In February 2016 the Manuscripts and Rare Books stacks of the Biblioteca Marciana, Venice were interested by a heavy humidity infiltration from the walls. The Library conservators activated the Emergency Disaster Plan in order to provide the first aid and make the collections safe. In a few months of forced ventilation and dehumidification the environmental conditions were re-set and then shelves and manuscripts were ready to be carefully dry-cleaned. The treatment was entrusted to professional conservators, who guaranteed the quality of the operations and allowed some preservation activities to be added for the control and ma intenance of the collection.