Mark Kleiman once wrote, "Compared to getting lead out of gasoline, everything else that happened in the 1980s to influence the health of children was a rounding error." That always struck me as a smart point. In 1986, lead was finally banned as a gasoline additive in the United States, and, in the years that followed, average blood-lead levels plummeted some 75 percent. That was huge: A 1985 EPA study estimated that nearly 5,000 Americans were dying of lead-related heart disease each year, to say nothing of the tens of millions of children who suffered from toxic exposure to lead from gasoline and were at risk for all sorts of developmental problems.

So the ban was good. But now researchers think that lead abatement might also have been a major driver in the great crime decline of the 1990s. On this theory, children who are exposed to lead paint or gasoline fumes are more likely to become violent teenagers. Rick Nevin, an economist, argues that the reduction in lead pollution in the 1970s and 1980s can account for most of the decline in New York City's crime rate over the past decade. That's... interesting. Meanwhile, Kevin Drum contends that "lead abatement could raise IQs in 6 million children by about 7 points for a cost of only $30 billion or so." Even if that estimate were off by quite a bit, further lead abatement would be a huge deal.

One problem, though. The Bush administration loves lead. Loves it. They want it everywhere. Okay, that's only a slight exaggeration: Back in 2002, the White House tried to stack an advisory committee on lead regulations with industry types. Last December, the administration announced that it would consider doing away with the standards that cut lead from gasoline, at the behest of battery makers and lead smelters. And its EPA has weakened a rule on removing lead paint from older residences. All that research on the toxic effects of lead exposure? Eh, who needs it.

In any case, another place where a massive lead-abatement really needs to happen is in the developing world. In Pakistan, some 80 percent of children have dangerous levels of lead in their bloodstream, which in turn affects childhood development and, presumably, intelligence. It wasn't until 2005 that sub-Saharan Africa finally phased out leaded gasoline, and the stuff is still used in a number of Third World countries. Lead batteries remain a major source of pollution all over the place. And so on.

P.S. Back in 2000, The Nation had a super-super-long piece on "The Secret History of Lead" that explained how lead got into gasoline in the first place, why companies continued to sell it even though they were well aware of the health effects, and why leaded gasoline was still being sold in the developing world. Some of it's a little dated, but it's a good read if you have a few hours to kill.