When used at the recommended maximum concentration of 1 oz/gal of gasoline, B-12 Chemtool Fuel Treatment is safe for use in all modern automobiles. While B-12 has greater solvency than reformulated (ethanol-based) gasoline, such as E10, E15, and E85, a good rule of thumb is if your vehicle can run on these “gasohol” fuels, then its fuel system is inherently compatible with the fuel treatment.