California requires a unique California Air Resources Board (CARB) gasoline with stricter chemical and emissions standards, so refineries must produce and handle it differently than standard U.S. gasoline.
And yet, all auto manufacturers produce, what's known as 50 state emissions compliant cars.
IOW, the cars themselves, are able to control their exhaust emissions to meet emissions standards in all 50 US states, including California...
I could re-fuel my California-registered car in Arizona, drive back to California, have it smog-checked immediately and it would pass.
Not because of the formulation of the gasoline, but because the car's computer is measuring and controlling exhaust emissions.