Notre-Dame's spire that collapsed in the fire contained hundreds of tonnes of lead - the particles of which scattered on occasion to nearby areas.

On July 25, two preschools in Paris were forced to close as dangerously high lead levels were measured in school yards. This despite local authorities saying for weeks that Parisians are not at risk of lead poisoning.

New samples have now been taken and, according to Paris Deputy Mayor Emmanuel Gregoire, the tests do not show dangerous levels:

"All tests that we have conducted within a radius of 500 meters around Notre-Dame are negative, which means that there is no danger," the deputy mayor told the television channel LCI on Tuesday.

The extensive fire in Notre-Dame destroyed much of the cathedral's roof. Photo: Stephane de Sakutin / AP / TT

Dangerously high lead levels within the radius

The statement comes after the health agency ARS (Agence régionale de santé) on Monday published a survey of the lead levels in the area around the cathedral in Le Parisien magazine. The tests show less than 70 micrograms of lead per square meter - which is considered a safe level.

At the same time, dangerously high lead levels of over 1,000 micrograms were measured at certain playgrounds and window boards outside the 500 meter radius, according to AFP.

Schools will now be "thoroughly cleaned" ahead of the upcoming school start in September and they "will not take any risks" according to Emmanuel Gregoire.

May cause neurological defects

Since the fire on April 15, 175 blood tests have been performed on children living near Notre-Dame. So far, two children have had lead levels in their blood above what is considered safe, 50 micrograms per liter of blood, writes Le Parisien. One of the children goes to school St. Benedict Street - where lead levels of 5,000 micrograms per square meter were measured.

"Lead levels observed in children do not require any special treatment, but will require regular monitoring," states ARS.

Intake of the lead particles can cause neurological defects, as well as nervous systems and kidney problems, according to the World Health Organization (WHO). Toddlers are especially vulnerable because they are more likely to come in contact with contaminated objects and put their fingers in their mouths, than adults, reports AFP.