Last month, restoration efforts at Notre Dame Cathedral were put on hold because of lead contamination concerns, but workers are now back on the job.

The Paris landmark caught fire on 15 April, melting a reported 440 tons of lead in the 850-year-old roof and steeple, and the toxic dust spread throughout the city. In the immediate aftermath of the disaster, authorities maintained that the risk of exposure was minimal and wet wipes would get rid of the dust, and by May, they were telling the public the air quality was nothing to worry about.

It wasn’t until late July that officials admitted their cleanup strategy was proving ineffective and shut down the cleanup, also closing two nearby schools with dangerously-high lead levels. The following day, according to France 24, environmental NGO Robin des Bois filed a lawsuit against the city alleging that lead pollution was endangering residents’ health. “One test result – in the private Sainte-Catherine primary school – showed 698 microgrammes of lead per square metre, nearly ten times higher than the 70-microgramme level considered potentially dangerous,” the paper reported.

Though the public was still allowed to get bafflingly-close to the cathedral before cleanup began on 19 August, when the work crew returned to the site, it was with precautionary practices and protective gear firmly in place. Per the AP, “activity resumed under strict new lead-protection measures for the stonemasons, cleanup workers and scientists working on the monument, according to the Culture Ministry. They include throwaway full-body clothing, obligatory showers and a new decontamination zone to ensure that no one tracks pollution outside the site.”

A few days prior, another AP report detailed lead prevention operations in the vicinity, including blocking off the cathedral with high fences and cleaning up nearby streets and schools. “Experts plan to use two decontamination techniques for the surrounding neighbourhoods,” the report says. “One method will feature high pressure water jets with chemical agents. Another involves spreading a gel on public benches, street lights and other fixtures to absorb the lead, letting it dry for several days before removing it.”
The lead removal should take about three weeks, and then it’s on to the debris cleanup, which will lay the groundwork for the reconstruction itself. Though French president Emmanuel Macron declared right after the fire that he wanted to see the cathedral rebuilt “more beautiful than before” within the next five years, the pros say it’s highly unlikely. “Restoring Notre Dame ‘will last a long time and cost a lot of money,’” Unesco director-general Audrey Azoulay told the Guardian, with another expert positing that it could even take several decades.