BHA

BHA (butylated hydroxyanisole)

Chemical name:	2-tert-butyl-4-hydroxyanisole; 3-tert-butyl-4-hydroxyanisole
Molecular formula:	C₁₁H₁₆O ₂
Description:	A white or slightyly yellow, waxy solid having a faint odor.

- Definitions -
butylated:	to bring a butyl (a hydrocarbon radical, C₄H₉ ) group into [a compound].
hydroxy:	an organic acid, having (besides the hydroxyl group of the carboxyl radical) an alcoholic hydroxyl group, and thus having the qualities of an alcohol in addition to its acid properties; as, lactic and tartaric acids are hydroxy acids.
anisole:	methoxybenzene;obtained from anisic acid. (Anisic acid is a crystalline volatile acid obtained from anise [a plant growing naturally in Egypt].)

BHA is a mixture of two isomers, 2-tert-butyl-4-hydroxyanisole (2-BHA) and 3-tert-butyl-4-hydroxyanisole (3-BHA), with the commercial compound containing 90% of the 3-isomer

BHA is a chemical antioxidant used since 1947 as a preservative in some edible fats and oils, fat-containing or oil-containing foods such as baked goods and pork sausage, chewing gum, cosmetics, pharaceuticals, animal feed, food packaging, and in rubber and petroleum products. It prevents spoilage by reacting with oxygen, thus keeping the oxygen from reacting with fats and oils. It slows the development of off-flavors, odors and color changes caused by oxidation.

Safety (MSDS) data for butylated hydroxyanisole lists the following warning: "Possible human carcinogen; apparently carcinogenic in animal experiments. May be harmful by ingestion or inhalation. May act as a skin, eye or respiratory irritant."

The National Toxicology Program, a branch of the US Department of Health and Human Services, lists the following test results: "This compound is toxic by ingestion. There is sufficient evidence that it is carcinogenic in animals. When heated to decomposition this compound emits acrid smoke and irritating fumes."

The World Health Organization and the U.S. Environmental Protection Agency consider BHA a possible carcinogen, and further warn, "This chemical may cause cancer. It is an allergen. It is a suspected endocrine disrupter. It may interfere with, mimic or block hormones." Their studies report, "In test animals, BHA has caused cancer in the forestomach. Humans do not have a forestomach, although the cause of any kind of tumors in animals is cause for concern. In test tube studies, BHA has mimicked the hormonal actions of estrogen. Repeated contact with skin may cause irritation and skin allergies/dermatitis." All published findings agree with the fact that BHA is a tumor promoter.

Toxicological studies by A. Gartner and U. Weser revealed that in dogs, BHA at levels of 1 and 1.3% induced liver enlargement, proliferation of the smooth endoplasmic reticulum, the formation of hepatic myelinoid bodies, and an increase in hepatic enzyme activity.
Biomimetic and Bioorganic Chemistry, Vol. 2 (F. Vogtle and E. Weber, Eds.), Springer, Berlin, 1986, p. 1.

The Report On Carcinogens, 11^th Edition, says "Butylated hydroxyanisole (BHA) is reasonably anticipated to be a human carcinogen based on sufficient evidence of carcinogenicity in experimental animals (IARC 1986, 1987). When administered in the diet, butylated hydroxyanisole induced papillomas and squamous cell carcinomas of the forestomach in rats of both sexes and male Syrian Golden hamsters."