Residents of Newark, New Jersey, are hunting for clean drinking water, as Democratic presidential hopeful Cory A. Booker faces renewed scrutiny from critics who question whether his stewardship of water management issues as the city’s mayor may have helped lay some of the groundwork for the current crisis.

There is no “smoking gun” failure, even his critics acknowledge, but they say Mr. Booker, who was mayor from 2006 to 2013, didn’t help matters with lax oversight of a scandal-plagued water commission, which had a key associate and others with ties to the group facing criminal charges.

“Booker has no credibility, especially on water,” said Brendan O’Flaherty, an economics professor at Columbia University who put together a 2011 report on the commission. “He did not leave a legacy of a well-functioning water treatment plant and engineering corps. He left a mess.”

Authorities said they found elevated lead levels in the city’s water supply and tied the problem to leaching in the pipe system.

Officials distributed tens of thousands of water filters to residents last year to try to alleviate their concerns, though the city repeatedly said the water was safe to drink.

Several samples of the filtered water were found this week to have elevated levels of lead, and Mayor Ras Baraka announced that the city would provide bottled water.

City and state officials are meeting with the Environmental Protection Agency to try to get a handle on the situation.

Mr. Booker, as mayor, nominally oversaw the Newark Watershed Conservation and Development Corp. (NWCDC), a nonprofit entity that was in charge of protecting the city’s water assets before it voted to dissolve in 2013.

A 2014 report from the state comptroller’s office found that the corporation operated free of meaningful oversight, allowing Executive Director Linda Watkins Brashear, a Booker ally, to write unauthorized checks to herself and dole out no-bid contracts to personal associates.

Ms. Watkins Brashear was sentenced to more than eight years in prison, and others have pleaded guilty to charges stemming from their ties to the group. Elnardo Webster, a Booker friend, also served as counsel for the NWCDC, though a spokeswoman has said that illicit funds were spent without his knowledge.

Mr. Booker was named but later dropped as a defendant in a lawsuit from the group seeking monetary damages from the city.

As Newark mayor, Mr. Booker technically served as the group’s chairman but never went to the meetings, said Guy Sterling, a former reporter for The Star-Ledger who worked to uncover some of the problems with the group.

“It was all over the place that the NWCDC was corrupt, you know, but he likes to pat himself on the back and take credit and certainly not take responsibility, even though he came in proclaiming he was going to [have] the greatest transparency and accountability that Newark had ever seen,” Mr. Sterling said. “Well, you know, that wasn’t the case.”

Mr. Booker told the comptroller’s office that he relied on the city’s business administrator to attend meetings on his behalf, though he never designated a replacement when the administrator resigned in May 2010, the report said.

Mr. Booker’s campaign dismissed the notion that the presidential candidate is to blame for the city’s water issues.

But Mr. O’Flaherty said there are “indirect” connections based on Mr. Booker’s lax oversight.

“The NWCDC was in charge of the water treatment plant. During [the] Booker years, there was no investment in human capital,” he said.

A report from the engineering firm CDM Smith released in October said a decrease of pH levels in the system was likely a major contributing factor to the elevated lead levels in the city’s water supply in 2017 and 2018. The lower pH levels caused the pipes to start leaching.

The pH range was 8.5 to 9.0 during the 1990s, fell to a range of 8.0 to 8.3 until 2013 and then decreased to the recent average of about 7.1, the report said.

Mr. O’Flaherty said a decision to reduce the pH levels from about 8 to 7 would have been made at some point between 2012 and 2016 — a time frame that overlaps with Mr. Booker’s tenure as mayor.

“That’s the cause of everything,” he said. “I do not know when the decision was made. I do not know who made it.”

As it stands, it’s not exactly fair to pin the blame on Mr. Booker and what he might or might not have done, said John Weingart, associate director of the Eagleton Institute of Politics at Rutgers University.

“So while the mayor of any city should be concerned about all environmental aspects, including the quality of the drinking water or the safety of drinking water, to my knowledge there was no red flag that arose at a time when the Booker administration could have or should have known [there was] a need to take action,” Mr. Weingart said.

Before the comptroller’s report and criminal issues that stemmed from the NWCDC, Mr. Booker mounted a campaign to transfer the NWCDC into a “municipal utilities authority” — a failed effort that Mr. Sterling said was a “black mark” on Mr. Booker’s time as mayor.

“If that had happened, these same people who later … were involved in incredibly criminal, brazen criminal activity would have had 10 times as much money at their disposal to loot,” he said. “I’ll be honest with you, and I’m surprised this issue hasn’t surfaced in the campaign.”

The campaign team has said Mr. Booker was trying to clean up the NWCDC.

“For years as mayor, Cory Booker waged a public battle to reform Newark’s water system and improve oversight and accountability, but those efforts were repeatedly blocked by opponents,” attorney Marc Elias told Politico in 2015 in response to the NWCDC’s lawsuit.

“When serious evidence of wrongdoing at the Watershed emerged, then-Mayor Booker took immediate action to dissolve it and bring its operations under direct control of the city,” Mr. Elias said.

Others say there is no justification to connect Mr. Booker to Newark’s lead issues.

“I do think just because he’s running for president of the United States, folks want to use this as an issue,” said Kim Gaddy, an environmental justice organizer for the group Clean Water Action and a Newark resident. “He did what was required of him when he was the mayor.”

The National Resources Defense Council, which has sued the city over water quality, puts the beginning of the issues after Mr. Booker left the mayor’s office.

“There may have been a problem, but it’s really become a pretty clear issue in 2017,” said Erik Olson, who works on drinking water issues at the NRDC. “At least the data we have suggests that it was after 2013.”

He said a 2003 NRDC report listed Newark as one of about 20 cities that had issues. The report cited excessive lead levels in tap water tests in Newark in 2000 and 2001.

“Apparently, they did install some corrosion control, but it started failing, apparently, around 2015 or thereabouts,” he said.

Mr. Booker and other members of New Jersey’s congressional delegation on Tuesday sent a letter to the EPA calling on the federal government to help state and local efforts to get clean drinking water to Newark’s residents.

The senator introduced legislation in May intended to give states more flexibility in using federal funds to upgrade their water infrastructure systems and pointed to the tainted water in Flint, Michigan.

“Flint is not an anomaly,” he said. “Communities across the country don’t have clean drinking water, and those communities are disproportionately low-income and communities of color.”

Sign up for Daily Newsletters Manage Newsletters

Copyright © 2020 The Washington Times, LLC. Click here for reprint permission.