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.

About the Program

Program in Brief

Cleanup and Remediation
Fact sheets from CDC and EPA on mold cleanup, removal and remediation.

General Information
Basic facts about molds, exposure, adverse health effects, and prevention.

Related Issues
Information and links on mold-related issues, such as hurricane-related damage.

Resources
Useful documents and FAQs about mold from various federal and state agency resources.

Quick Links

• Air Pollution & Respiratory Health
• Air Quality, Fires, and Volcanic Eruptions
• Asthma
• Carbon Monoxide Poisoning
• What's New
• National Center for Environmental Health (NCEH)

Links to non-federal organizations are provided solely as a service to our users. These links do not constitute an endorsement of these organizations or their programs by CDC or the federal government, and none should be inferred. CDC is not responsible for the content of the individual organization Web pages found at these links.

Key resources

Damp Indoor Spaces and Health [PDF, 608 KB]
Executive Summary of Institute of Medicine report. Summary [DOC, 35 KB] Also see the Full Report.

Mold Cleanup Fact Sheet [PDF, 114 KB]
After a flood, mold will grow in your house.

WHO Guidelines for Indoor Air Quality: Dampness and Mould [PDF, 2.5 MB]
World Health Organization review of scientific evidence on health problems associated with building moisture and biological agents.

(SMH Note: CDC is working on a summary of these WHO Guidelines, above)



Contact Us:

• Centers for Disease Control and Prevention
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• Page last reviewed: June 1, 2009
• Page last updated: June 1, 2009
• Content source: National Center for Environmental Health

2. From: http://www.cdc.gov/mold/dampness_facts.htm

Facts about Mold and Dampness

On this Page

• Mold and Your Health
• Mold and Your Home
• You Can Control Mold
• Mold Prevention Tips

Español

There is always some mold everywhere - in the air and on many surfaces. Molds have been on the Earth for millions of years. Mold grows where there is moisture.

Mold and Your Health

Exposure to damp and moldy environments may cause a variety of health effects, or none at all. Some people are sensitive to molds. For these people, molds can cause nasal stuffiness, throat irritation, coughing or wheezing, eye irritation, or, in some cases, skin irritation. People with mold allergies may have more severe reactions. Immune-compromised people and people with chronic lung illnesses, such as obstructive lung disease, may get serious infections in their lungs when they are exposed to mold. These people should stay away from areas that are likely to have mold, such as compost piles, cut grass, and wooded areas.

In 2004 the Institute of Medicine (IOM) found there was sufficient evidence to link indoor exposure to mold with upper respiratory tract symptoms, cough, and wheeze in otherwise healthy people; with asthma symptoms in people with asthma; and with hypersensitivity pneumonitis in individuals susceptible to that immune-mediated condition. The IOM also found limited or suggestive evidence linking indoor mold exposure and respiratory illness in otherwise healthy children.

In addition, in 2004 the IOM found sufficient evidence to link exposure to damp indoor environments in general to upper respiratory tract symptoms, cough, and wheeze in otherwise healthy people and with asthma symptoms in people with asthma. The IOM also found limited or suggestive evidence linking exposure to damp indoor environments in general to shortness of breath, to respiratory illness in otherwise healthy children and to potential development of asthma in susceptible individuals.

A link between other adverse health effects, such as acute idiopathic pulmonary hemorrhage among infants, memory loss, or lethargy, and molds, including the mold Stachybotrys chartarum (Stachybotrys atra), has not been proven. Further studies are needed to find out what causes acute idiopathic hemorrhage and other adverse health effects.

3. From http://www.cdc.gov/mold/basics.htm

• Mold

General Information

Basic Facts about Mold [Español]
FAQs about molds, where they are found, how to eliminate them, and how they can affect people's health... more

• Facts about Aspergillosis
  Aspergillosis is a pulmonary infection, usually with fever, cough, and chest pain, caused by inhalation of mold spores... more
• Facts about Stachybotrys chartarum and Other Molds
  FAQs about different types of toxic molds, how they grow, and what can be done to protect your health ...more

"Damp Indoor Spaces and Health": Summary of 2004 Institute of Medicine Report [DOC, 35 KB]

Facts About Mold and Dampness [Español]
Mold grows indoors and outdoors wherever there is a lot of moisture, but you can control mold growth. more

Public Service Announcements
Public Service Announcements (videos and audios) about mold and how you can get rid of it.

• Mold Removal After a Disaster (television)
• Preventing Mold After a Disaster (radio) [Español]

(SMH note: we are asking for, in this section:

Further info from the IOM findings such as the warning that dampness is a public health threat

at least one or two accurate paragraphs to be written by CDC using direct quotes from mold, dampness and health findings by WHO, for example:

• The [WHO] review concludes that the most important effects are increased prevalences of respiratory symptoms, allergies and asthma as well as perturbation of the immunological system. (WHO Abstract, p. IV)
• Indoor air pollution – such as from dampness and mould, chemicals and other biological agents – is a major cause of morbidity and mortality worldwide. (WHO Abstract,p. XI)
• studies after 2003 show indoor dampness is (now) associated with development of new asthma
• Exposure to microbial contaminants is clinically associated with respiratory symptoms, allergies, asthma and immunological reactions. (WHO, Executive Summary, p. XII)
• There is clinical evidence that exposure to mould and other dampness-related microbial agents increases the risks of rare conditions, such as hypersensitivity pneumonitis, allergic alveolitis, chronic rhinosinusitis and allergic fungal sinusitis.
• Toxicological evidence obtained in vivo and in vitro supports these findings showing the occurrence of diverse inflammatory and toxic responses after exposure to microorganisms isolated from damp buildings, including their spores, metabolites and components.
• While groups such as atopic and allergic people are particularly susceptible to biological and chemical agents in damp indoor environments, adverse health effects have also been found in nonatopic populations.
• Persistent dampness and microbial growth on interior surfaces and in building structures should be avoided or minimized, as they may lead to adverse health effects.
• The overall evidence shows that house dampness is consistently associated with a wide range of respiratory health effects, most notably asthma, wheeze, cough, respiratory infections and upper respiratory tract symptoms. (p.70)
• dampness-related exposure is not only associated with, but may cause, asthma in infants and children.(p.72)

The above page numbers from WHO Guidelines to Indoor Air Quality: Dampness and Mould, http://www.euro.who.int/document/E92645.pdf

Summary of 2004 IOM Report: Damp Indoor Spaces and Health

(SMH Note: this entire document is new)

In 2003, the Centers for Disease Control and Prevention (CDC) asked the Institute of Medicine (IOM) to review all scientific studies to date about the possible connection between damp or moldy indoor places and problems with breathing or allergies. In its report Damp Indoor Spaces and Health, released in May 2004, IOM concluded the following:

• The growth of some bacteria (germs) and molds is one effect of indoor dampness. Damp indoor environments also benefit house dust mites. Standing water supports cockroach and rodent (rats and mice) problems as well. Too much moisture may cause toxic chemicals to be released from building materials and furnishings.

• Mold spores are found in indoor air and on surfaces and materials. No indoor space is free of them.(SMH note: this was not a major conclusion of IOM related to damp indoor spaces and health, and misleads in this summary, minimizing their findings.)

• Damp indoor spaces may also allow the growth of bacteria that can cause negative health effects. (SMH note: this implies IOM focused on bacterial threats to health, while none for mold are mentioned. This is an inaccurate representation of the IOM findings.)
• Controlling moisture is the main way to control indoor mold growth.

After reviewing the studies, IOM determined that potential health effects of exposure to either damp indoor environments or to mold indoors could be classified in one of three ways: 1) “sufficient evidence of an association” between the exposure and the health effect, 2) “limited or suggestive evidence” of an association, or 3) “inadequate or insufficient information” to determine if an association exists. The following tables summarize these findings. The full report can be read here.

Table 1. Evidence supporting an association between exposure to damp indoor environments and certain health effects.

Table 2. Evidence supporting an association between the presence of mold (otherwise unspecified) indoors and certain health effects.

(SMH note: It is our opinion that this section, below, is entirely outdated and most statements are inaccurate. Newer paragraphs cite some of the IOM (2004) findings. WHO (2009) findings need to be incorporated, so that the public is adequately warned about the impact of indoor molds and dampness on health. Further, the EPA has developed a home ERMI test that may be self administered in order to detect hidden molds. This is further described on our Resources - Self-testing section. )

5. From http://www.cdc.gov/mold/basics.htm

• Mold
• General Information

Facts about Stachybotrys chartarum and Other Molds

• I heard about "toxic molds" that grow in homes and other buildings. Should I be concerned about a serious health risk to me and my family?
• How common is mold, including Stachybotrys chartarum (also known by its synonym Stachybotrys atra) in buildings?
• How do molds get in the indoor environment and how do they grow?
• What is Stachybotrys chartarum (Stachybotrys atra)?
• Are there any circumstances where people should vacate a home or other building because of mold?
• Who are the people who are most at risk for health problems associated with exposure to mold?
• How do you know if you have a mold problem?
• Does Stachybotrys chartarum (Stachybotrys atra) cause acute idiopathic pulmonary hemorrhage among infants?
• What if my child has acute idiopathic pulmonary hemorrhage?
• What are the potential health effects of mold in buildings and homes?
• How do you get the molds out of buildings, including homes, schools, and places of employment?
• What should people to do if they determine they have Stachybotrys chartarum (Stachybotrys atra) in their buildings or homes?
• How do you keep mold out of buildings and homes?
• I found mold growing in my home; how do I test the mold?
• A qualified environmental lab took samples of the mold in my home and gave me the results. Can CDC interpret these results?
• Summary

I heard about "toxic molds" that grow in homes and other buildings. Should I be concerned about a serious health risk to me and my family?

The term "toxic mold" is not accurate. While certain molds are toxigenic, meaning they can produce toxins (specifically mycotoxins), the molds themselves are not toxic, or poisonous. Hazards presented by molds that may produce mycotoxins should be considered the same as other common molds which can grow in your house. There is always a little mold everywhere - in the air and on many surfaces. There are very few reports that toxigenic molds found inside homes can cause unique or rare health conditions such as pulmonary hemorrhage or memory loss. These case reports are rare, and a causal link between the presence of the toxigenic mold and these conditions has not been proven.

In 2004 the Institute of Medicine (IOM) found there was sufficient evidence to link indoor exposure to mold with upper respiratory tract symptoms, cough, and wheeze in otherwise healthy people; with asthma symptoms in people with asthma; and with hypersensitivity pneumonitis in individuals susceptible to that immune-mediated condition. The IOM also found limited or suggestive evidence linking indoor mold exposure and respiratory illness in otherwise healthy children.

A common-sense approach should be used for any mold contamination existing inside buildings and homes. The common health concerns from molds include hay fever-like allergic symptoms. Certain individuals with chronic respiratory disease (chronic obstructive pulmonary disorder, asthma) may experience difficulty breathing. Individuals with immune suppression may be at increased risk for infection from molds. If you or your family members have these conditions, a qualified medical clinician should be consulted for diagnosis and treatment. For the most part, one should take routine measures to prevent mold growth in the home.

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How common is mold, including Stachybotrys chartarum (also known by its synonym Stachybotrys atra) in buildings?

Molds are very common in buildings and homes and will grow anywhere indoors where there is moisture. The most common indoor molds are Cladosporium, Penicillium, Aspergillus, and Alternaria. We do not have precise information about how often Stachybotrys chartarum is found in buildings and homes. While it is less common than other mold species, it is not rare.

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How do molds get in the indoor environment and how do they grow?

Mold spores occur in the indoor and outdoor environments. Mold spores may enter your house from the outside through open doorways, windows, and heating, ventilation, and air conditioning systems with outdoor air intakes. Spores in the air outside also attach themselves to people and animals, making clothing, shoes, bags, and pets convenient vehicles for carrying mold indoors.

When mold spores drop on places where there is excessive moisture, such as where leakage may have occurred in roofs, pipes, walls, plant pots, or where there has been flooding, they will grow. Many building materials provide suitable nutrients that encourage mold to grow. Wet cellulose materials, including paper and paper products, cardboard, ceiling tiles, wood, and wood products, are particularly conducive for the growth of some molds. Other materials such as dust, paints, wallpaper, insulation materials, drywall, carpet, fabric, and upholstery, commonly support mold growth.

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What is Stachybotrys chartarum (Stachybotrys atra)?

Stachybotrys chartarum (also known by its synonym Stachybotrys atra) is a greenish-black mold. It can grow on material with a high cellulose and low nitrogen content, such as fiberboard, gypsum board, paper, dust, and lint. Growth occurs when there is moisture from water damage, excessive humidity, water leaks, condensation, water infiltration, or flooding. Constant moisture is required for its growth. It is not necessary, however, to determine what type of mold you may have. All molds should be treated the same with respect to potential health risks and removal.

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Are there any circumstances where people should vacate a home or other building because of mold?

These decisions have to be made individually. If you believe you are ill because of exposure to mold in a building, you should consult your physician to determine the appropriate action to take.

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Who are the people who are most at risk for health problems associated with exposure to mold?

People with allergies may be more sensitive to molds. People with immune suppression or underlying lung disease are more susceptible to fungal infections.

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How do you know if you have a mold problem?

Large mold infestations can usually be seen or smelled.

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Does Stachybotrys chartarum (Stachybotrys atra) cause acute idiopathic pulmonary hemorrhage among infants?

To date, a possible association between acute idiopathic pulmonary hemorrhage among infants and Stachybotrys chartarum (Stachybotrys atra) has not been proved. Further studies are needed to determine what causes acute idiopathic hemorrhage.

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What if my child has acute idiopathic pulmonary hemorrhage?

Parents should ensure that their children get proper medical treatment.

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What are the potential health effects of mold in buildings and homes?

Mold exposure does not always present a health problem indoors. However some people are sensitive to molds. These people may experience symptoms such as nasal stuffiness, eye irritation, wheezing, or skin irritation when exposed to molds. Some people may have more severe reactions to molds. Severe reactions may occur among workers exposed to large amounts of molds in occupational settings, such as farmers working around moldy hay. Severe reactions may include fever and shortness of breath. Immunocompromised persons and persons with chronic lung diseases like COPD are at increased risk for opportunistic infections and may develop fungal infections in their lungs.

In 2004 the Institute of Medicine (IOM) found there was sufficient evidence to link indoor exposure to mold with upper respiratory tract symptoms, cough, and wheeze in otherwise healthy people; with asthma symptoms in people with asthma; and with hypersensitivity pneumonitis in individuals susceptible to that immune-mediated condition. The IOM also found limited or suggestive evidence linking indoor mold exposure and respiratory illness in otherwise healthy children.

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How do you get the molds out of buildings, including homes, schools, and places of employment?

In most cases mold can be removed from hard surfaces by a thorough cleaning with commercial products, soap and water, or a bleach solution of no more than 1 cup of bleach in 1 gallon of water. Absorbent or porous materials like ceiling tiles, drywall, and carpet may have to be thrown away if they become moldy. If you have an extensive amount of mold and you do not think you can manage the cleanup on your own, you may want to contact a professional who has experience in cleaning mold in buildings and homes. It is important to properly clean and dry the area as you can still have an allergic reaction to parts of the dead mold and mold contamination may recur if there is still a source of moisture.

If you choose to use bleach to clean up mold:

• Never mix bleach with ammonia or other household cleaners. Mixing bleach with ammonia or other cleaning products will produce dangerous, toxic fumes.
• Open windows and doors to provide fresh air.
• Wear non-porous gloves and protective eye wear.
• If the area to be cleaned is more than 10 square feet, consult the U.S. Environmental Protection Agency (EPA) guide titled Mold Remediation in Schools and Commercial Buildings. Although focused on schools and commercial buildings, this document also applies to other building types. You can get it free by calling the EPA Indoor Air Quality Information Clearinghouse at (800) 438-4318, or by going to the EPA web site at http://www.epa.gov/mold/mold_remediation.html.
• Always follow the manufacturer’s instructions when using bleach or any other cleaning product.

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What should people to do if they determine they have Stachybotrys chartarum (Stachybotrys atra) in their buildings or homes?

Mold growing in homes and buildings, whether it is Stachybotrys chartarum (Stachybotrys atra) or other molds, indicates that there is a problem with water or moisture. This is the first problem that needs to be addressed. Mold growth can be removed from hard surfaces with commercial products, soap and water, or a bleach solution of no more than 1 cup of bleach in 1 gallon of water. Mold in or under carpets typically requires that the carpets be removed. Once mold starts to grow in insulation or wallboard, the only way to deal with the problem is by removal and replacement. We do not believe that one needs to take any different precautions with Stachybotrys chartarum (Stachybotrys atra), than with other molds. In areas where flooding has occurred, prompt drying out of materials and cleaning of walls and other flood-damaged items with commercial products, soap and water, or a bleach solution of no more than 1 cup of bleach in 1 gallon of water is necessary to prevent mold growth. Never mix bleach with ammonia or other household cleaners. If a home has been flooded, it also may be contaminated with sewage. (See: After a Hurricane or Flood: Cleanup of Flood Water) Moldy items should be removed from living areas.

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How do you keep mold out of buildings and homes?

As part of routine building maintenance, buildings should be inspected for evidence of water damage and visible mold. The conditions causing mold (such as water leaks, condensation, infiltration, or flooding) should be corrected to prevent mold from growing.

Specific Recommendations:

• Keep humidity level in house between 40% and 60%.
• Use air conditioner or a dehumidifier during humid months.
• Be sure the home has adequate ventilation, including exhaust fans in kitchen and bathrooms.
• Use mold inhibitors which can be added to paints.
• Clean bathroom with mold-killing products.
• Do not carpet bathrooms.
• Remove and replace flooded carpets.

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I found mold growing in my home; how do I test the mold?

Generally, it is not necessary to identify the species of mold growing in a residence, and CDC does not recommend routine sampling for molds. Current evidence indicates that allergies are the type of diseases most often associated with molds. Since the reaction of individuals can vary greatly either because of the person’s susceptibility or type and amount of mold present, sampling and culturing are not reliable in determining your health risk. If you are susceptible to mold and mold is seen or smelled, there is a potential health risk; therefore, no matter what type of mold is present, you should arrange for its removal. Furthermore, reliable sampling for mold can be expensive, and standards for judging what is and what is not an acceptable or tolerable quantity of mold have not been established.

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A qualified environmental lab took samples of the mold in my home and gave me the results. Can CDC interpret these results?

Standards for judging what is an acceptable, tolerable or normal quantity of mold have not been established. If you do decide to pay for environmental sampling for molds, before the work starts, you should ask the consultants who will do the work to establish criteria for interpreting the test results. They should tell you in advance what they will do or what recommendations they will make based on the sampling results. The results of samples taken in your unique situation cannot be interpreted without physical inspection of the contaminated area or without considering the building’s characteristics and the factors that led to the present condition.

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Summary

In summary, Stachybotrys chartarum (Stachybotrys atra) and other molds may cause health symptoms that are nonspecific. At present there is no test that proves an association between Stachybotrys chartarum (Stachybotrys atra) and particular health symptoms. Individuals with persistent symptoms should see their physician. However, if Stachybotrys chartarum (Stachybotrys atra) or other molds are found in a building, prudent practice recommends that they be removed.

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• Links to non-federal organizations are provided solely as a service to our users. These links do not constitute an endorsement of these organizations or their programs by CDC or the federal government, and none should be inferred. CDC is not responsible for the content of the individual organization Web pages found at these links.

Contact Us:

• Centers for Disease Control and Prevention
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  Atlanta, GA 30333
• 800-CDC-INFO
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• Page last reviewed: July 13, 2009
• Page last updated: December 1, 2009
• Content source: National Center for Environmental Health
• 
  

Dr. Thomas Frieden

Director, Centers for Disease Control and Prevention

Public Health Service

1600 Clifton Rd, Mailstop D-14

Atlanta, GA 30333-9946

White House Contact info

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FAX: 202-456-2461

 President Barack Obama

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Susan Brinchman, Director

The Center for School Mold Help

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