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Your Environment. Your Health.

Mold

Introduction

mold on a wall

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.

More information, including a fact sheet, "Healthy Home Issues: Mold," is available on the HUD website.

What is NIEHS Doing?

Visit the Join an NIEHS Study Website

Join an asthma study!

The goal of the Natural History of Asthma with Longitudinal Environmental Sampling (NHALES) study is to help scientists understand how bacteria and other factors in the environment affect people who have moderate to severe asthma.

Who can participate?

  • Moderate to severe asthmatics.
  • Males and females, aged 18-60.
  • Females should not be pregnant or breastfeeding at the start of the study, but may still participate if they become pregnant during the study.
  • Nonsmokers who are also not around significant amounts of secondhand smoke.
  • No history of chronic obstructive pulmonary disease, emphysema, cystic fibrosis (CF), pulmonary fibrosis, non-CF bronchiectasis, sarcoidosis, unstable angina, or pulmonary hypertension.
  • Not allergic to methacholine.
  • Able to provide your own transportation to clinic visits on the NIEHS campus in North Carolina.

    For more information about this study:
    NHALES: Asthma Study
    Tel 855-MYNIEHS (855-696-4347)
    nhales@mail.nih.gov

After Hurricane Sandy in 2012, NIEHS made several resources on mold treatment and cleanup available.

NIEHS Research Efforts

Further Reading

Stories from the Environmental Factor (NIEHS Newsletter)

Fact Sheets

Additional Resources

  • 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
  • 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
  • Podcast: Environmental Chemicals Versus the Immune System - Dr. Dori Germolec, a biologist, studied how chemicals in our environment affect the immune system, including toxic or carcinogenic effects of molds and dietary supplements.

Related Health Topics

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