PARIS (WASHINGTON POST, NYTIMES) - France's interior minister said on Tuesday (April 16) that more than 500 firefighters had been mobilised to help extinguish flames that engulfed Paris's Notre-Dame Cathedral. But questions remained about whether any warning signs had been missed.
Paris Prosecutor Remy Heitz laid out a timeline in which an alarm went off at 6.20pm local time (12.20am on Tuesday Singapore time), but no evidence of fire was found. Only when a second alarm went off - 23 minutes later - was fire detected.
"In the meantime, the church was evacuated because a Mass just started a bit earlier," Mr Heitz said.
A spokesman for the Paris prosecutor's office later clarified that it was church staff, not firefighters, who looked into the initial alarm.
Monsignor Patrick Chauvet, the Notre-Dame rector, told French radio that the cathedral's "fire watchers" were on constant lookout and three times each day, made "assessments" in the vulnerable area under the wooden roof.
"In terms of security, I doubt we could have done more," Monsignor Chauvet said.
Buildings such as Notre-Dame - full of hidden nooks and passages, and composed of ancient timber and other old materials - are seen by fire prevention experts as particularly risky, especially when they are under renovation.
Mr Stewart Kidd, a consultant on heritage buildings in Britain, said that in old structures, by the time flames become visible, "they may have been burning for an hour" in unseen spaces. And when there is construction, he said, "the building is exposed to all sorts of dangerous activity".
French officials said they do not suspect foul play.
Mr Heitz said there were no indications that the blaze was started deliberately. Investigators plan to interview people from the five companies that were doing renovation work at the site. Before the fire, part of the Gothic structure had been encased in scaffolding.
Mr Frederic Letoffe, co-president of a group of French companies that specialise in work on older buildings and monuments, said Notre-Dame had fire detectors that functioned continuously, and was equipped with dry risers – empty pipes that firefighters can externally connect to a pressurised water source.
But he said that the cathedral – like many others in France – did not have automatic sprinklers in the wooden framework of the roof, and that its attic space was not compartmentalised with fire-breaking walls, which could have prevented a blaze from spreading.
Mr Letoffe added that contractors working on construction sites had to follow strict guidelines when using electrical tools, and that after finishing for the day, contractors working with heat must remain on site for two hours.
Mr Stephen Bern, who has served as an adviser on France’s monuments to President Emmanuel Macron, said that the contractor for the building’s scaffolding was “serious”, and that safety regulations were “codified”. But “it all depends on human beings”, he said.