Induction of forestomach hyperplasia by crude butylated hydroxyanisole, a mixture of 3-tert and 2-tert isomers, in Syrian golden hamsters is due to 3-tert-butylated hydroxyanisole.

Male Syrian golden hamsters were given 1.0% 2-tert- or 3-tert-butylated hydroxyanisole (BHA) or crude BHA for 1 to 4 weeks. The incidence of severe hyperplasia induced in the forestomach was high in the hamsters given 3-tert-BHA or crude BHA for 2 weeks or more, but was almost at the control level in those given 2-tert-BHA. Thus, the 3-tert isomer would appear to be responsible for the tumorigenicity of crude BHA.