Here's a recent L.A. Times article re a new study linking exposure to lead with criminal behavior: A new study on lead pollution and crime indicates that even relatively low exposure can affect a child for life. It also starkly shows that, in the big-picture world of environmental hazards, we live in a very small world indeed, in which all of us suffer collateral damage. The researchers found that regardless of socioeconomic or other factors, children exposed to lead developed smaller brains, particularly in the areas that regulate attention, impulse control and decision-making. They were more likely to be arrested for violent crimes. The higher the concentration of lead in the blood, the more likely was a criminal future, but negative effects were seen even among those with lead levels that are common among children today. The children with brain damage were obvious victims of lead exposure, but so were the victims of their crimes and the taxpayers who paid for policing and prisons. There may be other, undocumented costs as well. Many lead-exposed children probably develop learning disabilities, disrupting classrooms and contributing to a higher dropout rate. Who can calculate the economic cost of preventing generations of children from reaching their intellectual potential? The public hears all the time about what new environmental regulations will cost industry, but not about what we all will pay by failing to reduce pollution. Our ignorance on the subject costs us. Though the United States has sharply curtailed the use of lead, banning it from gasoline and paint, the Centers for Disease Control estimates that 310,000 preschool-age children still have levels of the heavy metal that exceed federal guidelines. The latest study indicates that there might be damage even at levels within the guidelines. The CDC recommends that all children be tested for lead, but too few doctors follow through. Physicians tend to think of lead as a problem afflicting only the poor, so although they're required to test young children on welfare, they seldom recommend it for others. In L.A. County, where about 80% of homes were built when lead paint was still in use, less than a quarter of children under 6 are tested. Old paint is commonly exposed by the repeated opening and closing of windows, which can grind the paint to bits that enter household dust. The lead study took three decades to complete. Meanwhile, the U.S. Environmental Protection Agency, which dragged its heels for 16 years on congressionally ordered regulations for lead paint removal, has been stalling on meaningful rules for mercury, another heavy metal that affects the brain. It will probably be decades more before the public learns what it has paid for these delays.