A scaffolding firm that was part of the renovation work at the Notre Dame cathedral in Paris, France, when it caught fire said some of its workers had smoked at the site, Reuters reported on Thursday. A spokesperson of the firm, however, ruled out that a cigarette butt might have started the fire that destroyed the cathedral’s oak-framed roof last week.

Marc Eskenazi, a spokesperson for the Le Bras Freres scaffolding company, said some workers had smoked at the site from time to time, reported AFP. “But in no way could a cigarette butt be the cause of the fire at Notre-Dame,” he said.

While confirming a report in the French weekly Le Canard Enchaine, Eskenazi told Reuters that some workers of its Europe Echafaudage scaffolding unit had informed police that they had sometimes smoked on the scaffolding, despite a smoking ban.

“We condemn it,” Eskenzai said. “But the fire started inside the building... so for company Le Bras this is not a hypothesis, it was not a cigarette butt that set Notre-Dame de Paris on fire.” Le Canard Enchaine had reported that the police had found the remains of seven cigarette butts in the cathedral.

A massive fire had engulfed the historic cathedral in Paris last week while renovation work was under way. The cathedral’s spire collapsed under the fire.

Eskenazi told Reuters it was impossible to set a log on fire with a cigarette butt. “If cigarette butts have survived the inferno, I do not know what material they were made of,” he said.

Le Canard Enchaine also reported that electrical wiring ran through the roof of the cathedral, but the church spokesperson denied that safety norms were not followed. “Nothing was ever done without the authorisation of the state,” said Notre Dame spokesperson Andre Finot. “There were no wires dangling, everything was properly installed.”