Exxon

There is a difference between states on whether premium gas specifically has ethanol in it or not. Or, more correctly, whether it's required to have it in it. Two states in the Union, Missouri and Montana, have specific exemption to allow ethanol-free premium gasoline. So if you live in one of those two states, you can be thankful. For the rest of us, we are faced with the unpleasant reality that the refineries are all but tied into putting ethanol in premium gas. This is because they have to use the ethanol to raise the octane level of their gasoline blend in order to satisfy the higher octane requirements of premium. This is one reason why you don't get better gas mileage with premium gas, because an essential part of that blend is a component that has less energy and forces the gas mileage down simply by nature. Check with your local Exxon dealer for specific details.