Such is only effective if a state has "opt-in/opt-out" authorization. Otherwise, the determination is solely a Federal issue. As best I can determine, Oregon presently has no Federal ethanol mandate. That may change when the much-increased, Federal national ethanol mandate goes further into effect, and that previous authorization is superceded.
Where I live, the Governor of the Commonwealth of VA has no opt-out ability, and we are stuck with E-10 in my local Hampton Roads area.
N.B. In spite of that, I can squeeze-out 45/46 MPG at 50-55 MPH on E-10 on open roads.