PARIS — The April fire that engulfed Notre Dame contaminated the cathedral site with clouds of toxic dust and exposed nearby schools, day care centers, public parks, and other parts of Paris to alarming levels of lead.
The lead dust came from the cathedral’s incinerated roof and spire, which contained about 460 tons of the dangerous metal.
Five months after the fire, French authorities have refused to fully disclose the results of their testing for lead contamination, sowing public confusion, while issuing reassuring statements intended to play down the risks.
Their delays and denials have opened authorities to accusations that they put reconstruction of the cathedral — which President Emmanuel Macron has pledged to complete in five years — ahead of the health of thousands of people.
A comprehensive investigation by The New York Times has helped fill out an emerging picture of a failed official response. It found significant lapses by French authorities in alerting the public to health risks, even as their understanding of the danger became clearer.
The April 15 blaze nearly destroyed the 850-year-old cathedral and brought immediate scrutiny to whether adequate fire protections had been in place to safeguard a gem of Gothic architecture visited by 13 million people a year.
The cathedral’s roof and spire succumbed to the flames that night and collapsed. But the billowing smoke carried its own perils. It contained massive quantities of lead, according to test results in confidential reports and in others released by the government.
The Times’ investigation drew from confidential documents, including warnings by labor inspectors, a police report, and previously undisclosed lead measurements by the Culture Ministry.
The documents, as well as scores of interviews, make clear that French authorities had indications that lead exposure could be a grave problem within 48 hours of the fire.
But it took a month before city officials conducted the first lead tests at a school close to Notre Dame. Even today, city and regional health officials have not tested every school in proximity to the cathedral.
The tests showed levels of lead dust above the French regulatory standard for buildings hosting children in at least 18 day care centers, preschools, and primary schools.
In dozens of other public spaces, like plazas and streets, authorities found lead levels up to 60 times over the safety standard.
The highest contamination levels, revealed in confidential Culture Ministry documents obtained by The Times, were at different spots in, or near, the cathedral site. Authorities failed to clean the area in the immediate aftermath of the fire and waited four months to finish a full decontamination of the neighborhood.
The Culture Ministry, which is responsible for cleaning the site and rebuilding Notre Dame, also failed or refused to enforce safety procedures for workers, leaving them exposed to lead levels more than a thousand times the accepted standard.
“These are astronomical levels, and the attitude of health authorities is inexplicable,” said Annie Thébaud-Mony, a prominent public health expert in France, who has been leading public calls for more transparency in the aftermath of the fire.
Some French officials and lead experts have cautioned against “paranoia” and argued that the test results may, in part, reflect broader underlying problems with lead contamination in Paris.
Lead exposure poses the greatest risk to children, pregnant women, and nursing mothers, who can pass lead on to their children.
If ingested, lead interferes with the normal development of the nervous system and can leave young children with permanent cognitive damage.
Even so, hundreds of children attended schools near Notre Dame for weeks before authorities began in mid-May to test for lead levels, or to clean the buildings.
In the aftermath of the fire, the official response was divided between city, regional, and national officials. Each had distinct responsibilities, and sometimes competing interests, as lines of authority collided, undermining accountability.
City officials said they had wanted to communicate more openly with the public but were following the lead of regional and national agencies.
“The state was afraid to make people afraid,” said Anne Souyris, the city’s deputy mayor in charge of health.
This month, Paris officials opened public schools for a new academic year and said none presented alarming lead levels any longer. Some private schools did not open on time, for fear of lead.
Only gradually did public awareness of the problem grow. It took a lawsuit, leaked test results in the French press, and public criticism from experts.
Many children were put at risk: More than 6,000 youngsters under age 6 live within a half-mile of sites that tested high for lead levels.
Health authorities’ refusal to require testing of children will make it nearly impossible to assess the full extent of exposure, since lead levels decline over time, as the element is eliminated from the body.