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MOLD IN THE
LIBRARY
Mold is
everywhere--in the air, on surfaces, outdoors, indoors, on the cheese in
our refrigerators. If it is all around us, why should we be concerned
about mold in the library?
Effect of Mold on Library
Materials
Active mold produces enzymes
that allow it to digest paper and cloth, which eventually weakens and
destroys these materials. Inactive mold does not damage library materials,
but the spores can be spread through the library if affected materials are
handled, and will become active if environmental conditions are conducive
to their growth. The musty odor of mold often remains in library materials
even after mold has been inactivated and removed by vacuuming or wiping
the mold off.
Active and Dormant Mold
Mold spores need a favorable
environment to germinate, or become active, grow, and spread. The most
important condition mold needs to germinate is moisture. Most molds will
germinate at 65% relative humidity (RH). It is also possible, however, for
some molds to grow at a lower RH. Higher temperatures and poor air
circulation can accelerate mold growth. If collection materials get wet,
they become more susceptible to mold growth. Water-damaged materials are
at risk of mold growth while they remain wet, but they are also more
susceptible to mold outbreaks later on, after they have been dried, if
environmental conditions become favorable for growth.
It can sometimes be difficult
to distinguish mold from dust, dirt, foxing, or cobwebs on collection
materials. Mold can be almost any color. Mold usually has a recognizable
musty odor, whether active or dormant. Active mold is soft and may smear
easily, and it may be damp or slimy. Inactive mold is dry and powdery, and
brushes off easily. Under magnification, it is easier to distinguish mold
from dust and dirt. In the early stages of mold germination, it forms
hair-like filaments in webs, then as it matures it develops a bushy
appearance.
Preventing Mold Outbreaks
It is
not possible to create an environment free of mold spores. Dormant spores
are everywhere, therefore the only dependable way to avoid mold problems
is to control the environment so that mold cannot become active. Control
of the environment means maintaining moderate temperature and RH (never
above 65%), good air circulation, keeping collections and collection
storage areas clean, and not bringing new collection materials with mold
into the library. It is also very important to keep books and other
paper-based collections from getting wet, and to treat wet books as an
emergency, since mold is likely to grow on such materials within 24 to 48
hours. Rook leaks and plumbing failures can result in library materials
getting wet, so proper building maintenance is also necessary to avoid
mold problems.
Procedures to Follow if
Mold is Found in the Library
1) What to Do With Moldy
Items
The first concern with
mold-contaminated collection materials is
health and safety. If you encounter a moldy collection item, avoid
handling it. Either isolate the moldy material by putting it into a
plastic bag, tie it closed, and bring it to the Preservation Department,
or leave materials where they are and alert Preservation staff right away.
If you are unpacking a box of gifts, for example, and it smells moldy or
you see something that appears to be mold, close the box back up and move
it to a location away from people, then contact the Preservation
Department.
The Preservation Department
is equipped to review individual, mold-contaminated materials. Adequate
protection includes wearing a properly fitted respirator with HEPA (high
efficiency particulate air) filters, disposable plastic gloves, and eye
protection. Once materials are in the Preservation Department, staff can
examine them safely in a self-contained fume hood. The air flow is drawn
away from the worker via an exhaust mechanism fitted with a HEPA filter,
which traps the mold particles.
2) What To Do If There's A
Mold Outbreak
The first concern with a mold
outbreak is
health and safety. If there is a mold outbreak in the library
(affecting a whole area of the building or collection) such as could occur
following a water disaster, or a failure in the HVAC system that results
in high temperature and high relative humidity, the first steps that need
to be taken are to notify Occupational Health and Safety and close off the
affected area so that staff and patrons cannot enter.
FIRST
During the week days, notify Library Facilities (ext. 6940). On weekends
and in the evening, notify Public Safety (911 or ext. 2222). Library
Facilities or Public Safety will contact Occupational Health and Safety.
After contacting Library Facilities or Public Safety, contact a member of
the Disaster Coordinating Team.
NEXT
The mold affected area should be closed off so that staff and patrons
cannot enter. Doors should be closed, plastic sheeting hung to separate
affected from unaffected parts of the collection. If possible, the air
circulation should be reduced so that it does not flow from affected areas
into unaffected areas.
After these first response
steps are taken care of, the next concern is to:
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Identify the cause of the
outbreak, and
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Inactivate the mold by
changing the environmental conditions.
Locate the source of high
humidity. Likely causes are leaks from windows, roof, or pipes, or
malfunctions in the heating and cooling systems (HVAC) that result in high
RH. Problems can also develop within the HVAC system, due to a malfunction
or lack of maintenance, and be spread through the building. Prime areas
for mold problems to form are heat exchange coils, drip pans, and duct
work.
Lower the humidity and
increase the air circulation. The goal is to change the environmental
conditions so that mold will be inactivated. Monitor the temperature and
relative humidity regularly, and aim to get the RH below 50% and the
temperature as low as possible, but at least down to 70 degrees F.
Possible methods for reducing the RH and temperature are to lower the
settings of the HVAC system, use fans to increase air flow, open windows
if the air outside is colder and drier than indoors, or use dehumidifiers.
Remove water-soaked items from the area, if present, such as ceiling
tiles, upholstered furniture, and carpeting.
For more information on
addressing mold problems, see
Managing a Mold Invasion and
Emergency Salvage of Moldy Books and Paper.
View the
presentation on Mold in the Library (September 2004).
Retention of Mold-Affected
Materials
In many cases, the best
decision for mold-affected items in the general collection without
artifactual value is to discard them. If their information content is
important for the collection, finding replacements is often a better
course of action than attempting to clean them. Rare and unique materials
that have become moldy, however, usually are worth the cost and effort to
clean. For potential gifts, only the most rare or scarce materials are
worth the difficulties presented by mold. Cleaning moldy materials is time
consuming and also carries some level of risk for staff who do this work.
In addition, materials that were once moldy are always susceptible to
future mold blooms to a greater extent than other materials, and must be
stored in appropriate environmental conditions and monitored.
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