Jacobs, now research director for the National Center for Healthy Housing, said the federal government funded studies in the 1980s and 1990s in Boston, Cincinnati and other cities that involved monitoring lead levels in hundreds of children living in homes that had undergone varying abatement work.
Jacobs noted that all the houses had undergone some remediation. "What would have been unethical, and what was not done in any of these studies, is [to] put kids in houses where there were known lead hazards and do nothing about them," he said.
At the time, he said, it wasn't clear that more aggressive treatment of lead paint was necessarily better. An earlier Kennedy Krieger study had found that full abatement methods once required in Baltimore actually exposed children to more lead dust.
Jacobs said studies like the one that is the target of litigation helped him push through reforms at HUD that led to "revision of all federal housing regulations" in 1999. The government poured more money into methods that were shown to work, he said, such as replacing lead-painted windows.
The studies were launched at "a terrible time,'' recalled David Rosner, a professor at Columbia University's Mailman School of Public Health and co-author of a 2013 book examining the nation's struggle to deal with childhood lead poisoning.
Lead paint was deemed a public health crisis in the early 1990s, one that was inextricably tied to a lack of decent, affordable housing for the poor. The paint had been used in practically every home built before 1950 in Baltimore, and landlords balked at removing it, arguing that the costs often exceeded what their properties were worth. Children hospitalized for lead poisoning often had no safe place to go when released.
Gerald Markowitz, Rosner's co-author, called Mark Farfel and other researchers involved in the Kennedy Krieger study "extraordinary people who really tried to work in the community to eliminate lead poisoning at a time when there was very little institutional support, and certainly very little societal support for doing something about it."
Markowitz, a history professor at John Jay College and the graduate center of City University of New York, said, "They tried to find a less expensive [abatement] that would lessen the amount of lead that children would be exposed to. And in the end, I think that that was a terrible compromise, born of their desire to help children and born of their desire to combat this scourge that has affected millions of children over the course of the 20th century."
Farfel now works for the New York City Department of Health and Mental Hygiene, overseeing a registry of emergency providers and others exposed to potentially harmful toxic chemicals, smoke and dust in the destruction of the World Trade Center on Sept. 11, 2001. A co-defendant in some of the lawsuits against Kennedy Krieger, he did not respond to requests for comment.
Rosner faults the Johns Hopkins institutional review board — which examined and approved the Kennedy Krieger study — and other health experts familiar with it for not recognizing the inherent risk that children could still get low but harmful exposures to lead.
There is greater oversight of medical trials now than in decades past, said Susan M. Reverby, a Wellesley College historian who wrote a book about the Tuskegee study.
But she said there remains a gap between what researchers say and what study participants understand, particularly if the studies are "nontherapeutic" and don't intend to treat anyone, such as the Baltimore lead study. Risks are not always clear, and participants often trust institutions they know or are blinded by hope that they will benefit.
Researchers, she said, "are people who generally think they are doing the right thing, but what they can't see is how it's read by someone else. ... It behooves these institutions to think about how they inform families, especially when children are involved."
Harris, interviewed by phone from prison, said he was "shocked" when he heard he'd suffered lead poisoning as a child.
"When they told me how it affects you, I was thinking that's why I'm having trouble. ... I felt relief," he said.
Harris said at least some of his disruptive behavior in school stemmed from his learning difficulties. "We'd all be reading a book, everyone would take a turn reading a chapter, and I'd get put out of class so I wouldn't have to." That led to more acting up.
Harris said he's taking a GED prep class. He's still struggling, but "trying my best" and hoping to go to a trade school.
"I don't feel so frustrated now because I understand why I was having trouble," he said.
The situation with lead poisoning is much improved, though an estimated 500,000 young children nationwide still have lead levels high enough to warrant steps to reduce exposure, according to the federal Centers for Disease Control and Prevention. More than 2,700 were in Maryland, mostly in Baltimore, according to 2012 state figures, the most recent available.
"We've made tremendous strides, but we have also as a society failed half a million children who are overwhelmingly poor, overwhelmingly, disproportionately African-American," said Markowitz. "It's a horrible society failure."