A former chief of staff of France’s armed forces, Georgelin was named by French President Emmanuel Macron to lead the reconstruction effort for Notre Dame.

He said the actual condition of the cathedral’s vaults is not fully known, which means he could not guarantee that “it won’t fall apart.”

“To make sure, we need to inspect them, to remove the rubble that is still on them, it’s a very difficult work that we have started,” he said.

He also noted that the fire relea sed tons of toxic lead dust into the nearby air and ground, which needs to be cleaned up, a requirement that is slowing down the work.