The former director of the Poison Control Center says that he voiced concerns about lead contamination in Newark’s drinking water 20 years ago.

Dr. Steven Marcus tells News 12 New Jersey that he spoke with former Newark mayors Sharpe James and Cory Booker about his concerns about the potential harm of lead exposure. But he says he received some push back on ways to combat the issue.

“It was always, ‘Who was going to pay for it?’ and when I met with the council, it was clear the council were the landlords and they were not going to pass a rule that was going to hit them in the pocketbook,” Marcus says.

Booker is now a U.S. senator and Democratic candidate for president. Marcus says that he had some hope when Booker became mayor.

“He should have understood, you know? And when he became mayor, everybody on the lead consortium said, ‘Now we're really going to do something in Newark.’ Nothing happened,” says Marcus.

The lead consortium gathered city and state health officials with poison control and hospital representatives to document cases of lead exposure from paint, soil and water.

“Talking about being proactive as far as testing houses before kids moved in, testing all sources of lead,” Marcus says.

Marcus says Booker personally attended several of those meetings. Marcus also addressed the Newark City Council on lead issues prior to 2002, including during years that Booker was a Newark city councilman.

Booker's presidential campaign released a statement that read in part, "From Newark City Hall to the Capitol, Cory Booker has been working for years to right the wrongs of environmental pollution that disproportionately impact low-income communities and communities of color, including the lead contamination issues highlighted by Mr. Marcus."

Marcus has evaluated lead exposure in children since the 1970s.

“There were always children that had elevated leads that we couldn't find the source,” he says. “They would start high, probably because they ate paint chips or were exposed to that higher level but even when their house was completely de-leaded, their lead levels just didn't drop.”

Marcus says that he and his team turned their scrutiny to water. And while children with high levels of lead from paint presented symptoms like convulsions, the effects of lower-level lead exposure from sources like water are harder to detect.

“In multiple studies, it appears the greatest changes in the curve that's associated with IQ and other scales of development, the greatest effect occurs apparently at those lower levels of lead,” Marcus says.

Marcus says that while he was at the Poison Control Center he was responsible for ending the killing spree of serial murderer Charles Cullen. In that case, he says that his insistence on following the rules and investigating fully put a killer behind bars for life. But in Newark, he says his pleas fell on deaf ears.

“I don't have good confidence in the city of Newark or the state of New Jersey, to be honest. They have failed in the past. I would like to believe they're not going to fail now,” he says. “It is a crime, I hate to use that term, but it is a crime that we continue to expose our children to levels of exposure that are unnecessary.

A spokesman for the Booker campaign said as mayor, the senator "fought to fund much-needed repairs to Newark's crumbling water infrastructure."