The national uproar over lead poisoning in Flint, Mich., has drawn renewed attention to a children's health crisis that has plagued Pennsylvania and Jersey for decades.
The states' own data show that 18 cities in Pennsylvania and 11 cities in New Jersey may have an even higher share of children with dangerously elevated levels of lead than does Flint.
The states' reports, released in 2014, were recirculated this week by health advocates trying to draw attention to the lead problem.
"We're not to trying to take anything away from Flint," said Elyse Pivnick, director of environmental health for Isles, Inc., a community development organization based in Trenton. "But whoa, we have to tell the story of lead in Pennsylvania and New Jersey, too."
Regional health officials on Thursday, while expressing concern for children exposed to lead, insisted that the advocates are mismatching data and failing to recognize the progress that has been made.
Though the focus in Flint is on water, the biggest source of lead remains chipping and flaking paint in old, poorly maintained houses. Despite improvements in recent years, blood lead levels remain high, especially among poorer children.
The controversy also shows that lead numbers are tough to interpret, and lead's impact on individuals can vary dramatically.
Tom Vernon, a Philadelphia physician and former director of Colorado's Department of Health, agrees that lead is less of a problem these days due to measures like removing lead from gasoline and paint.
"But that good news is offset by what we're learning about the effects on school achievement and executive function at lower and lower levels of lead exposure," Vernon said.
There is no safe level of lead exposure for children, according to the Centers for Disease Control and Prevention. But a blood lead level of 5 micrograms per deciliter is the threshold that should trigger public health action, according to the federal agency. That's a relatively new threshhold; a few years ago, 10 micrograms was the federal standard, and still is in New Jersey, according to its health department.
The debacle in Flint was created when the city opted for a cheaper municipal water supply. In 2015, 112 children of the 3,340 tested - or 3.3 percent - had a blood lead level of at least 5 micrograms, according to data collected by Michigan health authorities.
Comparisons between Flint and other cities are not perfect because of how the data are collected, and the differing test periods. But the numbers are striking.
Philadelphia, which has 15 times Flint's population, tested 35,863 children under the age of 7 during the 2014 calendar year. Of those, 3,655 - or 10.2 percent - had blood lead levels of 5 or greater.
Some states, including New Jersey, mandate lead testing, a position supported by the American Academy of Pediatrics. But in others, such as Pennsylvania, physicians determine which of their patients should be tested. Lower-income children in older houses are considered at highest risk.
"It only takes a couple of paint chips to substantially increase the blood lead level," said Marilyn Howarth, a physician at the Center of Excellence in Environmental Toxicology at the University of Pennsylvania.
"Although the CDC has established the reference level at 5 (micrograms), they're not saying that 5 is safe," Howarth said. "At 5 there is evidence that nerves are affected and there can be impact on IQ, development and behavior."
Lead poisoning often isn't even noticed because it can be subtle, Howarth said. Initial symptoms may include fatigue, lack of motivation, poor coordination and problems with speech and language.
"People rarely bring their child to a doctor because of those symptoms," Howarth said. "They are easily overlooked."
Long term, the damage can mean a lifetime of intellectual limitations and other neurological damage. Freddie Gray, whose death of injuries sustained while in police custody last year sparked riots in Baltimore, was tested for lead as a child six times, the Baltimore Sun reported. Gray and his two sisters had lead levels between 11 and 19 micrograms, according to legal documents, leading "to multiple educational, behavior and medical problems."
In Pennsylvania, 13,000 children under the age of 7 were known to have blood lead levels over 5, according to the 2014 Childhood Lead Surveillance Report. That marked a decrease of nearly 7 percent from the previous year. In the New Jersey report that year, more than 5,400 children were similarly affected.
Philadelphia data, collected by the Division of Disease Control in 2012, showed children with the highest lead levels concentrated in Center City, Roxborough/Manayunk, and a sizable swath of West Philadelphia.
"Unfortunately in a city where 39 percent of children are living in poverty, you then put them in a home or a daycare center where there is lead and it's a double whammy for that child," said Daniel Taylor, director of community pediatrics and child advocacy at St. Christopher's Hospital for Children.
"However, I'm a bit skeptical of the Philadelphia numbers," the pediatrician said. "We're in the epicenter of old homes, poverty, immigrants and refugees but I don't see lead poisoning in 1 of every 10 kids."
Pennsylvania health officials on Thursday signaled their concern over the situation without mentioning Flint. "The Department of Health is very concerned about elevated lead levels in children wherever they may occur," said Health Secretary Karen Murphy in a press release.
Jeff Moran, a spokesman for the Philadelphia health department, said comparing the city to Flint would be "inappropriate." In New Jersey, health department spokeswoman Donna Leusner said her state has been a national leader on the issue.
"Our cases have steadily declined, making comparisons with the acute crisis in Flint misleading and unfair."
"Of course, it's not exact," she said. "But we're trying to make the point that while there's attention being paid to Flint, we have a chronic problem of children being poisoned and it's not getting enough attention."
It costs about $8,000 per dwelling to remove lead. But the costs of lead poisoning are potentially far greater said Jay Schneider, who researches lead's effects on children at Thomas Jefferson University.
In addition to the burden on the health care system there also are costs for special education for children with neurological damage. Down the line, courts and prisons bear the load for behavior that has been linked to lead poisoning.
Lead poisoning is a danger even before birth, he explained. Lead is stored in the bones, and can be released during the stress of pregnancy.
"And now that lead has access to the fetus," he said.
Recent research also suggests lead poisoning can even alter human DNA, Schneider said, leading to damage that can be passed down to subsequent generations.
"If you can't get kids out of the lead environment, you'll have to find a way to deal with the kids after they've been poisoned," Schneider said.