School officials released some statistics about past tests indicated elevated levels of lead in drinking water at 30 schools in the state's largest city.
NEWARK -- Lead levels have been elevated in Newark schools since at least 2012, officials announced Wednesday. The announcement comes after the revelation earlier this month that water in 30 of the district's schools tested as high as 35 times above the federal action limit for lead.
Out of 2,067 water quality samples collected from taps at Newark school buildings between 2012 and 2015, about 12 percent reported being above the Environmental Protection Agency's "action level" of 15 parts per billion, the district announced. About 10 percent of the taps tested in 2015 showed elevated levels, officials said.
MAP: Which schools have elevated lead levels?
Though officials said they will not release the specific levels for the past three school years until Thursday morning, those "results are generally consistent with this last round of testing," which recorded levels ranging from 16 to 558 ppb, the school said.
In response to allegations by the Newark teachers union last week that the district knew about the lead levels for more than 10 years, the district said it is in the process of obtaining testing results dating back to 2004.
"Documentary evidence suggests that schools have been tested and remedial actions undertaken" since 2004, it said.
Over the past several weeks, the teachers union has released internal memos and dated photos suggesting that the district knew about elevated lead levels, and that remediation filters were not being properly maintained.
In a statement, Superintendent Chris Cerf called the photos "unauthenticated" and said that "the dates on the filter housing do not necessarily correspond to the dates of the filter replacement."
Cerf said he learned of the elevated levels last Monday, and coordinated with the state Department of Environmental Protection to conduct additional testing, and alert the public to the issue.
"(T)he District has handled this issue in the same way - via remediation protocols - since 2004. It was only this year, under my direction, that NPS changed course by bringing the matter to the public directly and by convening state and local experts to design appropriate remediation strategies."
Cerf said he did not mean to criticize the three superintendents who headed the state-controlled district before him, but chose to be more public with the results of the testing. The district has turned off all drinking taps at the affected school buildings, and students have been drinking bottled water since news of the elevated levels broke.
The school is also coordinating with the city to test 17,000 school children for elevated blood lead levels.
The DEP will begin re-testing taps at all of the district's 67 school buildings Saturday, officials said.
The "sampling plan also gives Newark Public Schools an opportunity to fully document comprehensive, baseline information across the entire district, and to easily refer to it for future testing and remedial actions going forward," DEP Commissioner Bob Martin said in the district's release.
Officials have said that the elevated lead levels are likely caused by infrastructure in the aging school buildings, and do not originate from the city's drinking water itself. Health experts backed city officials' assertions that the detected levels are not likely to cause serious harm to Newark students, and that the district is taking the proper precautions.
Past remediation practices carried out by the district include faucet replacement and filtering systems, the schools said.
Jessica Mazzola may be reached at jmazzola@njadvancemedia.com. Follow her on Twitter @JessMazzola. Find NJ.com on Facebook.