I'll ping Annie on this one. CA gas does require an oxygenate, and now that MTBE is banned, ethanol is a very common oxygenate, perhaps the most common. To meet the oxygenate content, CA gas would require at least 5.7% ethanol. But there is currently no mandate for minimum ethanol content specifically. More detail on CARB's site
here and
here. In the second link, make sure to scroll down to the middle. At the top of the page it states that there is a minimum ethanol content, but it corrects itself halfway down.