This is the first time I have heard that 15% ethanol in gasoline significantly reduces greenhouse gases. I would like some more links to verify this. The Government of Canada webpage is rather sparse on details, at least for this technical person.

Brazil was the first country to dilute gasoline with ethanol. This practice started in 1976 as a response to the Energy Crisis. Brazil had an ample supply of sugar cane farmers to produce the ethanol. Ethanol blends makes the refined gasoline go a little further.

The USA adopted this technology in early 2000's. But the drive was the farm lobby, who were looking for a new way to get rich. The American ethanol industry is highly subsidized. Critics say it takes more liters of diesel for tractors and combines to plant and harvest ethanol-based corn than the liters of artificial fuel that comes out of the process. The political power of the farming lobby is immense. So subsidies continue.

The gas line antifreeze is methanol, which has similar properties to ethanol. But it is most toxic to handle. If methanol goes through the car's engine, it is likely to be mostly burned up, same as ethanol. Its more toxic nature is not an issue after it is combusted.

Husky (gasoline retailer in Canada) has been selling a 10% or so ethanol blend for years. Canadian consumers already have a choice.