Methanol

Primary reference(s)

NCBI, 2020. PubChem Compound Summary for CID 887, Methanol. National Center for Biotechnology Information (NCBI). Accessed 8 October 2020.

WHO, 2014. Methanol poisoning outbreaks. Information Note, World Health Organization (WHO). Accessed 8 October 2020.

Additional scientific description

Methanol belongs to the class of organic compounds known as primary alcohols. Methanol’s chemical formula is CH3OH. Methanol is the primary alcohol that is the simplest aliphatic alcohol, comprising a methyl and an alcohol group. It has a role as an amphiprotic solvent, a fuel, a human metabolite, an Escherichia coli metabolite and a mouse metabolite. It is an alkyl alcohol, a one-carbon compound, a volatile organic compound and a primary alcohol (NCBI, 2020).

Methanol is a widely available chemical. It has many industrial applications and is also found in various household products, including varnishes, antifreeze, windscreen wash, and fuel for model aircraft. Globally, approximately 225 million litres of methanol are used each day (WHO, 2014a).

Methanol has a relatively low intrinsic toxicity; however, it is metabolised to highly toxic compounds, which can cause blindness, coma and severe metabolic disturbances that can be life-threatening (WHO, 2014a).

Methanol is well-absorbed through the gastrointestinal tract and is also absorbed through the skin and by inhalation. Methanol is only mildly inebriating; its toxic effects arise from its metabolism to formaldehyde and formic acid. Humans have a limited ability to detoxify formic acid and this metabolite therefore accumulates and causes toxic effects. The toxic dose of methanol varies depending on the individual and on the provision of treatment. Blood methanol concentrations above 500 mg/l are associated with severe toxicity, and concentrations above 1500–2000 mg/l will lead to death in untreated patients. Because patients with methanol poisoning often need intensive medical care, outbreaks of methanol poisoning can rapidly overwhelm medical facilities (WHO, 2014a).

Metrics and numeric limits

Not available.

Examples of drivers, outcomes and risk management

Outbreaks of methanol poisoning arise from the consumption of adulterated counterfeit or informally produced spirit drinks. There have been numerous outbreaks in recent years, including in Cambodia, Czech Republic, Ecuador, Estonia, India, Indonesia, Kenya, Libya, Nicaragua, Norway, Pakistan, Turkey and Uganda. The size of these outbreaks has ranged from 20 to over 800 victims, with case fatality rates of over 30% in some instances (WHO, 2014a). Shokoohi and co-workers (2020) reported on an outbreak in Iran due to individuals ingesting methanol who thought it might prevent or treat COVID-19.

The informal and illicit production of alcoholic drinks is practised in many parts of the world, including in countries where alcohol is banned. Some common names for these drinks include hooch/moonshine (USA), chang’aa/kumi kumi (Kenya), tonto/waragi (Uganda), tuak/tapai (Malaysia), samogon (Russia), and talla (Ethiopia). Such drinks are often sold in unlabelled containers in markets and at illegal drinking venues. Illicitly- or informally produced alcohol may also be sold in legitimate bars, particularly in some tourist areas. Consumers may choose these drinks because of their low cost compared to taxed alcohol (WHO, 2014s).

Some illicitly produced drinks are made to appear legitimate through bottle design and labelling and consumers can be misled into believing that they are buying a genuine brand of alcohol. Bottles may be sold in shops, markets and bars, often at a ‘bargain’ price (WHO, 2014a).

The WHO guidance on methanol poisoning outbreaks (WHO, 2014a) recommends the following risk management for prevention and control:

What can individuals do to protect themselves?

• Refrain from purchasing or producing illegal alcoholic drinks.
• Be suspicious about alcoholic drinks offered for sale in informal settings that are not licensed to sell alcohol, such as market stalls, and/or that are offered at a cheap price.
• Do not buy alcoholic drinks sold in unlabelled containers.
• Check branded products for labels that are poorly printed or with typographical errors, or bottles with broken seals. Do not buy these.
• Be aware of the symptoms of methanol poisoning and seek medical attention immediately if exposure is suspected.

What measures can countries take?

• Put in place a national strategy and legal framework to reduce the harmful use of alcohol.
• Use public health campaigns to promote awareness of the dangers of informally produced and illicit alcoholic drinks. These can be targeted towards particular high-risk groups, such as alcohol-dependent individuals, tourists.
• Since early recognition of an outbreak is vital to improve outcome, ensure that medical professionals are trained in the diagnosis and management of methanol poisoning.
• Where mass methanol poisonings have the potential to occur, establish a protocol for the management of these outbreaks.
• The ability of laboratories to undertake blood methanol analysis can help identify and guide clinical management of poisoned patients.
• Ensure accessible and affordable treatment is available for all, including antidotes (e.g., fomepizole, ethanol).
• Provide support to victims particularly those at risk of recurrent events, such as alcohol-dependent individuals.

The WHO is committed to reducing the health burden resulting from the harmful use of alcohol (WHO, 2014b). In 2010, the World Health Assembly endorsed a global strategy to reduce the harmful effects of alcohol. Ten recommended target areas were identified, including one addressing the need to reduce the public health impact of illicit alcohol and informally produced alcohol. Several policy options and interventions are suggested, including: developing good quality control with regard to production and distribution of alcoholic beverages; regulating sales of informally produced alcohol and bringing it into the taxation system; creating an efficient control and enforcement system, including tax stamps; developing or strengthening tracking and tracing systems for illicit alcohol; ensuring necessary cooperation and exchange of relevant information on combating illicit alcohol among authorities at national and international levels; and issuing relevant public warnings about contaminants and other health threats from informal or illicit alcohol (WHO, 2014b).

See WHO (2014b) for information on consumption and patterns of alcohol drinking, health consequences and policy responses in Member States.