Mold
Its Causes and How to Reduce the Threat

What is mold?

• a non-specific term of a type of fungus.
• mildew is sometimes used interchangeably, it is also a type of fungus.
• there are over 100,000 know types of fungi
• mold propagates by spreading a large number of spores, which travel through the air.
• because there are so many different types of fungi it is difficult to know how to fight an outbreak.

What causes mold to grow?

• mold spores are everywhere
• food (organic materials=paper, dust, cloth, starch, etc.)
• moisture from high humidity (70%)
• mold likes high temperatures (mid 70° F), darkness, and stagnant air

Why is mold a problem?

• mold can eat organic materials such as paper, dust, adhesives, leather, cloth, starches
• mold can stain paper, cloth, leather
• the conditions that sustain mold growth hasten chemical deterioration in books/paper (high heat and high humidity).
• some varieties of mold are toxic to humans (Aspergillus fumigatus)

How to combat mold:

DON'T ALLOW IT TO DEVELOP

• maintain moderate temperature and humidity (70-72° F and 55% or lower rh)
• circulate air
• dust regularly

If mold is discovered check to see if it is active (soft, fuzzy, smears easily) or dormant powdery, easy to wipe). If it is active and it is a single book consider withdrawing it from the collection. If it is dormant do the following:

Material is wet:

• air dry or freeze
• brush off spores working outdoors and (if possible) with a fan blowing the spores away

Material is dry:

• brush off spores working outdoors and (if possible) with a fan blowing the spores away or
• vacuum using a triple action filtration vacuum

Fumigation is no longer recommended for mold because fumigants are toxic to people, the residue remains on the object, and it does not prevent the mold from returning.

Always wear gloves and if possible coveralls or a lab coat. Wash hands after handling any object with mold or suspected to have mold.

If mold is discovered in large portions of the collection do not attempt to clean up without FIRST consulting a mycologist to determine if toxic molds are present.

Dartmouth College Library -- Preservation Services handouts/mold causes 6/96

For further information consult "The Invasion of the Giant Spore", SOLINET Preservation Program, Leaflet Number 5, Sandra Nyberg, November 1987.