Biodegradable oil for automotive use is now a reality. G-Oil is not petroleum based, but made from animal fat. One barrel of fat can yield one barrel of G-oil (green oil) when mixed with a proprietary chemical. Most amazing is that G-Oil can be converted into soil on which cattle can graze to produce the fat. Even the containers and labels are 100% recyclable.
It's produced by Green Oil Technologies who say G-Oil is the "first bio-based, high-endurance motor oil to provide superior performance during the maximum oil change interval recommended by vehicle manufacturers."