Everything you every wanted to know about mold and then some

Mold on TextileI appeared on The Doctors Don’t Let it Happen to You episode talking about lead in purses and other vinyl items. My segment was part of an episode on ultimate survival , and featured home improvement guru and safety expert Eric Stomer. Part of the discussion (at least during the filming) focused on mold from Eric’s experiernces following Katrina, and some misinformation was given out to the audience about how to clean up mold. So, I thought I would post about mold and mold remediation. It also seems particularly relevant since we are experiencing quite a bit of rain in Southern California.

Mold isn’t a toxic chemical, so to speak, but mold growth does concern most of us and can negatively impact indoor air quality.  Molds can cause health problems.  News reports have linked mold exposure to a range of adverse health effects, from minor allergic reactions to brain damage.  Infants are more susceptible to adverse health effects from mold exposure than healthy adults.

Molds are microscopic fungi. They are found everywhere. You cannot not and should not try to keep your home mold free. Molds can grow on virtually any organic substance, as long as food, moisture and oxygen are present.  They play an essential role in nature, breaking down dead organic matter, such as fallen leaves.  Molds are also useful to us.  Penicillin, for example, is obtained from a specific type of mold.

Molds reproduce by releasing tiny spores.  These spores are invisible to the naked eye.  The spores float through the air, both indoors and outdoors.  They can also be transported by water and insects.  If the spores land on a surface with the right conditions, they can start growing and forming mold colonies.  Mold will grow if it has moisture and nutrients.  Many building materials, including wood and sheetrock, provide enough food to support mold growth.  In fact, even the dust settling on building materials or furniture can be a sufficient food source for molds, if moisture is also present.

The presence of mold in your home’s air is normal, but mold growth should not be permitted.  Mold can cause adverse health effects, most typically allergic type responses.  It is generally accepted that a greater risk of health effects is associated with a higher concentration of mold spore counts over background levels. 

Mold growth is usually indicated by signs of water damage or water intrusion, discoloration, a musty or earthy smell, or visible mold growth.   If you have problems with dampness or moisture, or have had a water leak or water damage, you may have the necessary conditions to facilitate mold growth. It is estimated that almost 50% of U.S. homes have dampness or mold problems. Since mold can trigger respiratory problems and asthma type responses, molds and dampness conditions may well contribute to the rising incidence of asthma in the US. It is estimated that 21%, or 1 out of 5, of current asthma cases in the U.S. are attributable to dampness and mold exposure.

Mold and the damp environments are linked to several adverse health effects.  The Institute of Medicine’s comprehensive review of available studies found sufficient evidence of an association between the presence of mold or other agents in damp indoor environments and asthma symptoms in sensitized persons, cough, hypersensitivity pneumonitis in susceptible persons, upper respiratory (nasal and throat) tract symptoms and wheeze.  A review of available studies found a thirty percent (30%) to fifty percent (50%) increase in a variety of respiratory and asthma-related outcomes associated with building dampness and the presence of mold growth.

Infants and children may be affected more severely and sooner than others by exposure to elevated concentrations of mold. A study found significant increased risk between lower respiratory illnesses in the first year including croup, pneumonia, bronchitis and bronchiolitis and high indoor air levels of certain molds.  The study concluded that the risk of lower respiratory illnesses in infancy was increased by exposure to high fungal levels. The Institute of Medicine’s review found the evidence suggestive of a link between mold or other agents in damp environments and lower respiratory illness in otherwise healthy children.  Exposure to molds in infants may increase the risk of developing asthma.  In fact, one study found that exposure to mold and dampness in homes doubles the risk of asthma development in children.

Allergic reactions to mold are relatively common.  About ten percent (10%) of the population is allergic to mold.  Allergic reactions to mold include sneezing, runny nose, red eyes, runny eyes, throat irritation, coughing, and skin rash.  More severe allergic reactions include allergic bronchopulmonary aspergillosis, allergic fungal sinusitis, and hypersensitivity pneumonitis.  Molds can also trigger asthma attacks in asthmatics with mold allergies. 

Molds can also evoke an irritant response.  Mold exposure can irritate the eyes, skin, nose, throat, and lungs in both people who are allergic to molds and in people who are not allergic to mold.  Most molds emit microbial volatile organic compounds (“mVOCs”).  These mVOCs are the cause of the musty or earthy odors encountered with some molds.  The mVOCs may cause irritant responses in some individuals.  Exposed persons have reported headaches, fatigue and nausea resulting from exposure to mVOCs.  Also, beta-1,3-glucan is a major structural component of almost all fungal cell wells.  Exposure to beta-1,3-glucan is associated with headaches, although researchers are investigating the contribution of beta-1,3-glucan to irritant responses to mold.

Molds can cause infection, especially in susceptible people, although this is an uncommon adverse health effect of mold exposure.  That being said, the US Centers for Disease Control and Prevention has found that nine percent (9%) of hospital-acquired infections are caused by molds. It is important to keep immuno-compromised or otherwise sensitive individuals out of environments with elevated mold concentrations.    

 Some molds release small molecular toxins, called mycotoxins, under certain conditions. Mycotoxins may cause toxic effects in people.  In news stories, the molds that are capable of producing mycotoxins are often referred to as “toxic molds.”  Despite media hype, considerable debate exists in the scientific and medical communities about claimed toxic effects resulting from mold exposure by inhalation.  Both toxic effects resulting from ingesting mycotoxin-contaminated foods are well known.  But toxic effects resulting from inhalation of molds and mycotoxins is unresolved despite several high profile lawsuits and news reports.  Claimed toxic effects include wheezing, difficulty breathing, nasal and sinus congestion, light sensitivity, blurry vision, watery or runny eyes, sore thrown, cough, skin irritation, chronic fatigue, immune suppression, aches and pains, loss of memory, constant headaches, mood changes, diarrhea, and brain damage.  The health effects associated with long term exposure to mycotoxins are unknown.    

Molds only produce mycotoxins under specific environmental conditions.  So, just because you have a mold known to produce mycotoxins does not mean that the mold is in fact releasing mycotoxins.  Molds known to release mycotoxins under certain circumstances include Stachybotrys chartarum, Aspergillus versicolor and several toxigenic species of Penicillium.  When mycotoxins are present, they occur in both living and dead mold spores, and may be present in materials that have become contaminated with molds. The infamous “toxic black mold” discussed in news stores is Stachybotrys chartarum.  “Stachy” is a greenish-black mold that can grow on materials that contain cellulose, such as drywall or sheetrock, ceiling tiles and wood.  Not all greenish-black molds are Stachybotrys chartarum. It does not grow on glass or ceramic tiles or cement, so the mold in your shower is most likely not Stachy. 

So what can you do? It is important to limit mold growth by preventing the germination and growth of mold.  Key to mold growth is water.  Moisture makes mold happy.  Without water, mold growth cannot start.  Water damage, excessive humidity, water leaks, condensation, flooding, and water intrusion are all conditions that can lead to conditions that foster mold growth.  If you see signs of water damage or water intrusion, such as bubbling paint around a window sill, or staining at a ceiling corner, signal conditions that are likely to lead to mold growth and you should take action. Molds can colonize quickly.  Some molds germinate in four to twelve hours.  Left undisturbed, a mold colony can start forming within 24 to 48 hours after a water leak or water intrusion problem.  A quick response to water intrusion, including fixing the source of the water, can stop mold from growing. 

Common sources of water are:

  • Water leaks into the structure, such as the roof, walls, or floors;
  • Flooding from the outside sources, such as storm water, overflowing streams, storm surge, etc.;
  • Flooding from the indoor sources, such as overflowing sinks, tubs or toilets; air conditioner drain pans; or sewer systems;
  • Indoor plumbing leaks;
  • Broken water pipes;
  • Condensation caused by indoor humidity that is too high or surfaces that are too cold;
  • Indoor plumbing leaks or broken water pipes;
  • Outdoor sprinkler spray hitting the walls or improper landscaping drainage that allows collection of moisture against the building;
  • Inadequate ventilation;
  • Humidifier use;
  • House plants, especially if overwatered; and
  • Moisture from our bodies, including sweat, wet hair on pillows, and respiration.

You can keep an eye and nose out for mold. Mold growth is signaled by discoloration, musty odors and visible mold growth. For example, discoloration around baseboards or on walls may indicate mold growth. A musty or earthy smell may indicate hidden mold growth. If you have a noticeable musty, moldy or earthy odor, you should check around for signs of water intrusion or water damage, or discoloration.  You can also try using a moisture meter to check the moisture content of building materials.  For example, if you smell a noticeable musty odor in one corner of a room, but don’t see any signs of discoloration or water damage, you can use a moisture meter to test the moisture content of the sheetrock or other building material.  An elevated reading may signal a water problem behind the walls, and possibly a mold problem. 

Visible mold growth pretty clearly indicates mold.  Visible mold growth may look fuzzy, cottony, velvety, powdery, or sooty, and may be green, white, black, red, orange, yellow, blue, or brown.  If you have visible mold growth, it is important to properly address it.  However, most regulatory agencies do not recommend testing to determine what type of mold it is.  All molds should be treated in the same manner in terms of health risks and removal.  The old adage applies – be safe, not sorry.  Of course, there may be specific reasons to determine what type of mold you have.  If you can’t tell whether it is mold or not, place a small drop of household bleach onto the suspected spot.  (Borrow some from a neighbor if you are a green mama that doesn’t use bleach.)  If the stain loses its color or disappears, it may be mold.  If it doesn’t, it probably isn’t mold.  Of course, try this only if it is safe to do so and wear appropriate personal protective equipment.

You will never eliminate all mold and mold spores from your home.  But, you can control indoor mold growth. 

Fix water problems.  Molds cannot grow without moisture.  So, don’t make the mold happy.  If you fix plumbing leaks and other sources of water intrusion as soon as possible, then you will eliminate the environment that molds need in order to thrive.

Control humidity.  In your home, keep humidity levels below sixty percent (60%) or even below fifty percent (50%) if you can.

Use your eyes and nose.  Your eyes and nose can tell you a lot.  That musty odor?  A good indication that mold is present.  Signs of water damage?  A good sign of a water problem that might lead to mold.  If you see or smell mold, fix the moisture source and then remediate the mold.

Ventilate.  Make sure you have and maintain adequate ventilation in “wet” rooms, such as the bathroom, the kitchen, the laundry room, the basement, and the mud room.  Again, controlling moisture and humidity is the key to preventing mold growth.  And an ounce of prevention is better than a pound of cure.

Remediate mold.  The appropriate remediation of mold will depend on the area covered by mold growth and the material(s) involved.  Check the resources for information about mold cleanup.

Be safe, not sorry.  All molds should be treated in the same manner in terms of health risks and removal. 

Dry completely.  If you do have a water intrusion problem, then make sure you fix the problem, remediate the mold, and dry out completely.  After fixing the water problem and remediating the mold, make sure you dry out water damaged areas completely.  Porous and semi-porous materials may need to be disposed of if they get moldy or wet.

Change filters.  If you use an air condition or dehumidifier, make sure you change the filter regularly in accordance with the manufacturer’s instructions.

Discard moldy items.  Don’t be a packrat!  If you have moldy books, magazines, newspapers, clothing or other items, then appropriately discard them. 

Limit houseplants.  Houseplants, especially if overwatered, can contribute to dampness.  Mold can grow in the soil and on the bark and leaves. 

When cleaning up mold, you need to wear appropriate protective gear, which means a mask to prevent breathing in mold or mold spores (use an N-95 respirator), wear gloves and wear goggles. Whether you should cleanup mold yourself or hire a professional depends on the size of the area affected and whether the water is sewage or not. If the area is less than 10 square feet (less than about 3 feet by 3 feet), you can probably handle it yourself. But, if the area was contaminated with black or sewage water, contact a professional. If you are ill, hire a professional.

Before you clean up a moldy area, it is critical that you have eliminated the moisture source. If you haven’t, then mold will just come back. Once you have taken care of the moisture source and are ready to tackle the mold growth area, seal off the rest of the house. Cover heat registers or ventilation ducts/grills. Then bag and discard all moldy items. You must discard all porous materials – sheetrock, carpeting, etc. Then, use soap or detergent to clean with hot water and scrub the area affected by mold (for solid surfaces). After cleaning, rinse clean and dry, perhaps using a wet/dry vacuum. Before tackling a mold clean up project, I encourage you to read the EPA’s A Brief Guide to Mold, Moisture & Your Home.

Let me address one myth about mold. Please keep in mind that it is a MYTH you should routinely use bleach during mold cleanup. As stated by the EPA, “‘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.” And, just killing the mold is not enough, which is what bleach does. You must remove the mold. Dead mold can still cause allergic reactions in some people so mold must be removed.

For very minor mold spots in your shower, you can try 2 tablespoons tea tree oil with about 10 ounces of water in a spray bottle.

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