I am old enough to remember everyone saying when lead was removed from gasoline engines would seize and mileage would drop drastically. Didn't happen. I have been driving vehicles since the early fifties. Never worried about what type/kind of gasoline I was putting in the tank as long as it met the stated octane rating. I have owned and driven everything from a vehicle with a four cylinder engine to vehicles with engines that produced more horse power than any three vehicles had a need for. I owned one, one time that would spark knock on the highest octane available. I have driven in cities that the smog was so thick it looked like fog. Fuel I purchased years ago did not give me any better street mileage or prolonged vehicle life. One vehicle got a good 7 miles per gallon going down hill with a tail wind. Gas cost less than fifty cents a gallon and the thirty six gallon tank could be filled for less than twenty dollars. In two hundred and fifty miles stop and fill up again. The use of ethanol in gasoline was implemented to reduce using cancer causing chemicals. I personally have never had a vehicle, lawnmower two or four cycle or any other two or four cycle engine that was damaged by using gasoline purchased at a Service Station. In 2004, over 3.4 billion US gallons (2.8 billion imp gal/13 million m³) of ethanol was produced in the United States for fuel use. Some say the ethanol amount used today is two or three time the 2004 amount. What would be used in gasoline if the ethanol was removed? How much more would the Oil Companies charge for gasoline if they were supplying the additional 6-10 million gallon currently being supplied by ethanol? I shudder to think what a gallon of gasoline would cost. The cook can get sick on a Oil Tanker and gas prices at the pump increase $.10. Stopping the use of ethanol in gasoline would be like the tanker sinking when it come to what the Oil Companies would be demanding for a gallon of gasoline.
This information of fuel blending is informative:
Oxygenate blending adds oxygen to the fuel in oxygen-bearing compounds such as MTBE, ETBE and ethanol, and so reduces the amount of carbon monoxide and unburned fuel in the exhaust gas, thus reducing smog. In many areas throughout the US oxygenate blending is mandated by EPA regulations to reduce smog and other airborne pollutants. For example, in Southern California, fuel must contain 2% oxygen by weight, resulting in a mixture of 5.6% ethanol in gasoline. The resulting fuel is often known as reformulated gasoline (RFG) or oxygenated gasoline. The federal requirement that RFG contain oxygen was dropped 6 May 2006 because the industry had developed VOC-controlled RFG that did not need additional oxygen.[24]
MTBE use is being phased out in some states due to issues with contamination of ground water. In some places, such as California, it is already banned. Ethanol and to a lesser extent the ethanol derived ETBE are common replacements. Since most ethanol is derived from biomatter such as corn, sugar cane or grain, it is referred to as bio-ethanol. A common ethanol-gasoline mix of 10% ethanol mixed with gasoline is called gasohol or E10, and an ethanol-gasoline mix of 85% ethanol mixed with gasoline is called E85. The most extensive use of ethanol takes place in Brazil, where the ethanol is derived from sugarcane. In 2004, over 3.4 billion US gallons (2.8 billion imp gal/13 million m³) of ethanol was produced in the United States for fuel use, mostly from corn, and E85 is slowly becoming available in much of the United States, though many of the relatively few stations vending E85 are not open to the general public.[25] The use of bioethanol, either directly or indirectly by conversion of such ethanol to bio-ETBE, is encouraged by the European Union Directive on the Promotion of the use of biofuels and other renewable fuels for transport. However since producing bio-ethanol from fermented sugars and starches involves distillation, ordinary people in much of Europe cannot legally ferment and distill their own bio-ethanol at present (unlike in the US where getting a BATF distillation permit has been easy since the 1973 oil crisis.)