JEFFERSON CITY, Mo. &

Pushing the button for regular 87-grade octane, Steve Smith said he thought he was filling his SUV with ethanol-free gasoline.




"I don't buy super unleaded, knowing that it's ethanol," Smith said, citing concerns about how ethanol could affect his vehicle.




But Smith was buying ethanol-blended gasoline, just as he had done several times before. Although many pumps don't announce it, almost all the gasoline sold in Missouri has contained a blend with 10 percent ethanol for at least the past several months.




A law taking effect Tuesday makes Missouri just the third state &

behind Minnesota and Hawaii &

to implement a wide-ranging ethanol mandate. Because the corn-based fuel is cheaper than gasoline, most of Missouri's gas stations quietly made the switch months in advance.