In California we have all kinds of crap additives in our gas, with the winter blends being particularly crappy. Many of the lower-priced gas stations, and even some of the majors, include anywhere from 5 to 20% ethanol. Most don't disclose this. It's done partially for profit, and partially because of our clean-air regulations.
Ah, California. Nice weather most of the time, tons of things to do and places to see, and some of the most asinine and crippling laws in the country.