Leaded Gasoline... and Crime?! The Wild Link Between Gas, Brains, and Violence (1941–2015)

[Lexluther]

Buckle up, folks. This one’s straight out of the "truth is stranger than fiction" category.

So, back in the day, the U.S. was literally running on leaded gasoline — yup, gas filled with tetraethyl lead (TEL). Why? It made engines more powerful. Downside? It was crazy toxic, especially for developing brains.

Kids breathing that stuff in = lead in blood
🧠 Lead in blood = brain damage, especially in the frontal lobe
Damaged frontal lobe = more impulsive and aggressive adults
Fast forward 20 years = spike in violent crime

Here's the timeline:

1940s–1980s: Massive use of leaded gas
🧪 1970s: EPA starts phasing it out
1990s: Violent crime starts dropping… like a rock
🤯 Coincidence? Researchers say: NOPE

In 2000, environmental economist Rick Nevin dropped a bombshell study. His regression analysis showed that up to 90% of the rise and fall in U.S. violent crime could be statistically explained by lead exposure 20 years earlier. That’s a monster R².

Two big visuals tell the story:

Chart 1:

% of Americans with dangerous lead levels in blood

Violent crime rate (per 100k people, lagged 20 yrs)

Leaded gasoline consumption (in thousands of tons)

Chart 2 (from Nevin's study):

Leaded gas use per 1,000 people

Violent crime per 100,000 people

Reminder: correlation ≠ causation…
But Nevin did show causation using regression, and it’s wild. He argues that childhood lead exposure directly causes higher crime rates down the road. 20 years later, the crime wave crests.

TL;DR: Want to fight crime? Start with the air kids breathe.

What do you think — legit connection or statistical wizardry?
Anyone else got underrated causes of major social shifts like this?