David Mastio

USA TODAY Opinion

Now that the leaching of poisonous lead into the tap water of Flint, Mich., has been declared a national emergency, it might be time to dial back the panic just a notch (or two).

Flint's 8,000 children have not had their lives destroyed. Jesse Jackson can roll up his crime tape. Michael Moore can go back to promoting his latest film. Taken as a whole, in fact, Flint's kids are better off than the previous generations of Michigander kids in at least one important way. Even after Flint’s disaster, the city’s children have far less lead in their blood than their parents or grandparents did at the same age.

That's of little comfort, of course, to those exposed to higher levels than they should have been because of a nearly bankrupt local government, a scientifically incompetent city water utility, indifferent Michigan environmental regulators and a bumbling federal Environmental Protection Agency. And any lead has a long-term insidious health impact, even after it has left the blood. But amid the furor, it's important to take a deep breath and put the exposure levels in context.

Less lead than 10 years ago

In 2005, Michigan completed the years-long process of collecting 500,000 lead blood tests from children in the state under 6. Back then, 26% of kids tested — that's more than one in four — had blood lead levels (5 micrograms per deciliter or greater) that would cause concern today. In the hardest hit parts of Flint now, only 10.6% of kids have such concerning levels of lead in their blood.

How can that be? While drinking water management in Flint has obviously been a mess in recent years, it's a mess that comes amid one of the greatest public health and environmental triumphs in U.S. history.

Centers for Disease Control and Prevention data are clear. In the late 1970s, 88% of Americans ages 1 to 5 had at least 10 micrograms per deciliter of lead in their blood, or twice as much as today's level of concern.

By the early 1990s, only 4.4% of children were exposed to so much lead. And year by year since then, according to more than 31 million blood tests compiled by the CDC just since 2005, lead has been steadily disappearing from American kids’ blood.

Is that good enough? No. As any public health official will tell you, there is no safe level of lead. Once you are exposed, lead can haunt you even as it disappears from your blood. But reality is frustrating. We spent decades spewing lead into the air and coating our houses with it before we banned leaded gasoline and lead paint. Millions of American homes get water from lead pipes and millions more have copper pipes with lead solder.

New tighter lead laws

Getting to zero isn’t going to happen anytime soon, but government officials of both parties have steadily increased efforts to combat exposure to lead, which causes an array of health problems, including significantly lower IQs in children. In 2007 and 2008, the George W. Bush administration tightened rules for lead in the air and water. In 2011, President Obama signed a law tightening rules for lead in plumbing fixtures. In 2012, the CDC tightened its rules on what level of lead in blood raises concern.

After years of progress, context-free panic over events in Flint is counterproductive. It feeds the cynical idea that government always fails. And, when a more sober analysis of the health threat in Flint eventually emerges, it will damage the credibility of the politicians, public health advocates, scientists and journalists who raised alarms shorn of nuance.

Virginia Tech University researchers first brought proof of high lead levels in Flint water to public attention last September, performing three water tests in each of the more than 250 Flint homes. Lead levels were high enough to warrant urgent government action. But in a similar problem with Washington, D.C.’s tap water a little over a decade ago, hundreds of homes were found to have stratospheric lead levels of 300 parts per billion or more. In Flint, Virginia Tech found one home with such a high lead level in the water.

So how dangerous was that water? In 2015, the Michigan Department of Health and Human Services tracked one child in Flint whose initial blood test was so alarming it required hospitalization. A later, more accurate test showed a lower, but still dangerous level of lead at more than five times the CDC's level of concern. In contrast, 2005 CDC data show more than 300 people in Michigan with the same or worse confirmed test results.

Flint research complications

Michigan State University-backed research, comparing the lead in Flint children’s blood before and after poison-laced tap water flowed into their homes, did find a dangerous rise in blood lead. But in raising the alarm about a threat throughout Flint, researchers minimized results that cast doubt on the breadth of the health problem — neglecting to emphasize that, in three of the city’s nine wards, lead tests showed a nearly 50% decline in the number of kids testing positive. In a fourth, there was no change. The study also found that the number of children with elevated blood lead levels rose even for county residents whose water supply did not change.

One reason for such widely divergent results in Flint, where the percentage of children with elevated blood lead levels tripled in one place while nearby the percentage of kids affected fell, may be that some of the test results stem from an inaccurate screening test far less reliable than the procedure recommended by the CDC as the gold standard.

According to officials in the CDC's lead program, "capillary" test errors overestimate the amount of lead in a child's blood. Test results that show blood lead levels of 5 to 9 micrograms per deciliter, the lowest level of lead exposure now tracked by health officials, require only a single prick test. According to the CDC, the average error is 1 microgram per deciliter, a 10% to 20% overestimate in lead levels between 5 and 9. And federal rules allow laboratories to overestimate blood lead levels by as much as 4 micrograms per deciliter and still meet accuracy standards.

Howmany false positives?

The Michigan State University researchers who raised the alarm on blood lead levels in Flint refused to give USA TODAY their data on exactly what levels of lead they found. Michigan's health department maintains a similar database of 3,353 blood tests on children in Flint from 2015 and provided USA TODAY a preliminary analysis. Seventy-seven percent of the "positive" test results are in the lowest 5-9 micrograms per deciliter range most vulnerable to the inaccuracy of capillary tests, raising the possibility of a significant number of false positives. As one CDC analysis dryly notes, "the ratio of imprecision to measurement value, particularly at (blood lead levels of less than 10 micrograms per deciliter) is relatively high."

What happened in Flint starting in 2013 needlessly risked the health of thousands of people who deserve better, exposing anyone who drank tap water to poisonous lead that never should have been there. Of this, there is no question.

But it also true that the health threat in Flint is being exaggerated. While plenty of questions remain about who is most at fault and who is most at risk, one thing is for sure: Flint residents of only a decade ago would have counted themselves lucky to suffer the lead “poisoning” rates plaguing the city today.

David Mastio, the deputy editorial page editor of USA TODAY, was an environmental reporter for The Detroit News.