One of the potential drawbacks of using high concentrations of methanol (and other alcohols like ethanol) in fuel is its corrosivity to some metals, particularly aluminium. Methanol, although a weak acid, attacks the oxide coating that normally protects the aluminium from corrosion
Methanol has a high toxicity in humans. If ingested, for example, as little as 10 mL of pure methanol can cause permanent blindness by destruction of the optic nerve and 30 ml is potentially fatal[11], although a fatal dose is typically 100–125 mL (4 fl oz) (i.e. 1-2 ml/kg of pure methanol[12]). Toxic effects take hours to start and effective antidotes can often prevent permanent damage.[11] Because of its similarities to ethanol (the alcohol in beverages), it is difficult to differentiate between the two (such is the case with denatured alcohol).
Pure methanol has been used in open wheel auto racing since the mid-1960s. Unlike petroleum fires, methanol fires can be extinguished with plain water. A methanol-based fire burns invisibly, unlike gasoline, which burns with a visible flame. If a fire occurs on the track, there is no flame or smoke to obstruct the view of fast approaching drivers, but this can also delay visual detection of the fire and the initiation of fire suppression. The decision to permanently switch to methanol in American IndyCar racing was a result of the devastating crash and explosion at the 1964 Indianapolis 500 which killed drivers Eddie Sachs and Dave MacDonald.[18] In 2007 IndyCars switched back to ethanol.[19]
Methanol is readily biodegradable in both aerobic (oxygen present) and anaerobic (oxygen absent) environments. Methanol will not persist in the environment. The "half-life" for methanol in groundwater is just one to seven days, while many common gasoline components have half-lives in the hundreds of days (such as benzene at 10–730 days). Since methanol is miscible with water and biodegradable, methanol is unlikely to accumulate in groundwater, surface water, air or soil.
