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Mold: Remediation, Prevention and PPE

Quick Tips #210

Mold is one category of non-green, plant-like organisms (along with mildew, mushrooms, rusts, smuts and yeast) that fall within the fungus family. All fungal matter shares the common characteristic of being capable of growth without sunlight. Because of this, mold can be found almost anywhere and can grow on almost anything as long as moisture and oxygen are present. Many types of mold exists.

Currently, there are no threshold limit values (TLVs) assigned for airborne concentrations of mold or mold spores. The Occupational Safety and Health Administration (OSHA) does reference a sampling protocol for fungi (PathCon Technical Bulletin 2.4, A Suggested Air Sampling Strategy for Microorganisms in Office Settings) under the Indoor Air Quality heading on its website. The protocol states, "Fungal amplification (excessive levels of mold) should be considered when the indoor concentration is above 200 colony forming units per cubic meter of air and substantially exceeds that detected in the outdoor air."

According to the Environmental Protection Agency's (EPA's) Mold Remediation in Schools and Commercial Buildings resource, all mold has the potential to cause health effects. Mold can produce allergens that can trigger allergic reactions, asthma attacks or produce potent toxins and/or irritants. Hypersensitivity pneumonitis (lung inflammation) has also been linked to mold exposure. For more information on symptoms related to damp conditions and mold, see

Mold Prevention

Mold growth frequently occurs when excessive moisture or water accumulates indoors. There is no feasible way to eliminate all mold and mold spores indoors, so the most effective way to control indoor mold growth is to control moisture. In buildings where mold is a problem, the mold must be remediated and the sources of moisture eliminated.

It is important to dry water-damaged areas and items within 24 to 48 hours to prevent mold growth from starting. Water-damaged porous or absorbent materials, such as ceiling tiles, wallboard, cellulose and fiberglass insulation, should be discarded and replaced. Discard nonvaluable books and papers. Be sure to photocopy important paperwork before discarding the originals. Use a water extraction vacuum to remove water from carpeting. Then use dehumidifiers and fans to accelerate the drying process. Carpet that becomes moldy usually must be replaced. Nonporous surfaces can be vacuumed or wiped with mild detergent and allowed to dry completely.

Moisture Control

Identify and repair leaky plumbing and other sources of water in a timely fashion to prevent moisture and mold growth. You can minimize mold growth by reducing indoor humidity to 30 to 50%. This can be done by venting bathrooms, dryers and other moisture-generating sources to the outside; using air conditioners and dehumidifiers; increasing ventilation; and using exhaust fans whenever cooking, dishwashing and cleaning.

Also, reduce the potential for condensation on cold surfaces like windows, piping, exterior walls, roofing and floors by adding insulation. Do not install carpeting in areas where there is a continuous moisture problem, such as near drinking fountains, sinks or on concrete floors with leaks or frequent condensation.

Contamination Identification

A visual inspection is the most important initial step in identifying a possible contamination problem. The extent of any water damage and mold growth should be visually assessed. This assessment is important in determining mold remediation strategies.

Ventilation systems should also be visually checked, particularly for damp filters, but also for damp conditions elsewhere in the system and overall cleanliness. Ceiling tiles, gypsum wallboard, cardboard, paper and other porous surfaces should be given careful attention during a visual inspection.

The use of special equipment to view spaces in ductwork or behind walls, and/or by using a moisture meter to detect moisture in building materials, may be helpful in identifying hidden sources of mold growth and the extent of water damage.

Mold Remediation

The EPA's remediation guide for schools and commercial buildings offers detailed recommendations for a variety of mold removal scenarios and is a tremendous resource for anyone facing a mold problem.

Mold should be cleaned as soon as it appears. Small areas of mold can be cleaned using a detergent/soapy solution or an appropriate household cleaner and allowed to dry completely. For larger areas, there are commercial products that can be used for cleaning, disinfecting and sanitizing. Mold-resistant coatings are also available. A HEPA vacuum can be used to clean items such as furniture, concrete, carpeting or books after the material has been thoroughly dried.

For small areas of mold growth, an N95 respirator, goggles and gloves should be worn during cleaning. For larger mold remediation jobs, or in situations where high levels of airborne dust or mold spores are likely or long-term exposures are expected, the EPA suggests a full-face, powered air purifying respirator (PAPR) along with disposable coveralls, gloves and shoe covers. The cleaned area should be thoroughly dried. Dispose of any sponges or rags that were used to clean the mold, along with the used personal protective equipment (PPE).

If the mold returns quickly or spreads, it may indicate an underlying problem, such as a leak or excessive humidity. Any underlying water problems must be fixed to successfully eliminate mold problems. If mold contamination is extensive, an experienced remediation professional may need to be consulted.



EPA's "Mold Remediation in Schools and Commercial Buildings"

EPA's overall summary of mold related information

OSHA's guide to mold in the workplace

(Rev. 1/2012)

Find even more information you can use to help make informed decisions about the regulatory issues you face in your workplace every day. View all Quick Tips Technical Resources at

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Please Note:
The information contained in this publication is intended for general information purposes only and is based on information available as of the initial date of publication. No representation is made that the information or references are complete or remain current. This publication is not a substitute for review of the current applicable government regulations and standards specific to your location and business activity, and should not be construed as legal advice or opinion. Readers with specific questions should refer to the applicable standards or consult with an attorney.

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