Paris has many old buildings with lead, yet does not have rules about lead dust in public spaces.The issue has become an important concern after last spring's huge fire at Notre Dame Cathedral.The fire, in April, released thousands of kilograms of toxic lead dust into the atmosphere in just a few hours."When the Notre Dame fire happened, we didn't have any thresholdfor what represented dangerous lead levels outdoors," Anne Souyris told the Associated Press.She is the Paris City Hall deputy mayor in charge of public health."It was a wake-up call...the amount of lead that was burned in Notre Dame was unprecedented."The Associated Press (AP) news agency has found that many countries lack rulesabout lead in outdoor, public spaces.Other historic European capitals such as Rome and London do not have rules for outdoor lead dust levels.That is also the case for the U.S. Environmental Protection Agency and the World Health Organization.Poisoning from lead dust can cause permanent loss to mental ability, seizures, coma or death.Pregnant mothers and young children are at the greatest risk.Concerns about lead are especially strong in Paris.Lead is common in many parts of Paris' 19th-century buildings — in roofs, balconies, floors and terraces.Experts say because Paris is a highly preserved historic city it also is a danger spot for lead."Paris is a beautifully preserved city," Souyris said."But we realize we have also beautifully preserved its lead."Neil M. Donahue is a chemistry professor at Carnegie Mellon University in Pittsburgh, Pennsylvania."Preservation does make Paris unusual," he said."Incineration of one of the most famous roofs in the world may be especially dramatic,but there is no alchemy in this world. Lead will remain lead forever."The fire also brought attention, among officials and the public, to the dangers of lead.In June, Paris' Regional Health Agency advised that all pregnant womenand young children living near the site take a test for lead levels.The agency said 12 children in the surrounding areas tested positivefor elevated lead levels in their blood since the fire.None had to be hospitalized or given medication.One child's lead exposure came from a source other than the cathedral:the lead balcony of his family's apartment.It is unlikely the child would have been tested at all had it not been for the fire.Despite the lead fallout from the fire, experts say touristsshould not change their travel plans to one of the most visited cities in the world.However, poisonous lead dust remains a problem inside the fire-damaged cathedral.Aline Magnien is director of the Historic Monuments Research Laboratory.She recently sent a team of scientists to Notre Dame.Their goal is to find out how to remove leadfrom inside the famous religious building without causing more damage."It's a race against the clock," she said. "The lead is a real problem.The cathedral is exceptionally precious. And we don't have the luxury of time."