What is Toxic Mold?

When dealing with mold and mildew, the first thing you must remember is that no geographic location is really immune from mold problems. For some it's just an unsightly nuisance-but for others, it can cause severe health problems.

The perception that the South has the biggest mold problem in America just isn't true, according to Bob Thompson of the Environmental Protection Agency (see Resources, below, for more mold and mildew information from the EPA).

"Most people-when they think about mold and what states-they would think the Southeastern states like Florida, Alabama and Georgia. Actually, all states are having problems," he says.

The Science of Mold

What is mold exactly? The easiest answer: a type of fungi similar to mushrooms and yeasts. Even though mold is receiving ample media coverage these days, it's actually been around for centuries.

George Bean, Ph.D., a biologist in the department of Cell Biology and Molecular Genetics at the University of Maryland, says we really don't know how many different types (thousands, most likely) of mold there are.

"What we do know is they have tremendous variability in what they look like, where they're found, what they produce and so forth," he says. "Technically speaking, they're (mold) called filamentous fungi in the classification scheme of all living things, " he adds.

To most, mold only exists when they see it growing, however, the fact is that mold spores-the microorganisms that become mold -- are always present.

Did You Know? -There are more than 100,000 species of mold, and at least 1,000 are common in the United States.

How Do These Microscopic Spores Turn Into What's Called Mold?

"It's critical that if the organism wants to establish itself it's got to land on something it can grow on or into," Bean, who has studied mold his entire career, says. "The only way they can get nutrients, is by absorbing it through their systems through the microscopic threads that they have."

Mold spores use those threads to suck nutrients from dead organic materials, such as paper and other wood products. Mix in lots of moisture and you have the ingredients for mold!

"We have a number of examples of fungi that actually attack plants and produce lesions and reduce the yield and so forth that literally cause the loss of billions of dollars worth of foods and feeds each year in the world," Bean says.

Believe it or not, the same characteristic of mold-its ability to decompose other materials -- plays a crucial role in the environment.

"When one living thing dies there must be some decomposition. If there weren't decomposition, the total amount of organic matter that we are all composed of would continue to increase and increase, meaning that virtually there would be no room left," Bean says.

Mold can be beneficial in other ways as well, including statin drugs, which are used to treat high cholesterol and are the result of a byproduct created from mold. The antibiotic penicillin is derived from the mold fungus penicillium, which is also the source of those blue streaks in Roquefort cheese. The scientific name is penicillium roque fordi.

Exactly why some molds can be harmful and others relatively harmless is still somewhat of a mystery to scientists. There's not even agreement on the extent to which mold causes health problems in humans. It's known that mold can aggravate allergies.

Molds release spores (much like plants release pollen) as part of the reproduction cycle. The spores released cause the allergies people experience when exposed. In fact, mold allergies are so common that spore counts are frequently posted on weather web sites and in newspapers. (A blood or skin test can determine whether someone has mold allergies.)

Mold can also cause other problems ranging from irritation of the eyes, skin, nose and throat to conditions far more serious.

"We definitely know that some molds produce toxins," Thompson says. "And we also know that if you ingest or eat some of those molds, they can have some fairly severe health implications."

The Most Notorious of the Toxic Molds

Stachybotrys , the so-called "black mold," is the "bad boy" of molds. A written history documents the appearance of mold in the 19th century, but is only known to be problematic for humans and animals since the 1930s. Even though scientists have known about stachybotrys for decades, it's still unclear what level of exposure triggers serious health problems in humans. Nonetheless, this mold is an unwanted invader in anyone's home. The good news is that it doesn't show up very often, mainly because this fungus requires high levels of moisture-which means you should always be aware when your home has had extensive water damage.

How Can Mold Spores Enter the Home?

Clothing
Shoes
Bags
Open windows
Air-conditioning systems

MOLD. . . WHAT IS IT ALL ABOUT?

First, one must understand how mold lives. Many molds need simple things to exist and colonize. Most require a type of moist intrusion or humidity, otherwise known as "the wicking effect. " In some cases, it can take as little as 24 hours for this process to begin. After the source of the moisture has stopped, it does not mean that the mold has stopped growing.

Some molds are cryophytes (these adapt to low temperatures), some are thermo tolerant (they adapt to a wide range of temperatures) and some are thermophiles (they adapt to high temperatures). Depending on the species, these microbes will grow just about anywhere. Mold requires a compatible temperature for each species. Environmental factors (temperature, nitrogen, oxygen, etc. ) are necessary compounds for indoor molds to thrive.

Mold also needs an organic source of food. People might be confused as mold can grow on glass, tile, stainless steel, cookware, etc., but it is generally feeding off of some organic source deposited on this material (oils, film, dirt, skin cells, etc. ). The fiberglass insulation people like to say that mold does not grow on their product which is a fairly true statement, however, it grows on the organic debris that become trapped in their products. Mold also grows on things such as wood, fabric, leather, gypsum, fiberboard, drywall, stucco, and many insulation fibrous materials. All molds require some form of moisture to grow however, like temperature, the amount of moisture varies for different species. Some are xerophillic (colonize under very dry conditions) some are xerotolerant (colonize under a wide range of moisture levels) and some are hydrophilic (colonize at high moisture levels). It does not have to be a leak. . . Humidity or moisture content of the substrate can often be sufficient (relative humidity 50% start becoming problematic in many indoor cases.) It can spread very easily through any HVAC system.

Mycotoxins are examples of chemical substances that molds create generally as secondary metabolites, thought to possibly play a role in either helping to prepare the substrate on which they exist for digestion, as defense mechanisms, and some have suggested that they may be produced when the organisms are under stress, which could be related to competition/defense, or simply due to inhospitable environmental conditions. The mycotoxins, which are also neurotoxins (a toxin that is determined to cause neurological damage), most commonly reach people from the air, via spores from the molds in question. They are also found in small particulates at times which may often represent mold dust, small particles of mold that has dried and turned to dust. Spores, when inhaled, can begin to colonize in the sinuses and throughout the body, including the brain, lung and gut after a period of time.

One of the mycotoxins, aflatoxin, is produced by the fungi Penicillium, Aspergillus flavus and Aspergillus parasiticus. Four different aflatoxins, B1, B2, G1 and G2, have been identified with B1 being the most toxic, carcinogenic and prevalent. Another very dangerous family of toxin producers is Fusarium. The toxins zearalenone, trichothecenes or moniliformin can be formed by various types of Fusarium including F. moniliforme, F. oxysporum, F. culmorum, F. avenaceum, F. equiseti, F. roseum, and F. nivale.

Under certain growth and environmental conditions, black mold, otherwise known as Stachybotrys chartarum may produce several different mycotoxins, including a very strong class known as trichothecenes. Trichothecenes are also produced by several common molds including species in the genera Acremonium, Cylindrocarpon, Dendrodochium, Myrothecium, Trichoderma, and Trichothecium. The trichothecenes are potent inhibitors of DNA, RNA, and protein synthesis, and have been well studied in animal models because of concern about their potential misuse as agents of biological warfare, due to their ability to destroy human health (mentally and physically), and never show up in an autopsy. Sick buildings are one of the three major causes of fungal illness in industrialized nations today.

LEGAL PRESEDENT

. The Delaware Supreme Court upheld a $1.04 million award to two women whose landlord failed to address leaks and mold problems in their apartments, resulting in asthma attacks and other health problems. New Haverford Partnership v. Stroot, 2001 Del. Lexis 201 (May 7, 2001).

. In December, a homeowner settled a mold-related bad-faith lawsuit against his insurer, during trial, for $1.5 million. Blum v. Chubb Custom Insurance Co., No. 99-3563 (Nueces Co., Texas, Dist. Ct.).