What is methanol and why might it have been in tourists’ drinks?

An American man and two Danes also died, though their exact causes of death have not been released. A New Zealander also has been sickened.

The US State Department issued a warning to travellers to be “alert to the potential risk of methanol poisoning.” But what is methanol, and how do you avoid it?

What is methanol?

There are three main types of alcohol: ethanol, methanol and isopropyl.

Ethanol is what is found in consumer spirits and is the only one intended for consumption.

Isopropanol is the main ingredient in rubbing alcohol and hand sanitisers.

Methanol, commonly called wood alcohol because it is the byproduct of wood distillation, is frequently used as fuel and in products such as antifreeze and solvents.

What happens if you consume methanol?

According to the Methanol Institute, the global trade association for the industry, drinking just 25 to 90 millilitres of methanol can be fatal without proper medical treatment, but can be successfully treated if caught early.

Methanol poisoning can cause headaches, dizziness and decreased consciousness including coma, seizure, nausea, vomiting, blurred vision and multiple other symptoms, according to the US Centres for Disease Control.

The CDC recommends seeking medical attention immediately if methanol poisoning is suspected.

“Individuals vary in their response to methanol,” said toxicologist Alastair Hay from Britain’s University of Leeds.

“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.”

Why would it be in drinks if it’s not meant for consumption?

Methanol is sometimes added deliberately by unscrupulous bars to mixed drinks to give them more “kick” and to save money on using higher-priced ethanol-based spirits such as vodka or rum.

This practice is not specific to Laos or south-east Asia, but occurs wherever taxes on legitimate alcohol or the cost of legitimate alcohol is perceived as being too high, according to the Methanol Institute.

Methanol is also a normal product of the distillation process that produces ethanol, and in home-brew distilleries without strict controls — often found in poorer countries — it can end up in the mix.

How do you avoid methanol poisoning?

The answer is easy: don’t drink it.

But it’s colourless, odourless and tasteless, so that can be something of a challenge.

In guidance issued after the Laos poisonings, Britain’s Foreign Office recommends only purchasing alcoholic beverages from licensed liquor stores, buying drinks only from licensed bars and hotels, always checking if bottle seals are intact, and checking labels for poor print quality or incorrect spellings.

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

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