What is methanol, how does it end up in alcoholic beverages, and how can you avoid it? | World news

Four people have died and six British backpackers are in hospital in Southeast Asia after reports of suspected methanol poisoning.

Simone White, 28, from Orpington in Kent, is among those who fell ill after being offered “free shots” in the resort of Vang Vieng in Laos.

Bianca Jones, 19, from Melbourne, Australia, two Danish women in their 20s and a 56-year-old American citizen are reported to be dead.

New Zealand has confirmed that one of its citizens has also fallen ill.

Authorities are now warning travelers about the risk of methanol poisoning, how it happens and how to avoid it.

What is methanol?

Methanol, or CH3OH, is very similar to ethanol – the pure form of alcohol in alcoholic beverages.

Although, like ethanol, it is an odorless, tasteless and highly flammable liquid, it has a different chemical structure that makes it toxic to humans.

Otherwise known as wood alcohol, methanol is most commonly used to make solvents, pesticides, paint thinners and alternative fuels.

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What makes it so dangerous is the way our bodies metabolize it.

Once ingested, our enzymes convert methanol into formaldehyde, the substance used to make industrial glues and embalming agents, before breaking it down into formic acid.

“The formic acid disrupts the acid balance in the blood and the biggest consequence is initially the effect on someone’s breathing. There are effects on many other organs, the kidneys being one,” says Professor Alastair Hay, Emeritus Professor of Environmental Toxicology at the University of Leeds.

“Formaldehyde attacks nerves, especially the optic nerve, and blindness is a potential risk,” he adds.

How does it end up in alcoholic beverages?

In Southeast Asia and other popular tourist destinations, methanol can be found in alcoholic beverages for two main reasons.

First, it is cheaper than ethanol, so it is sometimes added instead to save costs before the adulterated alcohol is bottled and sold in stores and bars.

Alternatively, it can occur accidentally when alcohol is homemade – something common throughout Southeast Asia.

When alcohol is distilled and fermented without proper supervision, it can sometimes produce methanol in toxic amounts.

Because it is impossible to tell the difference between methanol and ethanol content without special equipment – homemade drinks are often offered to tourists without anyone knowing how dangerous they are.

What are the symptoms of methanol poisoning?

Methanol is highly toxic, so as little as 25ml can prove fatal.

Methanol poisoning can be treated by using ethanol to counteract the effects on the body – but only within the first 10 to 30 hours after ingestion.

This makes early diagnosis and warnings to others critical.

The most common symptoms are:

• Vomiting and nausea;
• Changes in vision, including blurring, loss of vision, and difficulty seeing in bright light;
• Stomach and muscle pain;
• Dizziness and confusion;
• Drowsiness and fatigue.

Methanol poisoning symptoms are similar to those from alcohol poisoning – but are often more severe. If drinks were left unattended or your symptoms seem disproportionate to the amount you drank, it could be methanol poisoning, authorities warn.

How is it treated?

Professor Hay says the treatment involves removing methanol from the blood via dialysis – while “keeping someone mildly intoxicated” by giving them ethanol at the same time.

“The principle behind ethanol administration is quite simple; it delays methanol metabolism,” he says.

“Both alcohols are broken down by the same liver enzyme alcohol dehydrogenase. But the enzyme prefers ethanol.

“So ethanol acts as a competitive inhibitor that largely prevents methanol breakdown, but slows it significantly so the body can vent methanol from the lungs and some through the kidneys and some through sweat.”

This avoids the process of methanol ultimately being metabolized as formic acid, he adds.

How can you avoid it while traveling?

UK travel advice for Laos and other parts of the region advises that the drinks most affected are:

• Local spirits, such as rice and palm spirits, are often labeled as “special” or “happy” drinks;
• Spirit-based mixed drinks such as cocktails;
• Counterfeit bottled alcohol is sold in bars and shops.

To minimize risks, travelers should:

• Only buy alcohol from licensed bars, hotels or shops;
• Check labels for signs bottles may be counterfeit, including poor print quality or misspellings;
• Avoid homemade alcohol;
• Make sure the bottles are properly sealed before drinking them;
• Avoid free drinks you didn’t see poured yourself;
• Do not leave drinks or food unattended.