Mold is present almost everywhere. In an indoor environment hundreds of different kinds of mold are able to grow wherever there is moisture and an organic substrate (food source). Mold can grow on building materials, including: the paper on gypsum wallboard (drywall); ceiling tiles; wood products; paint; wallpaper; carpeting; some furnishings; books/papers; clothes; and other fabrics. Mold can also grow on moist, dirty surfaces such as concrete, fiberglass insulation, and ceramic tiles. It is neither possible nor warranted to eliminate the presence of all indoor mold spores and fragments; however, mold growth indoors can and should be prevented and removed if present. If you have specific concerns or questions about mold in your home, workplace, school or other location, contact the Environmental Health division at 740-392-2200, Ext. 2222 or
Should 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.
Can 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.
Less 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.
What 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:
Nasal and sinus congestion
Eye irritation, such as itchy, red, watery eyes
Respiratory problems, such as wheezing and difficulty breathing
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 include:
Individuals with current respiratory sensitivities (e.g., allergies, asthma, or emphysema)
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.
How 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 walls. There 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:
The seal on the refrigerator door
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.
Cleaning Up Mold: How to get rid of it
The first step to mold cleanup is to control the moisture problem. The source of the water must be identified and corrected.
Porous materials with extensive mold growth should be discarded (e.g., drywall, carpeting, paper, and ceiling tiles).
All wet materials must be thoroughly dried. If that is not possible, they should be discarded.
Mold growing on hard surfaces (e.g. wood and concrete) can be cleaned. Small areas can be scrubbed with a cleaning rag wetted with diluted detergent. Rubber gloves and a dust mask are recommended for jobs other than routine cleaning. For a large mold problem or if you are highly sensitive to mold, an experienced professional should do the work.
In areas where it is impractical to eliminate the moisture source, a 10% bleach solution can be used to keep mold growth under control. In areas that can be kept dry, bleach is not necessary, as mold cannot grow in the absence of moisture. When using bleach, ensure that enough fresh air is available because bleach may cause eye, nose, or throat irritation.
Continue to monitor the area for new mold growth and signs of moisture. This may indicate the need for further repairs or material removal.
For more information on mold
Center for Disease Control - National Center for Environmental Health
U.S. Environmental Protection Agency Indoor Air
New York City Department of Health & Mental Hygiene Bureau of Environmental & Occupational Disease
Epidemiology Guidelines on Assessment and Remediation of Fungi in Indoor Environments
Minnesota Department of Health - Environmental Health in Minnesota Mold in Homes