Questions and Answers on Stachybotrys chartarum and other
molds
Questions
Summary
Answers
I heard about "toxic
molds" that grow in homes and other buildings. Should I be concerned
about a serious health risk to me and my family?
The term "toxic mold" is not accurate. While
certain molds are toxigenic, meaning they can produce toxins (specifically
mycotoxins), the molds themselves are not toxic, or poisonous. Hazards
presented by molds that may produce mycotoxins should be considered the
same as other common molds which can grow in your house. There is always
a little mold everywhere - in the air and on many surfaces. There are
very few reports that toxigenic molds found inside homes can cause unique
or rare health conditions such as pulmonary hemorrhage or memory loss.
These case reports are rare, and a causal link between the presence of
the toxigenic mold and these conditions has not been proven. A common-sense
approach should be used for any mold contamination existing inside buildings
and homes. The common health concerns from molds include hay fever-like
allergic symptoms. Certain individuals with chronic respiratory disease
(chronic obstructive pulmonary disorder, asthma) may experience difficulty
breathing. Individuals with immune suppression may be at increased risk
for infection from molds. If you or your family members have these conditions,
a qualified medical clinician should be consulted for diagnosis and treatment.
For the most part, one should take routine measures to prevent mold growth
in the home.
How common is mold, including Stachybotrys
chartarum (also known by its synonym Stachybotrys atra)
in buildings?
Molds are very common in buildings and homes and will
grow anywhere indoors where there is moisture. The most common indoor
molds are Cladosporium, Penicillium, Aspergillus,
and Alternaria. We do not have precise information about how often
Stachybotrys chartarum is found in buildings and homes. While it is less
common than other mold species, it is not rare.
How do molds get in the indoor
environment and how do they grow?
Mold spores occur in the indoor and outdoor environments.
Mold spores may enter your house from the outside through open doorways,
windows, and heating, ventilation, and air conditioning systems with
outdoor air intakes. Spores in the air outside also attach themselves
to people and animals, making clothing, shoes, bags, and pets convenient
vehicles for carrying mold indoors.
When mold spores drop on places where there is excessive
moisture, such as where leakage may have occurred in roofs, pipes, walls,
plant pots, or where there has been flooding, they will grow. Many building
materials provide suitable nutrients that encourage mold to grow. Wet
cellulose materials, including paper and paper products, cardboard, ceiling
tiles, wood, and wood products, are particularly conducive for the growth
of some molds. Other materials such as dust, paints, wallpaper, insulation
materials, drywall, carpet, fabric, and upholstery, commonly support
mold growth.
What is Stachybotrys chartarum (Stachybotrys
atra)?
Stachybotrys chartarum (also known by its synonym Stachybotrys
atra) is a greenish-black mold. It can grow on material with a
high cellulose and low nitrogen content, such as fiberboard, gypsum
board, paper, dust, and lint. Growth occurs when there is moisture
from water damage, excessive humidity, water leaks, condensation, water
infiltration, or flooding. Constant moisture is required for its growth.
It is not necessary, however, to determine what type of mold you may
have. All molds should be treated the same with respect to potential
health risks and removal.
Are there any circumstances
where people should vacate a home or other building because of mold?
These decisions have to be made individually. If you
believe you are ill because of exposure to mold in a building, you should
consult your physician to determine the appropriate action to take.
Who are the people who are
most at risk for health problems associated with exposure to mold?
People with allergies may be more sensitive to molds.
People with immune suppression or underlying lung disease are more susceptible
to fungal infections.
How do you know if you have
a mold problem?
Large mold infestations can usually be seen or smelled.
Does Stachybotrys chartarum (Stachybotrys
atra) cause acute idiopathic pulmonary hemorrhage among infants?<
To date, a possible association between acute idiopathic
pulmonary hemorrhage among infants and Stachybotrys chartarum (Stachybotrys
atra) has not been proved. Further studies are needed to determine
what causes acute idiopathic hemorrhage.
What if my child has acute
idiopathic pulmonary hemorrhage?
Parents should ensure that their children get proper
medical treatment.
What are the potential
health effects of mold in buildings and homes?
Mold exposure does not always present a health problem
indoors. However some people are sensitive to molds. These people may
experience symptoms such as nasal stuffiness, eye irritation, wheezing,
or skin irritation when exposed to molds. Some people may have more severe
reactions to molds. Severe reactions may occur among workers exposed
to large amounts of molds in occupational settings, such as farmers working
around moldy hay. Severe reactions may include fever and shortness of
breath. Immunocompromised persons and persons with chronic lung diseases
like COPD are at increased risk for opportunistic infections and may
develop fungal infections in their lungs.
How do you get the molds
out of buildings, including homes, schools, and places of employment?
In most cases mold can be removed from hard surfaces
by a thorough cleaning with commercial products, soap and water, or a bleach
solution of 1 cup of bleach in 1 gallon of water. Absorbent or porous
materials like ceiling tiles, drywall, and carpet may have to be thrown
away if they become moldy. If you have an extensive amount of mold and
you do not think you can manage the cleanup on your own, you may want
to contact a professional who has experience in cleaning mold in buildings
and homes. It is important to properly clean and dry the area as you
can still have an allergic reaction to parts of the dead mold and mold
contamination may recur if there is still a source of moisture.
If you choose to use bleach
to clean up mold:
- Never mix bleach with ammonia. Mixing bleach and ammonia can produce
dangerous, toxic fumes.
- Open windows and doors to provide fresh air.
- Wear non-porous gloves and protective eye wear.
- If the area to be cleaned is more than 10 square feet, consult the
U.S. Environmental Protection Agency (EPA) guide titled Mold Remediation
in Schools and Commercial Buildings. Although focused on schools
and commercial buildings, this document also applies to other building
types. You can get it free by calling the EPA Indoor Air Quality Information
Clearinghouse at (800) 438-4318, or by going to the EPA web site at http://www.epa.gov/mold/mold_remediation.html.
- Always follow the manufacturer’s instructions when using bleach
or any other cleaning product.
What should people to do
if they determine they have Stachybotrys chartarum (Stachybotrys
atra) in their buildings or homes?
Mold growing in homes and buildings, whether it is Stachybotrys
chartarum (Stachybotrys atra) or other molds, indicates
that there is a problem with water or moisture. This is the first problem
that needs to be addressed. Mold growth can be removed from hard surfaces
with commercial products, soap and water, or a bleach
solution of 1 cup of bleach in 1 gallon of water. Mold in or under
carpets typically requires that the carpets be removed. Once mold starts
to grow in insulation or wallboard, the only way to deal with the problem
is by removal and replacement. We do not believe that one needs to
take any different precautions with Stachybotrys chartarum (Stachybotrys
atra), than with other molds. In areas where flooding has occurred,
prompt drying out of materials and cleaning of walls and other flood-damaged
items with commercial products, soap and water, or a bleach
solution of 1 cup of bleach in 1 gallon of water is necessary to
prevent mold growth. Never mix bleach with ammonia. If a home has been
flooded, it also may be contaminated with sewage. (See: After
a Hurricane or Flood: Cleanup of Flood Water.) Moldy items should
be removed from living areas.
How do you keep mold out
of buildings and homes?
As part of routine building maintenance, buildings should
be inspected for evidence of water damage and visible mold. The conditions
causing mold (such as water leaks, condensation, infiltration, or flooding)
should be corrected to prevent mold from growing.
Specific Recommendations:
- Keep humidity level in house between 40% and 60%.
- Use air conditioner or a dehumidifier during humid months.
- Be sure the home has adequate ventilation, including exhaust fans
in kitchen and bathrooms.
- Use mold inhibitors which can be added to paints.
- Clean bathroom with mold-killing products.
- Do not carpet bathrooms.
- Remove and replace flooded carpets.
I found mold growing in
my home; how do I test the mold?
Generally, it is not necessary to identify the species
of mold growing in a residence, and CDC does not recommend routine sampling
for molds. Current evidence indicates that allergies are the type of
diseases most often associated with molds. Since the reaction of individuals
can vary greatly either because of the person’s susceptibility
or type and amount of mold present, sampling and culturing are not reliable
in determining your health risk. If you are susceptible to mold and mold
is seen or smelled, there is a potential health risk; therefore, no matter
what type of mold is present, you should arrange for its removal. Furthermore,
reliable sampling for mold can be expensive, and standards for judging
what is and what is not an acceptable or tolerable quantity of mold have
not been established.
A qualified environmental
lab took samples of the mold in my home and gave me the results. Can
CDC interpret these results?
Standards for judging what is an acceptable, tolerable
or normal quantity of mold have not been established. If you do decide
to pay for environmental sampling for molds, before the work starts,
you should ask the consultants who will do the work to establish criteria
for interpreting the test results. They should tell you in advance what
they will do or what recommendations they will make based on the sampling
results. The results of samples taken in your unique situation cannot
be interpreted without physical inspection of the contaminated area or
without considering the building’s characteristics and the factors
that led to the present condition.
Summary
In summary, Stachybotrys chartarum (Stachybotrys
atra) and other molds may cause health symptoms that are nonspecific.
At present there is no test that proves an association between Stachybotrys
chartarum (Stachybotrys atra) and particular health symptoms.
Individuals with persistent symptoms should see their physician. However,
if Stachybotrys chartarum (Stachybotrys atra) or other
molds are found in a building, prudent practice recommends that they
be removed.
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