Mold Outbreak at Boston Public Library Closes Rare Book Department

The rare book department at the Boston Public Library has closed for five to ten weeks after the staff discovered mold spores on a medieval manuscript as well as several other prized holdings in scattered locations throughout the department.

Boston Public Library's rare book department is located in the McKim Building in Copley Square. The building was completed in 1895, long before modern advances in archival climate control. The staff depends upon the central air conditioning system in the building as well as strategically deployed dehumidifiers. 

The McKim Building is in the middle of a major renovation. When the renovation was coupled with late season humidity it created a "perfect storm" of conditions according to Laura Irmscher, chief of collections strategy. In an interview with the Boston Globe, Irmscher continued, "I think the time of the year and the extended humidity really played a significant part in it."

Librarians will proceed to stabilize the humidity levels in the rare book department, then decontaminate the impacted materials. All 500,000 volumes in the collection -- widely considered one of the world's best -- will need to be hand-examined.