What is methanol poisoning? Full list of symptoms, why is it added to alcoholic drinks, holiday hotspots where most incidents occur - how to stay safe

Police have arrested the owner of the factory identified as the suspected source of the Laos methanol poisoning. The manufacturing plant is located outside the capital city Vientiane and is understood to have been making the local Tiger Vodka and Tiger Whiskey.

The rundown factory has been shut down by authorities and the sale and consumption of Tiger Vodka and Tiger Whisky has been banned in the country since the deadly outbreak. Melbourne teenagers Bianca Jones and Holly Bowles, both aged 19, were among six foreign tourists who died after falling ill while holidaying in Vang Vieng, a popular tourist town 129km north of Vientiane.

British lawyer Simone White, 28, two Danish women Anne-Sofie Orkild Coyman, 20, and Frela Vennervald Sorensen, 21, US man James Louis Hutson, 57, also died from after drinking contaminated drinks. Here we explain what methanol poisoning is, how to stay safe and which holiday hotspots see the most amount of incidents.

What is methanol poisoning?

Methanol poisoning is a severe condition that can occur when methanol is ingested, inhaled, or comes into contact with the skin. Methanol looks and tastes like alcohol, and initially people might not realise anything is wrong.

The harm happens hours later as the body attempts to clear it from the body by breaking it down in the liver. This metabolism creates toxic by-products called formaldehyde, formate and formic acid. These build up, attacking nerves and organs which can lead to blindness, coma and death.

Which drinks could contain methanol?

Affected drinks may include:

• local spirits, including local rice or palm liquor
• spirit-based mixed drinks, such as cocktails
• counterfeit brand-name bottled alcohol in shops or behind the bar

How can travellers avoid methanol poisoning?

MSF says the majority of methanol poisonings happen in Asia, but some also occur in Africa and Latin America. The advice for travellers is to know what you’re drinking and be aware of the risks.

Drink from reputable, licensed premises and avoid home-brewed drinks or bootleg spirits. The UK Foreign Office advises travellers: "Take care if offered, particularly for free, or when buying spirit-based drinks. If labels, smell or taste seem wrong then do not drink."

In order to minimise risks, travellers should:

• Buy alcohol only from licensed bars, hotels, or shops;
• Check labels for signs bottles may be counterfeit, including poor print quality or spelling errors;
• Avoid homemade alcohol;
• Check bottles are properly sealed before drinking from them;
• Avoid free drinks you have not seen poured yourself;
• Do not leave drinks or food unattended.

Why is methanol added to alcoholic drinks?

Methanol is produced during the brewing process and concentrated by distillation. Commercial manufacturers will reduce it to levels which are safe for human consumption. However, unscrupulous backyard brewers or others in the supply chain may sometimes add industrially produced methanol, to make it go further and increase profits.

Methanol was mixed into alcohol mostly for profit reasons, because it's cheaper and easily available. It is cheaper than ethanol, so it is sometimes added instead to save costs, before the counterfeit alcohol is bottled and sold in shops and bars.

Alternatively, it can occur by accident when alcohol is homemade - something common across southeast Asia. When alcohol is distilled and fermented without the appropriate monitoring, it can sometimes produce methanol in toxic quantities. Because it is impossible to tell the difference between methanol and ethanol content without specialist 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. The most common symptoms are:

• Vomiting and nausea;
• Changes in vision, including blurring, loss of sight, and difficulty looking at bright lights;
• Abdominal and muscle pain;
• Dizziness and confusion;
• Drowsiness and fatigue.

Where do most incidents occur?

A website by Doctors Without Borders that monitors methanol poisoning says many foreign tourists have fallen victim to methanol poisoning after consuming incorrectly distilled “arak” in Bali, Lombok and Gili Islands.

In September, several people were poisoned by methanol in Indonesia after consuming alcohol ordered off the internet, according to the website. In July, five students were poisoned after mixing tainted liquor with energy drinks, three of whom later died, it states.

Listed below are the countries that have had the most incidents since 2019 according to Doctors Without Borders.

1. Indonesia - 329

2. India - 125

3. Russia - 117

4. Pakistan - 38

5. Bangladesh - 34

6. China - 30

7. Iran - 28

8. Cambodia - 27

9. Kenya - 22

10. Vietnam - 21