NEW ORLEANS -- The New Orleans inspector general says the city hasn't adequately warned residents that ongoing street repairs and water system improvements could result in temporarily high lead levels in some buildings' tap water.

Inspector General Ed Quatrevaux's latest report says some old city water lines - and lines on private properties - are made of lead, which can affect the brain and nervous system when ingested. Chemicals added to the water form a protective coating in those pipes. But Quatrevaux cites experts who say disturbance of the aging lines can jar some of the coating loose and allow lead to contaminate the water.

Citing $2.4 billion in planned New Orleans Sewerage and Water Board infrastructure projects as well as numerous past water system and street projects Quatrevaux raises the possibility that individual homes or businesses might see spikes in lead levels in drinking water.

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"New Orleans residents living where infrastructure construction projects occur may be - or may have been - unknowingly exposed to elevated levels of lead in drinking water," the report said.

In a statement emailed Thursday, the city Sewerage and Water Board stressed its compliance with all state and federal laws and said the city's water is safe. It outlined its existing policies for educating customers by way of social media, direct mail and email about risks of lead exposure.

"There's no amount of education in this issue that's enough, and we're going to continue to do everything we can to keep the community informed," Executive Director Cedric Grant told CBS affiliate WWL-TV, "but I can tell you as we sit here today the water is safe, the water is in compliance with state and federal law."

The board's website offers information on water quality and tips to reduce lead in drinking water, posted in response to customer queries after the 2015 water crisis in Flint, Michigan. There, lead was discovered in the drinking water after the city began tapping Flint River water as a source. The river water was not properly treated, leading to lead leaching from old pipes and fixtures.

"The City and S&WB have taken proactive steps to inform residents of the potential for increased exposure to lead in water caused by partial replacement or disturbance of LSLs (lead service lines), as well as the steps the public should take to reduce the impacts of that temporary elevated lead exposure," the board's statement said.

Quatrevaux's report says the city's past efforts lacked a sense of urgency. He cited the board's 2015 report touring upcoming infrastructure improvements that had scant mention of the possibility that the work could cause a spike in lead levels.

Meanwhile, the city says it's taking steps to reduce the long term danger of lead pipes.

Because lead lines were an industry standard until the dangers of lead became known in the 1970s, the city has no special inventory of where its lead supply lines exist. The board said it began taking an inventory of its approximately 140,000 lines last year, at the request of Mayor Mitch Landrieu, to begin determining which lines are made of lead. That will help the city prepare for future replacements.