Envirologix: Putting Science to the Test

Toxic Molds / Indoor Air Quality General Information


More Resources and Related Websites


Molds

Molds are part of the natural environment. There are many types of mold, and they can be found almost anywhere. Molds can grow on virtually any organic substance, as long as moisture and oxygen are present; none of them will grow without water or moisture. Outdoors, molds play a part in nature by breaking down dead organic matter such as fallen leaves and dead trees, but indoors, mold growth should be avoided. It is impossible to eliminate all mold and mold spores in the indoor environment. However, indoor mold growth can be controlled by managing moisture indoors. When excessive moisture accumulates in buildings or on building materials, mold growth will occur, particularly if the moisture problems remain undiscovered or unaddressed. There are molds that can grow on wood, paper, carpet, foods, and insulation.1,2

Mold Spores

Molds reproduce by making spores that usually cannot be seen without magnification. Mold spores are naturally present in both indoor and outdoor air. Some molds have spores that are easily disturbed, wafting into the air and settling repeatedly with each disturbance. Other molds have sticky spores that will cling to surfaces and are dislodged by brushing against them or by other direct contact. When mold spores land on a damp spot indoors, they may begin growing and digesting whatever they are growing on in order to survive. Molds gradually destroy the things they grow on. Spores may remain able to grow for years after they are produced. In addition, whether or not the spores are alive, the allergens in and on them may remain allergenic for years.2

Health Effects of Molds

Many types of molds exist. All molds have the potential to cause health effects. Molds can produce allergens (substances that can cause allergic reactions), or can trigger asthma attacks in people allergic to mold. Others are known to produce potent toxins (mycotoxins) and/or irritants. Potential health concerns are an important reason to prevent mold growth and to remediate/clean up any existing indoor mold growth.1,2

Inhaling or touching mold or mold spores may cause allergic reactions in sensitive individuals. Allergic responses include hay fever-type symptoms, such as sneezing, runny nose, red eyes, and skin rash (dermatitis). Allergic reactions to mold are common, and can be immediate or delayed. Molds can also cause asthma attacks in people with asthma who are allergic to mold. In addition, mold exposure can irritate the eyes, skin, nose, throat, and lungs of both mold-allergic and non-allergic people. Symptoms other than the allergic and irritant types are not commonly reported as a result of inhaling mold.1

Toxic Molds and Health Effects

Some molds, such as Aspergillus versicolor and Stachybotrys atra (chartarum), are known to produce potent toxins (mycotoxins) under certain circumstances. Although some mycotoxins are well known to affect humans and have been shown to be responsible for human health effects, for many mycotoxins, little information is available, and in some cases research is ongoing. For example, some strains of Stachybotrys atra can produce one or more potent toxins.2

Furthermore, a toxin-producing fungi (mold) does not necessarily produce mycotoxins under all growth conditions, with production being dependent on the substrate it is metabolizing (food source), temperature, water content and humidity. According to several studies, species of toxin-producing molds generally have a higher water requirement than common household molds. They tend to thrive only under conditions of chronic and severe water damage; for example, Stachybotrys typically only grows under continuously wet conditions.6

Much of the information on the human health effects of inhalation exposure to mycotoxins comes from studies done in the workplace and some case studies or case reports. (Information on ingestion exposure, for both humans and animals, is more abundant--a wide range of health effects has been reported following ingestion of moldy foods including liver damage, nervous system damage, and immunological effects.)2

Many symptoms and human health effects attributed to inhalation of mycotoxins have been reported including: mucous membrane irritation, skin rash, nausea, immune system suppression, acute or chronic liver damage, acute or chronic central nervous system damage, endocrine effects, and cancer.2

Currently, there are no standard numerical guidelines for assessing whether there is a mold contamination problem in an area. In the U.S., there are no EPA regulations or standards for airborne mold contaminants (USEPA, 2001). Various governmental and private organizations have, however, proposed guidance on the interpretation of fungal measures of environmental media in indoor environments (quantitative limits for fungal concentrations). These organizations include the ACGIH, the U.S. Occupational Safety & Health Organization (OSHA), the American Industrial Hygiene Association (AIHA), the Canada Mortgage and Housing Corporation (CMHC), the Commission of the European Communities (CEC), and the World Health Organization (WHO), as well as numerous smaller and/or local organizations like the New York Department of Health.6

Other factors in addition to indoor spore counts may also be considered. For example, the University of Minnesota, Department of Environmental Health and Safety recommends consideration of several factors in addition to total spore counts when attempting to assess the severity of a mold contamination problem, including: the number of fungi indoors relative to outdoors, whether the fungi are allergenic or toxic, if the area is likely to be disturbed, whether there is or was a source of water or high relative humidity, if people are occupying the contaminated area or have contact with air from the location, and whether there are immune compromised individuals or individuals with elevated sensitivity to molds in the area (University of Minnesota, 1996).6

Specific effects depend on:
- an individual's sensitivity or allergies;
- the type, duration, and amount of mold exposure; and
- the general health and age of the affected individual.

New York City's Department of Health recommends that individuals with persistent health problems that appear to be related to fungi or other bioaerosol exposure should see their physicians for a referral to practitioners who are trained in occupational/environmental medicine or related specialties and are knowledgeable about these types of exposures. Infants (less than 12 months old) who are experiencing non-traumatic nosebleeds or are residing in dwellings with damp or moldy conditions and are experiencing breathing difficulties should receive a medical evaluation to screen for alveolar hemorrhage. Following this evaluation, infants who are suspected of having alveolar hemorrhaging should be referred to a pediatric pulmonologist. Infants diagnosed with pulmonary hemosiderosis and/or pulmonary hemorrhaging should not be returned to dwellings until remediation and air testing are completed.5

More studies are needed to get a clear picture of the health effects related to most mycotoxins. However, it is clearly prudent to avoid exposure to molds and mycotoxins.2

Research on mold, mycotoxins and health effects is ongoing. EPA brochures, and certainly this summary provide only a brief overview; they do not describe all potential health effects related to mold exposure. For more detailed information consult a health professional. You may also wish to consult your state or local health department.1,e

Mold Sources

Since mold requires water to grow, it is important to prevent moisture problems in buildings. Moisture problems can have many causes, including uncontrolled humidity. Some moisture problems in buildings have been linked to changes in building construction practices during the 1970s, 80s, and 90s. Some of these changes have resulted in buildings that are tightly sealed, but may lack adequate ventilation, potentially leading to moisture buildup. Building materials, such as drywall and exterior foam insulation, may not allow moisture to escape easily. Moisture problems may include roof leaks; poorly caulked window, door and vent openings; plumbing leaks; poorly grouted tiles, sink, tub and shower enclosures; improperly vented bathroom fans and clothes dryers; landscaping or gutters that direct water into or under the building; uncovered dirt crawl spaces; unvented basements and unvented combustion appliances; and stagnant water in appliances (e.g., dehumidifiers, dishwashers, refrigerator drip pans, and condensing coils and drip pans in HVAC [heating, ventilation and air conditioning] units). Delayed maintenance or insufficient maintenance are also associated with moisture problems in schools and large buildings. Moisture problems in portable classrooms and other temporary structures have frequently been associated with mold issues.2,6,e

Identifying Mold

Visual inspection for dampness, observable mold growth, and detection of musty odors, often obtained from occupant questionnaires, are the most frequently used methods to assess the potential for indoor mold exposure. Visual observation of mold growth, however, is limited by the fact that fungi are microscopic and their presence is often not apparent until growth is extensive. 6 Visible mold may be found where walls and ceilings are discolored or where there is a smell of mold (musty earth to foul stench).

Different molds have different colors, including black (many), greenish-black (Stachybotrys and others), grey-brown, grey-green, pink and, in the case of Aspergillus niger, white or yellow covered with dense black spores. They may be dry or slimy, depending on room conditions and the mold's stage of growth. They may be invisible, pin-head size, or large matted areas covering entire walls.

Hidden Mold

In some cases, indoor mold growth may not be obvious. It is possible that mold may be growing on hidden surfaces, such as the back side of drywall, wallpaper, or paneling, the top of ceiling tiles, the underside of carpets and pads, behind tub enclosures, etc. Possible locations of hidden mold can include pipe chases and utility tunnels (with leaking or condensing pipes), walls behind furniture (where condensation forms), condensate drain pans inside air handling units, porous thermal or acoustic liners inside ductwork, or roof materials above ceiling tiles (due to roof leaks or insufficient insulation). Some building materials, such as dry wall with vinyl wallpaper over it or wood paneling, may act as vapor barriers, trapping moisture underneath their surfaces and thereby providing a moist environment where mold can grow. You may suspect hidden mold if a building smells moldy, but you cannot see the source, or if you know there has been water damage and building occupants are reporting health problems. Investigating hidden mold problems may be difficult and will require caution when the investigation involves disturbing potential sites of mold growth?make sure to use PPE (personal protective equipment, such as gloves, goggles or glasses, and a facial respirator). For example, removal of wallpaper can lead to a massive release of spores from mold growing on the underside of the paper. If you believe that you may have a hidden mold problem, you may want to consider hiring an experienced professional. If you discover hidden mold, you should revise your remediation plan to account for the total area affected by mold growth.2

Safety tips while investigating and evaluating mold and moisture problems2
- Do not touch mold or moldy items with bare hands.
- Do not get mold or mold spores in your eyes.
- Do not breathe in mold or mold spores.
- Consult Table 2 and text (both in the EPA's guide "Mold Remediation in Schools and Commercial Buildings) for Personal Protective Equipment (PPE) and containment guidelines.
- Consider using PPE when disturbing mold. The minimum PPE is an N-95 respirator (available in many hardware stores), gloves, and eye protection.

Sampling for Mold

Until EnviroLogix introduced its tests for on-site detection of Stachybotrys and Aspergillus niger, there were no practical means of rapidly determining whether these molds were present in indoor samples. Characterizing any suspected mold contamination required culturing, microscopy, ELISAs6 (quantitative immunoassays) or PCR (DNA) analysis, all of which are time-consuming, more expensive, and require off-site handling and analysis.

In March 2003, EnviroLogix announced its QuickTox™ Kit for Stachybotrys and Aspergillus niger, an on-site, fast, reliable and easy method for detecting Stachybotrys chartarum, Stachybotrys sp. and Aspergillus niger mold spores in dust and air handling units, and on environmental samples such as drywall, ceiling tiles, and carpets. The QuickTox tests provide easily understood "yes/no" results on-site within 2-5 minutes. No additional lab analysis is required; there are no additional fees. Used by indoor air quality and environmental professionals, these tests are available in 50-test and 20-test kits ( ES 103 PRO 50 and ES 103 PRO 20).

In June 2003, EnviroLogix introduced the QuickTox™ Home Test for Toxic Mold, using the same technology but packaged in a convenient two-test format for homeowners. These kits detect both Stachybotrys and Aspergillus niger from a swabbed surface within 2-5 minutes, on-site. The kit format includes everything necessary for testing two different areas for mold: swabs, test strips, cups and extraction solution. ( ES 103 HOT)

This kit can be purchased by calling 1-866-860-MOLD (6653).

The newest QuickTox Kit for Aspergillus and Penicillium gives indoor air quality and environmental professionals equally rapid and accurate results for on-site identification of these troublesome molds. ( ES 110 PRO 20)



Getting Rid of Mold

While there are no standard numerical guidelines for assessing whether there is a mold contamination problem in an area6, and there is ongoing debate about methods of quantification and establishing causal links between molds, mycotoxins and specific illnesses or other health problems, there is broad agreement that molds should be removed from indoor environments.

As the State of California concluded in its report on Stachybotrys chartarum, "Exposure to high levels of Stachybotrys chartarum and other mold spores may cause problems in some individuals. Therefore any fungal growth should be cleaned off or removed as rapidly as possible to maintain a healthy indoor environment." 7 New York City's Department of Public Health concludes: "Building materials supporting fungal growth must be remediated as rapidly as possible in order to ensure a healthy environment. Repair of the defects that led to water accumulation (or elevated humidity) should be conducted in conjunction with or prior to fungal remediation. Specific methods of assessing and remediating fungal contamination should be based on the extent of visible contamination and underlying damage. The simplest and most expedient remediation that is reasonable, and properly and safely removes fungal contamination, should be used."5

It is impossible to get rid of all mold and mold spores indoors; some mold spores will be found floating through the air and in house dust. The mold spores will not grow if moisture is not present. Indoor mold growth can and should be prevented or controlled by managing moisture indoors. If there is mold growth in your home, you must clean up the mold and fix the water problem. If you clean up the mold, but don't fix the water problem, then most likely the mold problem will come back.1

The US EPA, New York City Department of Health, California Department of Health Services, Federal Emergency Management Agency and other agencies have extensive and very readable pamphlets available at no cost, in print or over the internet, for deciding how to handle cleanup and remediation. Links to a number of these publications can be accessed below.

In general, they recommend various levels of cleanup and containment depending on the size of the infestation or contamination. In their views, smaller areas of 10 square feet or less can be cleaned up by individuals, but larger areas, particularly those heavily infested or with difficult access to the mold sources, should be handled by experienced professionals. Persons with histories of strong allergic reactions, asthma, or immune-suppressed systems should not undertake cleanup themselves.

New York's guidelines identify five different levels of abatement. The size of the area impacted by fungal contamination primarily determines the type of remediation. The sizing levels below are based on professional judgment and practicality; currently there is not adequate data to relate the extent of contamination to frequency or severity of health effects. The goal of remediation is to remove or clean contaminated materials in a way that prevents the emission of fungi and dust contaminated with fungi from leaving a work area and entering an occupied or non-abatement area, while protecting the health of workers performing the abatement.

As the media are now reporting daily, countless contractors and consultants are taking advantage of concerns over mold to urge extensive and costly remediation. EPA urges that:

- If you choose to hire a contractor (or other professional service provider) to do the cleanup, make sure the contractor has experience cleaning up mold. Check references and ask the contractor to follow the recommendations in EPA's Mold Remediation in Schools and Commercial Buildings, the guidelines of the American Conference of Governmental Industrial Hygienists (ACGIH), or other guidelines from professional or government organizations.

- If you suspect that the heating/ventilation/air conditioning (HVAC) system may be contaminated with mold (it is part of an identified moisture problem, for instance, or there is mold near the intake to the system), consult EPA's guide Should You Have the Air Ducts in Your Home Cleaned? before taking further action. Do not run the HVAC system if you know or suspect that it is contaminated with mold - it could spread mold throughout the building. This guide is available at www.epa.gov/iaq/pubs/airduct.html, or by calling (800) 438-4318 for a free copy.

- If the water and/or mold damage was caused by sewage or other contaminated water, then call in a professional who has experience cleaning and fixing buildings damaged by contaminated water.

- If you have health concerns, consult a health professional before starting cleanup.



References

1 "A Brief Guide to Mold, Moisture, and Your Home" USEPA (EPA 402-K-02-003)
2 "Mold Remediation in Schools and Commercial Buildings" USEPA (EPA 402-K-01-001)
3 "Dealing with Mold & Mildew in Your Flood Damaged Home" US FEMA (Federal Emergency Management Agency)
4 "Aspergillosis Technical Information" US CDC Division of Bacterial and Mycotic Diseases
5 "Guidelines of Assessment and Remediation of Fungi in Indoor Environments" New York City Department of Mental Health and Mental Hygiene
6 "Healthy Homes Issues: Mold" U.S. Department of Housing and Urban Development, Healthy Homes Initiative
7 "Stachybotrys chartarum: A Mold that May be Found in Water-Damaged Homes" California Department of Health Services, November 2000.
e EnviroLogix text, linking or expanding cited resources.

More Resources and Related Websites