The science behind the mercury poisoning in S-town
WARNING: SPOILER ALERT - This article contains details of S-town, the latest podcast by the producers of Serial
What do mercury, antique clocks, hatmakers, and Woodstock, Alabama, have in common?
They've all been linked to mad hatter disease, a severe form of mercury poisoning.
The Mad Hatter is one of the characters Alice meets in Wonderland in the classic 1865 Lewis Carroll novel, Alice in Wonderland.
At first he comes across as simply zany, but it's likely that years of exposure to mercury vapors, common in hatmaking, contributed to his bizarre attitude.
The disease was recently re-examined due to the smash hit podcast S-town.
In the final episode, we learn that protagonist John B McLemore likely suffered from the disease from years of clock restoration - which may have affected his mental health and led to his eventual suicide.
Here, we reveal what the disease is and why its effects can have severe repercussions.
In Lewis Carroll's novel Alice in Wonderland, the Mad Hatter comes off as a zany character, but it's likely that years of exposure to mercury contributed to his bizarre behavior (seen left in the 1951 Disney adaptation and right in the 2010 Tim Burton adaptation portrayed by Johnny Depp)
To make hats into felt, animal skin had to be separated from the fur. Mercury nitrate is used to boil and dry the fur, which emits toxic mercury vapors. These vapors affect the neurological system resulting in delirium, irritability, tremors and suicidal tendency. It's likely that many hatters didn't use proper protection, such as the one pictured
Mad hatter disease is a common occupational disorder caused by a constant and prolonged exposure to mercury.
Doctors first began to identify the syndrome among hatmakers in the 19th century when, after years of being in the business, they began to exhibit strange behavior.
To make top hats and other hats from animal skins into felt, the skin had to be separated from the fur and then the fur had to be matted together.
The process became known as 'carroting' because it involved mercury nitrate, an orange mixture of mercury and nitric acid, to boil and dry the fur - which emitted toxic mercury vapors.
Very dangerous, it meant that the hatters were subject to erethism, a neurological disorder which affects the whole central nervous system.
Chronic mercury exposure can give rise to psychotic reactions such as delirium, hallucinations and suicidal tendencies.
Other associations include irritability, excitability, excessive shyness and insomnia - and continuing exposure can even cause tremors and muscle spasms to develop.
So was born the expression 'mad as a hatter'.
In his portrayal of the Mad Hatter role in the 2010 movie Alice in Wonderland, based on the Lewis Carroll novel, Johnny Deep told a Los Angeles Times reporter that his orange-haired character 'was poisoned...and it was coming out through his hair, through his fingernails and eyes'.
In the hit podcast S-town, host Brian Reed discussed the life of John B McLemore from Woodstock, Alabama. John (pictured) was an antique clock restorer and likely suffered from mad hatter disease because of it
John exhibited a great deal of eccentric behavior, including hours spent worrying about global warming and building an elaborate hedge maze in his backyard (pictured). He told Reed that was prone to mood swings, depression, anxiety, insomnia and spontaneous vomiting
In the popular podcast S-Town, protagonist John B McLemore is presented as eccentric to say the least.
He spends hours a day worrying about global warming, is an avid conspiracy theorist, has gold hidden on his property, built an elaborate hedge maze in his backyard - and is one of the most skilled antique clock restorers in the world.
And this last point may have been what fueled John's depression and eventual suicide.
Clock restoration often involves a process called fire gilding, which embellishes clocks with gold decoration.
Gold gets melted into mercury, the mixture is brushed onto a surface and then the mercury is evaporated with heat. Without proper safety equipment, a person practicing fire gilding could inhale those toxic mercury fumes.
John began performing fire gilding in college - and one friend of his said he did it 'dozens of times a year'.
'I do not have a definitive answer as to whether or not John had mercury poisoning and if that could have been a force behind some of his behavior, his personality, and even his suicide,' S-Town host, Brian Reed, said on the final episode of the podcast.
But he makes a strong case that mercury poisoning was likely a contributor to John's neurological and physical symptoms.
John had told Reed that was prone to mood swings, depression, anxiety, insomnia and spontaneous vomiting.
His autopsy revealed an enlarged brain and congestion in the lungs, which mercury experts told Reed is consistent with poisoning from the toxin.
While it's unknown for sure how much mercury was in John's body (the current owners of his property have refused to test his workshop for residue), mercury experts say there's a strong possibility he was poisoned.
'He was doing it for years, so the quantity of mercury in his workshop must have been unbelievable,' Dr Jack Caravanos, an environmental health professor at NYU, told Vox.
'So that's why his health effects, I think, are completely plausible.'
Clock restoration often involves a process called fire gilding, which embellishes clocks with gold decoration. Gold gets melted into mercury, the mixture is brushed onto a surface and then the mercury is evaporated with heat.
Without proper safety equipment, a person practicing fire gilding could inhale those toxic mercury fumes, which affects the nervous system. Without proper protection, it's likely John was exposed to toxic fumes for the majority of his life.
Dr Caravanos added that even if John were still alive, there's no test a neurologist can do to for mercury poisoning and, once poisoned 'there's no real treatment because your nerves are already damaged'.
And while mercury poisoning from elemental mercury (the type found in thermometers) is uncommon due to evolved health and safety regulations, gold miners in countries such as Indonesia and Peru, suffer mercury poisoning from artisanal gold processing, according to Caravanos.
Tiny amounts of rock with gold are farmed and mixed into mercury to extract the metal. This creates vaporous mercury, the same kind John McLemore was exposed to.
Caravanos and his nonprofit organization Pure Earth nonprofit are trying to teach miners to use other, less dangerous techniques to extract gold mainly with methods that allow for the gold ore to separate out from the materials surrounding it, instead of using mercury to draw it out.
However, the switch is stuff as mercury quicker and easier and while many countries have bans on the substance - they're not very effective.