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Fungi (or Mold) Facts


Fungi, more commonly known as "mold", are the big newsmakers these days. The general public discusses its potential health effects and businesses are concerned about the economic impact.

There are several guidance documents available, but there is no accepted national standard. Validated methods to measure contamination are just beginning. In some instances, building owners tend to ignore or dismiss potentially serious problems. In other instances, building occupants or public officials can react with excessive alarm to perceived potential threats, complicating the scientific component of the evaluation and making risk communication very difficult.

The following information provides a basic understanding of the fungi in our lives. In this document, the words fungi and mold are used interchangeably.

Basic Mold Information

Molds are microscopic fungi that live on plant or animal matter. They can be found all year round both indoors and outdoors. There are thousands of species of mold and they can be any color. Often, mold can be detected by a musty odor. Most fungi, including molds, produce microscopic cells called "spores" that spread easily through the air. Live spores form new mold growths (colonies) if conditions are right, such as warm and humid. Every one of us are exposed to fungal spores daily in the air we breathe.

Most, if not all, of the mold found indoors comes from outdoor sources. It needs moisture to grow and becomes a problem only where there is water damage, high humidity, or dampness. Common sources of indoor moisture that cause mold problems include flooding, roof and plumbing leaks, damp basements or crawl spaces, or any moisture condensation on cold surfaces. Bathroom showers and steam from cooking activities may also produce problems if not well ventilated.

Common indoor molds include:

  • Cladosporium
  • Penicillium
  • Alternaria
  • Aspergillus
  • Mucor

Limiting And Preventing Mold Growth

Controlling excess moisture is the key to preventing and stopping indoor mold growth. Keeping susceptible areas in the home clean and dry is very important. Ventilate or use exhaust fans (vented to the outdoors) to remove moisture where it accumulates, particularly in bathrooms, kitchens, and laundry areas. Clothes dryers should be vented to the outside. Repair water leaks promptly, and either dry out and clean or replace water-damaged materials. Materials that stay wet for more than 48 hours are likely to produce mold growth. Lowering humidity indoors helps prevent condensation problems, such as using air conditioners and dehumidifiers. Proper exterior wall insulation helps prevent condensation from forming inside during cold weather.

Small amounts of mold growth in workplaces or homes (such as mildew on a shower curtain) are not a major concern. But no mold should be allowed to grow and multiply indoors. Large quantities of mold growth may cause nuisance odors and health problems for some people. In addition, mold can damage building materials, finishes, and furnishings and, in some cases, cause structural damage to wood.

"Toxic Mold" and "Black Mold"

Some molds produce toxic substances called mycotoxins. The health effects of breathing mycotoxins are not well understood and are currently under study. More is known about the health effects of consuming moldy foods or feed containing mycotoxins than about the effects of breathing mycotoxins.

The news media often refer to "black mold" or "toxic black mold." It is usually associated withStachybotrys chartarum, a type of greenish-black mold commonly associated with heavy water damage. Molds that appear to be black are not always Stachybotrys. The known health effects from exposure to Stachybotrys are similar to other common molds, but have been inconclusively associated with more severe health effects in some people.

Visible Mold and Musty Odors

The most important step is to identify and fix the moisture sources causing mold growth. For small mold problems, use detergent and water to wash mold off hard surfaces, and dry completely. Replace moldy porous or absorbent materials (such as ceiling tiles, wallboard, and carpeting). If you do not see mold growth but notice a musty odor, mold may be growing behind water-damaged materials, such as walls, carpeting, or wallpaper. Persons cleaning mold should wear gloves, eye protection, and a dust mask or respirator to protect against breathing airborne spores. If you have health concerns, you should consult your doctor before doing any mold cleanup.

Looking for evidence of water damage and visible mold growth should be your first step. Testing for mold is expensive, and you should have a clear reason for doing so. In addition, there are no standards for "acceptable" levels of mold in the indoor environment. When testing is done, it is usually to compare the levels and types of mold spores found inside the home with those found outdoors. If you know you have a mold problem, it is more important to spend time and resources getting rid of the mold and solving the moisture problem causing the moldy conditions.

Dealing With Extensive Mold Contamination

A professional experienced in mold evaluation and remediation, such as an industrial hygienist, may need to be hired to address extensive mold growth in a building. It is important to correct large mold problems as soon as possible by first fixing the source of the moisture problem and removing contaminated materials, then cleaning the surfaces, and finally drying the area completely. If you use outside contractors or professionals, make sure they have experience cleaning up mold.

For additional information, please contact us.

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