Yes, but the very small percentages used would do little harm. Methanol, by the way attacks rubber (not neoprene) and aluminum. We had drain petcocks in the bottom of our Webers so the fuel wouldn't sit there. You also had to run Castrol R (lovely smell) or a synthetic oil as Methanol will not mix with a mineral oil. I do not know if Ethanol is the same but some people using small two stroke engines (chain saws) had problems with fuel containing Ethanol.