Outbreaks of methanol poisoning have occurred when methanol is used to adulterate moonshine (bootleg liquor). Methanol is toxic to humans. If as little as 10 ml of pure methanol is ingested, for example, it can break down into formic acid, which can cause permanent blindness by destruction of the optic nerve, and 30 ml is potentially fatal, although the median lethal dose is typically 100 ml (3.4 fl oz) (i.e. 1–2 ml/kg body weight) of pure methanol. This does not happen with ethanol, which breaks down into acetic acid, which is non-toxic in small amounts. Reference dose for methanol is 0.5 mg/kg/day. Toxic effects take hours to start, and effective antidotes, like ethanol, can often prevent permanent damage. Because of its similarities in both appearance and odor to ethanol (the alcohol in
