Mold and Mildew
The recent floods in Houston have heightened attention to what was already a major topic of discussion - mold and mildew. Several mold claims, including a jury award of more than $30 million, have received substantial publicity. The Texas Department of Insurance held a public hearing on June 26 and the State Bar of Texas conducted a full day seminar on June 29, 2001. Why all this attention to a substance that has been around for thousands of years and is even referred to in the bible?

Mold is a fungus that grows in moist conditions. There are hundreds of thousands of different types of mold, some of which are beneficial (e.g. penicillin) others are not and some produce mycotoxins that can be harmful. According to the Environmental Protection Agency (EPA) mold is probably found in the majority of structures. When mold is present in large quantities allergy-like symptoms may occur. Stachybotrys chartarum, the so-called "black mold," is a toxigenic mold that has been found in several buildings and homes recently and is receiving increasing attention. The Centers for Disease Control and Prevention reports that a causal link between the presence of toxic mold and pulmonary hemorrhage or memory loss has not been proven.

Molds produce tiny spores that float in the air, both outdoors and indoors. When these spores land on wet or damp spots they begin to grow, multiplying very rapidly. Mold thrives in warm humid conditions and in particular wet sheetrock, wallpaper, ceiling tiles, and carpeting. It is not possible to eliminate mold and mold spores completely, the way to control indoor mold is to control moisture. There are no guidelines for investigating, evaluating, and remediating moisture and mold in residential buildings. The EPA recently published mold remediation guidelines for schools and commercial buildings that can easily be applied to residential buildings. The EPA recommends that moisture problems be solved before they become mold problems and has listed a number of mold prevention tips:

Mold Prevention Tips

• Fix leaky plumbing and leaks in the building envelope as soon as possible.
• Watch for condensation and wet spots. Fix source(s) of moisture problem(s) as soon as possible.
• Prevent moisture due to condensation by increasing surface temperature or reducing the moisture level in the air (humidity).
• Keep heating, ventilation and air conditioning (HVAC) drip pans clean, flowing properly, and unobstructed.
• Vent moisture-generating appliances, such as dryers, to the outside where possible.
• Maintain low indoor humidity, below 60% relative humidity, ideally 30-50%, if possible.
• Perform regular inspections and HVAC maintenance as scheduled.
• Clean and dry wet or damp spots within 48 hours.
• Don't let foundations stay wet. Provide drainage and slope the ground away from the foundation.

The EPA developed the guidelines to help avoid the need for remediation of mold growth by taking quick action before growth starts. Table 1 presents strategies to respond to water damage within 24-48 hours.

Table 1: Water Damage - Cleanup and Mold Prevention
Guidelines for Response to Clean Water Damage within 24-48 Hours to Prevent Mold Growth*
Water-Damaged Material †	Actions
Books and papers	For non-valuable items, discard books and papers. Photocopy valuable/important items, discard originals. Freeze (in frost-free freezer or meat locker) or freeze-dry.
Carpet and backing - dry within 24-48 hours §	Remove water with water extraction vacuum. Reduce ambient humidity levels with dehumidifier. Accelerate drying process with fans.
Ceiling tiles	Discard and replace.
Cellulose insulation	Discard and replace.
Concrete or cinder block surfaces	Remove water with water extraction vacuum. Accelerate drying process with dehumidifiers, fans, and/or heaters.
Fiberglass insulation	Discard and replace.
Hard surface, porous flooring (Linoleum, ceramic tile, vinyl)	Vacuum or damp wipe with water and mild detergent and allow to dry; scrub if necessary. Check to make sure underflooring is dry; dry underflooring if necessary.
Non-porous, hard surfaces (Plastics, metals)	Vacuum or damp wipe with water and mild detergent and allow to dry; scrub if necessary.
Upholstered furniture	Remove water with water extraction vacuum. Accelerate drying process with dehumidifiers, fans, and/or heaters. May be difficult to completely dry within 48 hours. If the piece is valuable, you may wish to consult a restoration/water damage professional who specializes in furniture.
Wallboard, sheetrock (Drywall and gypsum board)	May be dried in place if there is no obvious swelling and the seams are intact. If not, remove, discard, and replace. Ventilate the wall cavity, if possible.
Window drapes	Follow laundering or cleaning instructions recommended by the manufacturer.
Wood surfaces	Remove moisture immediately and use dehumidifiers, gentle heat, and fans for drying. (Use caution when applying heat to hardwood floors.) Treated or finished wood surfaces may be cleaned with mild detergent and clean water and allowed to dry. Wet paneling should be pried away from wall for drying.

* If mold growth has occurred or materials have been wet for more than 48 hours, consult Table 2 guidelines. Even if materials are dried within 48 hours, mold growth may have occurred. Items may be tested by professionals if there is doubt. Note that mold growth will not always occur after 48 hours; this is only a guideline.

These guidelines are for damage caused by clean water. If you know or suspect that the water source is contaminated with sewage, or chemical or biological pollutants, then Personal Protective Equipment and containment are required by OSHA. An experienced professional should be consulted if you and/or your remediators do not have expertise remediating in contaminated water situations. Do not use fans before determining that the water is clean or sanitary.

† If a particular item(s) has high monetary or sentimental value, you may wish to consult a restoration/water damage specialist.

§ The subfloor under the carpet or other flooring material must also be cleaned and dried. See the appropriate section of this table for recommended actions depending on the composition of the subfloor.

Mold and Indoor Air Regulations and Standards - Standards or Threshold Limit Values (TLVs) for airborne concentrations of mold, or mold spores, have not been set. As of June 2001, there are no EPA regulations or standards for airborne mold contaminants.

Health Concerns - If building occupants have serious health concerns, they should consult a health professional.

Table 2 - presents remediation guidelines for building materials that have or are likely to have mold growth. The guidelines in Table 2 are designed to protect the health of occupants and cleanup personnel during remediation. These guidelines are based on the area and type of material affected by water damage and/or mold growth. Please note that these are guidelines; some professionals may prefer other cleaning methods.

Although the level of personal protection suggested in these guidelines is based on the total surface area contaminated and the potential for remediator and/or occupant exposure, professional judgment should always play a part in remediation decisions. These remediation guidelines are based on the size of the affected area to make it easier for remediators to select appropriate techniques, not on the basis of health effects or research showing there is a specific method appropriate at a certain number of square feet. The guidelines have been designed to help construct a remediation plan. When in doubt, caution is advised. Consult an experienced mold remediator for more information.

In cases in which a particularly toxic mold species has been identified or is suspected, when extensive hidden mold is expected (such as behind vinyl wallpaper or in the HVAC system), when the chances of the mold becoming airborne are estimated to be high, or sensitive individuals (e.g., those with severe allergies or asthma) are present, a more cautious or conservative approach to remediation is indicated. Always make sure to protect remediators and building occupants from exposure to mold.

 

SMALL - Total Surface Area Affected Less Than 10 square feet (ft2)
Books and papers	3	Minimum N-95 respirator, gloves, and goggles	None required
Carpet and backing	1,3
Concrete or cinder block	1,3
Hard surface, porous flooring (linoleum, ceramic tile, vinyl)	1,2,3
Non-porous, hard surfaces (plastics, metals)	1,2,3
Upholstered furniture & drapes	1,3
Wallboard (drywall and gypsum board	3
Wood surfaces	1,2,3
MEDIUM - Total Surface Area Affected Between 10 and 100 (ft2)
Books and papers	3	Limited or Full Use professional judgment, consider potential for remediator exposure and size of contaminated area	Limited Use professional judgment, consider potential for remediator/occupant exposure and size of contaminated area
Carpet and backing	1,3,4
Concrete or cinder block	1,3
Hard surface, porous flooring (linoleum, ceramic tile, vinyl)	1,2,3
Non-porous, hard surfaces (plastics, metals)	1,2,3
Upholstered furniture & drapes	1,3,4
Wallboard (drywall and gypsum board)	3,4
Wood surfaces	1,2,3
LARGE - Total Surface Area Affected Greater Than 100 (ft2) or Potential for Increased Occupant or Remediator Exposure During Remediation Estimated to be Significant
Books and papers	3	Full Use professional judgment, consider potential for remediator/occupant exposure and size of contaminated area	Full Use professional judgment, consider potential for remediator exposure and size of contaminated area
Carpet and backing	1,3,4
Concrete or cinder block	1,3
Hard surface, porous flooring (linoleum, ceramic tile, vinyl)	1,2,3,4
Non-porous, hard surfaces (plastics, metals)	1,2,3
Upholstered furniture & drapes	1,2,4
Wallboard (drywall and gypsum board)	3,4
Wood surfaces	1,2,3,4
* Use professional judgment to determine prudent levels of Personal Protective Equipment and containment for each situation, particularly as the remediation site size increases and the potential for exposure and health effects rises. Assess the need for increased Personal Protective Equipment, if, during the remediation, more extensive contamination is encountered than was expected. Consult Table 1 if materials have been wet for less than 48 hours, and mold growth is not apparent. These guidelines are for damage caused by clean water. If you know or suspect that the water source is contaminated with sewage, or chemical or biological pollutants, then the Occupational Safety and Health Administration (OSHA) requires PPE and containment. An experienced professional should be consulted if you and/or your remediators do not have expertise in remediating contaminated water situations. † Select method most appropriate to situation. Since molds gradually destroy the things they grow on, if mold growth is not addressed promptly, some items may be damaged such that cleaning will not restore their original appearance. If mold growth is heavy and items are valuable or important, you may wish to consult a restoration/water damage/remediation expert. Please note that these are guidelines; other cleaning methods may be preferred by some professionals. Cleanup Methods Method 1: Wet vacuum (in the case of porous materials, some mold spores/fragments will remain in the material but will not grow if the material is completely dried). Steam cleaning may be an alternative for carpets and some upholstered furniture. Method 2: Damp-wipe surfaces with plain water or with water and detergent solution (except wood - use wood floor cleaner); scrub as needed. Method 3: High-efficiency particulate air (HEPA) vacuum after the material has been thoroughly dried. Dispose of the contents of the HEPA vacuum in well-sealed plastic bags. Method 4: Discard - remove water-damaged materials and seal in plastic bags while inside of containment, if present. Dispose of as normal waste. HEPA vacuum area after it is dried. Personal Protective Equipment (PPE) Minimum: Gloves, N-95 respirator, goggles/eye protection Limited: Gloves, N-95 respirator or half-face respirator with HEPA filter, disposable overalls, goggles/eye protection Full: Gloves, disposable full body clothing, head gear, foot coverings, full-face respirator with HEPA filter Containment Limited: Use polyethylene sheeting ceiling to floor around affected area with a slit entry and covering flap; maintain area under negative pressure with HEPA filtered fan unit. Block supply and return air vents within containment area. Full: Use two layers of fire-retardant polyethylene sheeting with one airlock chamber. Maintain area under negative pressure with HEPA filtered fan exhausted outside of building. Block supply and return air vents within containment area.

Tables 1 and 2 contain general guidelines. Their purpose is to provide basic information to first assess the extent of the damage and then to determine whether the remediation should be managed by you or by outside professionals. The guidelines can then be used to help design a remediation plan or to assess a plan submitted by outside professionals.

There are a number of web sites that provide information on mold. Amongst these are -

The United States Environmental Protection Agency - Mold Remediation in Schools and Commercial Buildings http://www.epa.gov/iaq/molds/toc.html

The Centers for Disease Control and Prevention National Center for Environmental Health - Question and Answers on Stachybotrys chartarum and other Molds http://www.cdc.gov.nceh/asthma/factsheets/molds/default.htm

The New York Department of Health - Bureau of Environmental and Occupational Disease Epidemiology http://www.ci.nyc.ny.us/html/doh/html/epi/moldrpt1.html

Claims Magazine on-line, August 2000: "Mold & Mildew: A Creeping Catastrophe" http://www.claimsmag.com/issues/aug00/mold.asp

www.themoldsource.com