Streets in Paris close to the Notre-Dame Cathedral have been closed, as specialists move in to perform decontamination cleaning work.

Fences have been erected and a bridge installed in the surrounding area, after high levels of lead were detected in the area following the blaze that devastated the landmark back in April.

Repair work inside the cathedral itself was suspended in July following the discovery of elevated lead levels in the area, with work expected the resume following the decontamination. Health officials said a child from a nearby school was at risk of lead poisoning after hundreds of children were tested following the cathedral fire. The child doesn’t require treatment but is being monitored.

Many believe the lead may have come from the roof and spire of the cathedral, both of which melted and could have spread tons of lead into the local environment, although other reasons for the elevated lead levels are also being investigated.

France’s culture ministry confirmed two decontamination measures would be taken. The first involves a special gel being applied to public benches, street lights and fixtures to absorb the lead for several days, before it’s removed. The second involves high-pressure water jets with chemical agents being deployed to clean up the area.

Notre-Dame is one of France’s most popular tourist attractions, attracting an estimated 12 million people a year. No deadline has been set on reconstruction, but the French Parliament recently passed a law requiring the Cathedral be rebuilt exactly as it appeared before the fire.