Local authorities in Paris stressed Thursday that lead contamination from the fire at Notre-Dame cathedral posed no danger to the public after claims in a media report that pollution in local schools had been covered up.
Environmental groups warned soon after the disaster that 300 tonnes of lead in the roof of the Paris landmark had gone up in flames, posing a danger to residents in the area, particularly to children.
A report from the Mediapart investigative website on Thursday reported that high levels of the heavy metal -- as much as 10 times higher than the safe limit -- had been detected in schools and creches surrounding the cathedral.
But Deputy Paris Mayor Emmanuel Gregoire dismissed the article, saying that the author had misinterpreted the results of tests which showed that lead was well below the level considered a public health risk.
"If there was any risk, not only would schools not have reopened, but they will not reopen in September," he told a news conference.
Mediapart said that Paris authorities had waited until May before conducting tests in the 10 creches and schools that are within 500 metres (yards) of the monument on the Ile de la Cite island in central Paris.
One test result -- in the private Sainte-Catherine elementary school -- showed lead at a level of 698 microgrammes per square metre, 10 times higher than the 70-microgramme limit which it said was considered potentially dangerous, it said.
But Gregoire said that the maximum legal level was 1,000 microgrammes and that 70 microgrammes merely indicated that public authorities needed to investigate.
"When you go past this level you have to put in place a certain number of measures, but ultimately there is no health risk," he argued.
Earlier in the day, Paris health official Arnaud Gauthier had said that schools around the cathedral would undergo a "deep clean" over the summer holidays which would see all walls and furniture wiped and playgrounds hosed down.
Gregoire insisted this was normal procedure and nothing to do with the fire or lead contamination.
Lead pollution can cause neurological defects for humans, especially children, as well as nervous system and kidney problems.
- 'Except if you lick the pavement' -
During a tour of the cathedral on Wednesday, reporters saw workers wearing special masks because of the presence of lead that has seeped into some of the stonework.
The square at the entrance to the cathedral remains closed to the public because of the health risk.
Paris police chief Didier Lallement has also maintained the area around the cathedral is safe.
"I can't let it be said that people walking in the area are exposed to a risk," Lallement said earlier this month. "I want to reassure the public... there is no danger except if you lick the pavements."
The French parliament recently passed a law setting out the legal framework for the reconstruction of the cathedral, which President Emmanuel Macron wants completed within the next five years.
Macron created a furore by suggesting the spire which was lost in the inferno could be replaced by a steeple with a contemporary touch.
Paris prosecutors said in June that a poorly stubbed-out cigarette or an electrical fault could have started the fire and opened an investigation into criminal negligence, without targeting any individual.
On June 15, two months after the fire, clerics conducted the first mass inside the cathedral since the blaze, donning hard hats along with their robes for their safety.
In June, Paris health authorities urged children and pregnant women living around Notre-Dame cathedral to have the levels of lead in their blood checked, while residents have been advised to regularly clean their homes.