Applications
Butylated hydroxytoluene is primarily used as a food additive that exploits its antioxidant properties. It is approved for use in European Union under E321 and in the U.S. by the Food and Drug Administration via regulation: For example, 21 CFR §137.350(a)(4) allows BHT up to 0.0033% by weight in "enriched rice", while 9 CFR §381.147(f)(1) allows up to 0.01% in poultry "by fat content". Brands such as Avatar Corporation's Avox BHT and Eastman Chemical's Tenox BHT are listed for use in foodstuffs like "mixed nuts, margarine, chewing gum" and "enriched rice and frozen breaded shrimp".
BHT is also documented as an antioxidant additive in such diverse products as cosmetics, pharmaceuticals, rubber, electrical transformer oil (at 0.35%), and embalming fluid. In the petroleum industry, where BHT is known as the fuel additive AO-29, and distributed under brands including Rhine Chemie's Additin RC 7110 (99.8% pure BHT), it also finds uses in hydraulic fluids, turbine and gear oils, and jet fuels, among other applications. BHT is also used to prevent peroxide formation in diethyl ether and other laboratory chemicals.
Unlike the brands listed above, which contain BHT as their primary ingredient, many more additive products contain the chemical as a component of their formulation, where it is used alongside (or even replaced by, see below) the lesser-studied butylated hydroxyanisole (BHA).
Read more about this topic: Butylated Hydroxytoluene