BHA and BHT are found in cosmetics, animal feed, fuels, lubricants, medical supplies and packaged foods.
Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are two of the most common chemicals we encounter in our daily lives.
They’re antioxidants — synthetic preservatives made from petroleum used in food and manufacturing industries. They’re found in cosmetics, animal feed, fuels, lubricants, medical supplies and packaged foods. They’re also stabilizers for essential oils, paraffin and polyethylene plastics used in packaging.
Health and environmental hazards of BHA and BHT
Human health risks and concerns
BHA is detectable in human tissue, even fingernails. Not surprising given that people absorb most of the chemical in food. It’s also in soil, sedimentary matter, sewage, sludge and surface and groundwater. People are exposed to BHT from household dust.
Governments and the scientific community are concerned about the possible effects of BHA and BHT on human health. They recommend limiting their use.
Workers in certain industries, (e.g., food, rubber, livestock production and animal feed and cosmetic manufacturing and some petroleum workers) are exposed to higher levels of BHA. Workers serving fried and oily products in the fast food industry also have greater exposure. If you’re exposed to or BHA or BHT at work, talk to your employer about relevant laws and safe handling and storage practices.
The International Agency for Research on Cancer classified BHA as a possible human carcinogen in 1986. So why is it still used in consumer products and in some 4,600 different food items? Toxicity is complex and difficult to determine. Animal research, especially relating to pharmaceuticals and environmental agents, is a poor predictor of human impact. Available data aren’t definitive in establishing a link between human cancer and BHA exposure.
Environmental risks and concerns
BHA and BHT bioaccumulate — they build up in the environment and in wildlife. BHT is toxic to aquatic organisms; scientists have detected it in mollusks. Canada’s Chemicals Management Plan reports that BHT is harmful to the environment.
Regulatory status of BHA and BHT
Exposure to BHA is government regulated. It’s considered safe as a preservative in foods as long as it doesn’t exceed 0.02 per cent of the fat or oil content. When used in food packaging, BHA can’t exceed 0.005 per cent of materials. As an antioxidant in defoaming agents for processed foods, it must not exceed 0.1 per cent by weight of defoamer.
Current regulatory status of BHA and BHT in Canada
Health Canada categorizes BHA as a “high human health priority” on the basis of carcinogenicity. It lists BHT as a “moderate human health priority.” But the Government of Canada concludes BHA is not harmful to the general population at current exposure levels of. It also says BHA doesn’t constitute “a danger to the environment.”
Current regulatory status of BHA and BHT in other countries
- European Union. The EU has prohibited BHA as a fragrance ingredient in cosmetics. Its Scientific Committee on Consumer Safety has set limits on how much BHT can be in consumer goods due to its potential endocrine disrupting properties. It considers BHT safe as an ingredient up to a maximum concentration of 0.001 per cent in mouthwash and 0.1 per cent in toothpaste. BHT is considered safe up to a maximum concentration of 0.8 per cent in other leave-on and rinse-off products.
- United Kingdom. In 2024, the U.K. added BHT to its list of restricted substances in cosmetic products. Its BHT restrictions are slighter tighter than in the EU. The U.K. limits BHT in oral care products at 0.001 per cent. The EU limit is 0.8 per cent. Like the EU, the U.K. allows BHT concentrations up to 0.1 per cent in toothpaste and up to 0.8 per cent in other leave-on and rinse-off products.
- United States. The Food and Drug Administration designated BHA as “generally recognized as safe” in 1958. It’s been listed as a known carcinogen in California since 1990 and classified as “reasonably anticipated to be a human carcinogen” since 1991 by the National Toxicology Program. The FDA sets limits on BHA of no greater than 0.02 per cent of fat or oil content. For food packaging, BHA may not exceed 0.005 per cent of the material. If used as an antioxidant in defoaming agents for processed foods, BHA may not exceed 0.1 per cent by weight of defoamer. In California, products containing BHA have a warning label stating that the ingredient may cause cancer.
BHA and BHT function
BHA has been used since 1947 as a preservative in foods containing fats, vegetable oils and vitamin A. But its use and function have expanded widely since.
From the moment we get up in the morning, we’re absorbing BHA and BHT through our skin, inhalation and by drinking water or consuming food. BHA and BHT are part of many people’s daily beauty routine. They’re in lipstick, eyeshadow, shampoo and moisturizer. If we start our day with breakfast cereal, buttered toast or sausages, we’re eating BHA and BHT.
It doesn’t stop at breakfast. Lunch, dinner items and snacks often contain BHA, as do baked goods, nuts and nut products, potato chips, poultry and red meat products and beer. Food packaging also contains BHA. Even chewing gum contains BHT.
The pharmaceutical industry relies on BHA as a preservative. It’s found in biomaterials used to make things like catheters.
BHA is used as an antioxidant in defoaming agents for processed foods, e.g., to control foam in powdered drink formulations.
How to avoid BHA and BHT
A 2023 report in the Journal of the Science of Food and Agriculture recommends safe, non‐toxic and environmentally friendly alternatives to BHA and BHT due to possible “thyroid system damage, metabolic and growth disorders, neurotoxicity, and carcinogenesis.”
What to look for on labels
- BHA and BHT are identified by their acronyms on consumer labelling.
- BHT may be added to packaging material, where it vaporizes into food during storage. As an “incidental food additive” it legally doesn’t have to be listed with other labelled ingredients.
Substitutes and alternative methods
- Perfumers who want to avoid BHA and BHT preservatives can use alternatives such as vitamin E and rosemary and grapefruit seed extracts. Look for online resources showing how to create homemade perfume and body products using non-toxic ingredients.
- Vitamin E and rosemary and green tea extracts may help preserve food quality and extend shelf life.
- Properly storing food products can help prevent spoilage and extend shelf life.
- High pressure processing is a pasteurization method. It kills pathogens while preserving freshness and extending shelf life.
