"What foods contain BHA and BHT?"

"Common sources include breakfast cereals, potato chips and other snack foods, chewing gum, butter and lard, vegetable shortening, preserved meats, and packaged baked goods. Both are listed by name on ingredient labels, so checking is straightforward."

"Why is BHA still in food if it's listed as a probable carcinogen?"

"The NTP listing is based on animal studies using much higher doses than humans consume from food. The rodent tumors BHA caused are in the forestomach, which humans don't have. FDA still permits BHA because the evidence hasn't been considered sufficient to establish risk at current dietary exposure levels. This is an ongoing regulatory debate, not a settled question."

"Is BHT safer than BHA?"

"BHT is not on the NTP carcinogen list, which makes it look cleaner than BHA at first glance. But BHT's research record is genuinely mixed. Some studies have shown anti-tumor effects; others have found increased tumor promotion depending on dose and timing. Neither additive has a straightforward safety story."

"Can I avoid BHA and BHT?"

"Yes, without much difficulty. Both are listed by name on ingredient labels. Many cereal brands, snack brands, and cooking oils use alternative preservatives (tocopherols, vitamin C, rosemary extract) or no added preservatives at all. Reading labels is the most effective approach."

BHA and BHT: The Antioxidant Preservatives Under FDA Review

Quick Answer

BHA is listed as 'reasonably anticipated to be a human carcinogen' by the National Toxicology Program, based on animal studies. BHT has a more mixed record. Both are still FDA-permitted in food at very low levels, but both are on FDA's priority re-evaluation list. The amounts in food are small, and direct harm to humans isn't proven, but the uncertainty is real enough to justify caution.

The Science

Fat goes rancid. That’s not a metaphor. It’s chemistry.

When oxygen attacks the double bonds in unsaturated fats, a chain reaction starts. Free radicals form, then react with more fat molecules, creating a cascade that produces the aldehydes and ketones responsible for the smell and taste of spoiled fat. This process is called lipid oxidation, and it’s why old cooking oil smells off and stale potato chips taste wrong.

BHA and BHT are the food industry’s answer to that problem. They’re sacrificial antioxidants. They donate hydrogen atoms to free radicals before those radicals can attack fat molecules, interrupting the chain reaction before it starts. Think of them as catching the spark before it starts a fire.

That mechanism is straightforward and well-understood. The safety question is considerably less simple.

What BHA and BHT Actually Are

BHA stands for butylated hydroxyanisole. BHT stands for butylated hydroxytoluene. Both are phenolic antioxidants, meaning their core structure is a benzene ring with a hydroxyl group attached. Both are synthetic compounds developed in the mid-20th century and added to the FDA’s GRAS (Generally Recognized as Safe) list.

They’re not interchangeable. BHA and BHT have different molecular structures, different solubility profiles, and different stability characteristics across temperature ranges. Some applications use one, some use the other, and some use both together since they have a synergistic effect at low doses.

You’ll find them in:

Breakfast cereals (check the bag, not just the box)
Potato chips and other fried snack foods
Chewing gum
Vegetable shortening and lard
Preserved meats and sausages
Packaged crackers and cookies
The packaging itself in some cases (added to preserve the package material)

FDA permits both at levels up to 0.02% of fat content. That works out to roughly 200 mg per kilogram of fat in the product.

The BHA Problem

BHA is where the clearer concern lives.

The US National Toxicology Program (NTP) publishes the Report on Carcinogens, a federal document that lists substances with evidence of carcinogenicity. BHA appears in it as “reasonably anticipated to be a human carcinogen.” The 15th edition (2021) maintains this designation.

The evidence comes from animal studies. Rats and other rodents given high doses of BHA developed tumors in the forestomach. The forestomach is a pre-gastric compartment found in rodents but not in humans. This anatomical difference is why FDA has not banned BHA. The argument: if the tumor site doesn’t exist in humans, the finding may not translate.

That’s a reasonable scientific argument. It’s also not the same as saying BHA is safe.

EFSA re-evaluated BHA in 2011 and set an acceptable daily intake (ADI) of 1.0 mg/kg body weight per day. EFSA concluded that current use levels were within safe limits but flagged the forestomach carcinogenicity data as a concern worth monitoring.

California’s Proposition 65 added BHA to its list of chemicals known to cause cancer. That list has its own controversies (it includes chemicals at extremely low risk thresholds), but it’s another data point in the regulatory picture.

The BHT Situation

BHT’s story is genuinely messier.

It doesn’t have an NTP carcinogen listing. But the research record is far from reassuring in a different way: BHT has been shown to both inhibit and promote tumors depending on the study, the dose, the timing of administration, and the type of cancer being studied.

Some early studies found BHT reduced tumor incidence when given before cancer-causing agents, suggesting a protective effect. Later studies found that BHT could act as a tumor promoter (not a direct carcinogen, but something that accelerates the growth of existing tumors) in certain conditions. The direction of the effect isn’t consistent.

EFSA re-evaluated BHT in 2012 and set an ADI of 0.25 mg/kg body weight per day. That’s a conservative limit. EFSA expressed concern about the mixed carcinogenicity data and noted that some studies showed effects at doses that could be reached through dietary exposure.

The NTP has reviewed BHT but not listed it as a carcinogen, citing the inconsistency of findings.

Mixed evidence isn’t the same as clean evidence. For BHT, it means we genuinely don’t know the full picture.

How Much Are People Actually Eating?

Estimated daily intake of BHA and BHT from food in the US is generally well below the EFSA ADIs for most people. A reasonable estimate for BHA dietary exposure is in the range of 0.05-0.5 mg/kg body weight per day, depending on diet. This is below the 1.0 mg/kg ADI.

But two things complicate this.

First, estimates are based on average consumption. Someone eating multiple servings of preserved snack foods daily could come in at higher exposures than the average. The people at the upper end of the exposure distribution are the ones most relevant to safety assessment.

Second, the ADI doesn’t account for cumulative exposure from multiple sources over a lifetime. The animal study doses that caused tumors were high, but they were also sustained over the animals’ entire lifespans. Chronic low-dose exposure is harder to study.

What FDA Is Doing Now

BHA is currently on FDA’s priority list for re-evaluation. The agency committed in 2025 to reviewing a set of additives that have not been subject to modern toxicological assessment.

This doesn’t mean a ban is imminent. The FDA review process moves slowly. But it does mean the question of whether BHA should remain in food is officially open at the federal level.

BHT is not on the same priority list as of the time of writing, but given the overlapping concerns and similar use profile, it would be reasonable to expect it to face similar scrutiny.

The Verdict

The caution designation here isn’t a verdict of “this will harm you.” It’s a recognition that:

BHA carries a formal probable carcinogen designation from a US government body.
BHT has a research record too mixed to call clean.
Both are under active regulatory attention.
Both are easy to avoid when you look for alternatives.

The amounts in food are small. The rodent tumor evidence doesn’t map perfectly to human biology. But these additives serve a function (fat preservation) that can be achieved with alternatives like vitamin E (tocopherols), vitamin C (ascorbic acid), or rosemary extract. When it’s easy to choose a product with one of those alternatives instead, that’s a reasonable choice to make.

What This Means for You

BHA and BHT appear primarily in breakfast cereals, snack foods, chewing gum, and packaged cooking fats. Checking ingredient labels is straightforward since both are listed by name. Choosing products without them is easy in most categories. This isn't a reason to panic about a bowl of cereal you ate last year. It's a reason to prefer alternatives when the choice is convenient.