VOC emissions — i.e., it targets those chemical classes rather than antioxidant additives like BHA. OEKO-TEX Standard 100: no BHA-specific limit was identified in the published criteria. GREENGUARD / GREENGUARD Gold: a low-VOC chamber-emissions certification that measures aggregate emissions and does not screen for a specific additive such as BHA. In short, no mattress/textile certification reviewed names BHA explicitly. Industry — CertiPUR-US · OEKO-TEX |
| The 72-hour test window | Largely missed. BHA is a semi-volatile antioxidant additive (a waxy solid with a vapour pressure well below that of typical VOCs) that tends to migrate into house dust and onto surfaces rather than off-gas, so a short ~72-hour VOC emissions chamber test does not reliably capture it. Inferred — from the compound's volatility/emission profile versus the VOC focus of short chamber tests |
What it is
BHA is a synthetic phenolic antioxidant — a molecule whose whole purpose is to sacrifice itself to oxygen so that the fats and oils around it don't spoil. It has been used since 1947 across the food supply (it carries the E-number E320) and, just as importantly for this Atlas, extensively in cosmetics, especially lipsticks and eye shadow, with the IARC noting "widespread human exposure by ingestion and skin application." Regulatory — IARC Monograph Vol. 40 / Suppl. 7 It is the near-twin of BHT, differing by a methoxy group, and the two are usually discussed together.
Its toxicological reputation rests almost entirely on one finding, which is exactly why context matters.
How it relates to the bedroom
The skin-to-bedding route
BHA reaches the sleep environment the way the personal-care family does. It is a leave-on preservative in lipstick, eye shadow, lotions and makeup applied to skin and lips, so a residue transfers onto pillowcases and sheets through a night of contact. Inferred — leave-on cosmetic residues transfer onto bedding, as documented for personal-care ingredients generally For most people, dietary intake is actually the larger exposure route, but the cosmetic residue is the part that touches the bed.
The carcinogen label, read honestly
Here is where an Atlas built on evidence has to push past the headline. BHA is classified IARC Group 2B and is on California's Proposition 65 — but both rest on a single line of evidence: high-dose dietary BHA caused tumors in the forestomach of rats and hamsters. Regulatory — IARC Monograph Vol. 40 / Suppl. 7 Three facts reframe that. Humans have no forestomach; IARC itself later concluded the tumor-forming mechanism is not relevant to people (though it did not revoke the classification); and BHA is not mutagenic, even reducing the activity of other carcinogens in many tests. Peer-reviewed — Felter et al. 2021 A major safety review went further, concluding BHA poses no cancer hazard at food-additive use levels and may even be anticarcinogenic. Peer-reviewed — Williams et al. 1999 So the "carcinogen" badge substantially overstates the human cancer relevance — a case where the classification machinery and the risk are out of step. Regulatory — the Prop 65 listing followed automatically from the IARC 2B classification
The more legitimate modern question
If there is a defensible reason to limit BHA, it is not cancer but the endocrine system, and even that is unsettled. Laboratory studies have reported weak estrogenic and anti-androgenic activity, perturbation of steroid hormone synthesis, and thyroid effects in animals at higher doses — but the data are mixed, BHA has negligible direct estrogen-receptor binding, and the human significance at cosmetic and food levels is unresolved. Speculation — BHA's endocrine activity is weak and contested, with uncertain human relevance at use levels That makes it a reasonable compound to reduce if you prefer, particularly during pregnancy, rather than one to fear. Inferred — the precautionary case rests on contested endocrine signals, not cancer
What the research says
- IARC 2B / Prop 65 — but on contested grounds. Rodent forestomach tumors; mechanism judged not human-relevant; non-mutagenic. Regulatory — IARC Vol. 40 Regulatory — Felter 2021
- No cancer hazard at use levels. A major review found BHA may even be anticarcinogenic in food use. Peer-reviewed — Williams et al. 1999
- Widespread skin and dietary exposure. In cosmetics (lipstick, eye shadow) and foods since 1947. Regulatory — IARC Vol. 40
- Contested weak endocrine activity. The more legitimate, still-unresolved concern. Speculation
What helps reduce it
Read the label. "BHA" is listed plainly on cosmetics and foods, so avoiding it is straightforward if you choose to. Inferred
Prefer alternatives where it matters to you. Many products have dropped BHA for natural antioxidants like tocopherol (vitamin E); this is most relevant during pregnancy. Speculation
Keep the risk in proportion. Do not treat BHA as a high cancer risk — the evidence does not support that for humans at use levels. Peer-reviewed — Williams et al. 1999
What does NOT help
- Reading the Prop 65 listing as proof of human cancer risk. The listing followed automatically from a rodent finding judged not human-relevant. Peer-reviewed — Felter et al. 2021
- Air purifiers or bedding changes. BHA is a skin-and-diet exposure, not a bedroom-air pollutant. Inferred
Open research questions
- Whether BHA's weak endocrine activity has any measurable human effect at cosmetic and dietary exposure levels. Speculation
- How a hazard classification judged not human-relevant should be reconciled with consumer-facing warning labels. Speculation
The Embr Exposure Ledger: Butylated hydroxyanisole (BHA)
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 Vol. 40 / Supplement 7 (1986/1987): Butylated hydroxyanisole. Group 2B; forestomach tumors in rats/hamsters at high dietary doses; non-mutagenic; widespread food and cosmetic (lipstick/eye shadow) exposure by ingestion and skin. IARC / IPCS INCHEM Regulatory
- Felter SP, et al. (2021). Butylated hydroxyanisole: carcinogenic food additive or harmless antioxidant? Regulatory Toxicology and Pharmacology. IARC 2B from rodent forestomach tumors; mechanism judged not human-relevant; classification not revoked; triggered Prop 65 listing and product exclusions. Via Consensus. DOI 10.1016/j.yrtph.2021.104887 Peer-reviewed
- Williams GM, et al. (1999). Safety assessment of butylated hydroxyanisole and butylated hydroxytoluene as antioxidant food additives. Food and Chemical Toxicology. Concluded BHA/BHT pose no cancer hazard and may be anticarcinogenic at food-use levels. Via Consensus. DOI 10.1016/s0278-6915(99)00085-x Peer-reviewed
Frequently asked questions
What is BHA?
BHA — butylated hydroxyanisole — is a synthetic antioxidant used since 1947 to keep fats and oils from going rancid. It is in many foods (under the E-number E320) and is also used extensively in cosmetics, particularly lipsticks, eye shadow, lotions and other products. It is the close chemical sibling of BHT, and like BHT its job is to extend shelf life by mopping up the oxygen reactions that cause spoilage.
Is BHA a carcinogen?
It carries the labels — IARC Group 2B and a California Proposition 65 listing — but the story behind them is important. Those classifications rest on tumors in the forestomach of rats and hamsters fed very high doses. The catch is that humans do not have a forestomach, and IARC itself concluded the mechanism is not relevant to people; BHA is also non-mutagenic, and major reviews find no cancer hazard at normal use levels, with some evidence it is even protective. So the 'carcinogen' label substantially overstates the human cancer relevance.
Why does it matter in the bedroom?
Through the same skin-to-bedding route as the other personal-care entries. BHA is applied directly in lipstick, eye shadow, lotions and makeup, so residue transfers onto pillowcases and sheets overnight. The more legitimate modern concern is not cancer but a contested, weak endocrine effect — some laboratory studies suggest mild estrogenic, anti-androgenic and thyroid activity — though the human significance at use levels is unresolved.
Should I avoid it?
This is a reasonable reduce-if-you-prefer compound rather than one to fear. If the Prop 65 framing bothers you, BHA is named plainly on ingredient labels, so it's easy to avoid, and many products have dropped it. But the honest read is that its human cancer risk at cosmetic and food levels appears low, and a calmer reason to limit it would be the unsettled endocrine question, especially during pregnancy. Its sibling BHT is even lower-concern.
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.