Six tourists die in Laos after apparent methanol poisoning - what is it and why was it in drinks?

Six tourists have died, and several more are understood to be in hospital, after drinking suspected tainted alcohol in Laos.

Several people, including the manager and owner of a hostel, have been detained by police after the suspected mass poisoning in the popular backpacker town of Vang Vieng.

Among those who have died in 28-year-old British woman Simone White, who was working as a lawyer in London.

It is not yet known where the victims may have drank methanol.

Two days before check-out, the women had joined more than 100 other guests for free shots of Lao vodka offered by their hostel as a gesture of hospitality, the hostel manager said.

Staff said no other guest reported any issue, adding that the women had then gone for a night out, returning in the early hours of the morning.

The UK Foreign Commonwealth and Development Office has said it is "in contact with the local authorities”.

In response to the deaths, the US State Department has issued a warning to travellers to be “alert to the potential risk of methanol poisoning" - but how can it be avoided? What is methanol and why was it apparently in their drinks?

What is methanol?

Alcohol falls under three types:

• Ethanol - that's the alcohol you'd find in alcoholic drinks. It's the only type intended for consumption.

• Isopropanol - it's used in hand sanitiser. It is not safe for drinking.

• Methanol - often used as fuel or as an ingredient in antifreeze and solvents. It's colourless and smells similar to the ethanol we are used to drinking. But it is not safe for drinking.

What happens if someone drinks methanol?

Drinking just 15ml methanol - that's less than a single shot - can be fatal, says the University of Nottingham's Dr Wayne Carter. But proper medical treatment means methanol poisoning can be treated if caught early.

How methanol affects the body will vary based on the individual will vary. “Some will be able to tolerate more than others because we all have variability in the capacity of our enzymes to detox. But small quantities ... might be fatal for individuals; others may survive slightly more," says toxicologist Alastair Hay from the University of Leeds.

The alcohol can damage the kidneys and cause the brain to swell - as well as triggering symptoms of poisoning.

What are the symptoms of methanol poisoning to look out for?

It can take up to 24 hours for symptoms to start, which may include headaches, dizziness, nausea, confusion and seizures.

Professor Alastair Hay from the University of Leeds says that "initially the effect [is] on someone's breathing".

Methanol can affect the eyes, leading to blurred vision or blindness and wider pupils than usual. Stomach pain is another indicator.

Professor Oliver Jones of RMIT University says: "While thankfully rare, methanol poisoning is very serious, and treatment should be given at a hospital". This treatment can include feeding ethanol to patients, as well as dialysis to remove the poison.

Why would methanol be in drinks if it's not safe to drink?

Methanol is cheaper than ethanol, meaning some bootleg bars might add it to mixed drinks to save money.

This isn't a problem specific to Laos or Southeast Asia - it can happen anywhere where taxes on alcohol are high and unscrupulous bar owners want to scrimp on costs.

Methanol is also a byproduct of the distillation process that makes ethanol. This means it can often be present in home-brewed alcohol, even if unintended.

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How can you avoid methanol?

As its colour and smell are easily confused with safe-to-drink ethanol, it can be hard to avoid methanol.

Since the Laos poisonings, the UK Foreign Office has issued advice to purchase alcohol beverages only from licensed liquor stores, licensed bars or hotels. Check seals on bottles are intact and labels are legitimate with sound spelling and quality.

The Methanol Institute advises that beverages such as canned beer, cider, wine, pre-mix, and duty-free products tend to be safer and less easy to contaminate with methanol.

It also encourages people to be wary of homemade brews, and free drinks or drinks priced far below normal.

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