Minnesota was the first state to mandate E10 gasoline as a motor fuel in 1992.
Tester
E10 is not mandatory in Nevada, most of the state is rural, without pollution problems.
The use/sale of E10 has been a requirement of the county that I live in due to urban pollution. It was started in the late 1980’s during winter months because the air pollution becomes trapped in the valley due to the inversion layer.