What is E320?
Butylated hydroxyanisole (BHA) — a synthetic antioxidant carrying an IARC "possibly carcinogenic" classification that's never been formally lifted, despite later analysis questioning whether it applies to humans.
E320 (BHA) is a synthetic antioxidant that prevents fats and oils from going rancid. In 1986, IARC classified it as "possibly carcinogenic to humans" (Group 2B) based on stomach tumours in rodents, but IARC's own later analysis found the mechanism behind those tumours isn't considered relevant to human anatomy, and a 2025 European Commission safety review dismissed the cancer risk on the same grounds. EFSA's own re-evaluation actually raised its safe daily intake limit over time. The classification has never been formally revoked. Goodnessly rates it Avoid.
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Read the FAQ →
What is BHA?
Butylated hydroxyanisole is a fully synthetic antioxidant, working by neutralising the free radicals that cause fats and oils to oxidise and turn rancid. It's often used alongside a related antioxidant, BHT, and is generally considered less controversial than BHA by comparison, since BHA carries the IARC classification discussed below while BHT and TBHQ don't carry the same designation. Interestingly, in laboratory studies BHA has actually been shown to reduce the activity of various other mutagens and carcinogens — an antioxidant protective effect that sits alongside its own more controversial classification.
What's it used for?
- Preventing fats and oils from turning rancid
- Extending shelf life in shortenings and cooking oils
- Used in dry breakfast cereals
- Processed potato products
- Sometimes used in food packaging to protect the food inside
Where you'll find 320 on the shelf
Common wherever fats and oils need protection from rancidity.
Is BHA safe? What the research says
BHA's story is a genuine case of a cancer classification that hasn't kept pace with the scientific understanding of why it was made in the first place.
| Region | Status | What this means |
|---|---|---|
| AU/NZ Australia & New Zealand (FSANZ) | Permitted | Permitted as an antioxidant, must be declared by name or number on the ingredient list. |
| EU European Union (EFSA) | Permitted, ADI raised | Listed as E320. EFSA's 2011 re-evaluation found no genotoxicity concern and actually raised the Acceptable Daily Intake from 0.5mg to 1.0mg per kilogram of bodyweight per day, based on the same underlying rat forestomach data. |
| US United States (FDA) | GRAS | Holds Generally Recognized As Safe status, permitted at specific maximum levels (2 to 1,000 parts per million depending on the food). |
IARC classified BHA as Group 2B ("possibly carcinogenic to humans") in 1986, based on tumours found in the forestomach of rats, mice and hamsters exposed to high dietary doses. Humans don't have a forestomach, and IARC's own later technical review concluded this specific tumour mechanism isn't considered relevant to human cancer risk — though the original classification has never been formally withdrawn. No human epidemiological studies have established a link between BHA and cancer.
- 2025 European Commission review: the EU's Scientific Committee on Consumer Safety evaluated BHA (in the context of cosmetics use) and concluded the rodent forestomach tumours were not relevant to human risk, dismissing the cancer concern on that basis.
- California Proposition 65: BHA remains listed under this California regulation as a direct consequence of the original 1986 IARC classification, which continues to drive consumer concern and its exclusion from some "clean label" and children's product certifications, even as the scientific case for human relevance has weakened over time.
This section is checked periodically rather than continuously — if you're reading this well after the date above, it's worth confirming nothing has changed before citing it.
Who might want to limit or avoid it
- Anyone who prefers to steer clear of substances carrying an active IARC 2B classification, even where the mechanism behind it has been questioned
- Anyone shopping for "clean label" or children's products, since BHA is commonly excluded from these certifications specifically because of the Proposition 65 listing
- Anyone who prefers naturally-sourced antioxidants like Vitamin E (tocopherols) where practical
Goodnessly rates E320 Avoid. The forestomach-tumour mechanism behind its original classification is now widely considered not relevant to humans, and EFSA's own re-evaluation became more reassuring over time — but the IARC classification itself has never been formally withdrawn, which keeps it out of our Safe tier.
How to spot it on a label
E320 must be declared clearly. Look out for:
- Butylated hydroxyanisole
- BHA
- 320 or E320
- "Antioxidant (320)" in the ingredients list
Cooking oils, breakfast cereals and processed potato products are the most common places to find it.
Related additives
Frequently asked questions
Is BHA a proven carcinogen in humans?
No human studies have established a link between BHA and cancer. Its "possibly carcinogenic" classification is based entirely on tumours in the forestomach of rodents, an organ humans don't have, and IARC's own later analysis concluded that specific tumour mechanism isn't considered relevant to human cancer risk.
Why hasn't the IARC classification been removed if the mechanism doesn't apply to humans?
IARC classifications are formally revisited only periodically, and BHA's Group 2B status from 1986 has not gone through a formal re-evaluation process to update it, despite the agency's own later technical conclusions questioning its human relevance.
What's the difference between BHA and BHT?
They're related synthetic antioxidants, often used together, but BHA carries the IARC 2B classification discussed here, while BHT does not carry the same designation.
Does Goodnessly rate E320 as safe, caution, or avoid?
Goodnessly rates E320 (BHA) as Avoid. The forestomach-tumour mechanism behind its original classification is now widely considered not relevant to humans, but the IARC classification itself has never been formally withdrawn, which keeps it out of our Safe tier.
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