The ABCs of Mold Remediation
Individuals seeking medical attention should get a copy of all inspection results and interpretations to give to their medical practitioners.
- By Robert A. Ernst
- May 01, 2004
MOLD problems and reports of suspected mold-related illness and injury are quickly becoming a health issue for many safety professionals. When excessive moisture accumulates indoors, mold growth often occurs, bringing with it health complaints ranging from asthma to severe allergic reactions.
Some moisture problems in buildings have been linked to changes in building construction practices during the 1970s, '80s, and '90s that were attempting to produce more energy efficient structures. Tightly sealed buildings, with controlled ventilation, contribute to moisture buildup.
When mold starts to grow, it affects the look, smell, air quality, and in extreme cases in wood-framed structures, the structural integrity of the building. Moisture problems and mold occurrences can and do occur in all parts of the United States. Moisture problems also can result from roof leaks, landscaping or gutters that direct water into or under the building, and unvented combustion appliances. Delayed maintenance or insufficient maintenance can contribute to roof leaks, plugged gutters, and reduced ventilation and heating/ventilation/air-conditioning (HVAC) capacity, all of which can contribute to moisture build-up.
Health Effects of Mold Exposure
The terms fungi and mold are often used interchangeably, but mold is actually a type of fungi. Molds and fungi reproduce by physically spreading and by releasing spores, which are like seeds, small and light enough to be spread via air currents. They will begin to grow when they land on the right surfaces with the right conditions present. Mold spores continually float through the indoor and outdoor air.
If mold spores land on moist, organic material, they begin to digest it and form mold. Because it is impossible to eliminate all mold spores from the air, exposure to mold is all but unavoidable. If there are damp organic materials in the workplace, mold will result.
The risks of exposure to a particular mold can vary from individual to individual, making it difficult to set exposure limits for molds or mold-related contaminants. Breathing in mold spores can cause asthma attacks in some individuals. Molds can cause adverse effects by producing allergens. The onset of allergic reactions to mold can be either immediate or delayed; they include hay fever-type symptoms, such as irritation of the eyes, skin, nose, and throat.
Contact with molds may cause localized skin or mucosal infections but, in general, do not cause infections in humans, except for persons with impaired immunity, HIV/AIDS, uncontrolled diabetes, or those taking immune suppressive drugs.
Currently no OSHA or EPA regulations specifically address mold. However, OSHA addresses Indoor Air Quality (IAQ) hazards in §1910.94, Ventilation and 1926.57, Ventilation. Also, American National Standards Institute/American Society of Heating, Refrigerating and Air-Conditioning Engineers (ANSI/ASHRAE), Standard 62-2001, Ventilation for Acceptable Indoor Air Quality, sets minimum ventilation rates and other requirements for commercial and institutional buildings. Although this standard does not directly address molds, ventilation rates and effectiveness can affect mold distribution and moisture collection.
Sampling for Mold
According to information provided by the American Industrial Hygiene Association, it is not necessary to sample to identify the species of mold, and routine sampling for mold is not recommended. Once mold growth has been visually identified, the proper approach is removing the mold and remediating the cause.
Sampling is not necessary if there are no pending health claims or legal issues, AIHA says. Only in specific instances, such as cases where health concerns are an issue, litigation is involved, or where the source of mold contamination is unclear, sampling may be considered as part of the mold evaluation process.
Moisture is the Key
Moisture control is the key to mold control. When moisture or water accumulates indoors, act immediately. Any initial water infiltration should be stopped and cleaned up promptly. A quick response (within 48 hours) and thorough cleanup, drying, and/or removal of water-damaged materials will prevent or limit mold growth.
Mold prevention tips include:
- Repair plumbing leaks and leaks in the building structure as soon as possible.
- Look for condensation and wet spots. Fix source(s) of moisture incursion problem(s) as soon as possible.
- Prevent moisture from condensing by increasing surface temperature or reducing the moisture level in the air (humidity). To increase surface temperature, insulate or increase air circulation. To reduce the moisture level in the air, repair leaks, increase ventilation (if outside air is cold and dry), or dehumidify (if outdoor air is warm and humid).
- Keep HVAC drip pans clean, flowing properly, and unobstructed.
- Perform regularly scheduled building/HVAC inspections and maintenance, including filter changes.
- Maintain indoor relative humidity below 70 percent (25-60 percent, if possible).
- Vent moisture-generating appliances, such as dryers, to the outside where possible.
- Vent kitchens (cooking areas) and bathrooms according to local code requirements.
- Clean and dry wet or damp spots as soon as possible--but no more than 48 hours after discovery.
- Provide adequate drainage around buildings and slope the ground away from building foundations.
- Pinpoint areas where leaks have occurred, identifying the causes, and take preventive action to ensure that they do not recur.
- Do you have a mold problem?
- Is what you are dealing with actually a mold problem? Outside of expensive testing, how can you tell? Here are a few questions you can ask to help determine whether what you have is really a mold problem:
- Are building materials or furnishings visibly moisture damaged?
- Have building materials been wet more than 48 hours?
- Are there existing moisture problems in the building?
- Are building occupants reporting musty or moldy odors?
- Are building occupants reporting health problems that their health professionals think are related to mold?
- Has the building been recently remodeled or has the building use changed?
- Has routine maintenance been delayed or the maintenance plan been altered?
The goal of the remediation plan is to clean or remove the contaminated materials so that mold and fungi, and dust contaminated with mold and fungi, does not leave the work area and enter nearby areas, while at the same time protecting the health of the workers performing the abatement.
The remediation plan should include:
- An assessment of the extent of the problem, considering the possibility of hidden mold;
- An identification of the source of the moisture;
- Steps required to correct the water or moisture problem permanently;
- Inspection of the air ducts and air handling unit for mold problems;
- Identification of the appropriate personal protective equipment (PPE) and other methods required to protect cleanup workers from exposure;
- Steps to contain and remove moldy building materials in a manner that will prevent spreading mold and fungi outside of the work area; and
- In cases involving large areas of contamination, temporary relocation of some or all of the building occupants.
- Remember that the remediation plan may:
- Vary greatly, depending on the size and complexity of the job; and
- Require revision if circumstances change or new facts are discovered.
- If you suspect that the HVAC system is contaminated with mold, shut down the system until it can be inspected and cleaned, if necessary. Running the HVAC system with mold or fungi could spread contamination throughout the building.
When fungal growth requiring large-scale remediation is found, the building owner, management, and/or employer should notify occupants in the affected area(s) of its presence. Notification should include a description of the remedial measures to be taken and a timetable for completion.
You may wish to suggest that individuals with persistent health problems contact their medical professional for recommendations and guidance on working in this type of environment. Individuals seeking medical attention should be provided with a copy of all inspection results and interpretations to give to their medical practitioners.
Successful mold remediation requires that the moisture problem be dealt with to prevent mold re-growth. In all cases, the underlying cause of the moisture problem must be corrected. In the case of a single incident, such as a flood or sewer backup, stop and clean up the cause of the water infiltration within 48 hours of the event if possible. A thorough cleanup and drying out or removal of damaged materials will limit or prevent mold growth.
If the moisture problem is more systemic, then you must reduce the level of moisture temporarily and correct the cause(s) of the moisture problem so mold growth will not reoccur. Mold-contaminated materials must be removed in a manner to prevent human exposure and without spreading mold spores.
Keep these things in mind when performing mold remediation:
- Clean and dry any damp or wet building materials and furnishings within 48 hours;
- Segregate unoccupied work areas with plastic sheeting;
- Shut down the HVAC system and establish a full containment under negative pressure, if necessary;
- Use ventilation to move air into the remediation area, and vent air from the remediation area to the outside;
- Use dust suppression--wet misting, wet vacuuming, and HEPA-filtered vacuums;
- Wash and dry hard surfaces; and
- Discard porous materials that show signs of mold because the mold will be difficult or impossible to remove completely.
- Various cleanup methods are available, including:
- Wet vacuums to remove water from floors, carpets, and hard surfaces. Do not use on porous materials, such as gypsum board.
- Damp wipes to remove mold from nonporous surfaces. Dry these surfaces quickly and thoroughly to discourage further mold growth. Follow the label instructions for use.
- HEPA (high-efficiency particulate air filter) vacuums for final cleanup after materials have been thoroughly dried and contaminated materials removed. HEPA vacuums also are recommended for cleanup of dust that may have settled on surfaces outside the remediation area.
Contaminated materials that cannot be cleaned should be removed from the building in sealed, impermeable plastic bags. The outside of the bags should be cleaned with a damp cloth and a detergent solution or vacuumed (using a vacuum equipped with a HEPA filter) in the decontamination chamber prior to their transport to uncontaminated areas of the building. These materials may be disposed of as ordinary waste.
Biocides are chemicals used to kill or neutralize mold and fungi. In most cases, the use of biocides alone is not recommended, because even after molds have been treated with biocides they can continue to release harmful toxins. If using disinfectants or biocides, always ventilate the area and exhaust the air to the outdoors.
Certain biocides may be considered pesticides. Some states require that only registered pesticide applicators use these products in schools and commercial buildings. Know what your state requires, and obtain proper licenses where required.
Fungicides are commonly applied to outdoor plants, soil, and grains as a powder or spray. Do not use fungicides developed for outdoor use in any indoor application; they can be extremely toxic to animals and humans in an enclosed environment.
Isolating the Work Area and Creating the Clean Room
Depending on the circumstances and extent of the problem, you may wish to isolate the work area and establish a clean room where remediation workers can wash up and change.
For limited areas of contamination, hang polyethylene plastic sheet floor to ceiling around the affected area with a slit entry and covering flap. Maintain the area under negative pressure with a HEPA filtered fan unit. Turn off the HVAC system for that area of the building and block supply and return air vents within the containment area. Create a clean room using the same method.
For larger areas, use two layers of fire-retardant polyethylene sheeting with one airlock chamber. Maintain the area under negative pressure so that mold, fungi, and spores do not migrate into surrounding, uncontaminated areas. Turn off the HVAC system for that area of the building and block supply and return air vents within the containment area. Create a clean room using the same method.
Prior to removing the isolation barriers at the conclusion of remediation, the contained area and clean room should be HEPA vacuumed and cleaned with a damp cloth or mopped with a detergent solution and be visibly clean and dry.
Any remediation work that disturbs mold and causes mold spores to become airborne increases the degree of respiratory exposure. Train workers on the potential health hazards associated with mold and the use of PPE, and equip them with:
- Skin protection. Gloves protect the skin from contact with mold, as well as from potentially irritating cleaning solutions. The glove material should be selected based on the type of substance/chemical being handled. Check the MSDS for additional information.
- Eye protection. Use properly fitted goggles or a full facepiece respirator. Goggles must be designed to prevent the entry of dust and small particles. Safety glasses or goggles with open vent holes are not appropriate in mold remediation.
- Respiratory protection. Cleanup workers must be protected from inhaling airborne mold, contaminated dust, and other particulates that are released during the remediation process. Either a half mask or full facepiece air-purifying respirator can be used. A full facepiece respirator provides both respiratory and eye protection. More protective respirators may be necessary if toxic contaminants such as asbestos or lead are encountered during remediation.
- Protective clothing. Appropriate protective clothing is required to protect the wearer from the biological as well as the chemical hazards. Protective clothing should minimize cross-contamination between work areas and clean areas. It prevents the transfer and spread of mold and other contaminants to street clothing and eliminates skin contact with mold and potential chemical exposures.
When is Remediation Finished?
After correcting water or moisture infiltration, removing contaminated material, and making structural repairs, you have completed the primary response to mold contamination in buildings. Visible mold, mold-damaged materials, and moldy odors should no longer be present. Sampling, if conducted, should show that the level and types of mold and mold spores inside the building are similar to those found outside.
Monitor the site following remediation. Look for any signs of mold growth, moldy or musty odors, and new water damage. Examine work processes and maintenance routines that might contribute to moisture accumulation. Look for:
- Roof leaks, ice damming, and improperly functioning gutters;
- Water pooling at foundations and improper drainage away from foundations;
- Landscaping, paving, or turfed areas that may be contributing to moisture problems;
- Improperly functioning sump pumps; and
- Poorly built or improperly installed insulation, building walls, foundations, roofing, and so on.
Keep in mind that you cannot eliminate mold and fungi. All you can do is keep the conditions that encourage their growth from occurring in the workplace. A mold inspection plan and moisture control program will go a long way toward helping you keep mold from becoming a hazard in your workplace.
This article originally appeared in the May 2004 issue of Occupational Health & Safety.