Critics say a ban would violate the state's voter-approved legalization of recreational marijuana, which took effect in January.
The Environmental Protection Agency is proposing new rules requiring cleaner gasoline and lower-pollution cars nationwide.
One supporter of the plan calls it “the most significant air pollution policy President Obama will adopt in his second term.”
According to The Washington Post, which first reported the news last night, the proposed standards would increase the price of gas anywhere from less than one penny per gallon, to as much as nine cents per gallon in some places.
The higher estimate is from the oil industry, which has been lobbying for a delay in the rules.
Carmakers support the new standards.