Molds are microscopic organisms that play an important role in the breakdown of plant and animal matter. Outdoors, molds can be found in shady, damp areas, or places where leaves or other vegetation is decomposing. Indoor molds can grow on virtually any surface, as long as moisture, oxygen, and organic material are present. When molds are disturbed, they release tiny cells called spores into the surrounding air.
How do people get exposed to mold?
People are exposed to molds every day and everywhere, at home, at work, at school, both indoors and out. Molds are generally not harmful to healthy humans.
Inhalation is considered the primary way that people are exposed to mold. Mold spores and fragments can become airborne and get into the air we breathe. People may also be exposed to mold through the skin. Workers should be properly protected with safety equipment when remediating, or cleaning up mold after a disaster. In some cases, people may be exposed to mold through their diet.
What are the most common forms of mold?
According to the Centers for Disease Control and Prevention, the most common indoor molds are:
What are some of the health effects associated with mold exposure?
Symptoms stemming from mold spore exposure may include:
- Nasal and sinus congestion
- Eye irritation
- Blurred vision
- Sore throat
- Chronic cough
- Skin rash
After contact with certain molds, individuals with chronic respiratory disease may have difficulty breathing, and people who are immunocompromised may be at increased risk for lung infection. A study conducted by NIEHS-funded scientists shows that mold exposure during the first year of life may increase the risk of childhood asthma.
What can I do to get rid of mold in my home?
According to the U.S. Department of Housing and Urban Development (HUD), residents can do any of the following to prevent, and or get rid of, mold in their homes:
- Keep your house clean and dry.
- Fix water problems, such as roof leaks, wet basements, and leaking pipes or faucets.
- Make sure your home is well ventilated, and always use ventilation fans in bathrooms and kitchens.
- If possible, keep humidity in your house below 50 percent, by using an air conditioner or dehumidifier.
- Avoid using carpeting in areas of the home that may become wet, such as kitchens, bathrooms, and basements.
- Dry floor mats regularly.
After Hurricane Sandy in 2012, NIEHS made several resources on mold treatment and cleanup available.
The HEAL Study
The Head-off Environmental Asthma in Louisiana (HEAL) Project is a collaborative study conducted by the Tulane University Health Sciences Center and the New Orleans Department of Health. The purpose of the project is to learn about the effects of mold and other indoor allergens on children with asthma in post-Katrina New Orleans.
To learn more, visit .
Additional mold studies sponsored by NIEHS
- Guidelines for the Protection and Training of Workers Engaged In Maintenance and Remediation Work Associated with Mold
- Study Identifies Role of Mold in Asthma Development
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Stories from the Environmental Factor (NIEHS Newsletter)
- Study Identifies Role of Mold in Asthma Development (September 2011)
Printable Fact Sheets
- Mold Fact Sheet(1MB)
- Captafol Profile: Report on Carcinogens - Captafol was produced and used as a fungicide in the United States until 1987
- Controlling Allergens in Your Home - Partnerships for Environmental Public Health (PEPH) Podcast
- Guidelines for the Protection and Training of Workers Engaged In Maintenance and Remediation Work Associated with Mold - Sponsored by: NIEHS WETP; The Society for Occupational and Environmental Health; The Association of Occupational and Environmental Clinics; The Urban Public Health Program of Hunter College, CUNY; The New York City Department of Health and Mental Hygiene; The University of Medicine and Dentistry of New Jersey, School of Public Health.
- Healthy Home Issues: Mold - U.S. Department of Housing and Urban Development (HUD) Office of Healthy Homes and Lead Hazard Control.
- Mold - CDC's Mold Web site provides information on mold and health, an inventory of state indoor air quality programs, advice on assessment, cleanup efforts, and prevention of mold growth, and links to resources
- Mold - Occupational Safety and Health Administration Safety and Health Topics
- Mold - U.S. Environmental Protection Agency