2000 with an EPA draft proposal, which was addressed several times at the state level in the years to follow, and eventually cemented in place federally with a 9-year phaseout in 2005's Energy Policy Act, with significant proportions of fuel ethanol designated as the replacement antiknock agent for the US automotive fuel system. Congress' attempts to promote ethanol for its geopolitical use as a backstop on any attempts to limit the US' gasoline supply, and also its incentives to reward Iowan corn farmers, whose state political primaries hold a special place in the electoral system, escalated ethanol from an additive to be used as needed, then to a fixed blending proportion of 5%, and then 10%, which is today the most common US fuel blend. Ethanol has several issues as an antiknock additive. It is hydrophilic, pulling water vapor out of moist air, and it also increases the level of free oxygen in the fuel significantly. Both of these cause significant degradation to traditionally constructed engines, posing both residue and corrosion issues in increasing proportion with increasing fractions of ethanol. Whereas age-degraded gasoline may simply polymerize, evaporate, and thus lose its flammability, age-degraded gasoline-ethanol blends can cause severe damage if allowed to sit in an engine. Automotive engines addressed this with the mandated shift over to ethanol-tolerant metals and seals, and with the use of smart electronic fuel injection, which has some flexibility to adjust combustion properties and timing. Automotive engines did not see major issues because of these factors, and because automobiles in active use typically cycle through their gas tank in a matter of weeks. In small carburetor engines, like generators and lawnmowers, ethanol damage became the dominant mode of failure. MMT Methylcyclopentadienyl manganese tricarbonyl (MMT) has been used for many years in Canada and recently in Australia to boost octane ratings. It also allows old cars, designed to use leaded fuel, to run on unleaded fuel without the need for additives to prevent valve stem erosion. A large Canadian study from 2002 (funded by automakers, who are against its use) concluded that MMT impairs the effectiveness of automobile emission controls and increases pollution from motor vehicles. However, a later study by the Canadian government found that “no Notice of Defect was found to be potentially caused by MMT.” Many studies have been undertaken over time that confirmed the use of MMT is compatible with vehicles and safe