On the other hand, methanol has the disadvantage of being toxic and corrosive. Fuel supply systems must be designed to prevent people from being exposed to it. Mechanics must be trained to properly handle methanol systems, because the flame is invisible to the human eye. Furthermore, vehicles must be designed to withstand corrosive effects if they are to run on high concentrations of methanol. Propane Also known as liquefied petroleum gas, propane is derived from either natural gas or petroleum.
Propane is the third most common vehicular fuel today after gasoline and diesel.
When used in vehicles, propane is more comparable in range and octane rating to gasoline than some of the other alternative fuels. Propane-fueled vehicles meet today's current emissions requirements. On the other hand, vehicles require engine and fuel tank modifications to use propane. A large fuel-storage cylinder is necessary, which takes up room that could be used for cargo. And propane engines may need improvements to meet the 1998 emissions requirements.