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Isolate and control access to affected artifacts or contaminated
areas to reduce exposing people to mould. People entering the
isolated area or opening sealed objects should always wear the
appropriate PPE.
Determine the extent of the mould infestation, consider the
available resources, and determine whether the infestation can
be handled in-house or outside help is required.
Identify
and eliminate the causative agent
Determine the cause of the mould outbreak and take immediate
action to correct it. This may include measures to lower the
relative humidity, to increase air circulation, to lower room
temperature, and to remove any standing water. If necessary,
employ a company that specializes in desiccant drying to dry
the affected facilities and furnishings, such as carpets and
drapes.
Deactivate
the mould
The mould is actively growing if it feels damp and smears when
brushed or if a mouldy smell is present. Deactivating the mould
will stop its growth and prevent further damage to the artifacts.
This can be done either by air drying or by freezing, as discussed
below. Once the artifact is dry, mould can be removed. Keep
the dry artifact isolated and in a sealed container until it
can be cleaned. This will prevent any inactive, but still viable,
spores from dispersing.
Air drying
Artifacts can be air dried by lowering the relative humidity
and increasing air circulation. Because the mould spores of
most species are easily airborne, it is important to conduct
air drying in a way that does not disperse mould spores and
to take measures to prevent the spores from dispersing throughout
the building. Seal the return air vent and, if possible, open
windows to vent air outdoors. Select an isolated room, with
a minimum of furniture, that is easy to clean afterwards. Allow
artifacts to air dry naturally or use fans. If using fans, place
them so the airflow is directed away from the artifacts. This
will limit spore dispersal and keep the drying process slow
enough to reduce physical distortions, such as fine checks or
cracks that can result from an abrupt decrease in the object’s
moisture content. Objects made of a thick layer of organic material,
or objects that are composed of different elements (such as
inlays or veneers) joined together, are the most likely to undergo
high physical stresses leading to damage during air drying.
If air drying indoors cannot be accomplished without dispersing
mould spores, it is preferable to either freeze the material,
air dry a few at a time in a fume hood, or dry the material
outdoors. Air drying outdoors should be done on a clear day,
in a sheltered spot out of direct sunlight. Be sure to keep
the objects away from people and building air-intake systems,
and bring them in at night.
Freezing
Freezing is a quick method of killing actively growing mould.
However, although a mould’s vegetative growth will freeze
and break down, the spores are able to withstand the cold temperatures
and remain viable.
Freezing is a good option when there are numerous water-damaged
or mouldy objects as this method eliminates the urgency to safely
dry all wet artifacts within a short time frame. But freezing
is not appropriate for all artifacts. In general, it is safe
for textiles, furs, feathers, leather, paper, and wood. However,
it is not recommended for glass plate negatives, oil paintings,
or acrylic paintings. If in doubt, check with a conservator
first. Before freezing, seal the object in a clear polyethylene
bag or wrap with polyethylene film and seal with tape.
Household horizontal chest freezers, which generally operate
between -18°C and -28°C, can be used for a small number
of objects. Freezing on a large scale requires a larger freezer.
Large walk-in freezers can be rented. Freezer trucks can also
be rented and brought to a site. The labour-intensive drying
process can then be postponed until the staff is fully organized
and has secured the space, time, resources, and people to deal
with the artifacts.
Should the Mould
be Identified?
In general, identifying mould is not required in order to respond
to an outbreak in a heritage collection, to remove visible mould
from heritage material, or to treat artifacts damaged by mould.
Identifying mould is done for specific reasons, e.g. if there
is a health hazard concern or if some staff have health problems.
Health Effects
Mould is ubiquitous. Normal background concentrations of mould
do not usually affect healthy individuals. In contaminated environments,
however, the risk of health effects from exposure to mould increases.
Reactions are varied and depend on the nature of the species
involved, the metabolic products produced by these species,
the amount and duration of exposure to mould and mould products,
and the susceptibility of the individual. As well, people with
asthma or respiratory problems, those suffering from allergies
or an allergy to mould, those with compromised immune systems,
and anyone taking steroids may be affected.
Generally, health effects fall into the following categories:
irritation, allergy, toxicity, and infection (Ammann 2003).
Symptoms that result from exposure to abnormal levels of indoor
moulds, including toxigenic moulds, may include the following
(Johanning and Landsbergis 1999):
- nasal irritation, burning, itchiness, stuffiness and congestion,
bloody nasal discharge, throat irritation and soreness
- cough, shortness of breath, wheezing, chest congestion
and tightness
- severe headaches, concentration problems, irritability,
dizziness or lightheadedness, fatigue
- burning, irritated, blurry vision
- burning rash on skin
- low-grade fever, flu-like symptoms
People experiencing any of the above symptoms that may be related
to exposure to abnormal levels of indoor moulds should consult
their physician.
Personal Protective
Equipment (PPE)
Mould is a serious health concern, so every effort should be
made to limit human exposure to it. PPE that should be worn
when handling mouldy artifacts or when working in mould-contaminated
areas is described below. There is no conclusive research that
specifies a level of personal protection that is appropriate
at a certain number of square metres of contamination (Environmental
Protection Agency 2001). If in doubt regarding the appropriate
level of PPE, consult health and safety experts.
Respiratory
protection
For mould infestations in heritage collections, particulate
filters from the N series (N for not resistant to oil) are generally
appropriate. Filters described as N100 offer the greatest protection
against particulate matter. These filters are also referred
to as HEPA (high-efficiency particulate air) filters.
Some fungi produce volatile organic compounds that cause unpleasant
odours, including the characteristic mouldy smell associated
with damp areas or materials. The health effects of exposure
to microbial volatile organic compounds (MVOCs) have not been
well-studied. They may be responsible for headache, dizziness,
and eye and mucous membrane irritation (Levetin 1995). When a
mould smell is present, a filter that combines HEPA and organic
vapour cartridges is recommended. Some particulate disposable
respirators incorporate nuisance-level organic vapour relief
and may be appropriate for some circumstances. Half-face and
full-face respirators and some powered air purification respiratory
systems (PAPRs) can be fitted with combination HEPA and organic
vapour cartridges that protect against MVOCs.
Respirators, including disposable respirators, should be test
fitted by a qualified individual to ensure a proper fit. Respirators
should always be stored in a clean area or in a bag to avoid
buildup of particulate matter on the respirator. At the end
of each day of use, respirators should be cleaned according
to the manufacturer’s instructions. Used respirator filters
will support mould growth. To prevent this, allow the respirator
(and filters) to air out before storing them in a sealed bag.
|
|
Half-face
respirators
A half-face respirator consists of an assembled face piece worn
over the mouth and nose. Cartridges selected to protect against
a hazardous environment are attached to the face piece. Particulate
and combination cartridges are available. Half-face respirators
are more expensive than disposable respirators, but are re-usable
because the cartridges can be replaced. Half-face respirators
are available in different shapes, styles, and sizes. They are
not appropriate for people with facial hair.
Full-face
respirators
A full-face respirator consists of an assembled face piece worn
over the mouth, nose, and eyes. Cartridges selected to protect
against a hazardous environment are attached to the face piece.
Particulate and combination cartridges are available. Full-face
respirators can be re-used by replacing the cartridges as required.
Full-face respirators are available in different materials,
styles, and sizes. They are not appropriate for people with
facial hair.
It is not necessary to wear protective goggles with a full-face
respirator, but the seal of the respirator may be compromised
if the person wears prescription eyeglasses. It may be necessary
to consult with a reputable technical consultant of respiratory
equipment to select the most appropriate full-face respirator.
Full-face respirators or PAPRs are recommended when dealing
with extensive mould growth.
Powered
air purification respiratory systems (PAPRs)
PAPRs are positive-pressure airflow respirators that deliver
a steady supply of filtered air. Filtered air passes through
the breathing tube and into the headpiece. PAPRs protect individuals
with facial hair and do not require test fitting.
Goggles
Protective goggles must also be worn when dealing with mould.
The appropriate, recommended goggles are not ventilated and
must accommodate a disposable or half-face respirator. If the
user wears prescription eyeglasses, tight-fitting yet comfortable
goggles may be difficult to locate. In this case, full-face
respirators or PAPRs may be an option.
Gloves
Protective gloves should be worn when handling mouldy material.
Due to concerns about latex allergies, vinyl (PVC) or Nitrile
gloves are recommended. Disposable gloves should be replaced
as required. Torn gloves should be replaced immediately. Hands
should be washed with soap and water after handling contaminated
material, even when gloves have been worn.
Protective
clothing
When dealing with mouldy material, protective clothing must
be available for all personnel and it must be properly worn
and fastened. Coveralls and protective hair and shoe covers
should be used when significant amounts of mould spores might
be released into the air. Disposable clothing is recommended,
but re-useable protective clothing (lab coats or coveralls)
may be appropriate for small and medium-sized levels of contamination.
Protective clothing must not be worn outside the contaminated
area. It should be removed on-site and washed in hot water and
bleach.
Discarded
disposable PPE
There are no special requirements for discarding contaminated
PPE. However, it is important to exercise caution when handling
and discarding these items. Place disposable clothing, gloves,
etc., in thick (6 mil) plastic garbage bags or two layers of
thin plastic garbage bags. Seal and discard the bags in an outdoor
garbage container.
Recommended Personal Protective Equipment
(PPE)
| PPE
|
Level 1:
small isolated areas
(<0.3 m2) |
Level 2:
medium-size isolated areas
(0.3–3 m2) |
Level 3:
large isolated areas
(3–10 m2) |
Level 4:
extensive contamination
(>10 m2) |
| Minimum respiratory protection |
- N95 or N100 disposable respirator |
- half-face N100 respirator |
- full-face N100 respirator |
- full-face N100 respirator or PAPRs with HEPA filter
|
| Other |
- disposable gloves and protective goggles |
- disposable gloves, protective goggles, and protective
clothing |
- disposable gloves and protective clothing with head
and boots covered |
- disposable gloves and protective clothing with
head and boots covered
|
| Additional protection |
- appropriate respiratory, eye, and hand
protection for any wetting or cleaning agents (e.g. high
concentrations of bleach)
|
| Additional comments |
- disposable respirator with nuisance-level organic vapour
relief for MVOCs may be appropriate
|
- organic vapour cartridge for MVOCs may be
appropriate |
- organic vapour cartridge for MVOCs may be appropriate
- professional help likely required for collection recovery
on this scale
|
| - half-face respirator, gloves, goggles, and
protective clothing are recommended for collection recovery
at any scale where toxigenic fungi are known or suspected |
Summary
The information presented here will allow you to take the
first steps to address a mould infestation. It will enable you
to protect staff by selecting the appropriate PPE, to isolate
contaminated artifacts, and to prevent the dispersion of mould
spores to non-contaminated artifacts or the rest of the building.
It describes ways to deactivate the mould by air drying or freezing
the contaminated material. These are the first steps in coping
with a mould infestation in a collection.
Subsequent to these measures a cleaning methodology should
be devised and the collection recovery phase of the mould infestation
can begin. Mould spores do not have to be viable to retain allergenic
or toxigenic properties; therefore, exposure to dormant mould
is a health concern. The conscientious removal of mould and
the reduction of spores from contaminated artifacts is necessary.
For more information on collection recovery of mouldy artifacts,
refer to Mould
Prevention and Collection Recovery: Guidelines for Heritage
Collections (Technical Bulletin No. 26).
Suppliers
of Personal Protective Equipment (PPE)
(including respiratory protection, goggles, gloves, protective
clothing, head and shoe coverings, ear protection, back support
belts)
- Canadian Standards Association (for more information regarding
respirators)
- CSA Standard Z94.4-02 “Selection, Use, and Care of
Respirators”
(416)-747-4000 or 1-800-463-6727
- Fisher Safety Canada
- 1-800-243-7437 (customer service in Canada)
1-877-676-3639 (safety customer service in Canada)
1-800-772-6733 (customer service in the United States)
www.fishersci.ca
- Lab Safety Supply
- 1-800-356-0783 (Canada and the United States)
1-800-356-2501 (technical assistance)
608-754-7160 (International)
www.labsafety.com
Other Sources of Information
General Information
- Health Canada
- Contamination
of Indoor Air
Canada Mortgage and Housing Corporation (CMHC)- Indoor
Air Quality
- Fighting
Mold — The Homeowner’s Guide
Canadian Centre for Occupational Health and Safety (CCOHS)
U.S. Environmental Protection Agency (EPA)- Biological
Pollutants in Your Home
- A
Brief Guide to Mold, Moisture, and Your Home
- Mold
Resources
- Mold
Remediation in Schools and Commercial Buildings
American Industrial Hygiene Association (AIHA)- Mold
Resources
Guidelines for Mould Remediation
- Health Canada
- Fungal
Contamination in Public Buildings: A Guide to Recognition
and Management
Manitoba Department of Labour, Safety & Health Division
- Guidelines
for the Investigation, Assessment & Remediation of Mould
in Workplaces
New York City Department of Health, Bureau of Environmental
& Occupational Disease Epidemiology- Guidelines
on Assessment and Remediation of Fungi in Indoor Environments
Hiring a Conservator
Laboratories
- AIHA Accredited Labs
- www.aiha.org/LaboratoryServices/html/accred.htm
Aerotech Labs- www.aerotechlabs.com/index.asp
Environmental Microbiology Laboratory, Inc.- www.emlab.com
Paracel Laboratories Inc.- www.indoorairq.com
- www.ccil.com/paracel.doc
References
Ammann, H. Is
Indoor Mold Contamination a Threat to Health? (June
2003).
Environmental Protection Agency. “Table 2: Mold Remediation
Guidelines.” In Mold Remediation in Schools and Commercial
Buildings. Washington, D.C.: Office of Air and Radiation,
Indoor Environments Division, 2001, pp. 12–15.
Johanning, E., and P. Landsbergis. “Clinical Findings
Related to Indoor Fungal Exposure — Review of Clinic Data
of Specialty Clinic.” In Bioaerosols, Fungi and Mycotoxins:
Health Effects, Assessment, Prevention and Control (edited
by E. Johanning). Albany, New York: Eastern New York Occupational
& Environmental Health Center, 1999.
Levetin, E. “Fungi.” In Bioaerosols (edited
by H.A. Burge). Boca Raton, Florida: Center for Indoor Air Research,
CRC Press Inc., 1995. |
