Overview

This is the third installment of the industrial hygiene article series, which provides an overview of mold, its characteristics, how to remove mold, and how to prevent mold growth. Health effects of mold exposures and available resources are also included.

What is Mold?

Mold has become a focus in the work environment because of the increasing number of employees experiencing symptoms related to the presence of mold. Before we can effectively combat the source, we need to understand mold and its characteristics.

Mold is any fungus that produces spores. The spores reproduce and can be found anywhere in the environment. Mold can be present in any type of work environment and is present both indoors and out-of-doors.

Three primary types of mold are considered to be dangerous because they release mycotoxins.

• Aspergillus-over 185 species; color and characteristic depends on the species,
• Penicillium-soft, greenish-blue mold, and
• Stachybotrys-slimy, greenish-black mold.

Mycotoxins are the toxic by-products of fungal metabolism¹. The by-products, not the mold itself, are toxic. While individual reactions to the mycotoxins may vary, each exposure should be taken seriously.

What Makes Mold Grow?

Three elements must be present for mold to grow: moisture, temperatures within the range of 32°F-100° F, and a food source. The food source can be any type of organic matter, including materials used in constructing and furnishing most buildings. A building that leaks or experiences a flood which affects the carpets, walls, or wood furnishings and is kept at a comfortable 72°F is the perfect environment for mold to thrive.

Identifying and Discovering Mold

Usually, mold is not detected until it becomes a serious issue. Visible mold growth, damage caused by water or the evidence of water intrusion, and a distinct, musty odor are three signs of a mold problem. The odor is caused by volatile organic compounds and the odor indicates that the mold is actively reproducing.

Some areas prone to mold growth include heating, ventilation, and air conditioning (HVAC) systems; flooded areas (present and past); pipe chases; and any other dark, damp, musty area.

Mold types and spore counts can be identified by obtaining air samples and cultures. An industrial hygienist or an organization specializing in microbiological or environmental sampling should be enlisted to perform the specific tests.

Possible Symptoms of Exposure

Employees may have varying sensitivity levels to mold. Simply put, the severity of the symptoms may be different even if multiple employees are exposed to mold or mycotoxins at the same time in the same area. Health effects may include:

• Lung lesions
• Chronic Bronchitis
• Minor Allergic Reactions
• Learning Disabilities
• Mental Deficiencies
• Cancer
• Chronic Fatigue
• Multiple Sclerosis
• Lupus
• Fibromyalgia
• Rheumatoid Arthritis
• Multiple Chemical Sensitivity
• Asthma
• Memory loss
• Hearing Loss
• Acid Reflux

Can Mold Be Prevented?

Mold can be prevented but proper building construction and maintenance are key factors. The building should be constructed using high quality materials with water-proofing qualities in potentially high moisture areas. Regular maintenance should include the building’s HVAC system, plumbing, and any cracks or spaces capable of allowing leaks to occur. A thorough inspection should be conducted any time water enters a building. Humidity levels should be kept as low as possible to prevent creating an environment that is too moist.

Removing the Mold

Once mold has been identified it needs to be abated as soon as possible. A method appropriate for the work environment should be used. For some, the mold growth is so extensive that complete removal and replacement of affected materials is the best option. A contractor or knowledgeable individual, with specific mold abatement training, should perform the work to prevent further spread of the contamination, especially when dealing with airborne mold species.

If the area of mold growth is greater than ten square feet, or if the growth has invaded porous building materials such as drywall, a professional mold remediation contractor should be consulted. Before settling on a contractor to perform the abatement, ask them to provide you with business credentials, a list of materials they plan to use, and statements from the Environmental Protection Agency that the disinfectants they plan to use actually can be used to disinfect molds.²

The abatement process is a multi-step process and the extent of the mold contamination determines the specific measures necessary for cleanup³.

1. The mold should be accurately identified. Methods of identification include visual and industrial hygiene monitoring techniques such as air sampling and plating (collecting cultures on microbiology plates).


2. Contamination areas and the effects of the identified mold type should be communicated to employees working in the area, individuals performing the abatement, and those handling the hazardous materials.


3. Individuals performing the removal should wear the appropriate type of respiratory protection for the exposure with a HEPA filter to protect from particulates. Other personal protective equipment includes disposable tyvek to protect from head to shoe, gloves, and hand tools to reduce skin contact with objects that can damage protective gear exposing the skin to the mold.


4. Before work begins, an appropriate hand washing and decontamination staging area should be constructed to remove and clean contaminated gear.


5. The contaminated area, including ventilation ducts and other openings, should be completely isolated from other occupied spaces using plastic sheeting and duct tape.


6. Exposure to adjacent areas can be controlled by either removing workers from the area or, in areas with very small amounts of contamination, removing individuals that are sensitive to the effects of the type of mold being remediated. The fewer number of employees in the area, the fewer the number of potential exposures.


7. Exhaust fans should also be used and equipped with a HEPA filter.


8. Bleach and anti-microbial paint may be used with the HEPA exhaust fan if the fan is exhausting to the outside of the building and all windows are shut. If the fan is discharging inside the building, stop the HEPA exhaust fan during the bleach and paint application and turn the fan back on when the odor is not noticeable.


9. Any materials that cannot be cleaned should be removed from the building in sealed plastic bags. Larger items can be sealed inside a 55-gallon drum. Both containment options should be wiped down before exiting the containment area.


10. Once the abatement has been completed, the containment and decontamination areas should be HEPA vacuumed and visibly clean by using a detergent solution and a damp cloth or mop.


11. Before employees are allowed to re-occupy the area, visual inspections and air sampling should be conducted by an environmental professional to determine if the remediation was successful.

Encapsulation, or completely covering the mold, is the more economical choice for others. Also, if the mold has attached to dangerous surfaces, such as asbestos-containing tiles where removal would create a greater problem, encapsulation should be used. Encapsulation is appropriate in areas with a small amount of mold contamination and where there is limited mold growth. When selecting an encapsulating product or surface mold encapsulant, make sure it is constructed of non-porous material like steel or glass to prevent mold from penetrating.

In either case, according to the EPA, “the key to mold control is moisture control”⁴. Dry damaged areas within 24-48 hours, repair leaks and remove any excess water or moisture, wash surfaces and allow to dry completely. Discard and replace any material that cannot be completely cleaned of mold.

Resources

To determine if a mold problem exists, enlist the aid of the local health department for resources, the Department of Labor and Industry (DOLI), or a reputable company that specializes in environmental testing and remediation. The Virginia Department of Health does not provide mold testing services but can provide direction regarding remediation. The consultative side of DOLI can perform some air monitoring and provide guidance or instruction for identifying, correcting, and eliminating the mold problem.

Every employee exposure or potential employee exposure should be treated as a serious case. Investigation, observation, documentation, and remediation should be conducted. Mold can be controlled and prevention is the key!

¹ Gornick, Lawrence.Toxic Mold: The Next Asbestos?. Washington, DC, USA: Environmental Law Institute, 2002. p3.

² Berg, William and Sherertz ,Peter. Virginia Department of Health. (October 21, 1999.). Frequently Asked Questions About Flooding, Molds, and Health. Retrieved November 13, 2006, from http://www.vdh.virginia.gov/epi/publichealthtoxicology/moldQ&A.PDF.

³ University of Minnesota Environmental Health and Safety. (October 2000). Fungal Abatement Safe Operating Procedure. Retrieved November 9, 2006, from http://www.dehs.umn.edu/iaq/sop.html.

⁴ United States Environmental Protection Agency (n.d.). Mold Resources. Retrieved October 19, 2006, from http://www.epa.gov/iaq/molds/moldresources.html

Resources

American Industrial Hygiene Association. (n.d.). Mold. Retrieved October 19, 2006, from http://www.aiha.org/Content/Topics/mold.

Berg, William and Sherertz ,Peter. Virginia Department of Health. (October 21, 1999.). Frequently Asked Questions About Flooding, Molds, and Health. Retrieved November 13, 2006, from http://www.vdh.virginia.gov/epi/publichealthtoxicology/moldQ&A.PDF.

The General Clinical Research Center at Case Western Reserve University. (n.d.). How to Clean-up the Mold. Retrieved October 31, 2006, from http://gcrc.meds.cwru.edu/stachy/cleanup.htm.

Gornick, Lawrence. (2002). Toxic Mold: The Next Asbestos?. Washington, DC, USA: Environmental Law Institute.

Lilard-Roberst, Susan. (February 16, 2006). MOLD…What is it all about?. Retrieved October 19, 2006, from http://www.mold-help.org.

United States Environmental Protection Agency. (n.d.). Mold Resources. Retrieved October 19, 2006, from http://www.epa.gov/mold/moldresources.html.

University of Minnesota Environmental Health and Safety. (October 2000). Fungal Abatement Safe Operating Procedure. Retrieved November 9, 2006, from http://www.dehs.umn.edu/iaq/sop.html.