Questions and Answers on Stachybotrys chartarum and other molds
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
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 mold 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 weak bleach solution (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.
What should people to do if they determine they have Stachybotrys chartarum (Stachybotrys atra) in their buildings
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 can be cleaned off hard surfaces with a weak bleach solution. 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 weak bleach solution (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.
- 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.
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