Since 1978, the EPA has used the Clean Air Act to set the limit for gasoline that will be burned in vehicles that are not designated as flex-fuel vehicles at E10. Flex-fuel vehicle can handle everything up to E85. The EPA will be looking for any harmful emissions that E15 might cause and is accepting comments for the next 30 days. Engine and auto makers will likely put in their two cents regarding possible negative effects that E15 in the general supply would have on their products. The EPA must respond to the waiver request by December first.