BHA is generally used to keep fats from becoming rancid. It is also used as a yeast de-foaming agent. BHA is found in butter, meats, cereals, chewing gum, baked goods, snack foods, dehydrated potatoes, and beer. It is also found in animal feed, food packaging, cosmetics, rubber products, and petroleum products.
BHT also prevents oxidative rancidity of fats. It is used to preserve food odor, color, and flavor. Many packaging materials incorporate BHT. It is also added directly to shortening, cereals, and other foods containing fats and oils.
"...Specific toxic effects to the lung have only been observed with BHT. The other described toxic effects of BHA and BHT are less characteristic and often occur only after high dosage and long-term treatment. However, BHA induces in animals tumours of the forestomach, which are dose dependent, whereas BHT induces liver tumours in long-term experiments. ... all published findings agree with the fact that BHA and BHT are tumour promoters. In contrast to BHA and BHT, vitamin E is not carcinogenic." - Kahl R, Kappus
"The chronic ingestion of .5% butylated hydroxyanisole (BHA) or butylated hydroxytoluene (BHT) by pregnant mice and their offspring resulted in a variety of behavioral changes. Compared to controls, BHA-treated offspring showed increased exploration, decreased sleeping, decreased self-grooming, slower learning, and a decreased orientation reflex. BHT-treated offspring showed decreased sleeping, increased social and isolation-induced aggression, and a severe deficit in learning." - Stokes, JD & Scudder, CL
BHA is considered by the U.S. Food and Drug Administration (FDA) to be generally recognized as safe when the antioxidant content does not exceed 0.02% by weight of the food’s total fat or oil content. - Report on Carcinogens, Twelfth Edition
The International Agency for Research on Cancer classifies BHA as a possible human carcinogen. - IARC Monographs on the Evaluation of Carcinogenic Risks to Humans
The European Commission on Endocrine Disruption has also listed BHA as a Category 1 priority substance, based on evidence that it interferes with hormone function. - Study on Enhancing the Endocrine Disrupter Priority List with a Focus on Low Production Volume Chemicals