Butylated hydroxytoluene, commonly known as BHT, is an organic compound that is used in the food, cosmetic, and pharmaceutical industry as an antioxidant. BHT is a substituted derivative of phenol. BHT helps to prevent the formation of free radicals and oxidation. When used in food products, it delays oxidative rancidity of fats and oils, and prevents loss of activity of oil-soluble vitamins. It may be found in pharmaceutical gels, creams and liquid or gelatin capsules, tablets and other pharmaceutical dosage forms. The ability of oral BHT to lead to cancer is a controversial topic, but most food industries have replaced it with butylated hydroxyanisole (BHA). BHT was first used as an antioxidant food additive in 1954. BHT does have other commercial uses, as in animal feeds and in the manufacture of synthetic rubber and plastics, where it also acts as an antioxidant. The U.S. Food and Drug Administration has deemed that BHT is safe enough when used in limited concentrations. It currently permits its use in concentrations of about 0.01% to 0.02% in most foods. As an emulsion stabilizer in shortening, it may be used in a somewhat higher concentration, 200 parts per million.