The dangers of lead have been known for years; that's why it was banned from gasoline in the 1970s. It was known to reduce IQs and according to a 1996 study, "those with the highest concentrations of lead – still below government-recommended safe levels – had tests scores showing more aggression, attentional disorders and delinquency."
Now Kevin Drum has written a remarkable article in Mother Jones that ties the decline in the use of lead to the decline in crime across America. Not only that, the data are identical around the world; crime didn't decline because of abortion rules like the Freakonomics boys say, or because of Rudy Guliani, as Rudy Guliani says, but because of the one change that happened everywhere: The banning of lead in gasoline.
Put all this together and you have an astonishing body of evidence. We now have studies at the international level, the national level, the state level, the city level, and even the individual level. Groups of children have been followed from the womb to adulthood, and higher childhood blood lead levels are consistently associated with higher adult arrest rates for violent crimes. All of these studies tell the same story: Gasoline lead is responsible for a good share of the rise and fall of violent crime over the past half century.
In the Guardian, George Monbiot was surprised.
It seemed, at first, preposterous. The hypothesis was so exotic that I laughed. The rise and fall of violent crime during the second half of the 20th century and first years of the 21st were caused, it proposed, not by changes in policing or imprisonment, single parenthood, recession, crack cocaine or the legalisation of abortion, but mainly by … lead.
As is his wont, he read every study (and references them in his post) he concludes:
Lead poisoning in infancy, even at very low levels, impairs the development of those parts of the brain (the anterior cingulate cortex and prefrontal cortex) that regulate behaviour and mood. The effect is stronger in boys than in girls. Lead poisoning is associated with attention deficit disorder, impulsiveness, aggression and, according to one paper, psychopathy. Lead is so toxic that it is unsafe at any level.
It appears that most of the problem with lead came from the stuff in gasoline, although lead paint has historically been an issue. I wrote a few years ago about how new rules from the EPA on renovating old buildings might lead to more demolition and less restoration, and complained about the new rules.
Seriously, I spend a lot of time proselytizing that renovation creates labour intensive green jobs that can put a lot of unskilled people back to work. Now, on April 22, they become highly skilled and regulated jobs that require special tools, expensive bug suits, goggles and double gloves. People will just tear the things down instead.
Half the buildings in America need to be made more efficient. I suspect that the default move now will be simply to haul them to the dump, if every single building built before 1978 is now considered toxic waste.
Reading Kevin Drum, I think I understated the danger of the stuff.