Is the conversion to unleaded gas the reason why crime is at its lowest level in 50 years?

Yeah, yeah, I know. Whenever it’s reported that crime rates are declining, most Americans have a hard time believing it. That’s because they watch way too much television. (See HERE.)

But, in fact, crime rates generally have been declining. And Kevin Drum has an INTERESTING THEORY as to why:

I’ve written several posts recently about the idea that America’s great crime epidemic, which started in the 60s and peaked in the early 90s, was caused in large part by lead emissions from automobiles. Long story short, we all bought lots of cars after World War II and filled them up with leaded gasoline. This lead was spewed out of tailpipes and ingested by small children, and when those children grew up they were more prone to committing violent crimes than normal children. Then, starting in the mid-70s, we all began switching to unleaded gasoline. Our kids were no longer made artificially violent by lead poisoning, and when they grew up in the mid-90s they committed fewer violent crimes. This trend continued for two decades, and it’s one of the reasons that violent crime rates have dropped by half over the past 20 years and by more than that in our biggest cities. It’s one of the great underreported stories of our time: big cities today are as safe as they were 50 years ago…

Now, I know my readers, and first thing a lot of you are going to do is yell at me: “Correlation is not causation!” And that’s true. If this curve were the only bit of evidence we had, the connection between lead and violent crime would be pretty thin. But it’s not…[O]ver the last decade there’s been a tsunami of new medical research about just what lead poisoning—even at very low levels—does to children. It lowers IQ, of course, but it does a lot more than that…

We now have a huge amount of evidence linking lead to violent crime. We have evidence not just at the national level, but also at the state level, the city level, and the international level. We have longitudinal studies that track children from birth to adulthood to find out if higher blood lead levels lead to more arrests for violent crimes. And perhaps most important, this is a theory that just makes sense. Everything we now know about the effects of lead on the brain tells us that even moderately high levels of lead exposure are associated with aggressivity, impulsivity, ADHD, and lower IQ. And right there, you’ve practically defined the profile of a violent young offender.



  1. Interesting theory.

    Don’t forget lead paint as well. Please note that lead paint has been most common in poverty stricken/high crime areas.

  2. Craig Knauss

    Lead paint, as well as asbestos, were used all over. However, in older, deteriorating neighborhoods lead paint is more likely to still be present since it has not been removed or covered over. Do keep in mind that if you buy a “historic” home, you may still have lead paint under all that newer paint. But as long as the newer paint isn’t allowed to peal off, no problem. And in older homes the insulation around furnace ducts and steam pipes could still contain asbestos. Plan accordingly if you plan to do any home improvements.

    We’re demolishing much of the old Hanford Site buildings. Many of them contained lead paint and asbestos, so special precautions have to be taken.

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