Once again, its illegal to use that oil in California due to (imo bad) environmental regulations

If you are referring to American light crude oil grades such as WTI (West Texas Intermediate) that is not correct. That oil could be refined in California. It would have to come by tanker from the gulf coast through the Panama Canal to get there. Until recently it would have to come on a Jones Act US flagged tanker (expensive, scarce). That requirement has been temporarily waived.