Mold

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Families and Communities Health Professionals

Molds are fungi, such as mildew, yeasts, and mushrooms, that are present indoors and outdoors. Mold in homes and schools is common. Mold grows in moist, dark, and humid areas that may have water coming in from leaking roofs, pipes, etc. Mold exposure can occur in any area where water comes in contact with paper, fabric, rugs, wallpaper glue, wood, and other surfaces.

If disturbed, mold can release spores (usually not visible) that get inhaled. You can get mold on your skin or swallow mold if you eat spoiled food like moldy bread or sauces. Most people do not develop symptoms from these exposures.

Testing for mold in a home or school is usually not necessary.

Large amounts (more than 3 feet x 3 feet) of mold damage should be cleaned and the area repaired by professionals wearing appropriate personal safety gear. The area should be sealed before work begins.

Families and Communities

Families and school personnel are encouraged to read the guidance below to help prevent or reduce exposure to mold. This information can also be used to guide discussions with your child’s pediatrician or other health care provider.

If you think that your child has symptoms related to mold exposure in your home, early care and education center, or school, they should see a doctor. If you suspect the exposure is from school, you should also notify the school’s staff.

At home

At home, mold exposure is commonly found in bathrooms, but can also be in any part of the home that is damp or moist.

The best way to reduce mold exposure in your home is to remove water and moisture sources. This can be done by:

Fixing leaks
Drying damp areas
Lowering indoor air humidity
- use a dehumidifier in basements
- open a window while taking a shower in bathrooms with no exhaust fan or vent
Keeping heating, ventilation, and air conditioning drip pans clean, flowing, and unblocked
Venting moisture-generating appliances, such as dryers, to the outside
Maintaining low indoor humidity, ideally between 30-50%, but at least below 65% relative humidity
Allowing good air circulation between furniture and surfaces like floor, ceiling, and wall
Performing regular building/HVAC inspections and maintenance as scheduled
Cleaning and drying wet or damp spots within 48 hours
Preventing the home’s foundation from staying wet. The ground (and water) should slope away from the foundation

The best way to clean mold from small area surfaces (less than 3 feet by 3 feet) such as shower walls is to use detergent and water. Additional information about mold and mold removal can be found at the EPA Guide to Mold and the EPA web site Mold Cleanup in Your Home. For larger areas, it is best to contact a professional mold remediation. PEHSU has a resource on safer cleaning and disinfection.

Schools and Early Care and Education Centers

School and child care centers’ bathrooms, shower rooms, gyms and science labs are areas where mold will often grow. Schools and centers can reduce mold growth by:

Eliminating sources of leaking water. Personnel should correct leaks and other sources of moisture, and safely remove damp, water-stained, moldy ceiling tiles, and other moldy materials.
Cleaning small areas of mold. Maintenance personnel may be able to clean up small areas of mold. Masks, gloves, and other personal protective equipment should be worn.
Conducting regular building inspections for signs of mold, moisture, and leaks. Report all water leaks and moisture problems immediately to your maintenance staff.
Cleaning and drying damp or wet building materials and furnishings within 24–48 hours after a leak or spill.
Keeping indoor relative humidity between 30% and 50%.
Ventilating bathrooms, locker rooms, and other moisture-generating sources to the outside.
Using air conditioners and dehumidifiers.
Removing carpet from areas with ongoing moisture concerns such as near drinking fountains and classroom sinks.

Schools can also participate in U.S. EPA’s IAQ Tools for Schools Program. This program provides guidance on good maintenance practices that help prevent mold growth and other Indoor Air Quality (IAQ) problems.

Resources for schools and early care and education centers:

EPA Factsheet: Mold in Schools

NIOSH Alert: Preventing Occupational Respiratory Disease from Exposures Caused by Dampness in Office Buildings, Schools, and Other Nonindustrial Buildings

Integrated Pest Management: A Toolkit for Early Care and Education

Health Professionals

Molds can grow on many different surfaces, if conditions (moisture, source of carbon) are present. It is not uncommon for patients to present with symptoms related to mold exposure. Although the popular media has described many diseases due to mold exposure, rigorous research from around the world indicates that molds can cause allergic symptoms, generalized irritant symptoms, pneumonitis (rare), and infections (rare) – see below.

Molds reproduce by making small spores that can enter the air and settle on wet surfaces and grow to the visible forms of mold commonly seen in homes and schools. As fungi grow, they can produce chemicals called “volatile organic compounds” that cause the musty, sour, moldy smell. Under some circumstances, some fungi can produce mycotoxin.

Call out box: As climate change leads to higher temperatures, increased sea levels, and increases in severe storms and flooding, there can be more instances of unwanted water leaking into homes. This creates opportunities for mold growth.

Damp indoor spaces alone may produce air contaminants and odors which may cause irritation of the eyes, nose, throat and skin, asthma or asthma-like symptoms. Some people may experience general discomfort such as headaches, fatigue, and problems concentrating due to poor indoor air quality.

Health concerns related to mold exposure:

Allergy (Sensitization): Those allergic to molds may have a stuffy or runny nose, throat dryness, wheezing, difficulty breathing, or dry cough. Parents with allergies, eczema, or asthma are more likely to have children who develop these allergies. (Int J Hyg Environ Health)
Irritant Symptoms: Some people may experience general irritant symptoms like itchy or teary eyes, headaches, nasal congestion fatigue, or generalized weakness, when exposed to mold or damp spaces, even if they do not have a mold allergy.
Pneumonitis: Rarely, some people may develop a reaction in the lungs (hypersensitivity pneumonitis), due to other types of antibodies to mold.
Local or Systemic Infections: Mold infections in the respiratory tract or other parts of the body is rare. It is more likely in those with immunodeficiency.

If you have a patient who is exposed to mold and you have questions about how to help them, please reach out to your regional Pediatric Environmental Health Specialty Unit (PEHSU) staff.

Download this page as a fact sheet, click here.

Resources for health providers:

Updated August 29, 2024

Funder Disclaimer

The Pediatric Environmental Health Specialty Units (PEHSU) are supported by cooperative agreement FAIN: NU61TS000356 with the Centers for Disease Control and Prevention/Agency for Toxic Substances and Disease Registry (CDC/ATSDR). The U.S. Environmental Protection Agency (EPA) also provides support through Inter-Agency Agreement 24TSS2400078 with CDC/ATSDR. The Public Health Institute supports the PEHSU as the National Program Office. The content on this website has not been formally disseminated by CDC/ATSDR or the EPA and should not be construed to represent any agency determination or policy. Use of trade names that may be mentioned is for identification only and does not imply endorsement by the CDC/ATSDR or EPA.

The information contained on this website should not be used as a substitute for the medical care and advice of your/your child’s primary care provider. There may be variations in treatment that your provider may recommend based on individual facts and circumstances.