"Toxic Black Mold"
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Table of Contents (
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What is Toxic Black Mold?
Nasty Sounding Stuff, Isn’t It?
Mycotoxins and VOC's. (Volatile Organic Compounds)
Mold & Mildew: A Creeping Catastrophe
Know Your enemy
Mold and Medical Problems
Immediate Response Required
Roles of Adjusters and Experts
The Future of Mold Claims
Combating Mold and Mildew
13 Common Breeding Grounds for Mold / Solutions
It’s Doing that to my Health?
Dispose of it Properly or You’ll Just make matters worse.
Molds (and mildew) are fungi. Fungi are neither plant nor animal but, since 1969, have their own kingdom. The fungi kingdom includes such wonderful organisms as the delicious edible mushrooms, the makers of the "miracle drug" penicillin and the yeast that makes our bread rise and our fine wines ferment. Biologically, all fungi have defined cell walls, lack chlorophyll and reproduce by means of spores. Approximately 100,000 species of fungi have been described and it is estimated that there are at least that many waiting to be discovered. The vast majority of fungi feed on dead or decaying organic matter – they are one of the principle agents responsible for the natural recycling of dead plant and animal life.
The most common fungi are ubiquitous within our environment and we are constantly exposed to them. For the most part, however, diseases caused by these common fungi are relatively uncommon and are rarely found in individuals with normally functioning immune systems.(1) Nonetheless, mold has recently experienced high profile press coverage. There are a variety of inflammatory press reports concerning lawsuits over air quality in homes, courthouses and other buildings; parental concerns regarding school classroom environments; home insurers refusing to cover mold damage; and widely distributed news reports on so-called "toxic mold." But don't panic. Mold can be managed effectively in most cases and this guide will help you do that.
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There are 4 critical requirements for mold growth – available mold spores, available mold food, appropriate temperatures and considerable moisture. The removal of any one of these items will prohibit mold growth. Let's examine each requirement, one-by-one.
Mold Spores. Ranging in size from 3 to 40 microns (human hair is 100-150 microns), mold spores are ubiquitous – they are literally everywhere. There is no reasonable, reliable and cost-effective means of eliminating them from environments that humans inhabit. So, trying to control mold growth through the elimination of mold spores is not feasible.
Mold Food. If all three other requirements are met, almost any substance that contains carbon atoms (organic substance) will provide sufficient nutrients to support mold growth. Even the oil from your skin that is left when you touch an otherwise unsuitable surface, like stainless steel, or the soap residue left from a good cleaning will provide sufficient nutrients to support the growth of some molds. And many of the most common materials found in homes like wood, paper and organic fibers are among the most preferred of mold nutrients. Thus, eliminating mold food from your environment is a virtually impossible task.
Appropriate Temperatures. Unfortunately, most molds grow very well at the same temperatures that humans prefer. In addition, anyone who has cleaned out their refrigerator quickly realizes that temperatures close to freezing are not cold enough to prevent mold growth and temperatures that are much warmer than humans prefer, like those of the tropics, will grow abundant quantities of mold. Therefore, it is not feasible to control mold growth in our home environment through the control of temperature.
Considerable Moisture. Most molds requires the presence of considerable moisture for growth. Obviously, the word "considerable" is key here. The mycologists (fungi scientists) refer to "water activity" when describing the required conditions for mold growth. The various species of mold have different water activity requirements. A material's "water activity" is equivalent to the relative humidity of the air that would be in equilibrium with the material at that material moisture content. The vast majority of mold species require "water activity" levels that are equivalent to material equilibrium moisture contents corresponding to relative humidities of at least 70%. In fact, the great majority of serious, large mold outbreaks inside buildings occur where porous, cellulose-type materials have literally been kept wet by liquid water or sustained condensation.
Human beings prefer humidities that are below the critical relative humidity for mold growth. Thus, of the four basic requirements for mold growth, moisture availability is by far the easiest mold growth requirement to control in environments that humans like to inhabit. As you will see from the remainder of this guide, and from the vast majority of the literature on mold control, the consensus regarding effective mold control strategies consists of the combination of reducing the availability of moisture and killing and removing active mold growth colonies.
Determining if You Have Mold
Common household molds have a characteristic "musty" or "earthy" smell, somewhat like the forest floor deep in the woods. Growing colonies of mold can also be visually observed in many cases. Most people are familiar with moldy bread or mold growth on cheese or other food products that have been kept too long, so the "green fuzzy" characteristic of most mold growth is familiar. And those who have lived in Florida have heard the expression "green shoe syndrome" which refers to the fact that mold is particularly fond of leather products left unused for periods of time in dark humid places.
Although most active mold colonies appear greenish to black (typical of mold growing on bathroom tile grout) in color, the characteristics of mold colonies growing behind vinyl wall covering in buildings takes on very different characteristics. These mold outbreaks typically result in pinkish to yellowish staining of the wall covering. They are quite important because they indicate serious, detrimental moisture accumulations within the gypsum wallboard behind the wall covering that can not be removed by your air conditioning or dehumidification systems. Where these problems appear, they usually require the assistance of a professional equipped with pressure measurement and other diagnostic equipment to determine the source(s) of the moisture causing the problem.
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Practices That Will Minimize Mold Growth
The following practices will help minimize the growth of molds inside homes located in hot, humid climates like Florida's. Mold growth on the outside of homes is not covered here and readers are cautioned that these practices may not be applicable in other climates.
- Air Conditioner Operation: Always set the fan mode switch of your air conditioner thermostat in the AUTO position, never in the ON position. Why? When set to the ON position the blower fan runs continuously and the moisture which has condensed on your air conditioner's evaporator coil during cooling is re-evaporated and blown back into your home before it can drain off the coil and out of your home. This causes the relative humidity in your home to be significantly greater than if the air conditioner thermostat fan mode switch is set to the AUTO position. Even in the "auto" position, some air conditioners run the blower for 1-3 minutes after the compressor shuts off. To maximize dehumidification, it is best to disable this feature. A qualified mechanical contractor should be able to disable this feature so that the blower and compressor turn off simultaneously.
- Air Conditioner Selection: If you are building a new home and can choose, then choose an air conditioning system with a variable speed air handler and an operating selection mode for "enhanced moisture removal." This is a good option for multiple reasons: the units are SEER 14+, they are quiet and they do a better job removing moisture, particularly under part load conditions. They accomplish this by starting the air handler fan at a lower speed during each cycle, which improves moisture removal. The variable speed fan motors are intrinsically more energy efficient-- they use as little as 270 W/1000 cfm of air flow as compared with the typical 450 W/1000 cfm. Each of the major manufacturers have them. When used properly, they are ideal for Florida's climate.
- Air conditioner sizing. Oversizing of air conditioners is common. The more an air conditioner is oversized, the poorer its humidity removal performance, especially at higher thermostat settings. This is because, during each air conditioning on cycle, the moisture removal does not reach full capacity for about the first three minutes of operation. The more the system is oversized, the shorter the on-cycle during which moisture is removed. Thus, if a home is properly sized with a 2-ton air conditioner and a 4-ton system is installed, the 2-ton machine would do a much better job removing moisture even though the 4-ton machine had twice the nameplate humidity removal capability (Btu/hr). Remember, the shorter the air conditioner on-cycle, the less chance for effective moisture removal. This fact can be clearly seen in the figure below, which is taken from FSEC test data.
- Thermostat Set Point: Set the summertime thermostat to the highest temperature that is comfortable for you. A temperature of 78 F or greater is recommended.
Never lower the thermostat temperature in an attempt to control humidity in your home – this will not work. Why? Setting the thermostat temperature lower does two things that are counter to your goal of reducing the moisture content of the materials in your home. First, contrary to what you might intuit, it actually slightly increases the indoor relative humidity in your home! And second, and more important, it decreases the temperature of the materials in your walls, floors and ceilings of your home, thereby significantly increasing the potential for actual moisture condensation on these elements of your home. A side benefit of setting your thermostat at higher temperatures is that it significantly decreases cooling energy costs. In Florida, each one oF increase in thermostat temperature decreases air conditioning cooling energy costs by about 10%.
The following table of results from experiments that were conducted by the Florida Solar Energy Center illustrate the relative humidity impacts of both thermostat set point temperature and the position of the fan mode switch. (2)
Impact of Indoor Set Temperature and Fan Operation Mode
on Interior Relative Humidity*
Avg RH %
Run Time Fraction
| * AC operated alternatively for at least one week in each mode.|
- Interior Doors: Interior doors should be kept open when air conditioning unless your heating and cooling system has a fully ducted return air system from each room of the home or unless specific and sufficient return air transfer pathways have been installed to ensure that closed interior doors do not result in space depressurization problems in the home.
- Space Pressurization: It is important that homes in hot, humid climates be pressurized slightly with respect to outdoors. The reason is fairly straightforward but not very obvious. If homes are depressurized with respect to the outdoors, then hot, humid outdoor air will be pulled through the very small air pathways that exist in all building envelopes (walls, ceilings, floors, etc.). To get from the outside of the home to the inside, this air often must follow circuitous pathways. For example, the air may enter the wall system high on the exterior where an outdoor light fixture is mounted and exit the wall system low on the indoors where an electrical outlet is located. If the home is air conditioned, the gypsum wallboard will be relatively cold — often colder than the dewpoint temperature of the humid outdoor air that must flow along that gypsum wallboard to that indoor electrical outlet. In Florida, it is not uncommon for summertime outdoor air dewpoint temperatures to be greater than 80 F! When this occurs, the colder gypsum wallboard can act just like that ice tea glass that "sweats" like crazy when you take it outdoors — it can condense the moisture out of the air that is flowing along its back surface on its way to the electrical outlet that is serving as its pathway into the air conditioned home. As illustrated in the figure below, this can result in moisture accumulation within the wallboard, which, in turn, can result in significant mold growth.
The above wall diagrams from detailed computer simulations that model the combined impacts of heat, moisture and air transport (3) illustrate the importance of this air flow phenomena. The wall on the left bounds a space that is pressurized with respect to the outdoors and the one on the right bounds a space that is depressurized. The 2 Pa (Pascal) pressure gradient is very, very small — there are 101,325 Pa in one atmosphere. Clearly, it is the direction of the pressure gradient rather than its magnitude that is critically important here. You very much want your home slightly overpressurized in hot, humid climates so that dry, cool indoor air is pushed out of the home through the walls (figure on left) rather than have hot, humid outdoor air sucked into the home through the walls (figure on right). Fortunately, it is relatively easy to pressurize a home — all that is necessary is that slightly more air be brought into the home than is exhausted. This normally requires a positive mechanical ventilation system.
Things that may cause space depressurization in homes:
- Ceiling Fans: Use ceiling fans in the summer — they allow you to be comfortable at higher air conditioning thermostat temperatures. And they will save air conditioning energy costs if you use the most efficient ones (see Gossamer Wind® Series - available at Home Depot stores) and turn them off when no one is in the room.
- Measure the RH in Your Home: Invest in a digital temperature and relative humidity (RH) sensor (about $20) and observe your indoor relative humidities. Two sources for these sensors are Radio Shack and Therma-Stor Products (1-800-533-7533). During the hot summer months, with the air conditioning on, the RH should not exceed 55% during the day on a regular basis. If it does, you probably have problems either with leaks in your duct system or with your air conditioner unit itself – it could be too large, improperly charged or have insufficient air flow across the coil. Consult with a qualified air conditioning expert or mechanical engineer to determine the problem.
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The highest relative humidities in your home are likely to occur during mild weather when your air conditioner is not needed during the day. In Florida, the outdoor relative humidity reaches very near 100% on most nights, regardless of daytime temperatures. If your home is open to the outdoors during these periods, the materials in your home will adsorb moisture from this very humid air, again regardless of the temperature. If this moisture is not removed during the following day, the "water activity" of the materials in your home can stay at or above 75% for extended periods and mold is likely to grow on these surfaces. If you have RH levels exceeding 70-75% for extended periods, and find it difficult to control mold growth on surfaces in your home in spring, fall and winter, you may need to invest in some type of dehumidification system and should consult with a qualified mechanical system expert for advice.
- Vinyl Wall Covering: Impermeable interior surfaces like vinyl wall coverings can result in severe mold problems in hot humid climates such as Florida's. Moisture coming from outdoors can accumulate within the gypsum wallboard that is behind the vinyl wall covering. This normally occurs as a result of house depressurization where outdoor air is being sucked into the home through the very minute air pathways that exist in all normal wall systems. Where this problem occurs, outbreaks of mold often occur beneath the wall covering on the surface of the gypsum wallboard. This mold growth is normally characterized by pinkish to yellowish "splotches" on the vinyl wall covering. The moisture accumulation also can be severe enough to cause the gypsum wallboard to badly deteriorate and become "mushy." If you have noticed these symptoms, a building science professional should be consulted. Positive pressurization of your home is one method of minimizing the potential occurance of this problem.
- Return Air Pathways: It is important that there be sufficient air flow pathways for the supply air that is delivered to each room of a home to return to the air conditioner's air handler unit (the box with the blower fan). Otherwise, the part of the home containing the main return to the air handler unit will be "starved" for air, resulting in depressurization of this space with respect to the outdoors. If this occurs, outdoor air will be drawn through the small pathways that exist in the exterior building envelope. In hot, humid climates like Florida's, these air flows can result in the accumulation of moisture within the gypsum wallboard, especially if it has vinyl wall covering. This, in turn, can result in the rapid and abundant growth of molds — remember, the cellulose (paper) on gypsum wallboard makes an excellent, preferred mold food.
If room doors are kept open, there will be sufficient return air pathways. However, if rooms doors are closed, the rule-of-thumb is that there should be about 50 square inches of "free" air transfer area for each 100 cfm (cubic feet per minute) of supply air to the room. In this case, the term "free" means a simple, clear hole in the wall between the room and the remainder of the home. If, for appearance and privacy reasons, this hole is to be covered by grilles on each side of the wall, then the overall return air pathway area needs to be increased by about 40% to account for the air flow resistance of the grilles, or about 70 square inches per 100 cfm of supply air flow.
- Bathrooms: Most bathrooms, particularly tile in and around showers and tubs is regularly wet. As a result, most bathrooms grow mold and require regular cleaning. A weak solution of water and common household bleach can be used to regularly clean these areas and keep them free of mold. Low-noise bathroom fans are also recommended to remove excess moisture during periods when it is being generated by bathing or showering. (See also exhaust fans.)
- Whole-House Ventilation Fans — Opened Windows: Avoid the use of these fans when it is humid outdoors, especially if you have noticed mold growth in your home or you are having trouble controlling the relative humidity in your home. In addition, avoid opening windows for long periods when it is humid outside (e.g. during nights and evenings) if you are experiencing mold growth problems in your home.
- Air Conditioner Maintenance: Change your filters regularly and use pleated filters. Once a year get your air-conditioners professionally serviced. At that time make sure coils are clean, the condensate drains properly and that the drain pan has no mold.
- Exterior Water Management: Redirect water away from the home's exterior — redirect sprinklers so that they don't spray on the walls. Do not landscape with hills that direct water flow towards the home. Use gutters. Keep down-spouts free of debris and direct outflow away from the home.
- Small Leaks: Even small water leaks will cause mold problems. Rainwater leaks from improperly flashed windows, wall and roof penetrations and plumbing leaks should be promptly repaired. Periodically inspect under sinks and vanities for signs of water leakage. Use you nose and smell for "musty" or "earthy" odors – they usually indicate the presence of mold. Fix all water leaks promptly.
- Water Damage: Water damage from flooding or other major water intrusion in homes should be dried within 24 hours if at all possible. For severe flooding and severe water damage for more than 48 hours, a trained restoration professional should be consulted regarding cleanup procedures. Readers are also encouraged to consult the American Red Cross web site at the bottom of this page for further information.
- Moisture Condensation: Single-pane, metal windows, which are common in Florida, generally condense water on the inside in winter. It is good practice to remove this condensation before it can run off and be absorbed by porous materials like wood casing or gypsum wallboard. Condensation can also occur on other surfaces in homes. If condensation is noticed on interior surfaces in summer, it may indicate a number of problems, including inability to control indoor humidity; air conditioner supply registers aimed directly at interior surfaces; duct leakage problems and pressure imbalances; or all of the above. If you notice indoor surface condensation during summer, you should contact a professional to help diagnose the cause. However, during early spring when the ground is still cool, it is quite possible to experience some condensation on tile floors on slab-on-grade homes that are open to the outdoors. This should not be a regular occurrence, but only something that occurs rarely.
- Exhaust Fans: Make sure the clothes dryer vent goes all the way to the outside of the home, not to the crawlspace or to the inside of the attic or the house. The same goes for bathroom vent fans. It is also important for the kitchen range hood to vent to the exterior as well. Recirculating stove and kitchen vents provide no removal of stovetop moisture and inferior control of cooking related pollutants compared with venting completely to the outdoors. A major deterrent to the use of kitchen range hoods is noise. Choose an ultra-quiet, inline ventilation fan for your range hood. Kitchen and bath exhaust fans should only be used while cooking or using the bathroom to remove excess moisture generated by these activities.
It is best practice to either have bathroom vent fans interlocked with the light switch so they do not get left on or have them switched by a manual timer that will shut them off after a period of time, or control them by humidistat.
- Closets: Fungi like the dark and closets are rarely supplied with conditioned air as a standard part of air conditioning systems. As a result it is not all that uncommon to have mold or mildew occur in closets, especially on leather. Leaving the closet doors open to provide more conditioned air circulation or leaving the closet lights on with the door closed so as to raise the temperature (which lowers the RH) can reduce these problems.
- House Plants: Minimize live house plants, especially if you have any trouble controlling the relative humidity in your home.
Nasty sounding stuff isn’t it?
Stachybotrys Chartarum, Penicillium and Aspergillus – Toxic, Health threatening molds, found in homes, businesses and schools near you.
These molds can be found anywhere that dark and dank conditions permit them to grow. When you try to kill them, they take to the air, spreading themselves with no forethought to the damage they can cause. They are just trying to survive. And they’re good at it.
Remember the story of the opening of King Tut’s tomb? Mold was reportedly thick and pungent. The treasure hunters and laborers took ill after spending long days inside, and many died, but we now know it was NOT because the tomb was “ cursed.”
Only in the past decade or less have we begun to understand the potential health risks associated with exposure to mold contamination. Spores can be inhaled, absorbed through the skin or ingested on our food. And, because some people are more susceptible than others, one person may become debilitated by exposure to mold in the home, another person sharing the same environment is essentially unaffected.
Infants, the elderly and anyone with immune system deficiencies due to disease, chemotherapy, etc. are particularly susceptible to serious illness following exposure to microbial contamination.
Many species of mold and mildew (or the mycotoxins they produce) can cause or aggravate a number of ailments. Common effects from molds such as stachybotris atra, penecillium, cladosporium and several strains of aspergillius, are asthma, pneumonitis, upper respiratory problems, sinusitis, dry cough, skin rashes, stomach upset, headaches, disorientation and bloody noses. Numerous other species of mold and mildew are also toxic, and many mycotoxins are known carcenogens. Severe exposures can lead to internal bleeding, kidney and liver failure and pulmonary emphysema.
Such health risks due to the presence of mold in a dwelling are a serious concern to occupants, and can pose potential liability for owners of rental properties.
Contamination of residential properties by toxic mold and mildew is becoming more and more prevalent. Although mankind has been aware for thousands of years that mold thrives in damp conditions, only recently have we begun to understand how dramatically its presence can impact us. Toxic mold and mildew is not discerning, affecting both old and new buildings.
The odor or appearance of mold can signal a variety of problems. The moisture that gives life to fungal growth in older buildings can be either a moisture problem created by tenant’s use, or water intrusion due to leaky components, or both. In new construction, it could also indicate the existence of construction defects. < return to top >
”I Don’t Remember Mold Being a Concern Twenty Years Ago”
Molds and mildew are everywhere in our environment, and in nature, they perform the very important function of breaking down organic matter. These microbes need very little to survive and thrive: air, moisture (liquid water isn’t necessary, most species propagate with only 40%-60% relative humidity), and food. Fungi are especially fond of building materials like sheetrock and wood, carpets, and enjoy soft goods such as furniture and clothes. Every home offers a smorgasbord for eager spores!
There are a number of reasons for the increasing problem of mold and mildew in our homes, not the least of which is the fact that Title 24 to the United States Code of Federal Regulations, relating to energy conservation, brought new construction methods and materials, meaning that buildings don’t “breathe” as freely, trapping moisture vapors inside the building. Most newer homes are built on concrete slabs, which emit moisture for several years as they cure, and because they are porous, moisture from the soil beneath the slab also vaporizes into the living space. Leaky roofs, windows, and plumbing, whether caused by poor construction or lack of timely repairs, often result in colonization of mold and mildew spores. The microbial spores become airborne, spreading inside wall cavities, behind cabinets and wallpaper, and through ventilation systems. When moisture and temperature conditions are favorable, widespread contamination can occur in a surprisingly short time.
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A 1999 Mayo Clinic Study cites molds as the cause of most of the chronic sinus infections that inflict 37 million Americans each year. Recent studies also link molds to the soaring asthma rate. Molds have been an under recognized health problem, but that is changing. Health-care professionals now know that molds can cause allergies, trigger asthma attacks and increase susceptibility to colds and flu. Anyone with a genetic predisposition can become allergic if exposed repeatedly to high enough levels. Last year Dr. David Sherris at the Mayo Clinic performed a study of 210 patients with chronic sinus infections and found that most had allergic fungal sinusitis. The prevailing medical opinion has been that mold accounted for 6 to 7 percent of all chronic sinusitis. The Mayo Clinic study found that it was 93 percent - the exact reverse. Newsweek, 12/4/00
Mold nor spores cause illness, other than allergy and/or infections. It is the mycotoxins released when the molds' food source (moisture) is severed.
To help comprehend how small mycotoxins are, one common housefly could carry about 7.35 billion attached to its external body hairs. Consequently, IF 50,000 constitute a theoretically lethal dose, a housefly could carry a lethal dose for over 100,000 individuals.
Outdoor spores are not a usual cause of toxicity, (except for allergies and infection), but when growing inside, molds produce toxins, which are in much higher concentration and can cause illness.
Indoor mold spores indicate mold growth, which indicates mycotoxin production. Currently, we can measure spores, identify spores, but it is difficult to measure mycotoxins. Stachybotrys produces at least 170 known mycotoxins, and probably more that have not been identified.
Molds, a subset of the fungi, are ubiquitous on our planet. Fungi are found in every ecological niche, and are necessary for the recycling of organic building blocks that allow plants and animals to live. Included in the group "fungi" are yeasts, molds and mildews, as well as large mushrooms, puffballs and bracket fungi that grow on dead trees. Fungi need external organic food sources and water to be able to grow. Molds can grow on cloth, carpets, leather, wood, sheet rock, insulation (and on human foods) when moist conditions exist (Gravesen et al., 1999). Because molds grow in moist or wet indoor environments, it is possible for people to become exposed to molds and their products, either by direct contact on surfaces, or through the air, if mold spores, fragments, or mold products are aerosolized. Many molds reproduce by making spores, which, if they land on a moist food source, can germinate and begin producing a branching network of cells called hyphae. Molds have varying requirements for moisture, food, temperature and other environmental conditions for growth. Indoor spaces that are wet, and have organic materials that mold can use as a food source, can and do support mold growth. Mold spores or fragments that become airborne can expose people indoors through inhalation or skin contact.
Mold spores are fungal reproductive cells of about the same size as pollen grains. They can occur in various colors and shapes, such as round, spheroid, banana-shaped, or tadpole-shaped. They can occur in enormous quantities, and at all times of the year. Mold spores can be found and generated at serious levels indoors, as well as out.
Fungi can invade healthy individuals and can cause a variety of effects. The most common response is allergies (runny nose, sneezing, sinus congestion, and skin rashes). Allergies result from inhaling mold spores. When environmental conditions become conducive, many molds develop fungal hyphae, small appendages containing spores. These spores are analogous to plant seeds and can be spread by the billions when air currents pass over the hyphae. Even dead fungi are capable of causing allergic symptoms.
Mold spores can be airborne, and get indoors through doors, windows or cracks and crevices, or be carried in from the outdoors on shoes and clothing. Building materials that were left outside before use can harbor viable (living) mold spores for many years. Indoor environments are never entirely free of molds. As a general rule of thumb, in a "healthy" building the concentration of spores and the mix of mold species tend to be similar to outdoor environment levels.
If buildings are air-conditioned, or windows and doors are kept closed in summer, the concentration of spores within should even be lower than outside levels. High moisture (above 70.0% relative humidity) in a building will invariably lead to mold, mildew, or other microbial growth. This growth requires four things: a nutrient source (found in most building materials), proper temperature (usually found indoors), mold spores (ubiquitous in ambient air), and water.
Some molds also produce toxins (poisons) which are thought to be useful in killing competing molds in their vicinity. These toxins can also have deleterious effects on humans when ingested, inhaled or in contact with the skin. The fungi that produce toxins are known as toxigenic fungi. Many fungi produce secondary toxic metabolites which can produce adverse health effects (mycotoxicoses) in animals and human. These metabolite are collectively known as mycotoxins. The latest World Health Organization (WHO) publication on mycotoxins, available in 1990, indicated that there are more than 200 mycotoxins produced by a variety of common fungi. Historically, mycotoxins are a problem to farmers and food industries and in Eastern European and third world countries. However, many toxigenic fungi, such as Stachybotry chartarum (also known as Stachybotrys atra) and species of Aspergillus and Penicillium, have been found to infest buildings with known indoor air and building-related problems. Many indoor air quality related problems have been traced to the growth of fungus in buildings. Almost without exception, these buildings have usually had chronic water or moisture problems.
Molds can have an impact on human health, depending on the nature of the species involved, the metabolic products being produced by these species, the amount and duration of individual's exposure to mold parts or products, and the specific susceptibility of those exposed. Health effects generally fall into four categories.
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Allergy, Infection, Irritation, Toxicity
Toxicity Molds can produce other secondary metabolites such as antibiotics and mycotoxins. Antibiotics are isolated from mold (and some bacterial) cultures and some of their bacteriotoxic or bacteriostatic properties are exploited medicinally to combat infections.
Mycotoxins are also products of secondary metabolism of molds. They are not essential to maintaining the life of the mold cell in a primary way (at least in a friendly world), such as obtaining energy or synthesizing structural components, informational molecules or enzymes. They are products whose function seems to be to give molds a competitive advantage over other mold species and bacteria. Mycotoxins are nearly all cytotoxic, disrupting various cellular structures such as membranes, and interfering with vital cellular processes such as protein, RNA and DNA synthesis. Of course they are also toxic to the cells of higher plants and animals, including humans. Mycotoxins vary in specificity and potency for their target cells, cell structures or cell processes by species and strain of the mold that produces them. Higher organisms are not specifically targeted by mycotoxins, but seem to be caught in the crossfire of the biochemical warfare among mold species and molds and bacteria vying for the same ecological niche.
Mycotoxin Effects - The class of small fungal secondary metabolites which has been given the name "mycotoxins" is definitely known to include many compounds which are highly toxic to vertebrates (such as humans). Most of the well characterized toxic effects are from animal feeding situations, either natural mycotoxicosis outbreaks caused by contaminated animal feed, or laboratory experiments based on feeding (or connected artificial experimental situations such as parenteral injection of purified toxins into experimental animals). Ingestion of mycotoxin-contaminated foods by humans results in similar symptoms. Toxic effects have also been found in laboratory experiments in which animals are exposed to mycotoxins via the respiratory tract. In cases involving humans and airborne exposure, the most suggestive of a direct mycotoxin effect are those in which heavily mold-exposed workers develop severe symptoms reminiscent of animal mycotoxicoses or contaminated-food mycotoxicoses.
< return to top > Volatile Organic Compound’s & Mycotoxins :
A Primer for Homeowners
by Randy Penn: An independent licensed real estate inspector (Texas #5491) who specializes in mold testing and specimen recovery. He has a Bachelor of Science degree in engineering, is a member of the Indoor Air Quality Association, has invested hundreds of hours in researching and training on fungal microorganisms, has completed IAQA’s workshop on mold remediation and has provided mold related presentations to homeowners and real estate professionals.
Randy's site is at InspectorPenn.com.
You can find a lot of information on mold, but trying to understand it may be difficult to those who didn’t take biology and chemistry. Even after stumbling through the pronunciation of these words, not everyone can comprehend what was meant by the statement.
“Satratoxin, a low-molecular weight non-volatile organically derived agent, belongs to the macrocyclic trichothecene class of mycotoxins generated from fungal microorganisms.”
As an aid to the homeowner, this overview is intended to explain a few bad products of mold in a less scientific manner. It will focus on those types of mold that have been considered as problematic to the “indoor mold issue” and does not address other fungal organisms which may behave differently. Analogies presented are not intended to be scientifically accurate, but rather to illustrate complex behaviors in more simple terms.
The people who study mold (mycologists) have identified and described over 100,000 species and many believe that this is only a partial listing (estimates of 1.5 million species have been suggested). Try jotting down the names of the first 100,000 people you know then describe each person’s behavior in a specific setting. You will begin to understand the complexities of the problem facing these mold professionals.
Most people have associated mold with allergies and these reactions are certainly prevalent with most all species found indoors. In addition to causing an allergic response, molds can be irritating, infectious and even toxic to humans. Understanding the general behavior of mold provides insight into the adverse components produced by mold.
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Fungi can be considered nature’s garbage disposal. Without them, the term “biodegradable” would not be so significant to our planet and we would have mountains of leaves, dead trees, and other organic materials sitting around…all deposited since the beginning of time. This, in simple terms, is the ‘why’ of mold.
For the moment, think of mold as a weed. This weed has a root system, a vegetative stalk, and a seed pod. For mold, the root system is made up of hyphae (high-fee). As hyphae grows into a mass during the vegetative state, it becomes a mycelium (my-sill-ee-um). The spores, designed for reproduction, are similar to seeds.
Like a weed, mold needs food and water to survive (yes, both need more than that, however, we are simplifying things here). For mold, the food of preference is organic matter (things that once were living). Indoors, those things are wood, paper, organic dust and dirt, leather, skin flakes, body oils, etc.
When mold spores that are floating around in the air land on a food source, they sit there patiently waiting for water. If the item they land on should contain sufficient moisture, or water comes from another source (leaks, etc.), the spore germinates and hyphae grows. The hyphae branch out, secrete enzymes to breakdown the food, form the mycelium, and absorb nutrients to grow. As long as the food and water hold out, colonies will continue to grow. Note that individual hyphae and spores are very, very small and few can see them without a microscope. When you see visible mold, you are generally seeing that mass of mycelium.
Hyphae can intertwine into the fibers of the substrate, penetrating the pores. As it consumes the substrate, it can also create it’s own route by dissolving pathways into the material. This is one of the reasons it is so difficult to kill and/or clean up mold on organic substrates. If you remove the surface growth, those bits of hyphae within the substrate are ready for re-growth upon the return of moisture.
As the organism matures, it develops spores intended for reproduction. Spores vary in size, shape, weight and methods of distribution. Some are light and buoyant so they float easily through the air. Others are wet and sticky and may cling to insects, rodents, etc. as a mode of travel.
As mold “consumes” it’s food, the chemical reactions of enzymes, substrates and mold growth produce carbon dioxide, water, and volatile organic compounds (VOC’s). Because these items are a result of actions essential to the growth of the organism, they are classified as primary metabolites.
For mold, many types of VOC’s are produced and typically include aldehydes, alcohols, keytones, and hydrocarbons. They have complex structures and names like “2-methyl-1-propanol”, so if you are going to dig deeper into VOC’s, get ready for chemistry class.
They are called volatile in that they evaporate easily at room temperature and pressure. Fortunately, this volatility aids in dilution with fresh air to minimize concentrated build-up of these chemicals. Testing for VOC’s is often accomplished by using vacuum cylinders to obtain samples of the air with laboratory analysis obtained from sophisticated test instruments (gas chromatograph/mass spectrometer).
When you smell a “musty-moldy” odor, it’s generally the VOC’s you are noticing. VOC’s are often considered irritants to mucus membranes, however, are also capable of both short-term and long-term adverse health effects. If you do smell these odors, it’s a sure sign the mold is consuming and growing and you need to take action. (Note that VOC’s may also be derived from non-mold sources including natural materials used in cleaning agents.)
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Many molds are capable of producing compounds called mycotoxins which are toxic to other organisms, including people. Mycologists believe these toxins are produced as protection against competing organisms and therefore, humans are simply caught in the cross-fire of this fight for survival.
Since these toxins are not essential for growth, they are classified as secondary metabolites. Toxic secondary metabolites require extra work on the part of the organism so production does not occur at all times, or, with all types of mold.
Scientists have identified over 400 mycotoxins and unlike VOC’s, these compounds are usually non-volatile (don’t evaporate easily at room temperature and pressure). One strain of mold may produce multiple toxins and one type of toxin may be produced by multiple strains of mold. Research has indicated that the type of substrate (nutrients), the growing conditions, together with the species of mold, will impact which toxins are created.
Some of these toxic substances are considered extremely hazardous to people, unfortunately, quantified human dose-response data is limited. Lab and field studies have shown these compounds to produce severe toxic effects in both animals and humans and therefore, the general recommendation is to minimize exposure to potentially toxigenic mold. Symptoms from toxic exposure range from flu-like symptoms, skin rashes and lesions, bleeding, fatigue, difficulty breathing, depression, etc. to longer-term nerve and organ problems, altered immunity, and cancer.
Not all secondary metabolites are considered bad for people…the antibiotics such as penicillin have beneficial use. However, from the mycological standpoint, antibiotics are considered mycotoxins since they too are generated by mold to ward off microorganisms (i.e. competing bacteria).
When the organism is producing toxins, the toxins are known to be present in the cell wall of spores and hyphae. It’s relatively easy to test for spores and hyphae, however, testing these components to see if they contain toxins is significantly more complex. Whereas a single spore can be viewed under a microscope, identifying what compounds are contained in the cell wall is difficult.
In order to identify these toxic compounds, laboratories must have a sufficient quantity of toxin-containing spores and carefully process them through sophisticated and expensive equipment that is capable of isolating chemicals down to billionths of an gram (remember, mold spores are microscopic so what is contained within it’s cell wall is extremely small). This testing is made even more difficult since there are a few hundred toxins to analyze and the behavior of mold is such that a toxin-producing mold in the field doesn’t necessarily produce the same type and quantity of toxins in the lab.
Generally speaking, identifying a mold type that is known to be capable of producing toxins is sufficient information to warrant precautions and avoid exposure without submitting for toxic analysis. However, if trying to confirm specific adverse health effects, obtaining an analysis of both VOC’s and toxins can be beneficial but often expensive.
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As another example, classic stachybotryotoxicosis, described mostly from agricultural workers who handled or disturbed large quantities of material (usually hay or straw) contaminated by Stachybotrys chartarum, was characterized by
(1) "Cough, rhinitis, burning sensation in the mouth, (throat) and nasal passages, and cutaneous irritation at (points) of toxin contact"
(2). Nosebleeds were also common, and tracheal bleeding was occasionally reported. Whether such mycotoxin effects explain the symptoms seen in common building exposures has been disputed. It has been pointed out that, although the mycotoxins are often associated with disseminating fungal conidia, the quantities present may not be sufficient to explain the effects observed
(3), at least not in terms of classic toxicosis. A number of mycotoxins or conidia of mycotoxigenic fungi, however, have also been shown to have effects such as activation of pulmonary alveolar macrophages (PAMs), DNA fragmentation in PAMs, inhibition of the oxidative burst killing mechanism in PAMs, and slowing of respiratory ciliary beat
(e.g., 4). Such interactions with immune mechanisms may explain some symptoms not explained by toxicosis. Careful study of occupants of contaminated buildings suggests an association between inhalation of toxigenic fungi and nonspecific respiratory symptoms
(5) Moldy Odors are released from actively growing fungi may also pose a health risk. Not all molds produce mycotoxins, but numerous species do (including some found indoors in contaminated buildings). Toxigenic molds vary in their mycotoxin production depending on the substrate on which they grow (Jarvis, 1990). The spores, with which the toxins are primarily associated, are cast off in blooms that vary with the mold's diurnal, seasonal and life cycle stage (Burge, 1990; Yang, 1995). The presence of competitive organisms may play a role, as some molds grown in monoculture in the laboratory lose their toxic potency (Jarvis, 1995). Until relatively recently, mold poisons were regarded with concern primarily as contaminants in foods. More recently concern has arisen over exposure to multiple mycotoxins from a mixture of mold spores growing in wet indoor environments. Health effects from exposures to such mixtures can differ from those related to single mycotoxins in controlled laboratory exposures. Indoor exposures to toxigenic molds resemble field exposures of animals more closely than they do controlled experimental laboratory exposures. Animals in controlled laboratory exposures are healthy, of the same age, raised under optimum conditions, and have only the challenge of known doses of a single toxic agent via a single exposure route. In contrast, animals in field exposures are of mixed ages, and states of health, may be living in less than optimum environmental and nutritional conditions, and are exposed to a mixture of toxic agents by multiple exposure routes. Exposures to individual toxins maybe much lower than those required to elicit an adverse reaction in a small controlled exposure group of ten animals per dose group. The effects from exposure may therefore not fit neatly into the description given for any single toxin, or the effects from a particular species, of mold.
Few toxicological experiments involving mycotoxins have been performed using inhalation, the most probable route for indoor exposures. Defenses of there respiratory system differ from those for ingestion (the route for most mycotoxin experiments). Experimental evidence suggests the respiratory route to produce more severe responses than the digestive route (Cresia et al.,1987). Effects from low level or chronic low level exposures, or ingestion exposures to mixtures of mycotoxins, have generally not been studied, and are unknown. Effects from high level, acute sub-acute and sub-chronic ingestion exposures to single mycotoxins have been studied for many of the mycotoxins isolated. Other mycotoxins have only information on cytotoxicity or in vitro effects.
Effects of multiple exposures to mixtures of mycotoxins in air, plus other toxic air pollutants present in all air breathed indoors, are not known. Effects of other biologically active molecules, having allergic or irritant effects, concomitantly acting with mycotoxins, are not known.
Measurement of mold spores and fragments varies, depending on instrumentation and methodology used. Comparison of results from different investigators is rarely, if ever, possible with current state of the art. While many mycotoxins can be measured in environmental samples, it is not yet possible to measure mycotoxins in human or animal tissues. For this reason exposure measurements rely on circumstantial evidence such as presence of contamination in the patient's environment, detection of spores in air, combined with symptomology in keeping with known experiment allesions caused by mycotoxins, to establish an association with illness.
Response of individuals exposed indoors to complex aerosols varies depending on their age, gender, state of health, and genetic make-up, as well as degree of exposure. Microbial contamination in buildings can vary greatly, depending on location of growing organisms, and exposure pathways. Presence in a building alone does not constitute exposure.
Investigations of patients' environments generally occur after patients have become ill, and do not necessarily reflect the exposure conditions that occurred during development of the illness. All cases of inhalation exposure to toxic agents suffer from this deficit. However exposures to chemicals not generated biologically can sometimes be re-created, unlike those with active microbial growth. Indoor environments are dynamic eco systems that change over time as moisture, temperature, food sources and the presence of other growing microorganisms change. Toxin production particularly changes with age of cultures, stage of sporulation, availability of nutrients, moisture, and the presence of competing organisms. After-the-fact measurements of environmental conditions will always reflect only an estimate of exposure conditions at the time of onset of illness. However, presence of toxigenic organisms, and their toxic products, are indicators of putative exposure, which together with knowledge of lesions and effects produced by toxins found, can establish association.
Field exposures of animals to molds (in contrast to controlled laboratory exposures) show effects on the immune system as the lowest observed adverse effect. Such immune effects are manifested in animals as increased susceptibility to infectious diseases. It is important to note that almost all mycotoxins have an immune suppressive effect, although the exact target within the immune system may differ. Many are also cytotoxic, so that they have route of entry effects that may be damaging to the gut, the skin or the lung. Such cytotoxicity may affect the physical defense mechanisms of their respiratory tract, decreasing the ability of the airways to clear particulate contaminants (including bacteria or viruses), or damage alveolarmacrophages, thus preventing clearance of contaminants from the deeper lung. The combined result of these activities is to increase the susceptibility of the exposed person to infectious disease, and to reduce his defense against other contaminants. They may also increase susceptibility to cancer (Jakabet al., 1994).
Because indoor samples are usually comprised of a mixture of molds and their spores, it has been suggested that a general test for cytotoxicity be applied to a total indoor sample to assess the potential for hazard as a rough assessment (Gareis, 1995).
Animal experiments in which rats and mice were exposed intranasally and intratracheally to toxic strains of S. chartarum, demonstrated acute pulmonary hemorrhage (Nikkulin et al. 1996). A number of case studies have been more recently published. One involving an infant with pulmonary hemorrhage in Kansas, reported significantly elevated spore counts of Aspergillus/Penicillium in the patient's bedroom and in the attic of the home. Stachybotrys spores were also found in the air of the bedroom, and the source of the spores tested highly toxigenic. (Flappan et al., 1999). In another case study in Houston, Stachybotrys was isolated from bronchopulmonary lavage fluid of a child with pulmonary hemorrhage. (Elidemir et al., 1999), as well as recovered from his water damaged-home. The patient recovered upon removal and stayed well after return to a cleaned home. Another case study reported pulmonary hemorrhage in an infant during induction of general anesthesia. The infant was found to have been exposed to S. chartarum prior to the anesthetic procedure (Tripi et al., 2000). Still another case describes pulmonary hemorrhage in an infant whose home contained toxigenic species of Penicillium and Trichoderma (a mold producing trichothecene poisons similar to the ones produced by S. chartarum) as well as tobacco smoke (Novotny and Dixit, 2000) Toxicologically, S. chartarum can produce extremely potent trichothecene poisons, as evidenced by one-time lethal doses in mice (LD50) as low as 1.0 to 7.0 mg/kg, depending on the toxin and the exposure route. Depression of immune response, and hemorrhage in target organs are characteristic for animals exposed experimentally and in field exposures (Ueno, 1980; Jakab etal., 1994).
While there are insufficient studies to establish cause and effect relationships between Stachybotrys exposure indoors and illness, including acute pulmonary bleeding in infants, toxic endpoints and potency for this mold are well described. What is less clear, and has been difficult to establish, is whether exposures indoors are of sufficient magnitude to elicit illness resulting from toxic exposure.
The toxic mold environmental risk may be one of the next major real estate “due diligence” concerns, especially in property development areas where major flooding has occurred. The problem is that this not only includes known residential and commercial flood areas incidents, but also numerous minor water releases due to plumbing failures, conductive condensation, house water leaks and accidents. The toxic mold concern could also be a problem where fires occurred at residential properties.
The second major concern is that one might not be able to permanently eliminate the entire toxic mold from the structure. There also remains a great propensity for future reoccurrence. The health risk/hazard could be back again. Therefore, we must recommend that great care be exercised to remove and dispose of all products, which have been contaminated by the toxic mold contaminated. The Department of Health Administrations in many states supports this recommendation.
The third concern is that States’ Health Departments will consider ambiguous and genetic disposition as a response to the publics’ inquiries. There will be some people, especially children, that will exhibit more adverse reactions, including death, lung tissue damage, and memory loss, than other persons exposed to the toxic mold. This may depend on the chemical sensitivity, genetic disposition, predisposing health history (such as allergies, asthma, smoking, etc.). For some, the exposure to the toxic mold spores may just be a “health risk” and to others, it may be a real “health hazard” (potential life-threatening and loss of “quality of life”.) Whether a potential liability concern is a risk or hazard will be paramount in defining the critical level of due diligence and disclosure response by responsible parties. There are already several major lawsuits concerning toxic mold exposure in residential and commercial buildings throughout the United States. Currently, most health organizations consider exposure to Stachybotrys mold as a health hazard.
Also, keep in mind that most responses leading to testing, investigations, and abatement of the Stachybotrys toxic mold are due directly to occupant complaints or documented detrimental health effects. Stachybotrys mold may evolve to a point where it is regarded with the same cautions, response and liability concerns as those attributed to lead-base paint and asbestos. Health hazards and risks associated with concern to exposure to Stachybotrys are currently considered as short-term effects. Exposure to radon gas in houses is considered a long-term health risk and is not considered a short-term hazard.
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Mold & Mildew: A Creeping Catastrophe
In February 2000, a Texas grand jury found reason to continue a criminal investigation of child endangerment charges against an insurance company for its handling of a water damage claim. This investigation was prompted by a criminal complaint filed by the policyholder and follows the filing of a $100 million lawsuit in 1999 against the same insurance company for its handling of the claim. The policyholders say that the insurance company did not act properly or in a timely manner following the water damage claim. The allegation is that the house is now uninhabitable.
The family claims that, following the water damage, and while they were still living in the house during repairs, they were coughing up blood. The husband, the family claims, is now suffering from a cognitive dysfunction, among other injuries.
The problem? Mold. Stachybotrys chartarum (a.k.a. atra) to be specific. The mold developed following a water damage loss in 1998. The policyholders allege that neither the insurance company nor the company's expert informed the family that the home contained the deadly mold until their health was irreversibly damaged.
Is the Texas case merely an extreme example? Or is it a harbinger of things to come?
Many lawsuits have been filed and are being filed around the country involving the improper handling of covered water damage losses that have resulted in mold growth so extensive and severe as to present potentially serious - and in too many cases, actual - health hazards, not only to the occupants of the building involved but possibly to anyone who unwittingly enters the structure. Furthermore, mold growth can cause damage to building materials, such as paper and wood products. Mold contamination and growth may also pose a disclosure issue during a real estate transaction.
According to the Insurance Information Network of California and the Western Insurance Information Service, both sponsored by insurance companies, water damage from frozen and broken water pipes ranks second, behind hurricanes, in terms of the number of homes damaged and the amount of claim costs in the U.S. Damage from water is the most prevalent, yet least recognized, catastrophe. In addition to broken and frozen water pipes, we have to include losses from flood, rain, leaks and surface water, as well as water damage from putting out fires.
Some of these losses are covered, some are not. If the water damage is the result of a covered loss, the resultant damage, mold (including fungi, mildew, etc.), is probably also covered and must be considered in preparing the scope of damages and costs of repair.
The consensus of opinion from the EPA, FEMA, the Centers for Disease Control (CDC), mycologists and microbiologists is that mold may start to grow and spread within 24 to 48 hours in structures damaged by water. Mold can grow exponentially, given the right conditions of temperature, moisture and food sources, such as sheetrock.
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Know your enemy.
Fungi are a group of organisms with nuclei and rigid cell walls, but without chlorophyll. They may be unicellular or in multicellular filaments. The filaments are called hyphae. A fungus may produce a system of branching filaments, called the mycelium. The filamentous fungi are sometimes called molds. Unicellular fungi are often called yeasts. Some fungi may produce both yeast and mycelial mold phases. Mildew, in layperson's terms, describes the staining, and likely the degradation of the materials, caused by fungi or molds. Mildew is also used by plant pathologists to identify plant diseases, such as "powdery mildew," caused by fungi. or molds. Mildew is also used by plant pathologists to identify plant diseases, such as "powdery mildew," caused by fungi.
Mold, mildew and fungi are hardly new problems. In the book of Leviticus, chapters 13 and 14, there is reference to a plague, also called mildew in some translations. The description seems to fit that of a toxic mold. In Leviticus, the solution was to try cleaning: "Watch the plague and if the plague spreads, the unclean item or property must be removed and destroyed."
Stachybotrys chartarum was first identified and described by a scientist from wallpaper collected in a home in Prague in 1837. The toxic effects of Stachybotrys have been reported as early as the 1920s.
Reports and surveys on mold in homes have been published since at least the late 1970s. In 1986, the injurious effects of trichothecenes - a mycotoxin produced by Stachybotrys chartarum and a few other molds - were reported from a study of a family in Chicago. That report, by W.A. Croft, said that Stachybotrys could be commonly found in homes with water damage, could grow undetected behind walls and could grow profusely on sheetrock.
In 1993, the New York City Department of Health's Bureau of Environmental & Occupational Disease Epidemiology convened a panel of experts to study a growing and noted problem. Their report, "Guidelines on Assessment and Remediation of Stachybotrys Atra in Indoor Environments," was issued in 1994. An updated report, "Guidelines on Assessment and Remediation of Fungi in Indoor Environments," was issued in April 2000. The scope of the report was expanded to include all mold or fungi.
These guidelines serve as the accepted standard on how to deal with mold. The initial 1994 report focused on Stachybotrys, but was revised in 2000 to include all mold (fungi). The authors highly recommend that concerned readers download and print out copies for reference, which run about 17 printed pages. (For more information, contact he N.Y.C. Department of Health at (212) 788-4290.)
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Mold & medical problems
A wide variety of symptoms have been attributed to the toxic effects of different molds. The medical problems may be caused by toxic gases produced by the molds or by reactions to the mold particles themselves. Many allergies are also attributable to mold and fungi.
Commonly reported symptoms include runny noses, eye irritation, congestion, and aggravation of asthma, headaches, dizziness and fatigue. More severe symptoms may include reports of profusely bloody runny noses, the coughing up of blood, severe headaches, fibrous growth in the lungs and - at least in one reported instance - cognitive dysfunction and loss of memory.
In the previously described water damage and mold claim in Texas, a mold expert in the case underestimated the danger involved. The expert found himself throwing up for hours after spending just 30 minutes in the house. He has a severe hearing loss in one ear from his exposure to the mold.
In 1993 and 1994, a doctor from the Cleveland area attributed 37 cases of pulmonary hemorrhage and hemosiderosis in young infants to Stachybotrys. Twelve of the infants died. A recent CDC report questions the scientific validity of the doctor's conclusions and the causal linkage of the infant deaths to the toxic effects of Stachybotrys. However, the CDC does recognize that moldy homes are unhealthy for human occupancy. Other reports claim to confirm the linkage of Stachybotrys to instances of infant deaths in other locations.
Some of the most extreme cases of mold-related health problems, the so-called "yellow rain" attacks in Southeast Asia during the late 1970s, and the Iraqi attacks on some Kurd villages in the 1980s and 1990s have been attributed to use of mycotoxins produced by molds.
The conclusion to be reached from all of these dramatic cases is that molds are potentially dangerous and cannot be ignored. All molds should be removed. If the mold is attributable to a covered loss, it is the responsibility of the adjuster to include removal of the mold as part of the loss.
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Immediate response required
While all claims should be responded to and handled promptly, timeliness on covered water damage claims is especially critical. A prompt response and an immediate commencement of cleanup and drying is essential in reducing or eliminating further damage, particularly by mold. The sooner the water is removed and the property properly dried out, the less property damage there will be and any related claim will also be correspondingly minimized. Water damage that is not addressed within 24 to 72 hours may result in the growth and spreading of mold which could be toxic. (See "Wringing Out Excess Costs From Water Damage Claims" for proper drying procedures.)
A visual inspection is the most important step in identifying possible mold contamination. The inspection should include any areas damaged by water, e.g., behind cabinets, in attics, under carpets, inside wall cavities and any area with porous material or soft goods exposed to high humidity (over 60 per cent) or water for a period in excess of 72 hours.
The general rule of thumb is very simple: If you can see mold or smell mold, you have to remove it. Once you find and start removing the mold-damaged or contaminated materials, such as sheetrock, you should keep on removing the material until you find no more mold, either on the face of the sheetrock or on the back side of the sheetrock next to the studs. If the studs have mold contamination, you must consider the edge of the stud on which the other or exterior wall is attached.
Since the N.Y.C. Department of Health's panel of experts concluded that it was not possible to determine safe or unsafe levels of exposure for people with varying degrees of susceptibility, the guidelines essentially call for the removal of all visible mold.
The New York City guidelines state that in looking for mold following water damage, bulk sampling or air monitoring is not required. Remediation of all visibly identified mold contamination should proceed without further evaluation. However, if mold is not visible but is suspected because of circumstances such as water damage and unexplained illness, it may become necessary to test in order to rule out mold or to verify its presence. Porous materials, such as ceiling tiles, insulation and wallboards, with more than a small area of mold contamination should be removed and discarded. A small isolated area is defined as 10 square feet or less. A small area may be cleaned safely if done properly, without problems, and a check reveals no more mold.
Removal of the mold-contaminated material is only the first step. A certified mold remediation specialist should then remediate or decontaminate the structure and personal property involved.
Depending on such variables as the length of time from the initial water damage, the amount of water in the structure, the cleanliness of the water and the type of property involved, it may be necessary to remove carpets, pads and any other wet items (especially clothing and other soft goods) from the premises for proper drying, cleaning and treatment. Damp or wet carpets, pads or other items may provide a medium for potentially dangerous mold growth.
Flooding of property, pipe breaks in ceilings or walls, or standing water necessitates removing sheetrock that has been water-damaged, up to at least a foot or more above the high-water mark. Removal of at least some sheetrock may also be necessary to allow the wall cavities to drain and dry properly. Wet insulation, in the ceiling or walls, must be removed and replaced. Wet or damp insulation, especially in dark places like wall cavities is a breeding ground for mold. The insulation value is also reduced.
Prompt response and appropriate action is necessary to minimize damage in a water loss. A quick response will also allow the adjuster to determine if the mold is pre-existing or a result of the water damage. If the adjuster can inspect the loss within 24 or 48 hours of the initial damage, it is likely that any visible or detected mold may be the result of a pre-existing water problem, possibly a long-term leak. However, if the loss is not inspected or properly dried within 72 to 96 hours, it may be more difficult to determine if the mold was a pre-existing problem or a result of the covered loss, and thus also covered. The longer the delay in inspecting the loss, the more difficult it becomes to prove the mold was not caused by the covered loss.
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Roles of adjusters, experts
As the expert in claims handling and policy coverages, it is the adjuster's responsibility to seek out and identify any and all damage covered in the loss - either alone or with the assistance of the contractor - and then to extend to the insured any and all benefits available under the policy. This responsibility means including in the scope of damage any visually identifiable mold in a covered loss as possibly a part of the loss. Unless the adjuster can determine that the mold in a covered loss either pre-existed the loss or is not a result of the covered water damage, the mold has to be considered as part of the loss. Denial of the mold contamination as being excluded under the policy, either subject to the standard mold exclusion or as not being part of the covered loss itself, requires that the adjuster prove and document the basis for the denial.
Relative to the insured, the adjuster is operating from a position of superior knowledge on what should be expected in the way of damage, and what damage is or is not covered under the policy. Many adjusters see water damage claims on a frequent basis and have a much better idea than the insured on what might be damaged and where to look for hidden damages. If the adjuster is in doubt or lacks sufficient experience, he or she should work closely with the insured's contractor and make sure the scope of damage is complete.
If the water damage is more than a few days old, be sure and check for mold as a possible hidden damage in wall cavities or other areas damaged by water. Adjusters are not expected to be experts on determining whether or not the mold is dangerous; however, an adjuster is expected to detect visible mold, to look for mold in certain areas (such as water-damaged wall cavities), to include the mold in the scope of damage and to call in the appropriate experts to assist and advise. The job of the experts is to advise the adjuster concerning the mold and how to handle the mold.
A professional restoration consultant should be contacted when more than a small area of mold contamination is involved. Even a mid-sized isolated area - say, 10 to 30 square feet - requires special handling. Areas of 30 to 100 square feet require professionals, preferably certified in mold remediation and trained in handling hazardous materials. Areas of more than 100 square feet require special containment procedures and negative pressurization. Such areas may require asbestos-like remediation procedures; the removed material must be treated as hazardous waste.
During and after removal or remediation of the mold, it may be necessary to conduct sampling to determine if remediation has been successful.
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The future of mold claims
The Cleveland Plain Dealer, in August 1998, quoted Dan Zielinski, of the American Insurance Association, as saying, "Insurance companies will not take note of [Stachybotrys atra] until they are faced with numerous losses because if it."
One of the reasons may be the high cost of mold remediation, which should be done only by trained and experienced professionals. Some studies have shown that proper remediation and removal of contaminated building materials is about 10 times as expensive as regular tear-out and replacement. In some cases the remediation cost is more than $150 per square foot.
Insurance companies and adjusters should, however, be taking note of the dangers of mold contamination now. The insurance industry is being faced with numerous losses and lawsuits, some of them far more expensive than any remediation cost. In the last seven years in California, there have been a number of lawsuits involving mold following water damage. Many have settlement figures of more than $500,000. In one suit, the policyholder recovered more than $2.5 million. In another, the policyholder recovered over $9 million.
The case in Texas was filed demanding $100 million. Hardly a figure to sneeze at.
The examples cited above do not even touch on the liability, construction defect and "sick building syndrome" cases. In 1992, for example, a courthouse in Florida developed mold problems due to construction defects. A jury recently awarded more than $40 million in personal injury claims. There were over 200 workers' compensation claims and at least 180 separate lawsuits. In New York City, more than 300 tenants in an apartment complex with mold problems have filed a class action lawsuit in excess of $10 billion.
Previously, such lofty figures were seen only in asbestos or drug-related class actions. Now, we are starting to hear 11-digit figures mentioned in litigation concerning the lowly mold fungi.
While mold does not develop in every water damage loss, the adjuster must be aware of the potential for mold and its inherent costs. The adjuster must look for mold when the circumstances warrant and must call in appropriately qualified experts for guidance as needed. Mold remediation may be expensive, but failure to remediate a covered damage may be even more expensive, in terms of health as well as dollars.
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Combating Mold In Your Home
What's wrong with a little mold and mildew? As long as they stay put behind the laundry tub, out of sight under the basement carpet, or only peek around the edge of the bathroom wallpaper, who cares? Well, YOU should, because they're not only eating away at your house, they could be eating away at your health, too.
Here we'll take a look at what mold and mildew are, how they affect the health of you and your house and, finally, how you can prevent their growth and get rid of the stuff.
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MOLD AND MILDEW--BIG-TIME CONSUMERS
Though there are thousands of different types of mold and mildew, they all have two things in common: The first is that their mission on Earth is to digest the organic world around them. The second is that they all need moisture so their little digestive enzymes can go to work.
There are differences between mold and mildew, but for our purposes, we can call the entire gang mold. Molds are neither plants nor animals. They're microscopic organisms containing enzymes (responsible for digesting and decomposing) and spores (in charge of reproduction). Mold dwells within the fungi kingdom: a realm includes mushrooms, yeast and other seemingly unsavory characters. But the truth is, these decay organisms aren't unsavory at all. Without them, toppled trees, dead animals and fallen vegetables wouldn't decompose. Our land would get piled higher and higher with dead stuff. We wouldn't have foods and medicines like cheese and penicillin. The problems arise when mold starts chomping away at things we don't want them to--affecting the look, smell and structural integrity of your house.
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IT'S DOING THAT TO MY HOUSE?
Mold needs to consume something to survive, and it's perfectly happy eating your house if you let it. Some molds and mildews are fond of the cellulose in the paper backing on drywall, insulation and wallpaper. Others have a ravenous appetite for the glues used to bond carpet to its backing. Left unchecked, mold eventually destroys the parts of the drywall, wallpaper and carpet it attacks. But many molds just like to feast on the everyday dust and dirt that gather in the perpetually moist regions of your house. They won't destroy your house, but they can sure make it look, feel and smell bad. Mold can mar your walls with white spider web-like growths or clusters of small black specks. It creates the smell we often refer to as "musty." It can be slippery and dangerous when it grows on damp basement stairs.
Molds rarely go so far as to rot wood or do structural damage--they'll leave that to their fungal cousins--but they can wreak plenty of havoc. We can't overemphasize that mold needs moisture to get established, grow and reproduce. Mold problems and longstanding moisture or high humidity conditions go hand in hand. To conquer mold, you must also conquer moisture problems. Fig. B shows common hangouts for mold and some steps you can take to minimize its growth and the damage it inflicts. < return to top >
13 common breeding grounds for mold and mildew
Leaky air-conditioning duct joints, especially those running through a hot attic, create a moist environment for mildew.
Solution: Seal all duct joints with the special flexible mastic available heating and cooling supply stores.
In warm environments, impermeable vinyl wall coverings can trap moisture-laden air as it moves from the warm exterior to the cooler interior. Mold degrades the drywall and adhesive behind the vinyl wall covering.
Solution: Use paint or apply wall coverings with permeable paper backings that don't trap moisture on exterior walls.
When washing machines in a room without a floor drain overflow or hose connections burst, water with no point of exit will soak into adjacent carpet, drywall and insulation.
Solution: Always provide a floor drain near the washing machine. Install an overflow pan directly under the machine or install a 1-in. lip at the doorway to contain overflows in main-level or second-story laundry rooms. (An overflow pan is available for about $125 plus shipping from AMI, 800-929-9269.)
Water-resistant drywall used as a backer quickly degrades once subjected to moisture.
Solution: Install cement backer board, which will remain structurally sound even if repeatedly subjected to moisture.
Poorly ventilated bathrooms allow surface mold to grow.
Solution: Install a bathroom fan (or at least, open a window) to exhaust moisture. Remove surface mildew by scrubbing the area with a 1/2 percent bleach solution. When the area is dry, prime it with an alcohol-based, white-pigmented shellac, such as Zinsser Bullseye, and use a paint containing mildewcide.
Poorly constructed crawlspaces promote mildew growth. Bare earth floors transmit huge amounts of moisture.
Solution: There are many regional differences and solutions. Cover bare earth with 6-mil poly sheeting. Heat, cool and humidify the area the same as the rest of the house.
Freshly cut firewood stored indoors emits huge amounts of moisture.
Solution: Store it outside.
Humidifiers (especially reservoir-type central units and portable units) provide both a growth medium and a distribution system for mold and mildew.
Solution: Clean and treat the reservoir often with an antimicrobial solution, available at most hardware stores.
The condensation pan directly under the coil of your central air conditioner can harbor mold.
Solution: Before each cooling season, clean the pan with a 1/2 percent bleach solution and make sure the continuous drain is working.
Finished concrete basements that haven't been thoroughly waterproofed from the outside are problematic. When moisture migrates through the earth and non-waterproofed concrete walls, it can get trapped behind vapor barriers, carpet, layers of insulation and drywall.
Solution: Thoroughly waterproof the exterior of concrete walls before backfilling. Install 6 in. of gravel under concrete floors during construction to prevent moisture from wicking up through concrete floors and into floor coverings.
Yards that slope toward foundations invite water to enter basements and crawlspaces.
Solution: Re-grade yard surrounding house so it slopes away at a rate of 1 in. per foot.
Improperly flashed or caulked windows (and those with large amounts of surface condensation) let moisture seep the surrounding wood, drywall and insulation.
Solution: Properly flash and caulk windows during installation; minimize condensation with good ventilation and airflow.
Leaky flashings and shingles allow rain to infiltrate attics, insulation, eaves and other areas that can trap moisture and be difficult to inspect.
Solution: Perform yearly roof inspections--even if you do it from the ground with binoculars. < return to top >
IT'S DOING THAT TO MY HEALTH?
Besides damaging your house, mold can cause severe health problems.
One consultant we interviewed confessed he crawls around in moldy places day after day, month in and month out, and never suffers ill effects. Others--some estimate about 10 percent of the population--are severely allergic to mold. It's primarily the dinky reproductive spores that people react to. Twenty of them sitting side by side could fit across the period at the end of this sentence. That means they're hard to filter out. The spores also have an incredible "hang time" (as my teenage son would say); they're able to stay suspended in midair for hours on end. That means they're easily inhaled.
With even slight exposure to molds and spores, sensitive people may experience headaches, runny noses, skin rashes, nausea, sinus problems, memory loss and coughs. They may feel listless for long periods of time. In short, they feel as though they have a perpetual case of the flu. Newborns, the elderly, the sick, and those with compromised immune systems can be affected severely, even fatally. Babies and toddlers, who love to crawl around on possibly moldy carpets and stick possibly moldy things in their mouths, also are highly vulnerable to mold-induced illnesses.
Super-sensitive people often go to extremes to rid their houses of the materials that harbor the dirt and dust that molds feed on. They'll replace soft, textured materials with smooth, hard surfaces that are easier to keep clean and less likely to trap debris and moisture. Out go the carpets and draperies; in come hardwood floors and metal window blinds. Out go the cushy couches; in come the vinyl chairs.
Tightly sealed newer houses may be better at holding in heat, but they're also more likely to trap moisture and spores. Mechanical ventilation, like an air-to-air heat exchanger, is critical for healthy air quality in tightly sealed new homes.
In truth, most of us fall somewhere between the two extremes of invincibility and super sensitivity. But even "normal" folks will react to unusually high concentrations of mold and spores. And the time you're most likely to stir up spores and inhale and ingest them is the very time you're trying to get rid of the stuff. That's when you need to be the most careful.
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DISPOSE OF IT PROPERLY
OR YOU'LL JUST MAKE MATTERS WORSE
Step one in getting rid of mold is to fix the moisture problem that's setting the stage for its growth. This is key. You can scrub, dispose of and replace moldy materials, but until you fix the problem, mold will keep returning. The fix can be as simple as sealing up leaky air-conditioning ducts (Fig. B) or as daunting as re-shingling a leaky roof or re-grading your yard so water runs away from, rather than toward, your foundation. Sewer backups and floods also set up ideal environments for mold and mildew growth.
Once the moisture problems are fixed, get rid of the moldy materials carefully. Rough handling of damaged materials will not only stir up spores and spread them even farther around your house but also launch zillions of spores into the air, where you'll inhale them. One square foot of moldy drywall can harbor more than 300 million mold spores; slam-dunk that onto the basement floor and you're just opening another Pandora's box. Even dormant spores inhabiting dried-out materials are irritating to inhale, and if they find moist environs again, they can zip back to life and establish new colonies.
The smart way to get rid of moldy building materials
THE KEY TO REMOVING MOLDY MATERIALS is containment and thoroughness. Seal off the area. Create a crude "air lock" door to contain spores and dust by covering the opening with a sheet of poly slit in the center, and then cover that with another sheet or flap. Wear a respirator and work slowly and surely. Double-bag or wrap all materials, then wash all remaining hard surfaces with a 1/2 percent bleach solution and let dry.
* Wear a good cartridge-type respirator, available through a medical or safety equipment supplier. One good mask is a Willson triple-seal respirator (No. 03711; $30.75, plus shipping) with a P100 filter cartridge ($52 for a carton of 10) available from Direct Safety, (800) 528-7405. A simple dust or particulate mask doesn't offer adequate protection. Wear gloves and goggles if you're scraping.
* If your basement or main floor has flooded, get it as dry as possible within the first 72 hours, before mold and mildew can get established. Drill holes in drywall or remove lower sections of it to let the inner wall and insulation dry out.
* Close off any ventilation grilles with polyethylene sheeting and duct tape. Shut down your furnace so the blower doesn't spread spores and dust throughout the house.
* Remove everything--furniture, pictures, and lamps--from the room.
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Links to other informative articles and educational material can be found on our site at: Toxic Black Mold in your Home
Toxic Black Mold Solutions Page
We could not have compiled this manual for you without the excellent articles , brochures, books and general information provided by the following individuals, companies, universities and websites.
|Readers are cautioned that there is not full consensus among the medical and health science community on the potential health consequences of exposure to molds. Individuals with compromised immune systems, allergies, asthma, other lung diseases or other medical problems should consult their physician before physically contacting or disturbing any mold growths.|
ME.K. Khattar, ME.VS.. Swami and NO. Ramadan, "Another Aspect of Duty Cycling: Effects on Indoor Humidity," FSEC-PF-118-87, ASHRAM, 1987.
Swami, ME.S., Lining Go and Philip Fairy, 2001. Appendix K, Moisture Analysis and Condensation Control in Building Envelopes, Heinz R. Trechsel, Ed., pp.183-184, ASTM Stock No. MNL40, ASTM International, West Conshohocken, PA.
Environmental Protection Agency.
Kim Hickman, Esq.
www.inspectionone.com - 800-323-4677
Everette L. Herndon, Jr. & Chin S. Yang
School of Hard Knocks (experience)
And many contributions from the experts that visit us at StartRemodeling.com
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