BHA and BHT: Are These Common Preservatives Actually Safe?

What are BHA and BHT?

BHA (butylated hydroxyanisole) and BHT (butylated hydroxytoluene) are synthetic phenolic antioxidants developed in the 1940s and 1950s. Their function is to prevent oxidative rancidity in fats and oils — they essentially interrupt the chemical chain reaction that causes fat to go stale and develop off-flavors.

Both compounds are lipophilic (fat-soluble), which is why they appear primarily in fat-containing foods and products where fat content is high or where fat migration from packaging is possible. They are often used together because they have a synergistic effect — their combined antioxidant activity exceeds either additive alone.

In the US, both are classified as GRAS, with the GRAS determination largely dating to assessments conducted in the 1950s and 1970s. The FDA has acknowledged that some GRAS designations are based on outdated toxicology and has been gradually reviewing them — BHA and BHT are on that list.

The NTP carcinogen classification

The National Toxicology Program (NTP), a federal program within the Department of Health and Human Services, publishes periodic Reports on Carcinogens — an authoritative federal document listing substances with sufficient evidence to be considered carcinogenic or potentially carcinogenic.

BHA has appeared in the NTP Report on Carcinogens since the second edition (1981). The 15th edition (2021) retains BHA as "reasonably anticipated to be a human carcinogen" based on sufficient evidence of carcinogenicity in experimental animals. Specifically, rat and hamster studies showed BHA caused papillomas and squamous cell carcinomas in the forestomach — a stomach compartment present in rodents but not in humans, which is a critical caveat.

BHT does not appear in the NTP Report on Carcinogens. The evidence for BHT is more contradictory: some animal studies show it promotes tumor growth when animals are pre-exposed to a known carcinogen, while other studies show BHT inhibits tumors. This dual profile — promoter in some contexts, inhibitor in others — makes BHT harder to classify and is part of why it remains under review.

The FDA's position and ongoing reassessment

The FDA's current GRAS status for BHA and BHT reflects assessments that are decades old. Under 21 CFR 182.3169 (BHA) and 21 CFR 182.3173 (BHT), both are permitted in food with specific use limitations — primarily to protect the fat content of food from rancidity, at levels up to 0.02% of fat or oil content.

In 2023, the FDA's Coordinated Framework for GRAS Reassessment identified BHA as one of the additives warranting updated safety review. This is an acknowledgment that the original GRAS determination — made before modern toxicology methods existed — may not reflect current scientific standards. However, a GRAS reassessment is a lengthy process, and FDA has not announced a timeline for BHA or BHT decisions.

The situation creates a regulatory anomaly: one arm of the federal government (NTP) lists BHA as an anticipated carcinogen while another arm (FDA) continues to classify it as safe. These agencies have different mandates — NTP identifies hazards, FDA makes risk assessments that weigh hazard against actual exposure — but the disconnect is notable and has drawn criticism from consumer advocates.

Foods that commonly contain BHA or BHT

Both additives must be declared in the ingredient list by name — "BHA" or "BHT" — when added directly to food. However, they can appear unlisted when used as a component of packaging materials (where BHT migrates into the food) or in flavorings and other compound ingredients, where only the flavoring needs to be declared.

• Breakfast cereals (many varieties)

  BHA, BHT

• Instant mashed potatoes

  BHA

• Snack crackers and chips

  BHT

• Butter and lard

  BHA, BHT

• Chewing gum

  BHT

• Vegetable oils and shortening

  BHA, BHT

• Dry soups and bouillon

  BHT

• Enriched rice products

  BHA

• Sausage and pork products

  BHA

• Beer (packaging migration)

  BHT

EU restrictions: stricter but not banned

The EU permits BHA and BHT under Regulation (EC) No 1333/2008 but at significantly lower maximum levels and with categorical restrictions the US does not have. Both are prohibited in baby food, infant formula, and follow-on formula. Maximum use levels for BHA in fat-containing foods are set at 100-200 mg/kg of fat content in most categories — lower than the US limit of 0.02% (200 mg/kg) but in the same general range.

EFSA conducted a full safety reassessment of BHA (E320) and BHT (E321) in 2012. Its conclusion was that current permitted use levels were acceptable for adults but noted concerns about children's exposure relative to body weight. EFSA also flagged uncertainty about BHA's potential endocrine-disrupting properties — a concern that goes beyond the carcinogenicity debate and touches on hormonal effects at low doses. A follow-up assessment on endocrine disruption potential was scheduled but has not yet resulted in changed authorization levels.

Natural alternatives and industry trends

Consumer pressure and retailer policies have pushed many food manufacturers to replace BHA and BHT with alternative antioxidants. The most common replacements include:

• Tocopherols (vitamin E) — Most common replacement; naturally occurring in many plant oils; effective antioxidant
• Rosemary extract — Contains carnosic acid and carnosol; effective but can impart flavor
• Ascorbic acid (vitamin C) — Water-soluble; used in combination with other antioxidants
• Mixed tocopherols — Blend of alpha, beta, gamma, delta tocopherols; broader antioxidant spectrum

Several major US retailers — including Whole Foods Market — ban BHA and BHT from their private-label products. Target's Good & Gather line and some Kroger brands have also moved away from both additives. This market pressure has accelerated reformulation independent of regulatory action.

BHA and BHT in pet food

BHA and BHT are widely used as fat preservatives in dry dog and cat food. Kibble has a high fat content that would otherwise go rancid quickly; BHA and BHT extend shelf life significantly. The Association of American Feed Control Officials (AAFCO) permits both under 21 CFR 573 — a separate regulatory framework from human food — with BHA permitted up to 0.02% of total fat content.

Veterinary concern has grown alongside consumer awareness. In 2023, AAFCO reviewed preservative use in pet food as part of its model regulations update cycle. No restrictions were added, but the review acknowledged that several member states had received increased inquiries about synthetic antioxidants. The NTP carcinogen classification for BHA applies regardless of whether the exposure route is human food or pet food — the underlying animal toxicology data is the same.

The pet food market has responded to this pressure commercially. Major brands including Blue Buffalo, Orijen, and Acana now prominently market BHA/BHT-free formulations, typically using mixed tocopherols (vitamin E) as a replacement antioxidant. These formulations command a price premium and are positioned as cleaner options — though it is worth noting that tocopherols are less stable than BHA/BHT in some heat-processing conditions, which can affect shelf life.