[INTRO ♪].

On Christmas Eve 1926, more than 60 people ended up in a single hospital in New York City. They were violently ill and hallucinating.

And despite doctors’ best efforts, within a few days, about half of them died. But it wasn’t a virulent flu or poorly-chosen mushrooms that caused their deaths. It was alcohol that had been poisoned by the U.

S. government...which sounds like a conspiracy theory, but it’s the truth. In the ‘20s, a chemical war between government regulators and illegal booze sellers resulted in tens of thousands of poisonings and hundreds—maybe even thousands—of deaths. In the U.

S., the roaring ‘20s were a decade filled with jazz, flapper dresses, speakeasies and lavish parties like the ones in The Great Gatsby… even though America was supposed to be a dry country. The 18th Amendment, which banned the production, sale, import, and export of alcoholic beverages, came into effect in 1920, and it wasn’t repealed until 1933. But plenty of people still drank—even though that sometimes meant risking their lives.

When alcohol became illegal, people turned to the black market for their booze. And thanks to heavy enforcement at ports of entry, smugglers could only bring in so much. So the bootleggers that trafficked in illegal alcohol often stole industrial alcohol instead.

Ethanol—the main kind of alcohol in alcoholic beverages—is used in everything from cosmetics to pharmaceutical products to house paint. But at the turn of the century, import taxes made it really expensive to use pure ethanol that way, because it’s technically drinkable. So starting in 1906, almost 15 years before prohibition, the U.

S. government began adding toxic chemicals to industrial alcohol to make it cheaper—a tactic already used in other places like Europe. Industrial formulas were spiked with well-known toxic compounds like gasoline, chloroform and methanol. And because that made them undrinkable, when the 18th amendment went into effect, they weren’t covered by the ban.

But… for the most part, all one had to do to make them drinkable was distill them. That’s the process where alcohol is boiled and then its vapor is collected and cooled. And when done carefully, it can get rid of small amounts of toxic additives if their boiling points are different from ethanol’s.

During the first several years of prohibition, the U. S. Treasury Department estimated tens of millions of gallons of industrial alcohol were stolen for human consumption.

So in 1926, President Calvin Coolidge used the help of chemists to make these already toxic alcohols even more dangerous, particularly by adding methanol. There was already some methanol in most industrial alcohol formulations, but the government added more—a lot more—to the point where it was sometimes 10% of the entire product. And that change is probably what caused so many poisonings and deaths.

No alcohol is great for you, but methanol is much worse than ethanol. The two chemicals only differ by a carbon and two hydrogens, but that’s enough to make one drinkable and the other lethal. In your liver, an enzyme called alcohol dehydrogenase removes hydrogens from alcohols.

Ethanol is converted to acetaldehyde and then eventually to acetic acid—the same stuff in vinegar. Methanol is also processed by this enzyme, but the losses of hydrogens create formaldehyde and then formic acid instead. And formic acid is baaaaaad.

It inhibits a key enzyme that your cells need to convert sugar and oxygen into usable energy. So even though they’ve got plenty of food, your cells basically end up starved. That’s why the buildup of formic acid in someone’s body can cause a range of horrifying effects, from holes in the stomach and intestines, to vomiting blood and kidney failure.

One of the most common symptoms, though, is hallucinations—like the ones experienced by all those people rushed to that New York hospital in 1926. That’s because your optic nerves—the nerves that transfer visual information from your eyes to your brain—need a lot of energy to function, so they’re among the first to feel formic acid’s toxic effects. And that damage can be permanent, which is why methanol poisoning frequently causes blindness.

Now, in principle, even 10% methanol can be distilled away, but the bootleggers’ chemists didn’t have the best equipment, and they were pressed to work quickly. And since booze was illegal, no one was checking their product to make sure it was safe. Although the exact figures aren’t known, by the time prohibition ended in 1933, some estimate that over 10,000 people had died from drinking government-poisoned alcohol.

Killing people wasn’t the goal, but it was the result. And these deaths became a hot-button political issue, so as the '20s came to a close, regulators slowly started switching to less toxic dyes and noxious compounds that couldn’t be distilled away. For example, in 1930, the U.

S. government announced the discovery of alcotate, a sulfurous compound that smells like rotten eggs. Which isn’t exactly an appetizing scent for a gin and tonic. Some industrial formulations still included methanol, and some still do today, but when the 18th amendment was repealed, there was much less incentive to drink them.

So nowadays, thankfully, methanol poisonings in the US are relatively rare. Thanks for watching this episode of SciShow! If you want to learn more about how different drinks are made, you might like our episode on the science of alcohol. [OUTRO ♪].