Problems with rising lead levels in Suez's drinking water distribution system began years before the company's announcement in January that it had exceeded federal standards for the toxic metal, newly obtained documents show.

The water system that serves 800,000 people in Bergen and Hudson counties was on the cusp of exceeding standards in 2012 and again in 2015, according to correspondence between Suez and regulators obtained by NorthJersey.com and the USA TODAY NETWORK New Jersey.

The documents can be viewed at the end of the story.

Aside from adjusting the acidity of its water, Suez took no major action after a key measurement of lead samples taken from 2010 to 2012 came back at 14.3 parts per billion — the highest level in years and just shy of the 15 parts per billion that would require the utility to take preventive steps.

But when samples taken from 2013 through 2015 also hit 14 parts per billion, Suez executives realized they had a burgeoning problem, documents show.

No amount of lead in drinking water is considered safe, according to several government agencies and health organizations. Lead accumulates in the body over time and is especially harmful to the development of children, infants and fetuses.

Suez maintains there is no widespread health threat and that the majority of homes tested have little or no lead in their water.

But the problem was serious enough for the company to take several major steps to reduce its lead levels after the 2015 results. This included injecting an anti-corrosion chemical into the water supply to provide a protective interior coating on thousands of the utility's lead pipes and homeowners' plumbing fixtures to prevent leaching, documents show.

The 2015 readings were "a little too close for comfort," Michael Assante, Suez's superintendent of production, said in an interview this month. The company was trying to "make it better ahead of finding ourselves in a bad position."

While those efforts seemed to work at first, lead levels shot up in the second half of 2018 to 18.4 parts per billion — above the federal standard. It prompted Suez to embark on a multimillion-dollar effort this year to replace 25 percent of its lead pipes. The company still hasn't figured out what caused the spike.

"It may not be that it is one particular root cause," said Gene DeStefano, an engineering consultant working for Suez. "There may be multiple factors."

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Suez executives at the Haworth-based division of the worldwide company have downplayed the 2012 and 2015 lead readings in recent communications with NorthJersey.com because at the time the water system had not yet exceeded the U.S. Environmental Protection Agency's 15 parts per billion standard.

"During these years, Suez met all safety standards for lead," a company statement released this month reads. "Tests of our corrosion control treatment showed our water met all health standards."

Despite its own goals of having zero lead in drinking water, EPA forces public water systems like Suez to take corrective action only when more than 10 percent of lead samples in a given period exceed 15 parts per billion.

And after the high levels in 2015, Suez quietly embarked on a multi-year project to try to make sure it didn't cross that threshold, documents show.

A problem emerges

Suez water comes from a series of lakes beginning in Rockland County and is carried south via the Hackensack River to Bergen County's Oradell Reservoir, one of the largest drinking water sources in New Jersey.

Water that leaves Suez's treatment plant in Haworth has no detectable levels of lead.

Small amounts of the metal gets into the water from the utility's estimated 8,541 lead service lines that connect water mains from the street to the property line, 23,623 utility-owned lead connecting pipes called goosenecks, and an unknown number of household plumbing fixtures that contain lead.

Many factors contribute to how water is able to leach lead from pipes, but a major factor is the water's acidity. Water that is more acidic is likely to leach more lead.

The story continues following this photo gallery:

Until the 2015 lead results came in, Suez’s only anti-corrosion treatment was to add sodium hydroxide to its water at its Haworth treatment plant to balance the water’s pH, documents show.

While Suez had never exceeded the 15 parts per billion standard before 2018, its lead levels had slowly been increasing over the course of a decade, state records show.

2004: 7.7 parts per billion

2007: 11 parts per billion

2009: 11 parts per billion

2012: 14.3 parts per billion

2015: 14 parts per billion

The biggest jump came from samples taken between 2010 and 2012 that hit 14.3 parts per billion — just shy of the 15 parts per billion that would require action.

None of the 75 pages of documents obtained by NorthJersey.com from the state Department of Environmental Protection and Board of Public Utilities mentions any action taken by Suez after the 2012 lead readings.

In response to questions, Suez executives said they adjusted the water's acidity after the 2012 results, as had been done for decades, to try to lower lead levels.

Those adjustments didn't appear to work when tests from 2013 to 2015 continued to show lead levels at 14 parts per billion.

This prompted Suez to hire engineering firm CDM Smith to help develop a way to lower the lead levels “to meet the [federal] requirements and increase protection of public health," according to documents.

"We were being proactive and responsible when we hired the leading experts in the field to analyze the system in 2015," said Debra Vial, a Suez spokeswoman. "We were in compliance at that time, and we decided to take advantage of new studies and data in our commitment to further improve water quality and attempt to prevent an issue."

Suez asked the state DEP in February 2017 to approve a plan to add zinc orthophosphate to its water. Considered a food-grade compound, the chemical is often used to coat the inside lining of pipes in utilities that have a lead problem.

But this was a two-pronged attack. The phosphates would be used to coat the pipes, and the water's acidity had to be adjusted to reduce its ability to scrape lead off pipes. It would take a delicate balancing act to have the two efforts work effectively together.

The DEP said in its May 2017 approval of the pipe coating that Suez's "current pH of 8 is not optimal” and that it "strongly recommends" that the company make an adjustment.

Suez decided to hold off on adjusting the water's acidity until the system became acclimated to the zinc orthophosphate pipe coating,documents show.

Meanwhile, lead levels rose to 14.3 parts per billion in the first half of 2017.

In October 2017, Suez began putting a small amount of zinc orthophosphate into its system, and then doubled the dosage three months later.

The treatment appeared to be working.

Readings for the second half of 2017 came back at 11.4 parts per billion, more than 20 percent lower than the 2015 results.

Tests done in the first half of 2018 showed even better results: 10 parts per billion, a 30 percent drop from 2015.

Suez then began adjusting its pH from 8 to 7.6 over a six month period beginning in May 2018, documents show, to a dosage considered optimal for working with zinc orthophosphate coatings.

During that time, Suez began getting some higher lead readings from 108 homes it would sample from July 1 to the end of 2018.

It culminated in a reading of 18.4 parts per billion. Suez notified the DEP in early January.

A few weeks later, Suez announced the findings publicly. Executives did not mention the escalating lead levels from 2004 to 2015 other than to say the company never surpassed the federal standard.

"We have taken this test routinely and not tripped the limit under the lead action rule to this date," David Stanton, president of Suez North America, said at a Jan. 16 news conference.

"We know the science behind this with corrosion control, but we have not ascertained if anything unusual caused this population of homes to exceed the limit,” he said.

"Our pH levels are under control … they are exactly as they are supposed to be,” he said at the time.

But that is still being determined by Suez and its contractors.

In a Jan. 3 email to Suez executives, a CDM Smith environmental engineer said lowering the pH of the water "from 7.9 to 7.4 in five months" may have been done too fast and contributed to high lead levels.

In a statement to NorthJersey.com, Suez said it has "no reason to believe this led to the exceedance." Lowering the pH was prescribed by industry experts, the DEP and the manufacturer of the pipe coating, Suez said.

A mystery endures

Despite the DEP's order in January for Suez to develop a new corrosion control plan, the company wants to see if coating its pipes and adjusting acidity will make a difference. Suez has asked the DEP if it can delay any new action until the end of October, when the company can review summer samples.

Of 97 water samples taken since January, lead levels were at 13.1 parts per billion as of May 10, state records show.

This spring, Suez embarked on a $15 million project to remove 50,000 feet of its lead service lines by the end of the year. It would represent about 25 percent of the lead pipes in its system.

While work crews dig up streets and contractors test lead levels in homes, equally important work is being done at Suez's laboratory in Haworth. A team of chemists and engineers are trying to ensure that lead levels are lowered by changing the chemistry of Suez's water, if need be.

So far neither Suez nor its contractors can find an “immediate, readily-definable cause” of the high lead levels. An engineering report says everything from 2018’s record rainfall to disinfecting the water could have caused the lead levels to go up.

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Crews are reviewing data from 12 new monitors placed at pump stations around the system. At the Haworth plant, water is being run through lead pipes to see how much is leaching.

But the underlying cause of the gradual increase in lead levels in 2012 and 2015, followed by a dip in 2017 and then a spike last year, remains a mystery that may never be solved.

“Our water sort of has a fingerprint, in that it's unique, but it changes," said Andrea McElroy, the company's chief chemist. "Our water is very different from other systems because of where it comes from, its source, how it's treated through the plant, what chemicals are added for disinfectant purposes and what influences are around it, where it goes in the distribution system, what it mixes with.”