WHAT IS MOLD?
Mold works non-stop to keep the planet going by breaking down organic matter — but we still don’t want it in the house, and for awfully good reason. Mold can trigger rashes, headaches, allergies and asthma attacks, according to the Mayo Clinic. Certain types of mold can even cause brain infections and sepsis (blood poisoning).
Whether it’s black, brown, green or pink, experts agree you should get rid of it. “Any visible mold should be removed, no matter what its color or species,” says Tiina Reponen, PhD, professor of environmental health at the University of Cincinnati. “In a healthy building, you don’t have visible mold.”
Like most fungi, molds grow best in damp conditions — think bathrooms and basements. If the spores find a moist surface to land on, they grow.
Although “toxic mold” is a misnomer, according to the Centers for Disease Control and Prevention (CDC), the agency notes some molds do produce toxic substances called mycotoxins.
Here, a color guide to molds commonly found in the house.
If you see green mold, it could be just about any type of unwelcome fungus. There are more than a hundred thousand types of mold — and thousands of species of green mold, according to Neil Kao, MD, an allergist in private practice in Greenville and Spartanburg, South Carolina. So what does the color green tell you? Not much.
Olive-green, brown, grey or black
These are common molds in the Cladosporium genus. Outdoors, they lurk on plant leaves. Indoors, they’re often found on walls and insulation and can grow on damp carpet, too. They are linked to skin, eye and sinus infections. Very rarely, they can cause brain infections (fungal meningitis), according to the CDC.
Blue, green, or white
These molds, also common, belong to the Penicillium genus. You’re right if you think that a type of this mold was used to make penicillin many years ago. It’s usually found on food and walls. If you’re sensitive to mold, you may develop an allergic reaction to it.
Yellow, green or black
These may be Aspergillus molds. According to the CDC, people breathe in these molds every day, usually without getting sick. But those with existing lung problems or weakened immune systems may develop aspergillosis. This illness might entail coughing, wheezing and sinus inflammation. But aspergillosis can also be more serious, especially in people with existing lung problems or weakened immune systems, causing cavities in the lungs or forming “fungus balls” (ick) in them. This is known as chronic pulmonary aspergillosis.
Black or grey
These could be Alternaria, which is most common as an outdoor mold, growing around damp, dusty areas, soil and plants. But it has made its way indoors. In one study, Alternaria was found in more than 90 percent of house dust samples. Exposure to it may boost the risk of asthma.
The pink “mold” often seen in the bathroom in the form of a slimy, pinkish discoloration on sinks and tubs is actually bacteria, not mold. Specifically, it’s Serratia marcescens. It thrives on soap and shampoo residues and is linked to urinary tract and respiratory infections.
Don’t obsess about getting infected from pink bathroom slime, though. S. marcescens usually enters the urethra through catheters or the lungs through respirators, according to an article on the website of Scientific American magazine. It has also contaminated soap solutions in hospitals and contact lens cases, infecting the cornea of some contact lens wearers.
This mold, of the Stachbotrys genus, is the infamous “black mold” that some news reports have linked to severe health problems, including memory loss and lung bleeding. It’s less common than the molds described above — and possibly less dangerous than news reports would have you believe. According to the CDC, Stachbotrys has not be proven to cause either memory loss or lung bleeding. It prefers to live on high-cellulose, low-nitrogen surfaces, which include drywall, gypsum board, paper, dust and lint that is regularly exposed to moisture. The CDC notes, “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.”
Mold, Moisture and Your Home
Molds are organisms that may be found indoors and outdoors. They are part of the natural environment and play an important role in the environment by breaking down and digesting organic material, such as dead leaves. Also called fungi or mildew, molds are neither plants nor animals; they are part of the kingdom Fungi.
• The key to mold control is moisture control.
• If mold is a problem in your home, you should clean up the mold promptly and fix the water problem.
• It is important to dry water-damaged areas and items within 24 to 48 hours to prevent mold growth.
Why is mold growing in my home?
Molds are part of the natural environment. 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. Molds reproduce by means of tiny spores; the spores are invisible to the naked eye and float through outdoor and indoor air. Mold may begin growing indoors when mold spores land on surfaces that are wet. There are many types of mold, and none of them will grow without water or moisture.
Can mold cause health problems?
Molds are usually not a problem indoors, unless mold spores land on a wet or damp spot and begin growing. Molds have the potential to cause health problems. Molds produce allergens (substances that can cause allergic reactions), irritants and, in some cases, potentially toxic substances (mycotoxins). 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. They 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. Research on mold and health effects is ongoing. This article provides a brief overview; it does 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.
How do I get rid of mold?
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. Mold spores will not grow if moisture is not present. Indoor mold growth can and should be prevented or controlled by controlling 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 recur.
Who should do the cleanup?
This depends on a number of factors. One consideration is the size of the mold problem. If the moldy area is less than about 10 square feet (less than roughly a 3-foot by 3-foot patch), in most cases, you can handle the job yourself, following the guidelines below.
• If there has been a lot of water damage, and/or mold growth covers more than 10 square feet, consult with an InterNACHI inspector.
• 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 of the EPA, the guidelines of the American Conference of Governmental Industrial Hygenists (ACGIH), or other guidelines from professional or government organizations.
• Do not run the HVAC system if you know or suspect that it is contaminated with mold. This could spread mold throughout the building.
• 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.
How do I know when the remediation or cleanup is finished?
You must have completely fixed the water or moisture problem before the cleanup or remediation can be considered finished, based on the following guidelines:
• You should have completed the mold removal. Visible mold and moldy odors should not be present. Please note that mold may cause staining and cosmetic damage.
• You should have revisited the site(s) shortly after cleanup, and it should show no signs of water damage or mold growth.
• People should have been able to occupy or re-occupy the area without health complaints or physical symptoms.
• Ultimately, this is a judgment call; there is no easy answer. If you have concerns or questions, be sure to ask your InterNACHI certified inspector during your next scheduled inspection.
Moisture and Mold Prevention and Control Tips
• Moisture control is the key to mold control, so when water leaks or spills occur indoors, ACT QUICKLY. If wet or damp materials or areas are dried within 24 to 48 hours after a leak or spill happens, in most cases, mold will not grow.
• Clean and repair roof gutters regularly.
• Make sure the ground slopes away from the building’s foundation so that water does not enter or collect around the foundation.
• Keep air-conditioning drip pans clean and the drain lines unobstructed and flowing properly.
• Keep indoor humidity low. If possible, keep indoor humidity below 60% relative humidity (ideally, between 30% to 50%). Relative humidity can be measured with a moisture or humidity meter, which is a small, inexpensive instrument (from $10 to $50) that is available at many hardware stores.
• If you see condensation or moisture collecting on windows, walls or pipes, ACT QUICKLY to dry the wet surface and reduce the moisture/water source. Condensation can be a sign of high humidity.
Actions that will help to reduce humidity:
• Vent appliances that produce moisture, such as clothes dryers, stoves, and kerosene heaters, to the outdoors, where possible. (Combustion appliances, such as stoves and kerosene heaters, produce water vapor and will increase the humidity unless vented to the outside.)
• Use air conditioners and/or de-humidifiers when needed.
• Run the bathroom fan or open the window when showering. Use exhaust fans or open windows whenever cooking, running the dishwasher or dishwashing, etc.
Actions that will help prevent condensation:
• Reduce the humidity (see above).
• Increase ventilation and air movement by opening doors and/or windows, when practical. Use fans as needed.
• Cover cold surfaces, such as cold water pipes, with insulation.
• Increase air temperature.
Testing or Sampling for Mold
Is sampling for mold needed? In most cases, if visible mold growth is present, sampling is unnecessary. Since no EPA or other federal limits have been set for mold or mold spores, sampling cannot be used to check a building’s compliance with federal mold standards. Surface sampling may be useful to determine if an area has been adequately cleaned or remediated. Indoor Air Quality Testing is vital in that it gives the inspector as well as the customer the actual conditions within the home at the time the testing is performed. It will identify species present, amounts, and comparative data to conditions outdoors. Sampling for mold should be conducted by professionals who have specific experience in designing mold sampling protocols, sampling methods, and interpreting results. Sample analysis should follow analytical methods recommended by the American Industrial Hygiene Association (AIHA), the American Conference of Governmental Industrial Hygienists (ACGIH), or other professional organizations.
Suspicion of Hidden Mold
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 residents are reporting health problems. Mold may be hidden in places such as the backside of dry wall, wallpaper or paneling, the top-side of ceiling tiles, or the underside of carpets and pads, etc. Other possible locations of hidden mold include areas inside walls around pipes (with leaking or condensing pipes), the surface of walls behind furniture (where condensation forms), inside ductwork, and in roof materials above ceiling tiles (due to roof leaks or insufficient insulation).
Investigating Hidden Mold Problems
Investigating hidden mold problems may be difficult and will require caution when the investigation involves disturbing potential sites of mold growth. For example, removal of wallpaper can lead to a massive release of spores if there is mold growing on the underside of the paper. If you believe that you may have a hidden mold problem, consider hiring an experienced professional.
Cleanup and Biocides
Biocides are substances that can destroy living organisms. The use of a chemical or biocide that kills organisms such as mold (chlorine bleach, for example) is not recommended as a routine practice during mold cleanup. There may be instances, however, when professional judgment may indicate its use (for example, when immune-compromised individuals are present). In most cases, it is not possible or desirable to sterilize an area; a background level of mold spores will remain, and these spores will not grow if the moisture problem has been resolved. If you choose to use disinfectants or biocides, always ventilate the area and exhaust the air to the outdoors. Never mix chlorine bleach with other cleaning solutions or detergents that contain ammonia because toxic fumes could be produced.
Please note: Dead mold may still cause allergic reactions in some people, so it is not enough to simply kill the mold; it must also be removed.
For the best protection against mold control moisture in your home or business and have it tested regularly by a certified technician.