Lead and Race In Flint—And Everywhere Else

Marcy Wheeler comments today on the lead disaster in Flint: "Think about how effects of lead poisoning feeds the stereotypes about race and class used to disdain the poor."

Yep. Lead poisoning is equally bad for everyone, but certain groups were far more exposed to lead poisoning than others. Here's a chart showing the percentage of children who displayed elevated blood lead levels over the past four decades. The data is taken from various studies over the years that have reported data from the CDC's long-running NHANES program:

All the rest of the data on lead poisoning is exactly what you'd expect. Not only is it higher among blacks than whites, but it's higher in inner cities and it's higher among low-income families. And of course, this is on top of all the social problems these kids already have from being black, poor, and living in rundown neighborhoods.

Needless to say, lead didn't cause institutional racism. But lead sure made it worse. White children were severely affected by the postwar lead epidemic, but it produced nothing less than carnage among black kids. Before we finally got it under control in the late 80s, lead poisoning had created nearly an entire generation of black teenagers with lower IQs, more behavioral problems in school, and higher rates of violent behavior—which, as Wheeler says, feeds into already vicious stereotypes of African-Americans and the poor. The only good news is that as lead poisoning has declined, it's declined in blacks more than among whites. The difference today between black and white kids is fairly modest.

But what about Flint? The big problem with lead is that it does its damage in children, and once the damage is done the brain never recovers. We're seeing lower levels of violent crime today because most crime is committed between the ages of 17-25—and that age cohort was all born after 1990, when atmospheric lead had dropped close to zero. But the effects of lead continue to dog people in their 40s and 50s. Once it's there, it's there.

This is what makes Flint so scary: if elevated lead levels damage young children, they'll be damaged forever. So how much damage was actually done? And how much damage is still being done?

Those are hard questions to answer for two reasons. First, we don't have as much hard data as we'd like. Second, lead is a horror show. Nobody wants to say anything that quantifies the damage and runs the risk of minimizing it. Public health experts are dead serious when they say the only safe level of lead is zero. Because of this, they simply don't want to publicly declare that any specific rise in elevated blood lead levels is...is...anything. I don't want to say it either. It's just bad, full stop, and it needs to be fixed.

That means I was surprised to see this in the New York Times today:

“Our kids are already rattled by every kind of toxic stress you can think of,” Dr. [Mona] Hanna-Attisha said....She emphasized, however, that not every child exposed to lead would suffer ill effects. Kim Dietrich, a professor of environmental health at the University of Cincinnati College of Medicine, said that based partly on the blood lead levels of children in Dr. Hanna-Attisha’s study, he did not think serious long-term health problems would be widespread.

I've spoken with Dietrich, and he's not a guy who takes the effects of lead lightly. If he says the long-term effects in Flint are likely to be modest, I'd pay attention to him.

But why would the effects be modest? Three reasons. First, lead levels in Flint were elevated for about 18 months. That's a long time, but it's a lot less than having elevated levels for your entire childhood up to age five. Second, the use of filters and bottled water helped reduce the lead levels in the drinking water. And that in turn means that, third, the rise in kids with blood lead levels above 10 m/d was less than one percentage point—and the rise was less than three percentage points even if you use the more conservative level of 5 m/d. As recently as 2008, the levels seen during the Flint water crisis would have been cause for celebration.

And what about now? Data here is frustratingly hard to get. Marc Edwards, the water-treatment expert who first blew the whistle on Flint's water supply, says that (a) Flint's pipes are probably back in satisfactory shape now that water has been coming from Detroit for the past three months and is being properly treated, (b) the water is "much, much better than it was last August," and (c) there's a 50-50 chance it could even pass a full-bore federal testing regime. Beyond that, preliminary state data suggests that blood lead levels in children are now down to about where they were before the water crisis. That's good news, but it's tentative.

More recently, the US Public Health Service announced that 26 out of 4,000 water samples in Flint had lead levels above 150 parts per billion. This is important because above that level it's possible that filters won't work effectively. But it doesn't really tell us much about current lead levels in Flint's water. We can say that 99.4 percent of homes have levels below 150 ppb and are probably safe if the water is filtered. But how many are below the EPA "action level" of 15 ppb? And what's the "90th percentile" lead level, the standard way of measuring lead in tap water? We don't know any of that, even though 4,000 samples is enough to give us a pretty good idea. Overall, Flint's water is obviously much improved, but it's hard to say precisely how good or bad it still is.

Put this all together and what do we get? Several educated guesses:

  • At a public services level, the Flint water crisis was an unbelievable fiasco.
  • The long-term damage to Flint's kids is very real, but probably not catastrophic.
  • The water today appears to be safe in nearly all homes that use a filter.
  • However, there are also a small number of homes with astronomical lead levels in their water. It's unclear why, but these homes need to be the target of immediate crash remediation.

If anything positive comes out of the Flint debacle, it will be a better understanding of the dangers of lead. Ironically, though, it's not lead pipes that are really the biggest problem nationwide. Thousands of towns and cities have old lead pipes, and they generally don't cause any problems except when some bonehead decides to stop treating the water properly and the scale inside the pipes corrodes away. Rather, the biggest problems now are lead paint and lead in soil. Everyone knows about lead paint, and abatement programs are widely available. But lead in soil, the product of decades of leaded gasoline settling to the ground, just sits around forever and gets kicked back into the air every summer when the soil dries up. It remains a serious problem, and not surprisingly, it's most serious in heavily black, urban neighborhoods that had the highest levels of lead poisoning in the first place. You can read more about this in my piece about lead and crime (scroll to the bottom) or in this recent Vox piece by Matt Yglesias specifically about lead in soil.