Molds are microscopic organisms
that live on plant or animal matter. They aid in the break down of
dead material and recycle nutrients in the environment. Present virtually
everywhere, they can be found growing on organic material such as
soil, foods, and plant matter. In order to reproduce, molds produce
spores, which spread through air, water, or by insects. These spores
act like seeds and can form new mold growth if the conditions are
do molds grow?
Mold will grow and multiply under the right conditions, needing only
sufficient moisture (e.g., in the form of very high humidity, condensation,
or water from a leaking pipe, etc.), and organic material (e.g., ceiling
tile, drywall, paper, or natural fiber carpet padding).
mold become a problem in my home?
Mold growth may occur in your home if there is sufficient moisture
because mold spores are everywhere. Be on the lookout for these common
sources of moisture:
• Roof leaks
• Plumbing leaks, drainage problems
• Damp basements and crawl spaces
• Steam from the bathroom or kitchen
• Condensation resulting from poor or improper insulation or
• Wet clothes drying inside the home or a clothes dryer venting
• Poor or improper ventilation of combustion appliances
Indications of a moisture problem may include discoloration of the
ceiling or walls, warping of the floor, or condensation on the walls
or windows. The key to preventing mold growth is to control all moisture
I be concerned about mold in my home?
Mold can be a concern in the home and should not be allowed to grow.
Extensive mold contamination may cause health problems as well as
damage to the home.
mold make my family sick?
Exposure to mold can cause health effects in some people. The most
common effects are allergic responses from breathing mold spores.
These allergic responses include hay fever or asthma and irritation
of the eyes, nose, throat or lungs. We usually cannot say how much
mold is too much as our reactions to allergens can vary greatly depending
on individual sensitivity. Allergic responses can come from exposure
to dead as well as to living mold spores. Therefore, killing mold
with bleach and or other disinfectants may not prevent allergic responses.
common effects of mold exposure include infections and toxic effects.
Serious infections from living molds are relatively rare and occur
mainly in people with severely suppressed immune systems. Many types
of molds may produce toxins but only under certain growth conditions.
Toxic effects have been reported from eating moldy grain, but evidence
is weak that breathing mold spores in buildings causes toxic effects.
are common symptoms of mold exposure?
Allergy and irritation are the most common symptoms of mold exposure.
Although symptoms will vary, the most common symptoms seen in people
exposed to mold indoors include:
and sinus congestion
• Eye irritation, such as itchy, red, watery eyes
• Respiratory problems, such as wheezing and difficulty breathing
• Throat irritation
• Skin irritation, such as a rash
Who is most at risk for health problems
from mold exposure?
Exposure to high amounts of mold is not healthy for anyone, so obvious
mold growth in the home should be cleaned up. However, some individuals
may be more susceptible to health problems from mold exposure. These
with current respiratory sensitivities (e.g., allergies, asthma, or
• Individuals with a compromised immune system (e.g., HIV/AIDS
infection, organ transplant patients, or chemotherapy patients)
Are some molds more harmful than others?
Any extensive indoor mold growth should be treated as a potential
health concern and removed as soon as practical no matter what species
of mold is present. Identify and correct the source of moisture so
that mold will not grow back.
do I know if I have a mold problem?
A mold problem can usually be seen or smelled. Mold growth may often
appear as slightly furry, discolored, or slimy patches that increase
in size as they grow. Molds also produce a musty odor that may be
the first indication of a problem. The best way to find mold is to
examine areas for visible signs of mold growth, water staining, or
follow your nose to the source of the odor. If you can see or smell
mold, you can assume you have a mold problem. Other clues include
excess moisture and water damage. It may be necessary to look behind
and underneath surfaces, such as carpets, wallpaper, cabinets, and
are some areas of the home that are always susceptible to mold growth
and should be part of routine cleaning to keep them under control.
They are seldom the cause of significant health effects. These are:
seal on the refrigerator door
• Shower curtains
• Window moldings
• Shower stalls and bathroom tiles
• Surfaces on and around air conditioners
Should I have my home tested for mold?
Sampling can be expensive. The results are also difficult to interpret
partially because we have very limited information about what level
of mold exposure is associated with health effects. In some cases,
knowing the type of mold that is present can be helpful, but for most
cases, sampling is unnecessary. Overall, the best practice regardless
of the type or amount of mold is to promptly clean up any mold growth
in your home and to correct the water problem that caused it.