Six foreign tourists, including an unnamed U.S. man, have died of suspected methanol poisoning in Laos, Southeast Asia.
The tourists are thought to have fallen ill after drinking alcohol laced with the deadly chemical about a week ago in the backpacking town of Vang Vieng. But methanol poisoning is has not yet been confirmed.
Despite its toxicity, alcoholic drinks are sometimes tainted with methanol because it’s relatively cheap. It’s also often found in spirits distilled at home.
But consuming it is extremely dangerous, with less than two tablespoons a potentially fatal dose, according to the BBC.
What is methanol?
Methanol is a highly toxic form of alcohol. It’s commonly used as an industrial chemical and can be found in products like windshield washer fluid, antifreeze and perfume.
It’s also produced naturally when plants like agave, potato and fruit are fermented as part of the process of making alcoholic drinks.
Professional distillers use several methods to reduce the methanol content of their drinks, according to strict regulations. But the methanol content of bootlegged drinks cannot be guaranteed.
It’s “like the alcohol in our drinks — colourless and odourless,” Christer Hogstrand, professor of molecular ecotoxicology at King’s College London told the Science Media Centre. But, “it has a different carbon atom structure which completely changes how humans process it in the body, leading to these potentially fatal consequences.”
“If there is enough of it a person drinking it can go blind, get internal organ failure and even die”
What happens when you drink methanol?
When methanol breaks down in the human body, it forms dangerous chemicals called formic acid, formaldehyde and formate.
All three of these substances make it harder for mitrachondria — tiny structures inside our cells — to produce energy. This is particularly damaging to the brain.
Formic acid and formate can also reduce the pH level of blood, harming tissue throughout the body and leading to organ failure.
Initially, this can make breathing difficult. Eventually it can stop the heart from working.
At first, the chemical has similar effects to alcohol. Because of this, it’s often not clear for some time that someone has been poisoned. Other symptoms can take up to a day to emerge.
The chemical may initially cause symptoms like dizziness, weakness, slurred speech and disinhibition. Later, it may result in headaches, nausea, vomiting, abdominal pain, internal bleeding and convulsions.
Formaldahyde damages the nerves connecting the eyes and the brain, causing serious sight problems from blurred vision to hallucinations like flashes and dancing spots. Drinking less than a teaspoon of methanol can cause blindness in some people.
“In later stages, generally developing between 18 and 48 hours after methanol ingestion, drowsiness may progress to coma,” said Sir Colin Barry, professor of pathology at Queen Mary University London.
How is methanol poisoning treated?
Depending on how severely someone has been poisoned, they may be given ethanol and undergo dialysis to remove methanol from the blood.
“If the poisoning is not too severe, and only blood tests will determine this, ethanol alone may suffice,” said Alastair Hay, emeritus professor (emeritus) of environmental toxicology and the University of Leeds, told the SMC.
Ethanol — a very similar type of alcohol — is a go-to treatment for methanol ingestion because it slows down the metabolism of methanol.
“Both alcohols are broken down by the same liver enzyme,” Hay said. “But the enzyme prefers ethanol.”
This can allow the body “to vent methanol from the lungs and some through the kidneys, and a little through sweat.”
It’s crucial to avoid the production of toxic levels of formaldehyde, he added.
