PARIS — It took a blaze that nearly destroyed Paris’s most famous cathedral to reveal a gap in global safety rules for lead, a toxic building material found in many historic cities.
After the Notre Dame fire in April spewed dozens of tons of toxic lead dust into the atmosphere in just hours, Paris authorities discovered a problem with the city’s regulations: There was no threshold to gauge how dangerous the potentially deadly pollution was from the dust that settled.
Since then, the Associated Press has found this regulatory gap extends far beyond France. Officials in other European capitals such as Rome and London, as well as the US Environmental Protection Agency and the World Health Organization, also lack outdoor lead dust guidelines. The reason, they say, is that although there are lead regulations, no one contemplated a conflagration on a lead-laden building the scale of Notre Dame — whose spire towered nearly 330 feet high.
Poisoning from lead dust can cause permanent loss of cognitive ability, seizures, coma, or death — and exposure is of greatest risk to pregnant mothers and to young children, who can easily transfer toxic dust into their mouths.
Fire engulfed about 250 tons of lead on Notre Dame’s spire and roof on April 15. The authorities were forced to cobble together disparate and incomplete research to set a makeshift safety level in an attempt to reassure the public.
“When the Notre Dame fire happened, we didn’t have any threshold for what represented dangerous lead levels outdoors,” Anne Souyris, deputy mayor in charge of public health, told the AP. “It was a wake-up call . . . the amount of lead that was burned in Notre Dame was unprecedented.”
While safety guidelines exist in France for lead levels inside buildings, as well as in paint, soil and air, there were zero hazard guidelines for lead accumulations in public spaces, such as dust on the ground.
The inherent danger and the regulatory gap became impossible to ignore as lead dust collected on the cobblestones.
“The authorities basically tried to create safety guidelines after the fire by piecing together a mixture of old fragments of data and reports,” Souyris said. “But there was really nothing official.”
Three months after the inferno, Paris’s Regional Health Agency said it designated 5,000 micrograms per square meter as a concerning level for lead dust in public spaces.
The AP learned from health officials that this figure was compiled by using incomplete data, including a French Culture Ministry report assessing lead levels in Paris monuments.
Some media outlets reported that registered levels of lead contamination in locations around the fire-damaged cathedral ranged from 500 to 800 times the official safe levels. But health officials told the AP that Paris does not have any official regulatory threshold.
The World Health Organization said it has no outdoor safety guidelines for lead dust, either, and has no immediate intention to create any.
Britain had no lead-dust rules after the 2017 Grenfell Tower fire. The UK Environment Ministry said it doesn’t “have a specific threshold for unsafe lead dust levels in the UK in public places.” It said hazard focus after Grenfell, an apartment building constructed in the 1970s, “was more on asbestos than lead due to the age of the building.”
In the United States, where many buildings were constructed after lead hazards were widely recognized, the Environmental Protection Agency has no lead dust standards for outdoor public spaces.
Lead is ubiquitous in Paris’s 19th-century architecture — in roofs, gilded balconies, floors and terraces. In 1853, Napoleon III chose Baron Haussmann to carry out a near-total renovation of Parisian boulevards and parks in an era that used lead prolifically.
French officials say there are so few guidelines on lead dust because it was not a problem they had to confront until the Notre Dame fire. It took four months for the city to complete a deep-cleaning of sidewalks even as tourists, residents, and merchants walked the streets around the cathedral daily.
City Hall issued a new action plan this fall to address lead — including cleaning and testing in places that host children, increased monitoring of children with high levels of lead in their blood, and an independent epidemiological study of lead health impacts.
“Paris is a beautifully preserved city,” Souyris said. “But we realize we have also beautifully preserved its lead.”
In June, Paris’ Regional Health Agency advised that all pregnant women and children under 7 living near the site take a test for lead levels. The agency said 12 children tested positive for elevated lead levels. Officials said it was impossible to predict the long-term consequences.
Aline Magnien, director of the Historic Monuments Research Laboratory, recently dispatched scientists to figure out how to remove lead from inside Notre Dame, which is over 850 years old, without damaging it.
“It’s a race against the clock,” she said. “The lead is a real problem.”